A new trichothecene from Myrothecium roridum QDFE005, a symbiotic fungus isolated from Mactra chinensis.

A new trichothecene, 12'-episatratoxin H (1), together with three known analogs: roridin A (2), 16-hydroxyroridin E (3), and roridin E (4), was isolated from the culture broth of the symbiotic fungus Myrothecium roridum QDFE005, which was isolated from Mactra chinensis. Their structures were elucidated on the basis of spectroscopic methods, including 1D and 2D NMR (COSY, HMQC, and HMBC) techniques. Compound 1 exhibited significant cytotoxicity against the human tumor cell lines KB and HepG2 with IC50 values of 1.42 and 2.27 µM, respectively.