Bioassay-guided isolation of constituents from the endophytic fungi Fusarium solani inhabiting Rhizophora apiculata Blume.

Endophytic fungi (EF) are excellent sources of diverse and pharmacologically relevant molecules for drug development. The mangrove genus Rhizophora have been identified to contain fungal isolates. In this study, the EF Fusarium solani was isolated and characterized from R. apiculata. Disk diffusion assay of the crude ethyl acetate extract of F. solani on the ESKAPE clinical isolate pathogens showed inhibitory activities against Escherichia coli 5218S (ZOI 12.20 mm), methicillin-resistant Staphylococcus aureus 2729B (ZOI 8.90 mm), Klebsiella pneumoniae 4830WD (ZOI 12.58 mm), Acinetobacter baumannii 3975B (ZOI 12.85 mm), and Enterobacter cloacae 5276S (ZOI 15.53 mm). Bioassay guided isolation and spectroscopic analysis led to the identification of benzoic acid (1) and bis(3-methylhexyl) phthalate (2). Microtiter plate antimicrobial assay gave minimum inhibitory concentration (MIC) of 125 µg/mL for compound 1 and 250 µg/mL for compound 2. To the best of our knowledge, this is the first report on the isolation of F. solani from R. apiculata and the isolation of compounds 1 and 2 from the genus Fusarium. Hence, this study validated the importance of the EF as sources of bioactive molecules. [ABSTRACT FROM AUTHOR]