Rubichaetoglobin A, a new cytochalasan alkaloid isolated from the plant endophytic fungus Chaetomium tectifimeti S104.

Rubichaetoglobin A (1), a new cytochalasan alkaloid, together with nine closely related known ones (2-10), were isolated from the ethyl acetate extracts of the endophytic fungus Chaetomium tectifimeti S104 harbored in the root of Rubia podantha Diels. Their structures were elucidated based on comprehensive spectroscopic analysis. All isolated compounds were tested for cytotoxic, antibacterial, and nitric oxide inhibitory activities. The results showed that 2, 4, and 5 possessed moderate cytotoxicity against MDA-MB-231 cells with the IC50 values of 19.14, 11.43, and 10.27 µM, respectively.