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Timothy Omara

University of Natural Resources and Life Sciences, Vienna (BOKU), Department of Chemistry, Researcher

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Papers by Timothy Omara

Ethnobotany, floristic and phytochemical studies of medicinal plants used to treat uterine fibroids in Mbarara City, Uganda

by Timothy Omara and ivan kahwa

Phytomedicine Plus, 2025

Uterine fibroids (UF) are the most common non-cancerous benign gynaecologic tumours in premenopau... more Uterine fibroids (UF) are the most common non-cancerous benign gynaecologic tumours in premenopausal females. In Uganda, the prevalence of UF is estimated at 20%, and several risk factors have been identified as contributing to this prevalence. This study aimed to document the ethnobotanical knowledge of traditional medicine practitioners (TMPs) in Mbarara City, Southwestern Uganda on the use of medicinal plants for UF management. The TMPs play a vital role in the healthcare within this region, often incorporating conventional diagnostic methods such as ultrasound scans before providing herbal treatments. To achieve the study aim, data was collected from April 2024 to May 2024 using structured questionnaires administered. Twenty-six (26) respondents were selected using purposive and snowball sampling techniques. Data were gathered on sociodemographic characteristics, treatment-seeking behaviour, and use of herbal formularies for treatment of UF. Statistical analysis involved descriptive statistics, and computation of the frequency of citation, relative frequency of citation and fidelity level. Our results indicated that most TMPs knew about UF and valued conventional means of diagnosis before initiating herbal treatment. Forty-seven (47) plant species belonging to 32 families and 45 genera were identified. Fabaceae (10.6%), Asteraceae, Lamiaceae (8.5% each), Asparagaceae and Cucurbitaceae (6.4% each) were the most ordinary families. At the same time, Oxygonum sinuatum, Hoslundia opposita, Opuntia ficus-indica, Sesamum angustifolium, Phyllathus niruri, Ricinus communis, Erythrina abyssinica and Leonotis nepetifolia were the most frequently cited species. Leaves (47.6%), stems (17.5%) and flowers (9.5%) of herbs (61.7%), trees (23.4%) and shrubs (14.9%) were the primarily utilized plant parts for preparing decoctions that are administered orally (94%). Classical phytochemical screening of plant organs from the eight most cited species indicated flavonoids, phytosterols, terpenoids, saponins and alkaloids. With initial evidence of the bioactive secondary metabolites, this study underscores the need for further bioassay-guided studies to isolate and characterize bioactive molecules associated with the anti-fibroid efficacy of the species.

Ethnopharmacology, phytochemistry, pharmacology and toxicity of the genus Gouania

by Timothy Omara and Hannington Gumisiriza

Heliyon, 2024

The genus Gouania (Rhamnaceae) comprises at least 50 recognized species distributed across tropic... more The genus Gouania (Rhamnaceae) comprises at least 50 recognized species distributed across tropical and subtropical regions. Gouania species have been ethnomedicinally used to treat a variety of ailments. Despite their widespread medicinal use, there is no comprehensive documentation that consolidates the ethnobotanical knowledge, phytochemicals, pharmacological properties, and toxicity of Gouania species. Herein, this review details the ethnopharmacology, phytochemical constituents, pharmacological properties and toxicity of Gouania species to provide perspectives for future research on this genus. Based on available literature, herbal preparations from Gouania species have been used to treat ailments related to the digestive, cardiovascular, respiratory, skin, musculoskeletal, reproductive, endocrine and urological systems. Extracts and isolated compounds from seven Gouania species (G. leptostachya, G. longipetala, G. lupulozdes, G. macrocarpa, G. longispicata, G. obtusifolia, and G. ulmifolia) have demonstrated promising anticancer, antimicrobial, antioxidant, and antiviral properties, supporting their ethnomedicinal uses. To date, 64 compounds (including 6 phenolic compounds, 24 flavonoids, and 34 terpenoids) have been isolated and characterized in the genus mainly as gouaniasides I-IX, gouanogenins, and gouanic acids. Most Gouania species remain unexplored for their potential bioactivities. The identification of more than 54% as novel compounds from just seven Gouania species highlights the genus as a promising source for discovering new therapeutic agents to combat the growing challenge of multidrug-resistant pathogens. Conducting extensive phytochemical and pharmacological analyses across a broader array of Gouania species could unveil a more comprehensive profile of bioactive compounds, and pave way for innovative treatments against a diverse range of pathogens and diseases.

Sustainably addressing Africa’s antimicrobial pollution crisis

Nature Reviews Earth & Environment , 2024

Antimicrobial pollution in Africa is escalating rapidly, threatening ecosystems and human health.... more Antimicrobial pollution in Africa is escalating rapidly, threatening ecosystems and human health. Naturally occurring minerals, flora and microbial communities can support cost-effective and environmentally sustainable strategies to address this crisis and help achieve relevant Sustainable Development Goals.

Assessment of Potentially Toxic Elements and Their Risks in Water and Sediments of Kitengure Stream, Buhweju Plateau, Uganda

Earth, 2024

Artisanal and small-scale gold mining (ASCGM) provides a livelihood for many communities worldwid... more Artisanal and small-scale gold mining (ASCGM) provides a livelihood for many communities worldwide, but it has profound environmental impacts, especially on the quality of nearby water resources. This study assessed the impacts of ASCGM on the physicochemical quality of water and sediments from Kitengure stream, Buhweju Plateau, Western Uganda. Surface water (n = 94) and superficial sediments (n = 36) were sampled between October 2021 and January 2022 from three different sections of Kitengure stream (upstream, midstream around the ASCGM area, and downstream). The samples were analyzed for various physicochemical parameters and selected potentially toxic elements (PTXEs), namely: zinc (Zn), cadmium (Cd), lead (Pb), copper (Cu), and arsenic (As). A health risk assessment was performed using the hazard index and incremental life cancer risk methods. Pearson’s bivariate correlation, geoaccumulation, and pollution indices were used to establish the sources and potential risks that PTXEs in sediments could pose to aquatic organisms. The results indicated that water in Kitengure stream draining the ASCGM site was highly colored (1230.00 ± 134.09 Pt-co units; range = 924.00–1576.00 Pt-co units) and turbid (194.75 ± 23.51 NTU; range = 148–257 NTU). Among the five analyzed PTXEs, only Cd (0.082 ± 0.200–0.092 ± 0.001 mg/L) and Cu (0.022 ± 0.004–0.058 ± 0.005 mg/L) were detected in water, and Cd was above the permissible limit of 0.003 mg/L for potable water. Upon calculating the water quality index (WQI), the water samples were categorized as very poor for upstream samples (WQI = 227) and unfit for use (WQI = 965 and 432) for midstream and downstream samples, respectively. In sediments, the mean concentration ranges of Zn, Cd, Pb, Cu, and As were 0.991 ± 0.038–1.161 ± 0.051, 0.121 ± 0.014–0.145 ± 0.025, 0.260 ± 0.027–0.770 ± 0.037, 0.107 ± 0.017–0.422 ± 0.056, and 0.022 ± 0.002–0.073 ± 0.003 mg/kg, respectively, and they were all below their average shale, toxicity reference, and consensus-based sediment quality guidelines. Geoaccumulation indices suggested that there was no enrichment of the elements in the sedimentary phase and the associated ecological risks were low. However, there were potential non-carcinogenic health risks that maybe experienced by children who drink water from Kitengure stream. No discernable health risks were likely due to dermal contact with water and sediments during dredging or panning activities. It is recommended that further studies should determine the total mercury content of water, sediments, and crops grown along the stream as well as the associated ecological and human health risks.

Protective effects of Sphaeranthus indicus floral extract against BPSinduced testicular damage in rats occurs through downregulation of RIPK1/3-MLK-driven necroptosis and Fas-FasL-mediated apoptosis

Advances in Traditional Medicine, 2024

Bisphenol S (BPS) is one of the monomers preferred in the manufacturing of polycarbonate plastics... more Bisphenol S (BPS) is one of the monomers preferred in the manufacturing of polycarbonate plastics. Unfortunately, its estrogenic and genotoxic effects are similar to those of bisphenol A. The protective effects of Sphaeranthus indicus floral extract (SFE) against reprotoxic effects of BPS (50 µg/kg per body weight) in rats exposed to it via drinking water was investigated. Different SFE doses (25, 50, and 100 mg/kg) were administered via oral gavage for 10 weeks. Highperformance liquid chromatography (HPLC) results indicated that SFE was rich in polyphenols, with rutin and quercetin being important bioactive molecules modulating BPS-induced necroptosis and apoptosis. Biochemical analyses unveiled that rats administered BPS only exhibited considerable elevation of biomarkers of nitro-oxidative stress, necroptotic (RIPK1/RIPK3 and MLKL), and apoptotic mediators (Fas/FasL and caspase 3/caspase-8). These events caused changes in sperm characteristics (sperm motility, sperm head, and sperm viability), sperm count, and hormonal profile (thyroid stimulating hormone, luteinizing hormone, and follicle-stimulating hormone) of the rats. Histological analysis suggested that there was pronounced sloughing of Sertoli cells, reduced spermatogenic cell density, increased levels of seminiferous tubules, and disorganized morphometric parameters related to seminiferous tubules. The SFE supplementation in rats with BPS-containing water restored nitro-oxidative stress biomarkers, which led to the reduction of necroptosis and apoptosis. Reinstatement of all the biomarkers of oxidative stress, inflammation, necroptosis, and apoptosis after SFE supplementations restored the hormonal profile and normal histoarchitecture of the testes. Virtual screening elucidated that the key regulators of the necroptosis are RIPK3-rutin and RIPK1-quercetin complexes. Further studies are needed to assess its pharmacodynamics, kinetics, and effective concentration for daily use in humans.

Antibacterial and Antioxidant Activities of Flavonoids, Phenolic and Flavonoid Glycosides from Gouania longispicata Leaves

Microbiology Research, 2024

The leaves of Gouania longispicata Engl. (GLE) have been traditionally used to treat more than fo... more The leaves of Gouania longispicata Engl. (GLE) have been traditionally used to treat more than forty ailments in Uganda, including stomachache, lung and skin cancers, syphilis, toothache, and allergies. In this study, pure compounds were isolated from the methanolic extract of GLE leaves and their structures elucidated using ultraviolet visible spectroscopy, liquid chromatography–tandem mass spectrometry, high performance liquid chromatography, and 1D and 2D NMR techniques. The antibacterial and antioxidant activities of the compounds were assessed using the broth dilution and DPPH assays, respectively. Two known flavonoid glycosides (kaempferol-3-O-α-rhamnopyranoside and rutin), a phenolic glycoside (4,6-dihydroxy-3-methylacetophenone-2-O-β-D-glucopyranoside), and flavonoids (kaempferol and quercetin) were characterized. This is the first time that the kaempferol derivative, the acetophenone as well as free forms of quercetin, kaempferol, and rutin, are being reported in GLE and the Gouania genus. The compounds exhibited antibacterial activity against Streptococcus pneumoniae and Escherichia coli with minimum inhibitory concentrations between 16 µg/mL and 125 µg/mL. The radical scavenging activities recorded half-minimum inhibitory concentrations (IC50) ranging from 18.6 ± 1.30 µg/mL to 28.1 ± 0.09 µg/mL. The IC50 of kaempferol and quercetin were not significantly different from that of ascorbic acid (p > 0.05), highlighting their potential as natural antioxidant agents. These results lend credence to the use of GLE leaves in herbal treatment of microbial infections and oxidative stress-mediated ailments.

Antibacterial Properties of Phytochemicals Isolated from Leaves of Alstonia boonei and Aerial Parts of Ipomoea cairica

Natural Product Communications, 2024

Objective: The leaves of Alstonia boonei and aerial parts of Ipomoea cairica are used for treatme... more Objective: The leaves of Alstonia boonei and aerial parts of Ipomoea cairica are used for treatment of microbial infections among other ailments in African traditional medicine. The aim of this study was to investigate the antimicrobial phytochemicals in A. boonei leaves and Ipomoea cairica aerial parts to validate their traditional use in Ugandan herbal medicine. Methods: The plant materials were separately extracted using a dichloromethane/methanol (1:1) solvent system and subjected to repeated chromatographic separation to isolate pure compounds. The chemical structures of the isolated compounds were determined through 1 H NMR, 13 C NMR and 2D NMR (COSY, HSQC and HMBC). The antibacterial activity of the extracts and pure compounds were assessed using the agar well diffusion method. Results: Chromatographic fractionation of the extracts yielded trans-fagaramide and a pentacyclic lupane-type triterpenoid, lupeol, from A. boonei, and friedelin from I. cairica. Trans-fagaramide was identified for the first time in the Alstonia genus while friedelin was identified for the first time in I. cairica. The isolated compounds demonstrated antibacterial activity, with trans-fagaramide showing a minimum inhibitory concentration (MIC) of 125 μg/mL against Pseudomonas aeruginosa and 250 μg/mL against Staphylococcus aureus, Salmonella typhi and Escherichia coli. Friedelin exhibited a MIC of 125 μg/mL against Escherichia coli and 250 μg/mL against Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella typhi. Conclusion: The antibacterial activities observed in this study support the traditional use of A. boonei and I. cairica by indigenous communities in Uganda for treating microbial infections.

Spring Water Quality in a Flood-Prone Area of Kampala City, Uganda: Insights Furnished by Sanitary and Limnochemical Data

Resources, 2024

For millennia, springs have provided water for drinking, domestic use, balneological treatment, l... more For millennia, springs have provided water for drinking, domestic use, balneological treatment, liminality rites as well as tourist attractions. Amidst these uses, anthropogenic activities, especially urbanization and agriculture, continue to impair the functionality of springs. With the looming decadal climate change, freshwater springs could be a sustainable source of clean water for the realisation of Sustainable Development Goal 6. This paper presents the results of the sanitary inspection and assessment of limnochemical characteristics and quality of water samples (n = 64) from four freshwater springs (coded SPR1, SPR2, SPR3, and SPR4) in Kansanga, a flash flood-prone area in the African Great Lakes region of Uganda. Each sample was analysed for 17 parameters (temperature, pH, electrical conductivity, turbidity, fluorides, sulphates, chlorides, nitrates, orthophosphates, total dissolved solids, dissolved oxygen, total alkalinity, potassium, sodium, total, magnesium and calcium hardness) following the standard methods. Water quality index (WQI) was calculated to establish the quality of the water samples based on the physicochemical parameters measured. Based on the sanitary risk assessment results, the springs had medium- to high-risk scores, but most water parameters were within the WHO guidelines for potable water, except for nitrates (in SPR1 and SPR2), hardness levels (in SPR2), and dissolved oxygen (in all the samples). Sampling season and location had significant effects on the limnochemistry of the freshwater springs (p < 0.05). The water quality indices calculated indicated that the water from the springs was of good quality (WQI = 50–57), but there was a reduction in water quality during the wet season. The best water quality was recorded in samples from SPR4, followed by those for SPR3, SPR1, and SPR2. These results provide insights into the contribution of floods and poor sanitation facilities to the deterioration of spring water quality in Kansanga, and the need to leverage additional conservation strategies to support vulnerable communities in the area. Further studies are required to establish the risk posed by trace metals and microbes that may contaminate freshwater in the studied springs, especially following flood events.

Anticancer potential of delphinidin and its derivatives: therapeutic and mechanistic insights

Medicinal Chemistry Research , 2024

Anthocyanins are water-soluble naturally occurring flavonoids present in fruits, flowers, leaves,... more Anthocyanins are water-soluble naturally occurring flavonoids present in fruits, flowers, leaves, and roots of fruit plants and vegetables. One of the important anthocyanidin components of red wine and berries is delphinidin (DP). This review provides an update on the potential of DP in cancer therapy, with a further understanding of the mechanisms involved. Delphinidin has been shown to elicit inhibitory effects on catabolizing enzymes of human granulocytes and parasites, TNF-induced COX-2 expression in mouse epidermal cells, and reduce oxidative stress. It also inhibited anchorage-independent growth and caused cell death in breast cancer cell lines. Delphinidin increased Nrf2 expression, increased HO-1 production, and promoted mRNA expression of mitochondrial biogenesis-related factors. Further, DP has anti-proliferative and pro-apoptotic effects in various cancer cell lines such as lung, breast, and ovarian cancer cells. The mTOR-related pathway is the most important signaling pathway in the activation of autophagy, and DP has been shown to exert its cytotoxic effects on cancer cell lines via activating protein kinases. Among DP derivatives, delphinidin-3-O-glucoside has the best anticancer activity because it is easily absorbed. However, the metabolism of DP and its bioavailability in biological systems need to be explored to fully understand its benefits.

Gut-brain axis: A cutting-edge approach to target neurological disorders and potential synbiotic application

by Timothy Omara and Ivan Kahwa

Heliyon, 2024

The microbiota-gut-brain axis (MGBA) represents a sophisticated communication network between the... more The microbiota-gut-brain axis (MGBA) represents a sophisticated communication network between the brain and the gut, involving immunological, endocrinological, and neural mediators. This bidirectional interaction is facilitated through the vagus nerve, sympathetic and parasympathetic fibers, and is regulated by the hypothalamic-pituitary-adrenal (HPA) axis. Evidence shows that alterations in gut microbiota composition, or dysbiosis, significantly impact neurological disorders (NDs) like anxiety, depression, autism, Parkinson's disease (PD), and Alzheimer's disease (AD). Dysbiosis can affect the central nervous system (CNS) via neuroinflammation and microglial activation, highlighting the importance of the microbiota-gut-brain axis (MGBA) in disease pathogenesis. The microbiota influences the immune system by modulating chemokines and cytokines, impacting neuronal health. Synbiotics have shown promise in treating NDs by enhancing cognitive function and reducing inflammation. The gut microbiota's role in producing neurotransmitters and neuroactive compounds, such as short-chain fatty acids (SCFAs), is critical for CNS homeostasis. Therapeutic interventions targeting the MGBA, including dietary modulation and synbiotic supplementation, offer potential benefits for managing neurodegenerative disorders. However, more in-depth clinical studies are necessary to fully understand and harness the therapeutic potential of the MGBA in neurological health and disease.

Ethnomedicinal uses and nutritional composition of yams (Dioscorea hispida Dennst.) In Kitholhu, Kasese District, Uganda

VEGETOS, 2024

Yams (Dioscorea species) are traditionally valued as famine foods and medicinal lianas in countri... more Yams (Dioscorea species) are traditionally valued as famine foods and medicinal lianas in countries such as Uganda, Indonesia, Ethiopia, Sudan, Thailand and Singapore. However, little information exists on the traditional medicinal uses and nutritional composition of yams in Uganda, despite them being cultivated and considered to have medicinal benefits in Eastern and Western Uganda. This study was sought to document the ethnobotanical knowledge and assess the nutritional composition of Dioscorea hispida Dennst. (D. hispida) in Kasese District of Western Uganda. An ethnobotanical survey was carried out from November 2022 to May 2023 in Kitholhu subcounty, a flood-prone area in Kasese District to assess the indigenous knowledge on the medicinal uses of D. hispida. Using semi-structured questionnaires, a total of 47 respondents selected using snow ball technique were interviewed. The proximate composition (moisture, ash, crude fat, protein, crude fiber and total carbohydrate contents) of sampled D. hispida tubers were analyzed. The ethnobotanical data obtained was analyzed using descriptive statistics while nutritional data was subjected to a one-way analysis of variance at P<0.05. Up to 83% of the respondents cultivate D. hispida, with 94% of these indicating that the tuber is used in traditional management of typhoid, diabetes mellitus, malaria, yellow fever, intestinal inflammation, cancer, peptic ulcers and hypertension, among other ailments. Proximate analysis indicated that D. hispida samples from Kitholhu had 72.29±0.38% moisture, 6.08±0.15% crude fiber, 1.24±0.05% crude fat, 3.05±0.03% ash, 5.65±0.29% proteins and 11.67±0.52% carbohydrates. Our results suggest that there is rich ethnobotanical knowledge on the use of D. hispida for the treatment of ailments among the local communities of Kitholhu. Thus, D. hispida is a famine and medicinal plant that needs to be considered for conservation to enhance food security in Kitholhu and Uganda as a whole. Further studies are required to assess D. hispida for its claimed bioactivities against the reported diseases and conditions.

Comprehensive Review of Epidemiology and Treatment of Snakebite Envenomation in West Africa: Case of Benin

Journal of Tropical Medicine, 2024

Snakebite envenomation (SBE) constitutes a public health, social, and economic problem afecting p... more Snakebite envenomation (SBE) constitutes a public health, social, and economic problem afecting poor communities in intertropical and subtropical regions. Tis review sought to synthesize literature on snakebite envenomation in Benin to highlight research perspectives and strategies for better management of the menace. A literature search performed in multidisciplinary electronic databases showed that the prevalence of SBE is high in Benin, but the incidences, associated morbidities, and mortalities are greatly underestimated. Most snake envenomations are by Echis ocellatus in Northern Benin during the rainy season. Adults involved in agricultural activities are the most afected. Te absence of antivenin serum in the most afected areas explains the preference for alternative and traditional medicine as the frst-line treatment for SBE in Benin. In conclusion, it would be imperative to revitalize the snakebite reporting system in order to have better epidemiological data and to develop a sustainable national strategy for the control and management of snakebite envenomation.

Safety, Toxicological and Allergenic Aspects of Using Algae for Food. In: Kurniawan, T.A., Anouzla, A. (eds) Algae as a Natural Solution for Challenges in Water-Food-Energy Nexus

by Timothy Omara and kyarimpa christine

Environmental Science and Engineering. Springer, Singapore, Jul 14, 2024

Consumption of algae has been historically practiced, especially in East Asia and the Pacific reg... more Consumption of algae has been historically practiced, especially in East Asia and the Pacific region cultures. However, sporadic events and empirical studies have suggested that some compounds could be triggering intoxications, allergic reactions and mortalities in humans who consumed algae. This chapter is an effort to explore with in-depth attention the safety, toxicological and allergic reactions following human consumption of algae. Based on retrieved literature, it is clear that toxicities and allergies from ingestion of algae are not a rarity, and to date, at least seventy (70) illnesses, six (6) allergic reactions and fourteen (14) mortalities have been reported globally. Toxicities and mortalities from intake of edible algae has been reported in species of Gracilaria, Caulerpa and Acanthophora genus, and are associated with their bioaccumulation of contaminants such as excess iodine, heavy metals, cyanotoxins or toxic inherent compounds such as caulerpenyne, manauealides A and C, prostaglandin E2, polycavernosides, aplysiatoxins and their derivatives. Allergenicity has been reported in Arthrospira, Chlorella, Chondrus, Eucheuma, Gigartina and Palmaria species, with the sulfated polysaccharide (carrageenan) and the photosynthetic pigment (C-phycocyanin) being the implicated allergens. These allergic reactions are mediated through activation of innate immune pathways of inflammation that trigger NF-kB activation, modification of gut microbiota and thickness of mucus barrier. We contend that appropriate labelling of algae-derived food products, public education, proper cleaning of fresh algae before consumption and profiling of toxic and allergenic algal species and compounds could aid in reducing intoxications and allergic reactions from algae used in food and food products. Future studies should consider examining edible algae for contaminants of emerging concern such as microplastics, cyanotoxins, emerging per- and polyfluoroalkyl substances, pharmaceutical residues and personal care products.

Key regulatory aspects of prebiotics, probiotics, and synbiotics in the management of metabolic disorders. In: Synbiotics in Metabolic Disorders Mechanisms, Therapeutic Potential, and Future Perspectives. Neeraj Mishra, Sumel Ashique, Arshad Farid, A. Garg (Eds)

CRC Press, Taylor and Francis, 2024

The management of metabolic disorders has emerged as a critical healthcare challenge in recent ye... more The management of metabolic disorders has emerged as a critical healthcare challenge in recent years, with the global prevalence of conditions such as obesity, diabetes, and metabolic syndrome on the rise. Amidst this healthcare crisis, the potential therapeutic role of prebiotics, probiotics, and synbiotics has garnered substantial attention due to their capacity to modulate the gut microbiome and influence host metabolism. This chapter delves into the intricate interplay between the gut microbiota, host metabolism, and the development of metabolic disorders, shedding light on the pivotal role these bioactive compounds play in promoting metabolic balance. The chapter further navigates the complex landscape of regulatory oversight, offering insights into the regulatory frameworks and guidelines that govern the development, manufacturing, labelling, and marketing of prebiotic, probiotic, and synbiotic products for metabolic disorder management. Special emphasis is placed on international regulatory bodies and their harmonization efforts, as well as country-specific regulations, providing readers with a comprehensive understanding of the global regulatory landscape. Moreover, the chapter addresses critical considerations in clinical research and product development, exploring the design and execution of rigorous clinical trials that are essential for substantiating health claims and ensuring product safety. It also discusses labelling requirements and the importance of transparent communication to facilitate informed consumer choices. In conclusion, this serves as a valuable resource for researchers, healthcare professionals, policymakers, and industry stakeholders seeking to navigate the regulatory challenges and opportunities in harnessing the potential of these bioactive compounds to combat the growing epidemic of metabolic disorders. It provides a holistic view of the scientific, regulatory, and practical considerations necessary for the responsible development and deployment of prebiotics, probiotics, and synbiotics in the pursuit of improved metabolic health.

Enrichment, Bioaccumulation and Health Risks of Trace Metals in Soils and Leafy Vegetables Grown on the Banks of the Ugandan Lifeline River, River Rwizi

World, 2024

Urban vegetable farming in wetlands and riverbanks are common features of Ugandan cities. However... more Urban vegetable farming in wetlands and riverbanks are common features of Ugandan cities. However, urbanization has led to various anthropogenic activities that can lead to the pollution of water resources, enrichment of pollutants in soils and, consequently, pollutant bioaccumulation in edible tissues of plants cultivated on such soils. In this study, we report on the levels of six trace metals (TMTs) in 75 samples of leafy vegetables (Brassica oleracea L., Spinacia oleracea L., Amaranthus hybridus L., Cucurbita pepo L. and Solanum nigrum L.) and soils (n = 75) grown on the banks of River Rwizi, the second longest river in Uganda only after the Nile River. The concentrations of TMTs (Mn, Zn, Cd, Pb, Cr and Cu) in edible vegetable tissues and soils were quantified using flame atomic absorption spectrometry. The mean concentrations (in mg kg−1) of the TMTs in the soil samples were 205–373.84 (Mn), 12.72–65.04 (Zn), 0.26–0.42 (Cd), 3.36–16.80 (Pb), 5.96–25.06 (Cr) and 2.83–35.27 (Cu). In vegetable samples, the concentrations ranged from 43.25 to 110.00 (Mn), 1.08 to 1.83 (Cd), 41.06 to 71.20 (Zn), 4.31 to 6.16 (Pb), 0.65 to 0.81 (Cr) and 5.70 to 14.35 (Cu). With the exception of Mn and Cr, the rest of the TMTs were bioaccumulated in the edible vegetable tissues (bioconcentration factors = 1.03 to 10.71). Considering chronic daily intake through ingestion, dermal contact and inhalation of the TMTs in soils from the banks of River Rwizi, there are no potential non-cancer and carcinogenic health effects that could be experienced in both adults and children. Consumption of leafy vegetables could pose both non-cancer health risks (from ingestion of Zn, Pb, Cr, Mn and Cd) and cancer health risks (due to intake of Cd) in both children and adults. There is therefore a need to enforce regulations to mitigate the pollution of River Rwizi for a more sustainable economic development.

Matricin Modulates Carbamazepine-Induced Acute Tubulointerstitial Nephritis in Rat Models of Alzheimer’s Disease via MEK-JAK2-STAT3 Signaling

by Timothy Omara and Shabnoor Iqbal

Revista Brasileira de Farmacognosia, 2024

Carbamazepine is a first-choice anticonvulsant, and its medication is typically well tolerated wh... more Carbamazepine is a first-choice anticonvulsant, and its medication is typically well tolerated when compared to lithium and valproic acid. Patients of Alzheimer’s Disease who are administered carbamazepine tend to develop acute tubulointerstitial nephritis. In this study, we established an Alzheimer’s model using scopolamine in Sprague Dawley rats to find out the nephroprotective effect of matricin (a bioactive sesquiterpene isolated from chamomile flowers) against carbamazepine-induced acute tubulointerstitial nephritis and its underlying mechanism of action. Scopolamine (16 mg/kg) was intraperitoneally injected for induction of Alzheimer’s disease on the 28th day whereas carbamazepine (25 mg/kg) was given daily to induce acute tubulointerstitial nephritis. Treatment with matricin inhibited carbamazepine-induced mRNA expressions of RAS-ERK-MEK-JAK2-STAT3, cytokines (IL-1β, TNF-α, and IL-6), and restored the optimal levels of biomarkers of oxidative stress (MDA, SOD and CAT). Further, matricin treatments reinstated biomarkers of kidney function (creatinine, uric acid, and blood urea nitrogen), and refurbished the levels of MDA, SOD, and CAT. Histopathological analyses indicated that there was systemic dilation, tubular necrosis, interstitial edema, and glomerulus nephritis in the medulla region of the kidneys in rats with Alzheimer’s disease that received carbamazepine only. Treatment with matricin reconsolidated histopathology, and only mild glomerulus nephritis were observed in rats with Alzheimer’s disease. These results suggest that matricin could be utilized as a co-supplement with carbamazepine for the treatment of patients with Alzheimer’s disease to minimize the risk of kidney damage.

Exposure and Health Risks Posed by Potentially Toxic Elements in Soils of Metal Fabrication Workshops in Mbarara City, Uganda

by Timothy Omara, Caroline Nakiguli, OCAKACON SIMON, and Daniel Nimusiima

Journal of Xenobiotics, 2024

Metal fabrication workshops (MFWs) are common businesses in Ugandan cities, and especially those ... more Metal fabrication workshops (MFWs) are common businesses in Ugandan cities, and especially those producing metallic security gates, window and door frames (burglar-proof), and balcony and staircase rails. The objective of this study was to comparatively assess the pollution levels and potential health risks of manganese (Mn), chromium (Cr), cadmium (Cd), lead (Pd) and nickel (Ni) in pooled surface soil samples from four 5-, 7-, 8-, and 10-year-old MFWs (n = 28) and a control site (n = 8) in Mbarara City, Uganda. The concentration of the potentially toxic elements (PTEs) was determined using inductively coupled plasma–optical emission spectrometry. Contamination, ecological, and human health risk assessment indices and models were used to identify any risks that the PTEs could pose to the pristine environment and humans. Our results showed that PTE pollution of soils is occuring in the MFWs than at the control site. The mean concentrations of the PTEs (mg kg−1) in the samples were: Mn (2012.75 ± 0.23–3377.14 ± 0.31), Cr (237.55 ± 0.29–424.93 ± 0.31), Cd (0.73 ± 0.13–1.29 ± 0.02), Pb (107.80 ± 0.23–262.01 ± 0.19), and Ni (74.85 ± 0.25–211.37 ± 0.14). These results indicate that the PTEs could plausibly derive from the fabrication activities in these workshops, which is supported by the high values of contamination factors, index of geoaccumulation, and the overall increase in pollution load indices with the number of years of operation of the MFWs. Human health risk assessment showed that there are non-carcinogenic health risks that could be experienced by children who ingest PTEs in the soils from the 7-, 8- and 10-year-old MFWs. The incremental life cancer risk assessment suggested that there are potential cancerous health effects of Cd and Ni that could be experienced in children (who ingest soils from all the four MFWs) and adults (ingesting soils from the 8- and 10-year-old MFWs). This study underscores the need to implement regulatory guidelines on the operation and location of MFWs in Uganda. Further research should be undertaken to investigate the emission of the PTEs during welding operations in the MFWs.

Urban drainage channels as microplastic pollution hotspots into Lake Victoria, East Africa

by Timothy Omara, OCAKACON SIMON, and kyarimpa christine

DISC2023 – 3rd International Student Conference 5th December 2023, 2023

Microplastics (MPs) are microscopic and ubiquitous emerging organic contaminants with marked pote... more Microplastics (MPs) are microscopic and ubiquitous emerging organic contaminants with marked potential to bind, concentrate and act as carriers of other toxic compounds and pathogenic microorganisms. They have been extensively studied in the marine environment, but reliable data on them in freshwater ecosystems especially in developing countries remains scarce. This study investigated the spatiotemporal distribution, characteristics and sources of MPs in Nakivubo catchment which drains into Lake Victoria, the largest freshwater lake in Africa. Surface water was sampled from thirteen (13) different sites (S1 to S13; n = 117) along Nakivubo catchment during the dry and wet seasons as well as on the onset of the rains in 2022. The samples were digested using hydrogen peroxide, extracted using density separation method and subjected to microscopic and Fourier-transform infrared spectroscopy analyses. The results showed that all the samples had MPs ranging from 1568.59 ± 1473.83 particles/m3 during the dry season to 2140.39 ± 3670.07 particles/m3 during the wet season. The mean output of MPs (microplastic fluxes) from Nakivubo catchment into Lake Victoria was found to be approximately 293.96 million particles/day. The highest mean abundance of MPs (5,466.7 ± 6441.70 particles/m3) was for samples from site S3, which is near market areas, car washing bay and informal settlements. These places are characterized by poor waste management and direct discharge of wastewater into Nakivubo channel. However, the concentration of MPs was relatively lower in wastewater treatment plant effluent (580.56 ± 416.42 particles/m3) than expected possibly due to removal of MPs by Wastewater treatment processes. Filaments (79.7%) and fragments (17.9%) were the most common form of MPs and majorly originated from domestic effluents and surface runoff, while polyethylene (75.4%) and polyethylene-polypropylene (16.0%) were the major polymer types in the sample, explainable by its low density and wide usage in various consumer products. The abundance of MPs (2140.39 particles/m3) was highest during the wet season which could be linked to the lower flow rates of water in the catchment and higher residence times. These data support that MPs remobilization maybe occurring during intense rainfall events in the urban drainage channel of Nakivubo. There is therefore need to institute sustainable plastic waste management practices in the study area to mitigate MPs bioaccumulation, possible trophic transfer and biomagnification in biota and the sedimentary phase of Lake Victoria

Physicochemical and Microbial Quality of Water from the Ugandan Stretch of the Kagera Transboundary River

by Timothy Omara and Daniel Nimusiima

Limnological Review , 2023

Increasing global pollution of water resources undermines the efforts invested in the realisation... more Increasing global pollution of water resources undermines the efforts invested in the realisation of Sustainable Development Goals. In developing countries, for example, water pollution is exacerbated by poor regulatory structures and improper waste disposal. This study, for the first time, investigated the physicochemical and microbial parameters of surface water from the Ugandan stretch of the Kagera transboundary river. Surface water (n = 135) from downstream, midstream and upstream of the river was sampled between February 2021 and June 2021, and analysed following standard methods for the examination of water and wastewater. Further, the samples were analysed using flame atomic absorption spectroscopy for the presence of heavy metals: nickel, lead, chromium, cadmium and copper. The obtained results showed that turbidity (24.77 ± 5.5–43.99 ± 6.87 mg/L), colour (118 ± 8.90–145.2 ± 30.58 Pt-co units), Escherichia coli (4.96 ± 7.01 CFU/100 mL), lead (23.0 ± 11.0–43.0 ± 12.0 µg/L) and cadmium (3.3 ± 1.0–10.1 ± 10.0 µg/L) were at levels that surpassed their permissible limits as per World Health Organization guidelines for potable water. These results are lower than previously reported for the Rwandese stretch of this river, but still present potential health risks to the population whose livelihoods depend on the river. Measures should therefore be instituted by the East African Community member states to mitigate riverine pollution and ensure sustainable use of the Kagera transboundary river.

Bioethanol production from water hyacinth with isolated thermophilic microbial consortium from Kenya

Comptes Rendus Chimie, 2024

Bioethanol production from water hyacinth pretreated thermochemically through boiling in water wi... more Bioethanol production from water hyacinth pretreated thermochemically through boiling in water with or without sodium chlorite, followed by fermentation with a locally isolated thermophilic bacteria consortium in a partially consolidated bioprocessing was investigated. The time yielding the maximum total reducing sugars was 2 hours using 155 mg/g and 113 mg/g of pretreated and untreated water hyacinth samples, respectively. The optimized factors were inoculum dose (8.1%, v/v), temperature (48.8 ℃) and time (52.3 hours) which resulted into 7.2 g/L of predicted bioethanol concentration. In the experimental run, 7.7 g/L of ethanol was produced, which is close to the predicted value.

Ethnobotany, floristic and phytochemical studies of medicinal plants used to treat uterine fibroids in Mbarara City, Uganda

by Timothy Omara and ivan kahwa

Phytomedicine Plus, 2025

Uterine fibroids (UF) are the most common non-cancerous benign gynaecologic tumours in premenopau... more Uterine fibroids (UF) are the most common non-cancerous benign gynaecologic tumours in premenopausal females. In Uganda, the prevalence of UF is estimated at 20%, and several risk factors have been identified as contributing to this prevalence. This study aimed to document the ethnobotanical knowledge of traditional medicine practitioners (TMPs) in Mbarara City, Southwestern Uganda on the use of medicinal plants for UF management. The TMPs play a vital role in the healthcare within this region, often incorporating conventional diagnostic methods such as ultrasound scans before providing herbal treatments. To achieve the study aim, data was collected from April 2024 to May 2024 using structured questionnaires administered. Twenty-six (26) respondents were selected using purposive and snowball sampling techniques. Data were gathered on sociodemographic characteristics, treatment-seeking behaviour, and use of herbal formularies for treatment of UF. Statistical analysis involved descriptive statistics, and computation of the frequency of citation, relative frequency of citation and fidelity level. Our results indicated that most TMPs knew about UF and valued conventional means of diagnosis before initiating herbal treatment. Forty-seven (47) plant species belonging to 32 families and 45 genera were identified. Fabaceae (10.6%), Asteraceae, Lamiaceae (8.5% each), Asparagaceae and Cucurbitaceae (6.4% each) were the most ordinary families. At the same time, Oxygonum sinuatum, Hoslundia opposita, Opuntia ficus-indica, Sesamum angustifolium, Phyllathus niruri, Ricinus communis, Erythrina abyssinica and Leonotis nepetifolia were the most frequently cited species. Leaves (47.6%), stems (17.5%) and flowers (9.5%) of herbs (61.7%), trees (23.4%) and shrubs (14.9%) were the primarily utilized plant parts for preparing decoctions that are administered orally (94%). Classical phytochemical screening of plant organs from the eight most cited species indicated flavonoids, phytosterols, terpenoids, saponins and alkaloids. With initial evidence of the bioactive secondary metabolites, this study underscores the need for further bioassay-guided studies to isolate and characterize bioactive molecules associated with the anti-fibroid efficacy of the species.

Ethnopharmacology, phytochemistry, pharmacology and toxicity of the genus Gouania

by Timothy Omara and Hannington Gumisiriza

Heliyon, 2024

The genus Gouania (Rhamnaceae) comprises at least 50 recognized species distributed across tropic... more The genus Gouania (Rhamnaceae) comprises at least 50 recognized species distributed across tropical and subtropical regions. Gouania species have been ethnomedicinally used to treat a variety of ailments. Despite their widespread medicinal use, there is no comprehensive documentation that consolidates the ethnobotanical knowledge, phytochemicals, pharmacological properties, and toxicity of Gouania species. Herein, this review details the ethnopharmacology, phytochemical constituents, pharmacological properties and toxicity of Gouania species to provide perspectives for future research on this genus. Based on available literature, herbal preparations from Gouania species have been used to treat ailments related to the digestive, cardiovascular, respiratory, skin, musculoskeletal, reproductive, endocrine and urological systems. Extracts and isolated compounds from seven Gouania species (G. leptostachya, G. longipetala, G. lupulozdes, G. macrocarpa, G. longispicata, G. obtusifolia, and G. ulmifolia) have demonstrated promising anticancer, antimicrobial, antioxidant, and antiviral properties, supporting their ethnomedicinal uses. To date, 64 compounds (including 6 phenolic compounds, 24 flavonoids, and 34 terpenoids) have been isolated and characterized in the genus mainly as gouaniasides I-IX, gouanogenins, and gouanic acids. Most Gouania species remain unexplored for their potential bioactivities. The identification of more than 54% as novel compounds from just seven Gouania species highlights the genus as a promising source for discovering new therapeutic agents to combat the growing challenge of multidrug-resistant pathogens. Conducting extensive phytochemical and pharmacological analyses across a broader array of Gouania species could unveil a more comprehensive profile of bioactive compounds, and pave way for innovative treatments against a diverse range of pathogens and diseases.

Sustainably addressing Africa’s antimicrobial pollution crisis

Nature Reviews Earth & Environment , 2024

Antimicrobial pollution in Africa is escalating rapidly, threatening ecosystems and human health.... more Antimicrobial pollution in Africa is escalating rapidly, threatening ecosystems and human health. Naturally occurring minerals, flora and microbial communities can support cost-effective and environmentally sustainable strategies to address this crisis and help achieve relevant Sustainable Development Goals.

Assessment of Potentially Toxic Elements and Their Risks in Water and Sediments of Kitengure Stream, Buhweju Plateau, Uganda

Earth, 2024

Artisanal and small-scale gold mining (ASCGM) provides a livelihood for many communities worldwid... more Artisanal and small-scale gold mining (ASCGM) provides a livelihood for many communities worldwide, but it has profound environmental impacts, especially on the quality of nearby water resources. This study assessed the impacts of ASCGM on the physicochemical quality of water and sediments from Kitengure stream, Buhweju Plateau, Western Uganda. Surface water (n = 94) and superficial sediments (n = 36) were sampled between October 2021 and January 2022 from three different sections of Kitengure stream (upstream, midstream around the ASCGM area, and downstream). The samples were analyzed for various physicochemical parameters and selected potentially toxic elements (PTXEs), namely: zinc (Zn), cadmium (Cd), lead (Pb), copper (Cu), and arsenic (As). A health risk assessment was performed using the hazard index and incremental life cancer risk methods. Pearson’s bivariate correlation, geoaccumulation, and pollution indices were used to establish the sources and potential risks that PTXEs in sediments could pose to aquatic organisms. The results indicated that water in Kitengure stream draining the ASCGM site was highly colored (1230.00 ± 134.09 Pt-co units; range = 924.00–1576.00 Pt-co units) and turbid (194.75 ± 23.51 NTU; range = 148–257 NTU). Among the five analyzed PTXEs, only Cd (0.082 ± 0.200–0.092 ± 0.001 mg/L) and Cu (0.022 ± 0.004–0.058 ± 0.005 mg/L) were detected in water, and Cd was above the permissible limit of 0.003 mg/L for potable water. Upon calculating the water quality index (WQI), the water samples were categorized as very poor for upstream samples (WQI = 227) and unfit for use (WQI = 965 and 432) for midstream and downstream samples, respectively. In sediments, the mean concentration ranges of Zn, Cd, Pb, Cu, and As were 0.991 ± 0.038–1.161 ± 0.051, 0.121 ± 0.014–0.145 ± 0.025, 0.260 ± 0.027–0.770 ± 0.037, 0.107 ± 0.017–0.422 ± 0.056, and 0.022 ± 0.002–0.073 ± 0.003 mg/kg, respectively, and they were all below their average shale, toxicity reference, and consensus-based sediment quality guidelines. Geoaccumulation indices suggested that there was no enrichment of the elements in the sedimentary phase and the associated ecological risks were low. However, there were potential non-carcinogenic health risks that maybe experienced by children who drink water from Kitengure stream. No discernable health risks were likely due to dermal contact with water and sediments during dredging or panning activities. It is recommended that further studies should determine the total mercury content of water, sediments, and crops grown along the stream as well as the associated ecological and human health risks.

Protective effects of Sphaeranthus indicus floral extract against BPSinduced testicular damage in rats occurs through downregulation of RIPK1/3-MLK-driven necroptosis and Fas-FasL-mediated apoptosis

Advances in Traditional Medicine, 2024

Bisphenol S (BPS) is one of the monomers preferred in the manufacturing of polycarbonate plastics... more Bisphenol S (BPS) is one of the monomers preferred in the manufacturing of polycarbonate plastics. Unfortunately, its estrogenic and genotoxic effects are similar to those of bisphenol A. The protective effects of Sphaeranthus indicus floral extract (SFE) against reprotoxic effects of BPS (50 µg/kg per body weight) in rats exposed to it via drinking water was investigated. Different SFE doses (25, 50, and 100 mg/kg) were administered via oral gavage for 10 weeks. Highperformance liquid chromatography (HPLC) results indicated that SFE was rich in polyphenols, with rutin and quercetin being important bioactive molecules modulating BPS-induced necroptosis and apoptosis. Biochemical analyses unveiled that rats administered BPS only exhibited considerable elevation of biomarkers of nitro-oxidative stress, necroptotic (RIPK1/RIPK3 and MLKL), and apoptotic mediators (Fas/FasL and caspase 3/caspase-8). These events caused changes in sperm characteristics (sperm motility, sperm head, and sperm viability), sperm count, and hormonal profile (thyroid stimulating hormone, luteinizing hormone, and follicle-stimulating hormone) of the rats. Histological analysis suggested that there was pronounced sloughing of Sertoli cells, reduced spermatogenic cell density, increased levels of seminiferous tubules, and disorganized morphometric parameters related to seminiferous tubules. The SFE supplementation in rats with BPS-containing water restored nitro-oxidative stress biomarkers, which led to the reduction of necroptosis and apoptosis. Reinstatement of all the biomarkers of oxidative stress, inflammation, necroptosis, and apoptosis after SFE supplementations restored the hormonal profile and normal histoarchitecture of the testes. Virtual screening elucidated that the key regulators of the necroptosis are RIPK3-rutin and RIPK1-quercetin complexes. Further studies are needed to assess its pharmacodynamics, kinetics, and effective concentration for daily use in humans.

Antibacterial and Antioxidant Activities of Flavonoids, Phenolic and Flavonoid Glycosides from Gouania longispicata Leaves

Microbiology Research, 2024

The leaves of Gouania longispicata Engl. (GLE) have been traditionally used to treat more than fo... more The leaves of Gouania longispicata Engl. (GLE) have been traditionally used to treat more than forty ailments in Uganda, including stomachache, lung and skin cancers, syphilis, toothache, and allergies. In this study, pure compounds were isolated from the methanolic extract of GLE leaves and their structures elucidated using ultraviolet visible spectroscopy, liquid chromatography–tandem mass spectrometry, high performance liquid chromatography, and 1D and 2D NMR techniques. The antibacterial and antioxidant activities of the compounds were assessed using the broth dilution and DPPH assays, respectively. Two known flavonoid glycosides (kaempferol-3-O-α-rhamnopyranoside and rutin), a phenolic glycoside (4,6-dihydroxy-3-methylacetophenone-2-O-β-D-glucopyranoside), and flavonoids (kaempferol and quercetin) were characterized. This is the first time that the kaempferol derivative, the acetophenone as well as free forms of quercetin, kaempferol, and rutin, are being reported in GLE and the Gouania genus. The compounds exhibited antibacterial activity against Streptococcus pneumoniae and Escherichia coli with minimum inhibitory concentrations between 16 µg/mL and 125 µg/mL. The radical scavenging activities recorded half-minimum inhibitory concentrations (IC50) ranging from 18.6 ± 1.30 µg/mL to 28.1 ± 0.09 µg/mL. The IC50 of kaempferol and quercetin were not significantly different from that of ascorbic acid (p > 0.05), highlighting their potential as natural antioxidant agents. These results lend credence to the use of GLE leaves in herbal treatment of microbial infections and oxidative stress-mediated ailments.

Antibacterial Properties of Phytochemicals Isolated from Leaves of Alstonia boonei and Aerial Parts of Ipomoea cairica

Natural Product Communications, 2024

Objective: The leaves of Alstonia boonei and aerial parts of Ipomoea cairica are used for treatme... more Objective: The leaves of Alstonia boonei and aerial parts of Ipomoea cairica are used for treatment of microbial infections among other ailments in African traditional medicine. The aim of this study was to investigate the antimicrobial phytochemicals in A. boonei leaves and Ipomoea cairica aerial parts to validate their traditional use in Ugandan herbal medicine. Methods: The plant materials were separately extracted using a dichloromethane/methanol (1:1) solvent system and subjected to repeated chromatographic separation to isolate pure compounds. The chemical structures of the isolated compounds were determined through 1 H NMR, 13 C NMR and 2D NMR (COSY, HSQC and HMBC). The antibacterial activity of the extracts and pure compounds were assessed using the agar well diffusion method. Results: Chromatographic fractionation of the extracts yielded trans-fagaramide and a pentacyclic lupane-type triterpenoid, lupeol, from A. boonei, and friedelin from I. cairica. Trans-fagaramide was identified for the first time in the Alstonia genus while friedelin was identified for the first time in I. cairica. The isolated compounds demonstrated antibacterial activity, with trans-fagaramide showing a minimum inhibitory concentration (MIC) of 125 μg/mL against Pseudomonas aeruginosa and 250 μg/mL against Staphylococcus aureus, Salmonella typhi and Escherichia coli. Friedelin exhibited a MIC of 125 μg/mL against Escherichia coli and 250 μg/mL against Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella typhi. Conclusion: The antibacterial activities observed in this study support the traditional use of A. boonei and I. cairica by indigenous communities in Uganda for treating microbial infections.

Spring Water Quality in a Flood-Prone Area of Kampala City, Uganda: Insights Furnished by Sanitary and Limnochemical Data

Resources, 2024

For millennia, springs have provided water for drinking, domestic use, balneological treatment, l... more For millennia, springs have provided water for drinking, domestic use, balneological treatment, liminality rites as well as tourist attractions. Amidst these uses, anthropogenic activities, especially urbanization and agriculture, continue to impair the functionality of springs. With the looming decadal climate change, freshwater springs could be a sustainable source of clean water for the realisation of Sustainable Development Goal 6. This paper presents the results of the sanitary inspection and assessment of limnochemical characteristics and quality of water samples (n = 64) from four freshwater springs (coded SPR1, SPR2, SPR3, and SPR4) in Kansanga, a flash flood-prone area in the African Great Lakes region of Uganda. Each sample was analysed for 17 parameters (temperature, pH, electrical conductivity, turbidity, fluorides, sulphates, chlorides, nitrates, orthophosphates, total dissolved solids, dissolved oxygen, total alkalinity, potassium, sodium, total, magnesium and calcium hardness) following the standard methods. Water quality index (WQI) was calculated to establish the quality of the water samples based on the physicochemical parameters measured. Based on the sanitary risk assessment results, the springs had medium- to high-risk scores, but most water parameters were within the WHO guidelines for potable water, except for nitrates (in SPR1 and SPR2), hardness levels (in SPR2), and dissolved oxygen (in all the samples). Sampling season and location had significant effects on the limnochemistry of the freshwater springs (p < 0.05). The water quality indices calculated indicated that the water from the springs was of good quality (WQI = 50–57), but there was a reduction in water quality during the wet season. The best water quality was recorded in samples from SPR4, followed by those for SPR3, SPR1, and SPR2. These results provide insights into the contribution of floods and poor sanitation facilities to the deterioration of spring water quality in Kansanga, and the need to leverage additional conservation strategies to support vulnerable communities in the area. Further studies are required to establish the risk posed by trace metals and microbes that may contaminate freshwater in the studied springs, especially following flood events.

Anticancer potential of delphinidin and its derivatives: therapeutic and mechanistic insights

Medicinal Chemistry Research , 2024

Anthocyanins are water-soluble naturally occurring flavonoids present in fruits, flowers, leaves,... more Anthocyanins are water-soluble naturally occurring flavonoids present in fruits, flowers, leaves, and roots of fruit plants and vegetables. One of the important anthocyanidin components of red wine and berries is delphinidin (DP). This review provides an update on the potential of DP in cancer therapy, with a further understanding of the mechanisms involved. Delphinidin has been shown to elicit inhibitory effects on catabolizing enzymes of human granulocytes and parasites, TNF-induced COX-2 expression in mouse epidermal cells, and reduce oxidative stress. It also inhibited anchorage-independent growth and caused cell death in breast cancer cell lines. Delphinidin increased Nrf2 expression, increased HO-1 production, and promoted mRNA expression of mitochondrial biogenesis-related factors. Further, DP has anti-proliferative and pro-apoptotic effects in various cancer cell lines such as lung, breast, and ovarian cancer cells. The mTOR-related pathway is the most important signaling pathway in the activation of autophagy, and DP has been shown to exert its cytotoxic effects on cancer cell lines via activating protein kinases. Among DP derivatives, delphinidin-3-O-glucoside has the best anticancer activity because it is easily absorbed. However, the metabolism of DP and its bioavailability in biological systems need to be explored to fully understand its benefits.

Gut-brain axis: A cutting-edge approach to target neurological disorders and potential synbiotic application

by Timothy Omara and Ivan Kahwa

Heliyon, 2024

The microbiota-gut-brain axis (MGBA) represents a sophisticated communication network between the... more The microbiota-gut-brain axis (MGBA) represents a sophisticated communication network between the brain and the gut, involving immunological, endocrinological, and neural mediators. This bidirectional interaction is facilitated through the vagus nerve, sympathetic and parasympathetic fibers, and is regulated by the hypothalamic-pituitary-adrenal (HPA) axis. Evidence shows that alterations in gut microbiota composition, or dysbiosis, significantly impact neurological disorders (NDs) like anxiety, depression, autism, Parkinson's disease (PD), and Alzheimer's disease (AD). Dysbiosis can affect the central nervous system (CNS) via neuroinflammation and microglial activation, highlighting the importance of the microbiota-gut-brain axis (MGBA) in disease pathogenesis. The microbiota influences the immune system by modulating chemokines and cytokines, impacting neuronal health. Synbiotics have shown promise in treating NDs by enhancing cognitive function and reducing inflammation. The gut microbiota's role in producing neurotransmitters and neuroactive compounds, such as short-chain fatty acids (SCFAs), is critical for CNS homeostasis. Therapeutic interventions targeting the MGBA, including dietary modulation and synbiotic supplementation, offer potential benefits for managing neurodegenerative disorders. However, more in-depth clinical studies are necessary to fully understand and harness the therapeutic potential of the MGBA in neurological health and disease.

Ethnomedicinal uses and nutritional composition of yams (Dioscorea hispida Dennst.) In Kitholhu, Kasese District, Uganda

VEGETOS, 2024

Yams (Dioscorea species) are traditionally valued as famine foods and medicinal lianas in countri... more Yams (Dioscorea species) are traditionally valued as famine foods and medicinal lianas in countries such as Uganda, Indonesia, Ethiopia, Sudan, Thailand and Singapore. However, little information exists on the traditional medicinal uses and nutritional composition of yams in Uganda, despite them being cultivated and considered to have medicinal benefits in Eastern and Western Uganda. This study was sought to document the ethnobotanical knowledge and assess the nutritional composition of Dioscorea hispida Dennst. (D. hispida) in Kasese District of Western Uganda. An ethnobotanical survey was carried out from November 2022 to May 2023 in Kitholhu subcounty, a flood-prone area in Kasese District to assess the indigenous knowledge on the medicinal uses of D. hispida. Using semi-structured questionnaires, a total of 47 respondents selected using snow ball technique were interviewed. The proximate composition (moisture, ash, crude fat, protein, crude fiber and total carbohydrate contents) of sampled D. hispida tubers were analyzed. The ethnobotanical data obtained was analyzed using descriptive statistics while nutritional data was subjected to a one-way analysis of variance at P<0.05. Up to 83% of the respondents cultivate D. hispida, with 94% of these indicating that the tuber is used in traditional management of typhoid, diabetes mellitus, malaria, yellow fever, intestinal inflammation, cancer, peptic ulcers and hypertension, among other ailments. Proximate analysis indicated that D. hispida samples from Kitholhu had 72.29±0.38% moisture, 6.08±0.15% crude fiber, 1.24±0.05% crude fat, 3.05±0.03% ash, 5.65±0.29% proteins and 11.67±0.52% carbohydrates. Our results suggest that there is rich ethnobotanical knowledge on the use of D. hispida for the treatment of ailments among the local communities of Kitholhu. Thus, D. hispida is a famine and medicinal plant that needs to be considered for conservation to enhance food security in Kitholhu and Uganda as a whole. Further studies are required to assess D. hispida for its claimed bioactivities against the reported diseases and conditions.

Comprehensive Review of Epidemiology and Treatment of Snakebite Envenomation in West Africa: Case of Benin

Journal of Tropical Medicine, 2024

Snakebite envenomation (SBE) constitutes a public health, social, and economic problem afecting p... more Snakebite envenomation (SBE) constitutes a public health, social, and economic problem afecting poor communities in intertropical and subtropical regions. Tis review sought to synthesize literature on snakebite envenomation in Benin to highlight research perspectives and strategies for better management of the menace. A literature search performed in multidisciplinary electronic databases showed that the prevalence of SBE is high in Benin, but the incidences, associated morbidities, and mortalities are greatly underestimated. Most snake envenomations are by Echis ocellatus in Northern Benin during the rainy season. Adults involved in agricultural activities are the most afected. Te absence of antivenin serum in the most afected areas explains the preference for alternative and traditional medicine as the frst-line treatment for SBE in Benin. In conclusion, it would be imperative to revitalize the snakebite reporting system in order to have better epidemiological data and to develop a sustainable national strategy for the control and management of snakebite envenomation.

Safety, Toxicological and Allergenic Aspects of Using Algae for Food. In: Kurniawan, T.A., Anouzla, A. (eds) Algae as a Natural Solution for Challenges in Water-Food-Energy Nexus

by Timothy Omara and kyarimpa christine

Environmental Science and Engineering. Springer, Singapore, Jul 14, 2024

Consumption of algae has been historically practiced, especially in East Asia and the Pacific reg... more Consumption of algae has been historically practiced, especially in East Asia and the Pacific region cultures. However, sporadic events and empirical studies have suggested that some compounds could be triggering intoxications, allergic reactions and mortalities in humans who consumed algae. This chapter is an effort to explore with in-depth attention the safety, toxicological and allergic reactions following human consumption of algae. Based on retrieved literature, it is clear that toxicities and allergies from ingestion of algae are not a rarity, and to date, at least seventy (70) illnesses, six (6) allergic reactions and fourteen (14) mortalities have been reported globally. Toxicities and mortalities from intake of edible algae has been reported in species of Gracilaria, Caulerpa and Acanthophora genus, and are associated with their bioaccumulation of contaminants such as excess iodine, heavy metals, cyanotoxins or toxic inherent compounds such as caulerpenyne, manauealides A and C, prostaglandin E2, polycavernosides, aplysiatoxins and their derivatives. Allergenicity has been reported in Arthrospira, Chlorella, Chondrus, Eucheuma, Gigartina and Palmaria species, with the sulfated polysaccharide (carrageenan) and the photosynthetic pigment (C-phycocyanin) being the implicated allergens. These allergic reactions are mediated through activation of innate immune pathways of inflammation that trigger NF-kB activation, modification of gut microbiota and thickness of mucus barrier. We contend that appropriate labelling of algae-derived food products, public education, proper cleaning of fresh algae before consumption and profiling of toxic and allergenic algal species and compounds could aid in reducing intoxications and allergic reactions from algae used in food and food products. Future studies should consider examining edible algae for contaminants of emerging concern such as microplastics, cyanotoxins, emerging per- and polyfluoroalkyl substances, pharmaceutical residues and personal care products.

Key regulatory aspects of prebiotics, probiotics, and synbiotics in the management of metabolic disorders. In: Synbiotics in Metabolic Disorders Mechanisms, Therapeutic Potential, and Future Perspectives. Neeraj Mishra, Sumel Ashique, Arshad Farid, A. Garg (Eds)

CRC Press, Taylor and Francis, 2024

The management of metabolic disorders has emerged as a critical healthcare challenge in recent ye... more The management of metabolic disorders has emerged as a critical healthcare challenge in recent years, with the global prevalence of conditions such as obesity, diabetes, and metabolic syndrome on the rise. Amidst this healthcare crisis, the potential therapeutic role of prebiotics, probiotics, and synbiotics has garnered substantial attention due to their capacity to modulate the gut microbiome and influence host metabolism. This chapter delves into the intricate interplay between the gut microbiota, host metabolism, and the development of metabolic disorders, shedding light on the pivotal role these bioactive compounds play in promoting metabolic balance. The chapter further navigates the complex landscape of regulatory oversight, offering insights into the regulatory frameworks and guidelines that govern the development, manufacturing, labelling, and marketing of prebiotic, probiotic, and synbiotic products for metabolic disorder management. Special emphasis is placed on international regulatory bodies and their harmonization efforts, as well as country-specific regulations, providing readers with a comprehensive understanding of the global regulatory landscape. Moreover, the chapter addresses critical considerations in clinical research and product development, exploring the design and execution of rigorous clinical trials that are essential for substantiating health claims and ensuring product safety. It also discusses labelling requirements and the importance of transparent communication to facilitate informed consumer choices. In conclusion, this serves as a valuable resource for researchers, healthcare professionals, policymakers, and industry stakeholders seeking to navigate the regulatory challenges and opportunities in harnessing the potential of these bioactive compounds to combat the growing epidemic of metabolic disorders. It provides a holistic view of the scientific, regulatory, and practical considerations necessary for the responsible development and deployment of prebiotics, probiotics, and synbiotics in the pursuit of improved metabolic health.

Enrichment, Bioaccumulation and Health Risks of Trace Metals in Soils and Leafy Vegetables Grown on the Banks of the Ugandan Lifeline River, River Rwizi

World, 2024

Urban vegetable farming in wetlands and riverbanks are common features of Ugandan cities. However... more Urban vegetable farming in wetlands and riverbanks are common features of Ugandan cities. However, urbanization has led to various anthropogenic activities that can lead to the pollution of water resources, enrichment of pollutants in soils and, consequently, pollutant bioaccumulation in edible tissues of plants cultivated on such soils. In this study, we report on the levels of six trace metals (TMTs) in 75 samples of leafy vegetables (Brassica oleracea L., Spinacia oleracea L., Amaranthus hybridus L., Cucurbita pepo L. and Solanum nigrum L.) and soils (n = 75) grown on the banks of River Rwizi, the second longest river in Uganda only after the Nile River. The concentrations of TMTs (Mn, Zn, Cd, Pb, Cr and Cu) in edible vegetable tissues and soils were quantified using flame atomic absorption spectrometry. The mean concentrations (in mg kg−1) of the TMTs in the soil samples were 205–373.84 (Mn), 12.72–65.04 (Zn), 0.26–0.42 (Cd), 3.36–16.80 (Pb), 5.96–25.06 (Cr) and 2.83–35.27 (Cu). In vegetable samples, the concentrations ranged from 43.25 to 110.00 (Mn), 1.08 to 1.83 (Cd), 41.06 to 71.20 (Zn), 4.31 to 6.16 (Pb), 0.65 to 0.81 (Cr) and 5.70 to 14.35 (Cu). With the exception of Mn and Cr, the rest of the TMTs were bioaccumulated in the edible vegetable tissues (bioconcentration factors = 1.03 to 10.71). Considering chronic daily intake through ingestion, dermal contact and inhalation of the TMTs in soils from the banks of River Rwizi, there are no potential non-cancer and carcinogenic health effects that could be experienced in both adults and children. Consumption of leafy vegetables could pose both non-cancer health risks (from ingestion of Zn, Pb, Cr, Mn and Cd) and cancer health risks (due to intake of Cd) in both children and adults. There is therefore a need to enforce regulations to mitigate the pollution of River Rwizi for a more sustainable economic development.

Matricin Modulates Carbamazepine-Induced Acute Tubulointerstitial Nephritis in Rat Models of Alzheimer’s Disease via MEK-JAK2-STAT3 Signaling

by Timothy Omara and Shabnoor Iqbal

Revista Brasileira de Farmacognosia, 2024

Carbamazepine is a first-choice anticonvulsant, and its medication is typically well tolerated wh... more Carbamazepine is a first-choice anticonvulsant, and its medication is typically well tolerated when compared to lithium and valproic acid. Patients of Alzheimer’s Disease who are administered carbamazepine tend to develop acute tubulointerstitial nephritis. In this study, we established an Alzheimer’s model using scopolamine in Sprague Dawley rats to find out the nephroprotective effect of matricin (a bioactive sesquiterpene isolated from chamomile flowers) against carbamazepine-induced acute tubulointerstitial nephritis and its underlying mechanism of action. Scopolamine (16 mg/kg) was intraperitoneally injected for induction of Alzheimer’s disease on the 28th day whereas carbamazepine (25 mg/kg) was given daily to induce acute tubulointerstitial nephritis. Treatment with matricin inhibited carbamazepine-induced mRNA expressions of RAS-ERK-MEK-JAK2-STAT3, cytokines (IL-1β, TNF-α, and IL-6), and restored the optimal levels of biomarkers of oxidative stress (MDA, SOD and CAT). Further, matricin treatments reinstated biomarkers of kidney function (creatinine, uric acid, and blood urea nitrogen), and refurbished the levels of MDA, SOD, and CAT. Histopathological analyses indicated that there was systemic dilation, tubular necrosis, interstitial edema, and glomerulus nephritis in the medulla region of the kidneys in rats with Alzheimer’s disease that received carbamazepine only. Treatment with matricin reconsolidated histopathology, and only mild glomerulus nephritis were observed in rats with Alzheimer’s disease. These results suggest that matricin could be utilized as a co-supplement with carbamazepine for the treatment of patients with Alzheimer’s disease to minimize the risk of kidney damage.

Exposure and Health Risks Posed by Potentially Toxic Elements in Soils of Metal Fabrication Workshops in Mbarara City, Uganda

by Timothy Omara, Caroline Nakiguli, OCAKACON SIMON, and Daniel Nimusiima

Journal of Xenobiotics, 2024

Metal fabrication workshops (MFWs) are common businesses in Ugandan cities, and especially those ... more Metal fabrication workshops (MFWs) are common businesses in Ugandan cities, and especially those producing metallic security gates, window and door frames (burglar-proof), and balcony and staircase rails. The objective of this study was to comparatively assess the pollution levels and potential health risks of manganese (Mn), chromium (Cr), cadmium (Cd), lead (Pd) and nickel (Ni) in pooled surface soil samples from four 5-, 7-, 8-, and 10-year-old MFWs (n = 28) and a control site (n = 8) in Mbarara City, Uganda. The concentration of the potentially toxic elements (PTEs) was determined using inductively coupled plasma–optical emission spectrometry. Contamination, ecological, and human health risk assessment indices and models were used to identify any risks that the PTEs could pose to the pristine environment and humans. Our results showed that PTE pollution of soils is occuring in the MFWs than at the control site. The mean concentrations of the PTEs (mg kg−1) in the samples were: Mn (2012.75 ± 0.23–3377.14 ± 0.31), Cr (237.55 ± 0.29–424.93 ± 0.31), Cd (0.73 ± 0.13–1.29 ± 0.02), Pb (107.80 ± 0.23–262.01 ± 0.19), and Ni (74.85 ± 0.25–211.37 ± 0.14). These results indicate that the PTEs could plausibly derive from the fabrication activities in these workshops, which is supported by the high values of contamination factors, index of geoaccumulation, and the overall increase in pollution load indices with the number of years of operation of the MFWs. Human health risk assessment showed that there are non-carcinogenic health risks that could be experienced by children who ingest PTEs in the soils from the 7-, 8- and 10-year-old MFWs. The incremental life cancer risk assessment suggested that there are potential cancerous health effects of Cd and Ni that could be experienced in children (who ingest soils from all the four MFWs) and adults (ingesting soils from the 8- and 10-year-old MFWs). This study underscores the need to implement regulatory guidelines on the operation and location of MFWs in Uganda. Further research should be undertaken to investigate the emission of the PTEs during welding operations in the MFWs.

Urban drainage channels as microplastic pollution hotspots into Lake Victoria, East Africa

by Timothy Omara, OCAKACON SIMON, and kyarimpa christine

DISC2023 – 3rd International Student Conference 5th December 2023, 2023

Microplastics (MPs) are microscopic and ubiquitous emerging organic contaminants with marked pote... more Microplastics (MPs) are microscopic and ubiquitous emerging organic contaminants with marked potential to bind, concentrate and act as carriers of other toxic compounds and pathogenic microorganisms. They have been extensively studied in the marine environment, but reliable data on them in freshwater ecosystems especially in developing countries remains scarce. This study investigated the spatiotemporal distribution, characteristics and sources of MPs in Nakivubo catchment which drains into Lake Victoria, the largest freshwater lake in Africa. Surface water was sampled from thirteen (13) different sites (S1 to S13; n = 117) along Nakivubo catchment during the dry and wet seasons as well as on the onset of the rains in 2022. The samples were digested using hydrogen peroxide, extracted using density separation method and subjected to microscopic and Fourier-transform infrared spectroscopy analyses. The results showed that all the samples had MPs ranging from 1568.59 ± 1473.83 particles/m3 during the dry season to 2140.39 ± 3670.07 particles/m3 during the wet season. The mean output of MPs (microplastic fluxes) from Nakivubo catchment into Lake Victoria was found to be approximately 293.96 million particles/day. The highest mean abundance of MPs (5,466.7 ± 6441.70 particles/m3) was for samples from site S3, which is near market areas, car washing bay and informal settlements. These places are characterized by poor waste management and direct discharge of wastewater into Nakivubo channel. However, the concentration of MPs was relatively lower in wastewater treatment plant effluent (580.56 ± 416.42 particles/m3) than expected possibly due to removal of MPs by Wastewater treatment processes. Filaments (79.7%) and fragments (17.9%) were the most common form of MPs and majorly originated from domestic effluents and surface runoff, while polyethylene (75.4%) and polyethylene-polypropylene (16.0%) were the major polymer types in the sample, explainable by its low density and wide usage in various consumer products. The abundance of MPs (2140.39 particles/m3) was highest during the wet season which could be linked to the lower flow rates of water in the catchment and higher residence times. These data support that MPs remobilization maybe occurring during intense rainfall events in the urban drainage channel of Nakivubo. There is therefore need to institute sustainable plastic waste management practices in the study area to mitigate MPs bioaccumulation, possible trophic transfer and biomagnification in biota and the sedimentary phase of Lake Victoria

Physicochemical and Microbial Quality of Water from the Ugandan Stretch of the Kagera Transboundary River

by Timothy Omara and Daniel Nimusiima

Limnological Review , 2023

Increasing global pollution of water resources undermines the efforts invested in the realisation... more Increasing global pollution of water resources undermines the efforts invested in the realisation of Sustainable Development Goals. In developing countries, for example, water pollution is exacerbated by poor regulatory structures and improper waste disposal. This study, for the first time, investigated the physicochemical and microbial parameters of surface water from the Ugandan stretch of the Kagera transboundary river. Surface water (n = 135) from downstream, midstream and upstream of the river was sampled between February 2021 and June 2021, and analysed following standard methods for the examination of water and wastewater. Further, the samples were analysed using flame atomic absorption spectroscopy for the presence of heavy metals: nickel, lead, chromium, cadmium and copper. The obtained results showed that turbidity (24.77 ± 5.5–43.99 ± 6.87 mg/L), colour (118 ± 8.90–145.2 ± 30.58 Pt-co units), Escherichia coli (4.96 ± 7.01 CFU/100 mL), lead (23.0 ± 11.0–43.0 ± 12.0 µg/L) and cadmium (3.3 ± 1.0–10.1 ± 10.0 µg/L) were at levels that surpassed their permissible limits as per World Health Organization guidelines for potable water. These results are lower than previously reported for the Rwandese stretch of this river, but still present potential health risks to the population whose livelihoods depend on the river. Measures should therefore be instituted by the East African Community member states to mitigate riverine pollution and ensure sustainable use of the Kagera transboundary river.

Bioethanol production from water hyacinth with isolated thermophilic microbial consortium from Kenya

Comptes Rendus Chimie, 2024

Bioethanol production from water hyacinth pretreated thermochemically through boiling in water wi... more Bioethanol production from water hyacinth pretreated thermochemically through boiling in water with or without sodium chlorite, followed by fermentation with a locally isolated thermophilic bacteria consortium in a partially consolidated bioprocessing was investigated. The time yielding the maximum total reducing sugars was 2 hours using 155 mg/g and 113 mg/g of pretreated and untreated water hyacinth samples, respectively. The optimized factors were inoculum dose (8.1%, v/v), temperature (48.8 ℃) and time (52.3 hours) which resulted into 7.2 g/L of predicted bioethanol concentration. In the experimental run, 7.7 g/L of ethanol was produced, which is close to the predicted value.

Thermoacoustic sensor-based system for detection of respiratory diseases in chicken (Gallus domesticus L

by Timothy Omara and Gilbert Gilibrays

Research Square, 2022

Objective Diseases such as avian in uenza, infectious laryngotracheitis and Mycoplasma gallisepti... more Objective Diseases such as avian in uenza, infectious laryngotracheitis and Mycoplasma gallisepticum responsible for huge losses in poultry target the respiratory system of birds. The aim of this study was to design and assemble a system which can be used to detect respiratory diseases among chicken basing on the abnormal vocalization and temperature of chicken. Results The proposed system was assembled and operated in a way that the acoustic and thermal sensors acquire sound and temperature from the chicken environment, sends them to a microcontroller which then interprets the input and in case of abnormal sounds or temperature due to cough or snore, the system administrator and the farmer are noti ed. The results illustrated that the system could be used to improve the detection of respiratory disease outbreaks in chicken, which can potentially minimize losses in poultry farming.

Aflatoxigenic contamination of freshly harvested white maize (Zea mays L.) from some selected Ugandan districts

Peer J preprints, 2019

The moisture content and total aflatoxin (AF) content of 27 samples of freshly harvested white ma... more The moisture content and total aflatoxin (AF) content of 27 samples of freshly harvested white maize (Zea mays L.) from Mubende (n = 3), Ibanda (n = 3), Jinja (n = 3), Mayuge (n = 3) , Buikwe (n = 3), Hoima (n = 3), Mpigi (n = 3), Masindi (n = 3) and Bugiri (n = 3) districts of Uganda representing the agroecological zones: Lake Victoria crescent, Western Highlands, South East and Lake Albert Crescent were determined in the second season harvest of January 2019 to March 2019. Moisture content ranged from 12.9 to 18.8% (mean moisture content varied from 13.9±0.35-17.2±1.55%) with the highest moisture recorded in maize from Ibanda. The highest mean AF contamination of 11.0±3.01 μg/kg was recorded in maize from Hoima while the lowest AF content of 3.8±1.30 μg/kg was recorded in maize from Mpigi. Despite the fact that all the samples had detectable aflatoxins, none of the maize samples had aflatoxin greater than WHO regulatory limit of 20 μg/kg. White maize in Uganda are precontaminated by aflatoxins prior to harvest. Whereas the spectre of aflatoxigenic contamination of foods remains a ticklish challenge to address, strategic adaptation and deployment of appropriate interventions can help secure a safe harvest. Farmers should plant maize varieties with established maturity periods to ensure timely harvesting. Further research should assess the presence of other mycotoxins as zearalenone, sterigmatocystin, ochratoxin A, citrinin, vomitoxin and diacetoxyscirpenol that may co-occur with aflatoxins in freshly harvested maize.

Physicochemical and microbial quality of water from the Ugandan stretch of Kagera transboundary river

by Timothy Omara, Daniel Nimusiima, and Emmanuel Ntambi

Increasing global pollution of water resources undermine the efforts invested in the realization ... more Increasing global pollution of water resources undermine the efforts invested in the realization of Sustainable Development Goals. In developing countries, for example, water pollution is exacerbated by poor regulatory structures and improper waste disposal 1. This study, for the first time, investigated the physicochemical and microbial parameters of surface water from the Ugandan stretch of Kagera transboundary river. Water samples (n = 135) from downstream, midstream and upstream of the river were sampled between February 2021 and June 2021, and analyzed following standard methods for examination of water and wastewater. Further, the samples were analyzed using flame atomic absorption spectroscopy for the presence of heavy metals: nickel, lead, chromium, cadmium and copper. The obtained results showed that temperature (23.38 ± 0.49 to 23.43 ± 0.54 o C), turbidity (24.77 ± 5.5 to 43.99 ± 6.87 mg/L), colour (118 ± 8.90 to 145.2 ± 30.58 Pt-co units), Escherichia coli (4.96 ± 7.01 CFU/100 mL), lead (0.023 ± 0.011 to 0.043 ± 0.012 mg/L) and cadmium (0.0033 ± 0.001 to 0.0101 ± 0.01 mg/L) were at levels that surpassed their permissible limits as per Uganda National Bureau of Standards and WHO guidelines for potable water 2. These results are lower than previously reported for the Rwandese stretch of this river [3,4], but still presents potential health risks to the population whose livelihoods depend on the river. Measures should therefore be instituted by the East African Community member states to mitigate riverine pollution and ensure sustainable use of the Kagera transboundary river.

Assessment of Contamination Levels of Potentially Toxic Elements in the Sediments of an Urban Industrial and Fish Landing Site in Uganda

by Timothy Omara and Patrick Onen

World Environmental & Water Resources Congress 2023, American Society of Civil EngineersAt: Henderson, Nevada, USA; 21st-25th May, 2023, 2023

Globally, aquatic ecosystems are highly polluted with heavy metals (HMs) arising from anthropogen... more Globally, aquatic ecosystems are highly polluted with heavy metals (HMs) arising from anthropogenic and terrigenous sources. The objective of this study was to investigate the heavy metal pollution levels and potential human health risks of the sediments of an urban industrial and fish landing site on Lake Victoria (L. Victoria) in Port Bell, Uganda. Sediment grab samples were collected in triplicate from three points, digested, and analyzed using atomic absorption spectroscopy (AAS) for the presence of copper (Cu), lead (Pb), cadmium (Cd), and chromium (Cr). The average daily dose through dermal contact and hazard quotient (HQ) were calculated to assess the health risks associated with dredging works. Geochemical indices; contamination factor (CF), geochemical accumulation index (Igeo), pollution load index (PLI), and potential ecological risk (PERI) were estimated for the detected hazardous metals. The results showed that the mean HM content of Cu (6.111–7.111 mg/kg) and Pb (40.222–44.212 mg/kg) occurred at the highest concentrations. Pollution load indices showed that the contamination levels are not above the threshold as per the US EPA sediment quality guidelines. However, PERI showed considerable pollution of Port Bell sediment, particularly with Cd since it had reached severe enrichment in the sediments (CF-11.510). The enrichment and contamination factors PLI and Igeo values showed that the sediment in the study area was polluted with Cu, Pb, Cd, and Cr. Though the pollution load indices show that the contamination levels raise no serious concerns, it is recommended that the spatial variations

Bioethanol production from thermochemically-pretreated water hyacinth via partially consolidated bioprocessing with isolated thermophilic microbial consortium from Kenya

rom Laboratory to Industry: Green Chemistry for a Circular EconomyAt: Dnyanprassarak Mandal’s College and Research Centre, Goa University, Assagao, Bardez Goa, India; 18th May 2023, 2023

Bioethanol production from water hyacinth pretreated thermochemically through boiling in water wi... more Bioethanol production from water hyacinth pretreated thermochemically through boiling in water with or without sodium chlorite, followed by fermentation with a locally isolated thermophilic bacteria consortium in a partially consolidated bioprocessing was investigated. The time yielding maximum total reducing sugars was 2 hours using 155 mg/g and 113 mg/g of pretreated and untreated water hyacinth samples, respectively. The optimized factors were inoculum dose (8.1%, v/v), temperature (48.8 ℃) and time (52.3 hours) which resulted into 7.2 g/L of predicted bioethanol concentration. In the experimental run, 7.7 g/L of ethanol was produced, which is close to the predicted value. These results suggest that utilizing sodium chlorite/boiling water (as a pretreatment) and the locally isolated thermophilic bacterial consortium from Kenya (as fermentation microbes) is a promising strategy for utilization and management of the pleustophytic ecological plague (water hyacinth) in Lake Victoria, East Africa

The Future of Ethnopharmacology in East Africa: Some Examples on the Current Status, Challenges and Opportunities

by Timothy Omara and Ambrose KIPROP

21st International Congress of International Society for Ethnopharmacology

The East African Community is a treasure trove of medicinal plants and other natural products tha... more The East African Community is a treasure trove of medicinal plants and other natural products that have traditionally been utilized in the management of various diseases and conditions. This speech highlights some of the progresses, challenges and opportunities for drug discovery from natural products in the East African Community. Marked strides in ethnopharmacology has been (1) increased ethnomedicinal surveys across different ethnic communities in the region, (2) hosting of the Centers of Excellence in Phytochemicals, and Pharmaceutical-Biotechnology and Traditional Medicine, (3) development of a national natural products library, (4) formulation of herbal products such as Covidex, Covilyce and a potential a COVID-19 cure (UBV-01N), (5) formation of Presidential Scientific Initiative on Epidemics (PRESIDE), and (6) strengthening of the regional Natural Products Society: The Natural Products Research Network for Eastern and Central Africa. Collaborations among regional universities, research institutions and with other Universities and laboratories outside the region in natural products research have improved with Makerere University, University of Nairobi, Moi University, Mbarara University of Science and Technology and Kenya Medical Research Institute partnering with University of Potsdam, the Technical University of Berlin, the Neubrandenburg University of Applied Sciences (Germany), and University of Lorraine (France). Whereas regional funding towards ethnopharmacological studies have increased in the 21st century (especially in the crucible of the COVID-19 pandemonium), these are still inadequate given the limited instrumentation and laboratory structures in the region. Ambiguity in ethnomedicinal information captured and the strict regulatory requirements for clinical trials poses additional challenges. This therefore highlights the need for; increased budgetary allocation for research and innovations in natural products, addressing issues surrounding intellectual property rights and benefits sharing, conducting elaborate ethnomedicinal surveys, fostering collaboration between research institutions, governments and researchers to identify and bridge research gaps; enhancing commercialization of research as well as developing a regional natural products library.

Kenyan Antivenin Plants: Ethnobotany and Future Perspectives

International Conference on Phytochemistry, Textiles & Renewable Energy for Sustainable Development. Moi University, Uasin Gishu County, Eldoret, Kenya, 2020

Snake envenomation is one of the neglected tropical diseases which have left an intolerable death... more Snake envenomation is one of the neglected tropical diseases which have left an intolerable death toll and severe socio-economic losses in Kenya. In a continued effort to identify some antiophidic East African botanical species, this study generated ethnobotanical information on antivenin plants reported in Kenya, with a view to identify potential species which could be subjected to in vitro and clinical studies for possible development into antivenoms. Data retrieved through searches done in multidisciplinary databases indicated that 54 plant species belonging to 45 genera, distributed among 27 families are used for management of snakebites in Kenya. Most species belonged to family Asteraceae (11%), Malvaceae (11%), Fabaceae (9%), Annonaceae (6%), Combretaceae (6%) and Lamiaceae (6%). The main growth habit of the species is as herbs (35%), shrubs (33%) and trees (28%). Antivenin preparations are usually from leaves (48%), roots (26%) and stem bark (8%) through decoctions, infusions, powders and juices which are applied topically or administered orally. The most frequently encountered species were Combretum collinum, Euclea divinorum, Fuerstia africana, Grewia fallax, Microglossa pyrifolia, Solanecio mannii and Solanum incanum. Indigenous knowledge on medicinal antivenom therapy in Kenya is humongous, and therefore studies to isolate and evaluate the antivenom compounds in the claimed plants are required to enable their confident use in antivenom therapy alongside commercial antivenin sera.

Chemical composition and insecticidal activity of Pinus caribaea Morelet var. hondurensis needles against Sitophilus zeamais Motschulsky and Callosobruchus maculatus Fabricius

International Conference on Phytochemistry, Textiles & Renewable Energy for Sustainable DevelopmentAt: Moi University, Uasin Gishu County, Eldoret, Kenya, 2020

Plant allelochemicals from essential oils have recently received considerable attention in pharma... more Plant allelochemicals from essential oils have recently received considerable attention in pharmaceutical, cosmetic and agricultural sectors due to their biodegradability and low toxicity. This study analyzed the chemical composition of essential oils of Pinus caribaea Morelet var. hondurensis needles. Thirty-nine (39) organic compounds were identified using gas chromatography/mass chromatography and gas chromatography, and the most abundant components were limonene (38.6%), α-pinene (27.6%), borneol (6.7%) and myrcene (3.5%). Aristolene, ledol and guaiol were reported for the first time in P. caribeae needles. The chemical composition of the needles was dominated by monoterpene hydrocarbons (77.2%) followed by oxygenated monoterpenes (12.0%), sesquiterpene hydrocarbons (4.7%) and then lastly oxygenated sesquiterpenes (1.7%). In fumigant toxicity, the highest concentration of 8 µL/ml recorded 100% mortality of C. maculatus after 2 hours of exposure and 5 hrs for S. zeamais. The LC50 were 6.3 and 5.2 µL/ml for maize and bean weevils.

PHYTOCHEMICAL COMPOSITION, ANTIOXIDANT AND ANTIBACTERIAL ACTIVITIES OF Albizia coriaria LEAVES FROM THREE AGROECOLOGICAL ZONES OF UGANDA TIMOTHY OMARA

Moi University, 2021

Oxidative stress-induced conditions and bacterial diseases constitute some of the major causes of... more Oxidative stress-induced conditions and bacterial diseases constitute some of the major causes of mortality worldwide. Their treatment is becoming a challenge due to antimicrobial resistance, prohibitive costs, inaccessibility and side effects of the conventional drugs. Thus, traditional medicine is becoming popular in the treatment of these diseases in various parts of the world. The objectives of this study were to;(1) identify the secondary metabolites in extracts of Albizia coriaria leaves (EOACL), (2) determine the total phenolic and total flavonoid contents of EOACL, (3) establish the antioxidant activity of EOACL, (4) evaluate the antibacterial activity of EOACL, and (5) characterize the phytochemicals in the most active EOACL used in traditional treatment of oxidative stress-induced conditions and bacterial diseases in Uganda. The leaves were sampled from Jinja, Kole and Mbarara districts of Uganda, representing the South East, Mid Northern and Southern drylands agroecological zones, respectively. Shade-dried samples were ground into powder and successively extracted with ethyl acetate, ethanol and distilled water. The extracts were chemically profiled using classical phytochemical screening, ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy and gas chromatography-mass spectrometry (GC-MS). The total phenolic content, total flavonoid content, antioxidant and antibacterial activities were determined using; Folin-Ciocalteu method, aluminum chloride assay, 1,1-diphenyl-2-picrylhydrazyl assay and culture-based agar disc diffusion method, respectively. The results obtained varied for the three agroecological zones; Mbarara leaf extracts had many secondary metabolites and exhibited the highest bioactivities, followed by Kole and Jinja extracts. Phytochemical screening results indicated that phenols, alkaloids, saponins, flavonoids, cardiac glycosides and tannins were the major secondary metabolites in EOACL. These results were confirmed by UV-Vis spectra (with absorption maxima of 338 nm, 470 nm, 534 nm, 607 nm and 664 nm) and FTIR spectra which indicated the presence of O-H stretch (3370.27 cm-1), C=O (1739.70 cm-1), N-H (3261.46 cm-1) and aromatic-C=C (1454.48 cm-1). Total phenolic and flavonoid contents, and antioxidant activity were found to be highest for ethanolic extracts, with the highest contents (101.72 ± 0.22 mg GAE/ g DW and 13.23 ± 0.03 mg QE/ g DW) and antioxidant potential (IC50 = 18.65 ± 0.06 mg/mL) being for EOACL from Mbarara district. The high antioxidant potential of EOACL suggests their potential role in the prevention of oxidative stress-induced conditions. Antibacterial screening indicated that ethanolic extracts had the highest antibacterial activities with mean zones of inhibition of 6.00 ± 1.73 to 10.00 ± 1.73 mm, 5.00 ± 1.00 to 12.30 ± 1.53 mm, 17.00 ± 0.00 to 25.00 ± 2.65 mm and 9.00 ± 1.73 to 16.00 ± 1.73 mm for Escherichia coli (E. coli), Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi, respectively. Ethyl acetate EOACL from Kole and Mbarara were active against E. coli with inhibition zones of 3.00 ± 0.00 mm and 4.00 ± 2.00 mm respectively. Ethyl acetate EOACL from Jinja and all the aqueous extracts showed no antibacterial activity. Characterization of fractions of the most active (ethanolic) EOACL using GC-MS led to the identification of nine compounds: lupeol (7), lupenone (8), betulinic acid (9), benzyl alcohol (12), betulin (13), oleanolic acid (14), oleanolic acid acetate (15), undecanol (16) and pterin-6-carboxylic acid (17) of which compounds 13-17 are being reported for the first time in Albizia coriaria. In conclusion, EOACL were established to have compounds with antioxidant and antibacterial activities, giving credence to their use in traditional management of oxidative stress-induced conditions and bacterial diseases. Clinical trials using the active EOACL and the identified compounds should be done.

Chemical composition and insecticidal activity of Pinus caribaea Morelet var. hondurensis needles against Sitophilus zeamais Motschulsky and Callosobruchus maculatus Fabricius

Advances in Phytochemistry, Textile and Renewable Energy Research for Industrial Growth – Nzila et al. (Eds), 2022

Plant allelochemicals from essential oils have recently received considerable attention in pharma... more Plant allelochemicals from essential oils have recently received considerable attention in pharmaceutical, cosmetic and agricultural sectors due to their biodegradability and low toxicity. This study analyzed
the chemical composition and bioinsecticidal activity of essential oils of Pinus caribaea Morelet var. hondurensis needles. Thirty-nine (39) organic compounds were identified using gas chromatography/mass chromatography and gas chromatography, and the most abundant components were limonene (38.6%), α-pinene (27.6%), borneol
(6.7%) and myrcene (3.5%). The chemical composition of the needles was dominated by monoterpene hydrocarbons (77.2%) followed by oxygenated monoterpenes (12.0%), sesquiterpene hydrocarbons (4.7%)
and then lastly oxygenated sesquiterpenes (1.7%). In fumigant toxicity, 100% mortality was recorded at 10 μL/ml for bean weevils after 2 hours of exposure whereas the same concentration caused 100% mortality
of maize weevils after 5 hours of exposure. In repellency bioassay using aliquots of acetonic essential oils, 100% repellence was recorded in bean weevils after 60 minutes of exposure while the same concentration
(8 μL/ml) gave 100% repellence activity in maize weevils after 150 minutes. The essential oils showed higher insecticidal activity against bean weevils than maize weevils. Based on the results of this study, pine
needles could be a suitable source of green insecticides for control of maize and bean weevils in stored food products.