Secondary metabolites from Colletotrichum fioriniae F18, an endophytic fungus isolated from the medicinal plant Mahonia fortunei

Chemical investigation on the rice culture of an endophytic fungus Colletotrichum fioriniae F18, inhabiting in the stems of the medicinal plant Mahonia fortunei, led to the isolation of nine compounds. They included a new indole alkaloid, makomotindoline B (1), and two known indole derivatives, 3-indoleacetic acid methyl ester (2) and N-acetyltryptamine (3), together with six known aromatic compounds, 2-(4-hydroxyphenyl) acetic acid (4), 4-(2-hydroxyethyl)phenol (5), 2-(4-methoxyphenyl)acetic acid (6), 4-hydroxyphenethyl 2-(4-hydroxyphenyl)acetate (7), regiolone (8) and N-phenethylacetamide (9). The structures of these compounds were elucidated based on the analysis of spectroscopic data including MS and NMR. The absolute configuretion of compound 1 was determined by electronic circular dichroism (ECD) calculation. Antibacterial activity assay indicated that compounds 1-9 had no antibacterial activities against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, as well as no quorum sensing inhibitory (QSI) activity for Chromobacterium violaceum.