Prospecting for Antibacterial Compounds from A Basidiomycete JO5191

Abstract

The need for new antibacterial compounds with different modes of action to manage drug-resistant bacterial strains is urgent. The molecular basis of most antimicrobial agents is now fairly well known and thus it is now possible to develop new compounds with improved antimicrobial properties. lliougli there are several drug targets that have been idcntiticd and upon which most antil>actc|'ial agents act. there is still great need and potential to prospect from novel sources for new drug candidates. liasidioinycctes have proved to be cwellcnt producers of secondary metabolites \\‘llll vast activities. Picliniinaiy scicemiig of nude extracts from a basidiomyccte .IO5l9l, revealed strong antibacterial activity against two Urani-negative bacteria: /;'.\'1'/11'1"/1'/rm ¢‘n// and .S'rlln/um’/lu !4i'/r/Iinzu/"Imn. lhls resealcli piojettt involved the purification of the compounds using column chromatography and semi preparative lll’LC followed by structure elucidation of the compounds responsible for the observed antibacterial activity. The fungus was cultivated in 25 replicates of I litre~scale in nutrient liquid media for 22 days and crude extracts prepared from both the myccliuin and the culture filtrate immediately allcr stopping growth. The crude extracts were screened for anti- bacterial activity and the compounds purified by bioassay-guided fractionation on silica gel and reverse phase high-pressure liquid chromatography. The chemical structures of the purified compound(s) were detennined using spectroscopic techniques: infrared (IR), nuclear magnetic resonance (NMR) in conjunction Willi MS and CD and found to be flavanones. The antibacterial activities were detennined by the calculation of minimum inhibitory concentrations (MIC), which were found to be in the range 3ig/ml - l2tg/ml. agreeing considerably well with those from the literature. -