Chemical investigation of the diethyl ether extract of the stem bark of Khaya ivorensis A Chev (Meliaceae) afforded ten limonoids of angolensates, ring D-opened limonoids and mexicanolides. The structures of the limonoids isolated were determined by comparison of their (1)H and (13)C NMR data with those reported in the literature. These compounds were evaluated for their antifungal activity against the plant pathogenic fungus Botrytis cinerea Pers. Methyl 6-hydroxyangolensate and 3,7-dideacetylkhivorin were also tested for their antifungal and antibacterial activities on several fungal and bacterial species. Methyl angolensate and 1,3,7-trideacetylkhivorin displayed the highest antifungal activity against B. cinerea, with respectively 62.8 and 64.0% mycelial growth inhibition at 1000 mg litre(-1), and 73.3 and 68.6% mycelial growth inhibition at 1500 mg litre(-1). 3,7-Dideacetylkhivorin showed stronger antifungal and antibacterial activities than methyl 6-hydroxyangolensate against all of the test fungi and bacteria except Penicillium expansum Link. This is the first report on the antifungal and antibacterial effects of these limonoids. Structure-antifungal activity relationships of the limonoids isolated are discussed.

Abstract:The fresh green and yellow banana peel of, (Musa, cv. Cavendish) fruits were treated with 70% acetone, which were partitioned with chloroform (CHCl 3 ) and ethyl acetate (EtOAc), sequentially. The antioxidant activities of the extracts were evaluated by using the thiocyanate method, ß-carotene bleaching method and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical elimination. While, antimicrobial activities of the extracts and isolated components were evaluated using paper disc methods and Minimum Inhibition Concentration (MIC). The EtOAc and water soluble fractions of green peel displayed high antimicrobial and antioxidant activity, respectively. Antioxidant activity of water extracts was comparable to those of synthetic antioxidants such as butylated hydroxyanisole and butylated hydroxytoluene. Among all isolated components ß-sitosterol, malic acid, succinic acid, palmatic acid, 12-hydroxystrearic acid, glycoside, the d-malic and 12-hydroxystrearic acid were the most active against all the Gram-negative and positive bacterial species tested. The MIC of d-malic and succinic acid was varying between 140-750 ppm, respectively.

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