Antibacterial polyketide from Lasiodiplodia theobromae, inhabiting the lichen host, Pyrenula bahiana on mangrove ecosystems in Puttalam lagoon, Sri Lanka

Abstract

Lasiodiplodia theobromae is one of the frequently isolated fast growing endolichenic fungus. This fungus was isolated from the lichen host, Pyrenula bahiana collected from the mangrove ecosystems in Puttlam lagoon and identity was confirmed based on rDNA-ITS sequence homology. Secondary metabolites of L. theobromae were extracted into ethyl acetate and subjected to antibacterial assay against Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC25923) and Bacillus subtilis (ATCC6051). Crude extract at a concentration of 6.8 μg/ml showed good anti-bacterial activity against the bacterial strain S. aureus compared with the activity of the standard Azithromycin at a concentration of 5.0 μg/ml. Active crude extract was partitioned to obtain methanol,