Identification and characterization of potent antimicrobial secondary metabolite generated from endophytic fungi isolated from jamblang plant (Eugenia cumini L.)

Abstract

Objective: Colletotrichum capsici endophytic fungi were isolated from Jamblang plant (Eugenia cumini L.). The secondary metabolites of this plant have potent antibacterial efficacy as well as antidiarrheal and antidiabetic. This research focused on isolation of the endophytic microbes from branches of Jamblang plants and their secondary metabolites. Methods: Isolation of endophytes was performed in potato dextrose agar using direct seed plant. Endophytic fungi isolates with strongest antimicrobial activity against the bacteria Staphylococcus aureus and Escherichia coli were fermented in potato dextrose yeast to produce large scale of the metabolites. Supernatant was extracted with ethyl acetate (EtOAc) solvent. EtOAc extract fractionated by column chromatography (SiO3, n-hexane:EtOAc=50:1~1:1) and obtained three fractions. Further, agar diffusion method was performed to assess their antimicrobial activity. Results: Antibacterial test results indicated that fraction III had potent antibacterial activity S. aureus with inhibition zone diameter of 10.7 mm but no observed activity against E. coli. Furthermore, identification by gas chromatography-mass spectrometry showed that compounds present in fraction III were mainly fatty acid and phenolic compounds. Conclusion: Secondary metabolites isolated from Jamblang plants branches contained predominantly fatty acid and phenol-related compounds that could be responsible for its potent antimicrobial activity.