Browsing by Author "Ndakala, Albert"

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    Antiplasmodial Compounds from Millettia Dura
    (Kabale University Interdisciplinary Research Journal, 2022) Buyinza, Daniel; Derese, Solomon; Ndakala, Albert
    Malaria still poses a big challenge to the health care of many tropical countries. The plasmodium resistance to the conventional drugs is the major hitch in its treatment. Higher plants have produced single line antimalarials and given important lead molecules. On this basis, flavonoids isolated from millettia dura by chromatographic techniques were screened againest W2 and D6 strains of plasmoduim falcipalum. Both, the crude and pure compounds tested showed mild activities against the test organisms. The crude extract of the stem bark had the highest respective activity of 63.7±8.6 and 46.1±4.5 μg/ml against W2 and D6. Of the pure compounds, milletosin was active towards both W2 and D6 with a respective IC50s of 87.9±8.9 and 66.70±30.3 μg/ml. Synergistic effect might have contributed to the relative high activity of the crude than the pure compounds. Basing on the structure activity relationship of the tested compounds, suitable structural modification could be ideal to enhance the antiplasmodial activity.
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    A Coumestan and a Coumaronochromone from Millettia Lasiantha
    (Biochemical Systematics and Ecology, 2021) Buyinza, Daniel; Derese, Solomon; Ndakala, Albert; Yenesew, Abiy; Koch, Andreas; Oriko, Richard
    The manuscript describes the phytochemical investigation of the roots, leaves and stem bark of Millettia lasiantha resulting in the isolation of twelve compounds including two new isomeric isoflavones lascoumestan and lascoumaronochromone. The structures of the new compounds were determined using different spectroscopic techniques.
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    Cytotoxicity of Isoflavones from Millettia Dura
    (Natural Product Research, 2021) Buyinza, Daniel; Yang, Li Jun; Derese, Solomon; Ndakala, Albert; Wong, Vincent Kam Wai; Möller, Heiko M.; Yenesew, Abiy
    The first phytochemical investigation of the flowers of Millettia dura resulted in the isolation of seven isoflavones, a flavonol and a chalcone. Eleven isoflavones and a flavonol isolated from various plant parts from this plant were tested for cytotoxicity against a panel of cell lines, and six of these showed good activity with IC50 values of 6-14 μM. Durmillone was the most active with IC50 values of 6.6 μM against A549 adenocarcinomic human alveolar basal epithelial cancer cell line with low cytotoxicity against the non-cancerous cell lines BEAS-2B (IC50 = 58.4 μM), LO2 hepatocytes (IC50 78.7 μM) and CCD19Lu fibroblasts (IC50 >100 μM).
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    Flavonoids and Isoflavonoids of Millettia dura and Millettia ferruginea: Phytochemical review and chemotaxonomic value
    (Biochemical Systematics and Ecology, 2020) Buyinza, Daniel; Chalo, Duncan Mutiso; Derese, Solomon; Ndakala, Albert; Yenese, Abiy
    The phytochemical information on Millettia dura Dunn, M. ferruginea (Hochst.) Baker and M. ferruginea subsp. darassana (Cufod.) J.B. Gillett was reviewed. All the three taxa elaborate mainly isoflavones (33 reported), occurring in the flowers, seeds/seed pods, stem bark and root bark. Out of the 33 isoflavones reported, some 19 (ca. 58%) contain prenyl at C-8 or its modification as 2,2-dimethylchromene ring at C-7/C-8, occurring in all the three taxa. Except for three isoflavones isolated from M. ferruginea subsp. darassana, all the isoflavones of these taxa are 5-deoxygenated. In these taxa, oxygenation at C-6 is a common feature, while isoflavones with C-8 oxygenation are rare, only three reported, and all of these from M. dura. There are 7 rotenoids reported from these taxa, and occur almost entirely in the seeds/seedpods of these plants. The major rotenoid with methylenedioxy group at C-2/C-3, millettone and its 12a-hydroxy derivative, millettosine, occur only in M. dura, this appears to distinguish M. dura from M. ferruginea.
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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.