Kolokosides A-D: triterpenoid glycosides from a Hawaiian isolate of Xylaria sp.

Four new triterpenoid glycosides, kolokosides A−D (1−4), along with the known compound 19,20-epoxycytochalasin N, were isolated from cultures of a Hawaiian wood-decay fungus (Xylaria sp.). The structures and relative configurations of 1−4 were determined primarily by analysis of NMR data, and the absolute configuration of 1 was assigned by application of the exciton chirality method. Compound 1 exhibited activity against Gram-positive bacteria.