ACL-4, an Endophytic Fungus Isolated from Ageratum conyzoides Leaves Possesses the Unique Potential of Generating Low Molecular Weight Bioactive Lead Compounds . http://www.doi.org/10.26538/tjnpr/v6i12.24

Abstract

Over the years, endophytic fungi have generated novel bioactive lead molecules for drug development. A detailed chemical investigation of ACL-4, an endophytic fungus previously isolated from Ageratum conyzoides, led to the isolation of eight low molecular weight bioactive secondary metabolites. The metabolites generated by the axenic fungus, when grown on rice medium using solid fermentation, were extracted using ethyl acetate. Further chromatographic separation of the crude extract led to the isolation of compounds 1-8. The chemical structures of these compounds were determined using a combination of HPLC-DAD, and NMR analyses. The fractions from which the compounds were isolated were also subjected to antimicrobial screening using Agar well dilution techniques. The chemical structures of the compounds were elucidated as 2-hydroxy-6- (1'-hydroxyethyl) benzoic acid (1), 2-(4'-hydroxyphenyl) ethanol (2), 4-hydroxybenzoic acid (3), 2-(4'-methylphenyl) ethanol (4), 3-methoxy-4-hydroxybenzoic acid (5), epiguaymasol (6), 2- {4'- (4''hydroxyphenyl) methylphenyl) ethanol (7), and protocatechuic acid (8). The tested fractions displayed varying degrees of antimicrobial activity, with MICs ranging from 0.125 – 0.5 mg/mL. The antimicrobial activities shown by the fungal extract and fractions may be as a result of the presence of some of these compounds, which have been previously reported as antimicrobial agents.