Cytotoxic cytochalasans from Aspergillus flavipes PJ03-11 by OSMAC method

Abstract Two new cytochalasans flavichalasine N ( 1 ), flavichalasine O ( 2 ), together with six known cytochalasans ( 3 – 8 ), were isolated from Aspergillus flavipes PJ03-11 through the application of OSMAC (one strain many compounds) strategy. Flavichalasine O ( 2 ) represented the first example of cytochalasans possessing a nitrogen-oxygen heterocycle at the macrocyclic ring part. Their structures were established on the base of extensive spectroscopic analysis. Compounds 1 – 4 exhibited significant cytotoxic activities against three human cancer cell lines (THP1, HL-60 and PC3) with IC 50 values ranging from 3.00 to 15.10 μM.