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

•Three new isopimaranes and a new eremophilane were isolated from Xylaria allantoidea.•The structure was elucidated on the basis of spectroscopic data interpretations.•Biological activities of the new compounds were evaluated. 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 17μg/ml), while eremoxylarin C (7) exhibited activity against Plasmodium falciparum K1 (IC50 3.1μg/ml) and cytotoxicity to NCI-H187 cells (IC50 6.7μg/ml).