Antimalarial (9Z)-9-methoxystrobilurins from cultures of Basidiomycete Favolaschia xtbgensis TBRC-BCC 18687

Twelve previously unsubscribed compounds, (9Z)-9-methoxystrobilurins B (1) and G (2), oudemansin Y (3), 10,14-dehydrooudemansin B (4), favolasin B (5), favolasinones A (6) and B (7), favodehydes G (8) and K (9), 3-methylbenzo[b]oxepin-7-carboxylic acid (10), the prenylated primary benzamide 11, and its hydroxamine derivative 12, together with sixteen known compounds were isolated from the fungus Favolaschia xtbgensis TBRC-BCC 18687. Compounds in the class of strobilurins and oudemansins, 1, 2, and 4, exhibited strong to moderate antimalarial and cytotoxic activity against NCI–H187 cells. The most potent antimalarial compound was the (9Z)-9-methoxystrobilurins G (2, IC50 0.090 μM), which was comparable to that of its (9E)-isomer (IC50 0.061 μM), even though the 3D structures of these two compounds were quite different.