Browsing by Author "Owor, Richard Oriko"

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    Antibiotic susceptibility of zoonotic bacteria isolated from oral cavities of indigenous dogs from semi-urban areas in Uganda.
    (Wiley, 2024) Mukasa, Paul; Ogwang, Patrick Engeu; Owor, Richard Oriko; Lejju, Julius B.; Gumisiriza, Hannington; Ntulume, Ibrahim; Adaku, Christopher
    Dog bites are a source of zoonotic infections to humans, such as pasteurellosis and meningitis. Zoonotic bacterial identification and their antibiotic susceptibility assessment are key towards the successful management of such infections. This study isolated and identified zoonotic bacterial species from the oral cavities of indigenous dogs and also determined their antibiotic susceptibility profile. Oral swab samples collected from 54 indigenous dogs (domestic [36] and stray [18]) were cultured on agar media, and then on selective-differential media. The colony morphology and conventional biochemical tests were used to identify the bacterial isolates. Antibiotic susceptibility was evaluated using the Kirby–Bauer disk diffusion method. A total of 232 bacterial isolates were obtained, from which 29 bacteria species (18 Gram-negative and 11 Gram-positive) belonging to 19 genera and 13 families were identified. Aerobic and anaerobic bacteria species constituted 69% and 31%, respectively. The most prevalent bacteria species was Staphylococcus aureus (10.8%) followed by Escherichia coli (9.5%), while Yersinia enterocolitica (0.4%) was the least common. Most bacteria species belonged to family Enterobacteriaceae (11) followed by Vibrionaceae (04). All the sampled dogs had a number of multi drug–resistant superbugs in their oral cavities. However, all the tested bacterial isolates were only susceptible to imipenem and chloramphenicol. All the identified bacteria species were resistant to metronidazole, amoxicillinclavulanic acid and ceftazidime. Therefore, antibiotics such as imipenem and chloramphenicol could be of better choice for managing dog bite infections compared to the antibiotics recommended by Uganda Clinical Guidelines, such as metronidazole and amoxicillin-clavulanic acid. Keywords: dog bites | oral cavities | susceptibility | zoonotic bacteria
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    In vitro antiplasmodial activity, acute toxicity and phytochemical quantification of selected medicinal plants used for the management of uncomplicated malaria in eastern Uganda.
    (Elsevier Ltd., 2025) Obakiro, Samuel Baker; Nabitandikwa, Catherine; Kiyimba, Kenedy; Ocan, Moses; Gavamukulya, Yahaya; Andima, Moses; Lukwago, Tonny Wotoyitide; Maseruka, Richard; Chebijira, Mercy; Opio, Moses; Hokello, Joseph Francis; Kibuule, Dan; Nabatanzi, Alice; Orena, Stephen; Waako, Paul; Owor, Richard Oriko
    Ethnopharmacological relevance The emergence of artemisinin resistance and limited antimalarial drug access in Uganda has increased reliance on herbal medicines as complementary and alternative therapies. Indigenous use of Albizia coriaria, Zanthoxylum chalybeum, Entada abyssinica, Maytenus senegalensis, and Kigelia Africana for malaria treatment is widespread but scientific evidence of their efficacy and safety was limited. Aim of the study This study aimed to validate the traditional antimalarial use of the five medicinal plants by evaluating their phytochemical composition, acute toxicity, and in vitro antiplasmodial activity against chloroquine-sensitive (3D7), chloroquine-resistant (Dd2) and clinical P. falciparum isolates. Materials and methods Phytochemical screening and quantification was conducted on 70 % hydroethanolic extracts from dried plant samples using UV–Vis spectrophotometry. The acute oral toxicity testing was conducted in Wistar albino rats using OECD 423 limit dose test. The antiplasmodial efficacy was evaluated using a 72-h SYBR Green assay on Plasmodium falciparum laboratory strains (3D7, Dd2) and clinical isolates. Results Alkaloids, flavonoids, tannins, and terpenoids were present in all the plant samples in varying quantities. Z. chalybeum was the most potent extract (IC50 0.81–1.28 μg/ml), followed by A. coriaria and E. abyssinica (IC50 10–50 μg/ml). M. senegalensis showed weak activity while K. africana was largely inactive (IC50 > 100 μg/ml). A. coriaria and M. senegalensis showed moderate acute toxicity (LD50 < 2000 mg/kg), while the other extracts showed no severe signs of acute toxicity in Wistar albino rats (LD50 > 2000 mg/kg). Conclusion Zanthoxylum chalybeum, Albizia coriaria and Entada abyssinica demonstrated promising antiplasmodial activity that supports their traditional use in management of malaria. However, more efficacy studies using in vivo models, sub-chronic and chronic toxicity studies particularly on A. coriaria and advanced phytochemical profiling are needed to delineate their therapeutic potential before being prioritized for development of standardized herbal remedies and novel antimalarial drugs.
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    Phytochemical profile, antibacterial activity and acute toxicity of rhoicissus tridentata used to manage dog bites.
    (Elsevier Ltd., 2025) Mukasa, Paul; Ogwang, Patrick Engeu; Adaku, Christopher; Andima, Moses; Obakiro, Samuel Baker; Lejju, Julius Bunny; Ntulume, Ibrahim; Byamugisha, Denis; Ntambi, Emmanuel; Ren, Yuhao; Owor, Richard Oriko
    Dog bites often result into polymicrobial wound contamination, which pose several health risks including bacterial infections. In Uganda, Rhoicissus tridentata is traditionally used to manage dog bites, yet its secondary metabolite profile, antibacterial efficacy, and in-vivo toxicity had remained unexplored. Thus, the metabolites and the scientific evidence to validate the antibacterial activity and safety of the plant was limited. Identification of potent antibacterial agents could be crucial to manage dog-bite-related bacterial infections. The root extracts were analyzed using UHPLC–HRMS/MS—qTOF, followed by MZmine processing, and the metabolites characterized with GNPS Feature-Based Molecular Networking. For the first time, the high-resolution metabolomic approach resulted into annotation of 15 bioactive polyphenols like flavonoids, tannins. The antibacterial activity of the extracts was evaluated against standard strains of the zoonotic oral bacteria commonly associated with dog bites, namely: Enterococcus faecalis (ATCC 29,212), Streptococcus aureus (ATCC 25,932), Streptococcus mutans (ATCC 25,175), Proteus mirabilis (ATCC 25,933), Klebsiella pneumoniae (ATCC 700,603), and Escherichia coli (ATCC 25,922). The extracts exhibited moderate antibacterial activity against all the strains. The MIC and MBC ranged from (0.78 to 6.25) and (1.56 to 12.5) mg/mL respectively. The MBC/MIC ratios were between 1.9 and 2, signifying bactericidal extracts. In vivo acute toxicity testing, the extract showed no adverse signs of toxicity at doses up to 5000 mg/kg (LD50 > 5000 mg/kg), suggesting a favorable safety margin. These findings support the ethnopharmacological use of R. tridentata in managing dog bite-related bacterial infections and merit further investigations on its bioactive constituents identified for future antibacterial discovery Keywords: Rhoicissus tridentata, Phytochemicals, Antibacterial compounds, Toxicity
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    Unraveling the therapeutic potential of tephrosia linearis : anti-inflammatory, analgesic activity, and molecular docking approaches.
    (Elsevier Ltd, 2025) Opio, Moses; Kiyimba, Kenedy; Nabitandikwa, Catherine; Maseruka, Richard; Wotoyitidde, Tony Lukwago; Andima, Moses; Chebijira, Mercy; Edeya, Sharon Tracy; Nabatanzi, Alice; Gavamukulya, Yahaya; Kibuule, Dan; Waako, Paul; Owor, Richard Oriko; Obakiro, Samuel Baker
    Background Inflammatory diseases such as arthritis affect over 300 million people globally. The current treatment mainly involves the use of Non-Steroidal Anti-inflammatory drugs (NSAIDS) which possess several adverse drug reactions that are sometimes life threatening. This has prompted many patients to gain interest in plant-based remedies. Tephrosia linearis (Willd.) Pers (Fabaceae) is widely used in Uganda to manage symptoms of inflammation. However, there was a paucity of information concerning its analgesic and anti-inflammatory activities. This study investigated the anti-inflammatory, analgesic, and acute toxicity effects of ethanolic extracts from the aerial parts of Tephrosia linearis in Wistar albino rats. Methods Plant samples were collected from Katakwi District, Eastern Uganda and extracted using 70 % ethanol. Quantitative phytochemical analysis was conducted using UV/Vis spectroscopy. Acute toxicity was assessed using Lorke’s method, while analgesic and anti-inflammatory activities were evaluated through Complete Freud’s Adjuvant-induced arthritis model. Three doses of T. linearis (200, 400, and 800 mg/kg) were compared with a control group receiving 20 mg/kg of diclofenac. Three marker compounds were assessed using in silico modeling to predict their pharmacokinetic properties, organ toxicity, and binding energy against selected protein targets involved in inflammation. Results The ethanolic extract contained significant concentrations of flavonoids (82.9 ± 0.1 mg/g), tannins (140.2 ± 0.9 mg/g), alkaloids (93.4 ± 1.0 mg/g), and triterpenoids (76.1 ± 1.5 mg/g). No toxic effects were observed at doses below 2000 mg/kg, with an estimated LD50 of 2692 mg/kg. The extract exhibited a non-dose dependent analgesic and anti-inflammatory activities that were significantly lower than that of diclofenac (p < 0.05). Molecular docking revealed strong binding affinities for apigenin, luteolin, and velutin with COX2, PLA2, and TNFα. Conclusion This study supports T. linearis as a safe herbal remedy for managing inflammation, suggesting further optimization through active ingredient isolation for enhanced therapeutic outcomes.