Xylarichalasin A, a Halogenated Hexacyclic Cytochalasan from the Fungus Xylaria cf. curta.

Abstract

A cytochalasan, xylarichalasin A, was obtained from the endophytic fungus Xylaria cf. curta harbored in Solanum tuberosum. Its structure was elucidated by comprehensive spectroscopic methods including HRESIMS, 1D/2D NMR, and residual dipolar coupling analysis as well as quantum chemistry calculations including DFT GIAO 13C NMR and ECD calculation. It has an unprecedented 6/7/5/6/6/6 fused polycyclic structure. In bioassay, xylarichalasin A showed cytotoxicity against human cancer cell lines with IC50 value ranging from 6.3-17.3 μM.