Chemical compounds from the Kenyan polypore <i>Trametes elegans</i> (Spreng:Fr.) Fr (Polyporaceae) and their antimicrobial activity

Abstract

Over the years, natural products have been used by humans in tackling infectious bacteria and fungi. Higher fungi have potential of containing natural product agents for various diseases. The aim of the study was to characterise the antimicrobial compounds from the polypore Trametes elegans. The dried, ground fruiting bodies of T. elegans were extracted with methanol and solvent removed in a rotary evaporator. The extract was suspended in distilled water, then partitioned using ethyl acetate solvent to obtain an ethyl acetate extract. The extract was fractionated and purified using column chromatographic method and further purification on sephadex LH20. The chemical structures were determined on the basis of NMR spectroscopic data from ¹H and ¹³C NMR, HSQC, HMBC, ¹H-¹H COSY, and NOESY experiments. Antimicrobial activity against clinically important bacterial and fungal strains was assessed and zones of inhibition were recorded. The polypore yielded six known compounds namely ergosta-5,7,22 trien-3-ol (1) 5α,8α–epidioxyergosta-6,9(11),22-trien-3β-ol (2), 5α,8α–epidioxyergosta-6,22-dien-3β-ol (3), ergosta-7,22-dien-3β,5α,6β-triol (4), Lupeol (5) and 9,19-cycloartane-3,30-diol (6). From this study, the isolated compounds of T. elegans displayed varying antimicrobial activities with zones of inhibition ranging from 8.0 0.58 to 9.7 0.33 mm at (p≤0.05). Thus, Trametes elegans, could be considered as a potential source of natural antimicrobials.

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Keywords: Higher fungi, triterpenoids, disc diffusion assay