Browsing by Author "Koki, Mkhuseli"

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    Characterization of new pyrone-containing flavones from Helichrysum petiolare Hilliard & B.L. Burtt
    (Elsevier B.V., 2025) Makhaba, Masixole; Yalo, Masande; Koki, Mkhuseli; Nako, Ndikho; Mabusela, Wilfred T.; Pearce, Keenau; Benjeddou, Mongi
    Helichrysum petiolare Hilliard & B.L. Burtt. (Asteraceae), native to the Cape Floral Region of South Africa, is traditionally used in the management of wounds, respiratory complaints, and diabetes. Although extensive studies on its extracts, few have focused on the bioactivity of the individual phytochemicals. In this study, chromatographic processing of the H. petiolare leaf total extract led to the isolation and identification of ten compounds C1–C10) using NMR, FTIR, and HRESIMS spectroscopy. Two pyrone-containing flavones (C1 and C2) are reported for the first time from natural sources. The known compounds identified included flavonoids (C3–C5), phenolics (C6–C9), and a sterol (C10). The MTT assay revealed dose-dependent cytotoxicity of C1–C4 only against MDA-MB-231 (breast cancer), HeLa (cervical cancer), and HEK-293 (non-cancerous kidney) cell lines after 24 h exposure. Notably, C4 demonstrated selective activity toward HeLa cells (45 % viability reduction at 100 µM; IC₅₀ = 89.19 µg/mL). This is the first report of compounds C1–C10 from H. petiolare and their in vitro cytotoxic profile. Despite moderate activity, this work provides a foundation for further pharmacological investigations of derivatives of these metabolites in cancer management.
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    Isolation and characterization of natural products from selected Rhus species
    (University of Western Cape, 2020) Koki, Mkhuseli; Mabusela, T.W
    Searsia is the more recent name for the genus (Rhus) that contains over 250 individual species of flowering plants in the family Anacardiaceae. Research conducted on Searsia extracts to date indicates a promising potential for this plant group to provide renewable bioproducts with the following reported desirable bioactivities; antimicrobial, antifungal, antiviral, antimalarial, antioxidant, antifibrogenic, anti-inflammatory, antimutagenic, antithrombin, antitumorigenic, cytotoxic, hypoglycaemic, and leukopenic (Rayne and Mazza, 2007, Salimi et al., 2015). Searsia glauca, Searsia lucida and Searsia laevigata were selected for this study. The aim of this study was to isolate, elucidate and evaluate the biological activity of natural products occurring in the plants selected.