Bioactive natural products from traditional Indonesian medicinal plant-associated fungi

The rapid emergence of antibiotic-resistant pathogens has driven the discovery of new drug leads from natural sources, particularly rarely encountered microorganisms. Traditional medicinal plants have long been investigated as sources of bioactive molecules, many of which are polyketides or peptides. It is established that natural products from these structure classes are biosynthesised by microorganisms, therefore we hypothesise that many of these bioactive molecules originally isolated from plants are in fact microbial products. Thus we have initiated a genetic-based screening program of culturable endophytes to identify strains capable of producing bioactive polyketides and peptides. The rich biodiversity and traditional history of Indonesia make it an attractive target for the discovery of novel therapeutic compounds from medicinal plants and their endophytic fungi.

Plant-associated fungal isolates from selected Indonesian traditional medicinal plants have been genetically screened for the presence of PKS and NRPS genes as indicators of bioactivity. Preliminary antimicrobial screening against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Mycobacterium avium has been carried out on the organic extracts of the PKS/NRPS-containing isolates as a means of prioritising strains for downstream analyses. Bioassay-guided fractionation has been carried out on selected potent isolates to obtain pure compounds. Chemical characterisation of these compounds will be presented.