Xylarinic acids A and B, new antifungal polypropionates from the fruiting body of Xylaria polymorpha.

Two new polypropionates designated as xylarinic acids A and B were isolated from the fruiting body of Xylaria polymorpha. Their structures were established as 4,6,8-trimethyl-2,4-decadienoic acid and 2,4,6-trimethyl-2-octenoic acid, respectively, on the basis of extensive spectroscopic analysis. Both compounds displayed significant antifungal activity against plant pathogenic fungi Pythium ultinum, Magnaporthe grisea, Aspergillus niger, Alternaria panax, and Fusarium oxysporium, whereas they did not show antibacterial and cytotoxic effect.