Bioactive Compounds from Aspergillus Terreus MP15, an Endophytic Fungus Isolated from Swietenia Macrophylla Leaf

Abstract

Endophytes are important sources for the discovery of bioactive compounds. They are known as potential producers of novel compounds with antimicrobial activity. In this study, it aimed to study the bioactive metabolites present in the ethyl acetate extract from the endophytic fungus Aspergillus terreus MP15 of Swietenia macrophylla leaf. The ethyl acetate extract showed promising antibacterial activity against Gram-positive foodborne bacteria (Bacillus cereus, Bacillus spizizenii, Bacillus subtilis and Staphylococcus aureus) in disc diffusion assay. The extract was then subjected to thin layer chromatography (TLC) using dichloromethane: methanol (9:1) as a mobile solvent system and eleven spots with diverse polarities were obtained. The TLC chromatogram with bioactive spot was localized with bioautography assay and the result showed that the yellow spot with Rf value of 0.523 exhibited promising antibacterial activity against the four Gram-positive bacteria tested. Upon partial purification of the yellow bioactive fraction using column chromatography, the fraction 2a exhibited promising antibacterial activity. The GC-MS analysis of the yellow fraction 2a resulted in the detection of a major compound, di-n-octyl phthalate with 80% matching factor. Therefore, this compound may largely contribute to the antibacterial activity of the fraction and has potential to be food preservative and as a colorant. These results indicate that endophytic fungi isolated from medicinal plants could be a potential source for bioactive compounds.