Two new isopimarane diterpenoids from the endophytic fungus Xylaria sp. SNB-GTC2501

Abstract Two new isopimarane diterpenoids, xylabisboein A ( 1 ) and B ( 2 ), as well as three known secondary metabolites (i.e., (−)-5-methylmellein ( 3 ), mellein-5-carboxylic acid ( 4 ) and ergosterol peroxide ( 5 )), were isolated from a solid culture of the endophytic fungus Xylaria sp. SNB-GTC2501. The structures were elucidated by spectroscopic analysis and the absolute configuration of xylabisboein A ( 1 ) was determined by X-ray crystallographic analysis. All of the compounds were tested for their antimicrobial and cytotoxic activities.