Cytochalasans from endophytic fungus Diaporthe sp. SC-J0138.

Five new cytochalasans, diaporthichalasins D-H (1-5), along with five known cytochalasans (6-10) were isolated from solid cultures of the endophytic fungus Diaporthe sp. SC-J0138 isolated from the leaves of Cyclosorus parasiticus. Their structures were elucidated by analysis of spectroscopic data and theoretical calculations of electronic circular dichroism spectra. Compounds 1 and 5 showed noticeable cytotoxicity against human carcinoma A549, HeLa, and HepG2 cells. The structure-activity relationships in cytotoxicity were discussed for this group of compounds.