The antibacterial activity of Malaysian marine endophytic fungi fractions against gram negative bacteria

Marine natural products reported to exhibit various bioactivity such as antimicrobial, anti-tuberculosis, antiviral, antiprotozoal, anti-oxidant, immunomodulatory, anti­ diabetes, anti-inflammatory and anticancer. Biologically active metabolites obtained from marine endophytic fungi reported to have excellent sources for treatment of various diseases particularly against antibacterial resistance. In this study three marine endophytic fungi extracts Gracilaria coronopifolia (CN), Gracilaria arcuata zanardin (MV) and Chaemotorpha minima (UF) were used to investigate the antibacterial activity against three pathogenic gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli and Salmonella typhimurium). These three marine endophytic fungi extracts previously exhibited promising antibacterial activity. In order to verify the antibacterial component of these three marine endophytic fungi extracts, the antibacterial component was isolated by using bio-guided fractionation assay. Bioassay guided fractionation was performed on the ethyl acetate of marine endophytic fungi extracts to isolate the active fractions. The fractions of extracts (CN, MV, and UF) exhibited highest bacterial inhibition against Pseudomonas aeruginosa (82.1 %). Salmonella typhimurium showed the least inhibition after being treated with fractions extracts (30.1 %). Out of three extracts, MV fractions showed the highest activity against Pseudomonas aeruginosa. Therefore, these active identified fractions might have a great potential to be an alternate source as antibacterial agent against Pseudomonas aeruginosa. Further studies should be carried out to isolate the potential identified active fractions. In conclusion, the active fractions of three marine endophytic fungi extracts were successfully identified.