Talarindigotin A: a cytotoxic indigotin derivative, from the mangrove endophytic fungus Talaromyces amestolkiae SCNU-F0041

A new indigotin alkaloid, named talarindigotin A (1), along with the analogue 5H, 6H-quinindolin-11-one (2) were isolated from the mangrove endophytic fungus Talaromyces amestolkiae SCNU-F0041. Their structures were assigned on the basis of NMR, HRMS, and single-crystal X-ray diffraction analysis. In the cytotoxic bioassay, compound 1 showed great cytotoxicity against HepG2, Hela, HCT116, and Huh7 human cancer cell lines with IC₅₀ values ranging from 2.08 to 4.58 μM.