Three new antimicrobial metabolites from the endophytic fungus phomopsis sp

Two new chromones, phomochromone A and B (1 and 2), and one new natural cyclopentenone derivative, phomotenone (3), together with six known compounds, phomosines A-D (4-7), (1S,2S,4S)-trihydroxy-p-menthane (8), and 5-methylmellein (9), have been isolated from the endophytic fungus Phomopsis sp. through a bioassay-guided procedure. The structures of the new compounds were assigned on the basis of the 1H and 13C NMR spectra, DEPT, and 2D COSY, HMQC, HMBC, and NOESY experiments, supported by molecular modelling. The absolute configurations of compounds 1-3 were assigned by TD-DFT CD calculations and, surprisingly, the two related phomochromones A and B have an opposite configuration at C-2. Compounds 1-3 show good antifungal (Microbotryum violaceum), antibacterial (Escherichia coli, Bacillus megaterium), and antialgal (Chlorella fusca) activities. Compound 8 shows good antialgal and antibacterial activity. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.