Isopimaranes and eremophilanes from the wood-decay fungus Xylaria allantoidea BCC 23163

Three new isopimarane diterpenes, xylallantins A–C (1–3), a new eremophilane sesquiterpene, eremoxylarin C (7), and an O-methyl derivative of diplosporin (10), together with seven known compounds, xylarenolide (4), hymatoxins E (5) and K (6), eremoxylarin A (8), 07H239-A (9), acuminatopyrone (11), and coriloxin (12), were isolated from the fermentation broth of the wood-decay fungus Xylaria allantoidea BCC 23163. The structures were elucidated by analyses of NMR spectroscopic and mass spectrometry data. Xylallantin A (1) showed cytotoxicity to NCI-H187 cells (IC50 17 μg/ml), while eremoxylarin C (7) exhibited activity against Plasmodium falciparum K1 (IC50 3.1 μg/ml) and cytotoxicity to NCI-H187 cells (IC50 6.7 μg/ml).