Antimicrobial compounds from the Kenyan Ganoderma adspersum (Schulz.) Donk species

Abstract

The emergence of antibiotic resistant pathogens has continuously increased, leading to a growing worldwide health threat due to infectious diseases. And therefore in our search for antibacterial and antifungal compounds from the polypore Ganoderma adspersum, the dried, ground fruiting bodies of G. adspersum 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. Compound (1), ergosta-7,22-dien-3-one weakly inhibited the growth of Gram positive bacteria Streptococcus pneumonia and a fungus Cryptococcus neoformans. Compounds ergosta-7,22-dien-3-ol (2) and ergosta-5,7,22-trien-3-ol (3) also inhibited gram positive Streptococcus pyogenes bacteria.

Keywords: Polypores, steroid compounds, antimicrobial activity.