Abstract

• An endophytic fungal strain Phomopsis sp. was isolated from the leaves of Psidium guajava L. For the extraction of the bioactive compounds, 12L large fermentation of strain Phomopsis sp. and antimicrobial activity of fermented broth with Bacillus subtilis, Candida albicans, Escherichia coli, Malassezia furfur, Salmonella typhi and Staphylococcus aureus were carried out at Microbiology Laboratory, Department of Botany, University of Yangon. Then, the filtrate was extracted with methanol on Ambilites XAD 2 resin column and the methanol extracts showed high against six test organisms. Isolation and purification of the bioactive compounds from the methanol extracts were done by utilizing silica gel columns and Sephadex LH 20 gel columns with various solvent systems at Department of Organic Chemistry, Ramkhamhaeng University, Bangkok, Thailand. The isolated compounds were characterized by FT-IR spectra, 1D-NMR (1H-NMR, 13C-NMR) and 2D-NMR (COSY, HSQC, and HMBC) spectra. The three isolated compounds were identified as phomopsolide B, adenosine and emerimidine C. Antimicrobial activity of the bioactive compounds was evaluated on six test organisms and showed highest activity against Xanthomonas oryzae and weak activity against Candida albicans and Escherichia coli.