Cyclo(Ile-Leu) shows cytotoxic activity in vitro.

To study the metabolites of mangrove fungus Penicillium oxalicum from the south China sea and search for new anti-tumor compounds. METHODS AND RESULTS:Compounds were isolated by silica gel,ODS column chromatography,Sephadex LH-20 column chromatography and reversed-phase HPLC purification.Structural elucidation was achieved by physico-chemical constants and spectroscopic analysis MTT assay was used to evaluate the bioactivities in vitro.Six cyclic dipeptides were isolated from the acetone extracts of mycelium of fungus and elucidated as cyclo-(Phe-Ile)(1),cyclo-(Phe-Val)(2),Cyclo(Ile-Leu)(3),cyclo-(Val-Val)(4),cyclo-(Pro-Val)(5),cyclo-(Pro-Gly)(6).Coumpouds 2,3 and 5 could evidently inhibit the growth of cancer cell lines HepG Ⅱ and LNCaP at the concentration of 50 μg·mL-1. CONCLUSIONS: All of Compounds are obtained from the marine fungus for the fist time.Compounds 2,Cyclo(Ile-Leu) and 5 show cytotoxic activity in vitro.