Browsing by Author "Owor, Richard Oriko"

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    Acute and subacute toxicity profile of ethanolic stem bark extract of Albizia coriaria Welw. ex Oliv. in Wistar albino rats Author links open overlay panel
    (Elsevier Ltd, 2024-06) Obakiro, Samuel Baker; Kiyimba, Kenedy; Owor, Richard Oriko; Andima, Moses; Lukwago, Tonny Wotoyitide; Kawuma, Carol; Gavamukulya, Yahaya; Nabatanzi, Alice; Kibuule, Dan; Kato, Charles Drago; Anywar, Godwin; Waako, Paul
    Abstract Albizia coriaria (Fabaceae) crude extracts are key ingredients of several licensed and unlicensed herbal products in East Africa. However, there is limited and often contradicting information regarding its toxicity. We therefore evaluated the acute and subacute toxicity of the ethanolic stem bark extract of A. coriaria in mature healthy Wistar albino rats following Lorke’s method and OECD guidelines 407. The LD 50 of the ethanolic stem bark extract of A. coriaria was 2000 mg/kg. The acute toxicity signs observed included piloerection, hyperventilation, lethargy, and loss of righting reflex. There was a significant increase in aspartate aminotransferase, alkaline phosphatase, red blood cells and haemoglobin in rats after 28 days at the dose of 500 mg/kg. Histological analyses revealed multifocal random parenchymal necrosis and scattered periportal mononuclear inflammatory cells infiltration in the liver, interstitial nephritis in the kidney and multifocal lymphoid accumulation in the peribronchiolar and perivascular lung tissue at 500 mg/kg. The ethanolic stem bark of A. coriaria was therefore moderately toxic to the rats when administered in a single high oral dose within 24 h. The extract caused a dose dependent toxicity with significant damage to the kidney, liver and lung tissues at a dose of 500 mg/kg after 28 days. Herbal medicines containing A. coriaria extracts should be consumed cautiously due to likelihood of toxicity particularly at higher doses greater than 500 mg/kg. ga1 • This study assesed the acute and subacute toxicity effects of the ethanolic stem bark extract of A. coriaria, a key ingredient of several licensed and unlicensed herbal products on Uganda market. • The ethanolic stem bark extract of A. coriaria was found to be moderately toxic when administered in a single high oral dose within 24 h with a median lethal dose of 2000 mg/kg. • In repeated daily doses of 500 mg/kg, the ethanolic stem bark extract of A. coriaria caused significant toxicity to the lungs, liver and kidney tissues. • Herbal medicines containing A. coriaria extracts should be consumed cautiously due to likelihood of associated toxicity particularly at higher doses greater 500 mg/kg.
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    Ethnobotanical survey and phytochemistry of medicinal plants used in the management of HIV/AIDS in Eastern Uganda
    (Elsevier Ltd, 2024-06) Owor, Richard Oriko; Kawuma, Carol; Nantale, Gauden; Kiyimba, Kenedy; Obakiro, Samuel Baker; Ouma, Simple; Lulenzi, Jalia; Gavamukulya, Yahaya; Chebijira, Mercy; Lukwago, Tonny Wotoyitide; Egor, Moses; Musagala, Peter; Andima, Moses; Kibuule, Dan; Waako, Paul; Hokello, Joseph
    Currently, highly active antiretroviral therapy is unable to cure HIV/AIDS because of HIV latency. This study aimed at documenting medicinal plants used in the management of HIV/AIDS in Eastern Uganda so as to identify phytochemicals with HIV latency reversing potential. An ethnobotanical survey was conducted across eight districts in Eastern Uganda. Traditional medicine practitioners were interviewed using semi-structured questionnaires. Qualitative and quantitative phytochemical tests were respectively, performed to determine the presence and quantity of phytochemicals in frequently mentioned plant species. Data were analysed and presented using descriptive statistics and Informant Consensus Factor (ICF). Twenty-one plant species from fourteen plant families were reported to be used in the management of HIV/AIDS. Six plant species with the highest frequency of mention were: Zanthoxylum chalybeum, Gymnosporia senegalensis, Warbugia ugandensis, Leonatis nepetifolia, Croton macrostachyus and Rhoicissus tridentata. Qualitative phytochemical analysis of all the six most frequently mentioned plant species revealed the presence of flavonoids, tannins, terpenoids, alkaloids and phenolics. Quantitative analysis revealed the highest content of flavonoids in L. nepetifolia (20.4 mg/g of dry extract) while the lowest content was determined in C. macrostachyus (7.1 mg/g of dry extract). On the other hand, the highest content of tannins was observed in L. nepetifolia. (199.9 mg/g of dry extract) while the lowest content was found in R. tridentata. (42.6 mg/g of dry extract). Medicinal plants used by traditional medicine practitioners in Eastern Uganda to manage HIV/AIDS are rich in phytochemicals including flavonoids and tannins. Further studies to evaluate the HIV-1 latency reversing ability of these phytochemicals are recommended to discover novel molecules against HIV/AIDS.
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    Synergistic anti-inflammatory activities of a new flavone and other flavonoids from Tephrosia hildebrandtii vatke
    (Natural Product Research, 2021) Owor, Richard Oriko; Bedane, Kibrom Gebreheiwot; Openda, Yolande Ikala; Z€uhlke, Sebastian; Derese, Solomon; Ong’amo, George; Ndakala, Albert; Spiteller, Michael
    A new flavone, named hildeflavone (1) along with 7 other known flavonoids were isolated from the aerial parts of Tephrosia hildebrandtii Vatke. Their characterisation was based on NMR and MS data analysis. The anti-inflammatory properties of the crude extract, isolated compounds and combination of the compounds were investigated in lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMCs). Treatment of the LPS-stimulated PBMCs with the isolated flavonoids at a concentration of 100 µM significantly reduced the production of interleukins (IL-1β, IL-2 and IL-6), interferon-gamma (IFN-γ), granulocyte macrophage-colony stimulating factor (GM-CSF) and tumour necrosis factor-alpha (TNF-α). It was also found that the combination of a flavone and flavanones exhibited remarkable synergistic anti-inflammatory effects on the production of the cytokines.