Marine derived fungi of peninsular Malaysia - A biochemical perspective

In an effort to tap into natural products harboured by marine derived fungi in Malaysia, selected marine derived endophytic and manglicolous fungi from the coastlines of Peninsular Malaysia were investigated for their antibacterial potential. Forty-one strains were isolated from marine associated plants, comprised and comprised 12 and 19 endophytic strains from Vitex rotundifolia and Ipomoea pes-caprae respectively, while 10 manglicolous strains were from decaying mangrove wood collected in Peninsular Malaysia. In preliminary experiments, a plug assay was employed to study the antibacterial activities of all 41 fungi isolates. Fifteen of the endophytic isolates and nine of the manglicolous isolates displayed antibacterial activities against at least one of the test bacteria. Based on the plug assay, the endophytic fungi from Ipomoea pes-caprae were shown to display higher antibacterial potential in comparison to the endophytic fungi from Vitex rotundifolia. In particular, Minimidochium sp. and Bipolaris sp. (ISB0014) displayed antibacterial activities against 5 or more test bacteria. Potential fungi isolates with good antibacterial activities were further analysed through a broth microdilution assay. Minimidochium sp. and Dyfrolomyces rhizophorae exhibited promising antibacterial activities with minimum inhibitory concentrations not higher than 0.5 mg/ml. Bioactivityguided fractionation of D. rhizophorae extracts resulted in the isolation of fatty acids, palmitic and linoleic acid. Though ubiquitous in nature, linoleic acid is known as an essential health supplement and both fatty acids are used as biodiesel replacing conventional fuels.