Alkaloid metabolites of mangrove endophytic fungus ZSU-H26 from the South China Sea

Six alkaloids,2-(1H-indol-3-yl)-4H-benzo[d]oxazin-4-one(1),methyl o-(indole-3-carboxamido) benzoate(2),cyclo(Ile-Leu-Val-Va1)(3),cyclo(Phe-Gly)(4),cyclo(Leu-Leu)(5),and cyclo(Ala-Leu)(6),were isolated from the mangrove endophytic fungus ZSU-H26 from the South China Sea.Their structures were elucidated by spectral data.Indole alkaloids 1 and 2 were both isolated from microorganism for the first time.In the preliminary bioassay,1 and 2 show inhibitory activity on the hepG2 cell line with IC50 values of 20μg/mL and 35μg/mL,respectively.