α-Pyrone derivatives with cytotoxic activities, from the endophytic fungus Phoma sp. YN02-P-3

Abstract Four new α -pyrone derivatives phomones C-F ( 1 − 4 ) together with four known compounds ( 5 − 8 ) were isolated from the endophytic fungus Phoma sp. YN02-P-3. Compound 1 is the first example of 6- α , β -unsaturated ester-2-pyrone dimers via intermolecular symmetrical [2 + 2] cycloaddition. The chemical structures of these compounds were determined from spectroscopic data (1D/2D NMR, MS and IR). The acetylated product ( 9 ) of 1 along with compounds 1 – 8 were then tested for their cytotoxicity against HL-60, PC-3 and HCT-116 cell lines. Compounds 2 , 3 , 5 and 9 with acetyl groups showed significant inhibitory activities against the three cell lines with IC 50 values in the range 0.52–9.85 μM. while compounds 1 , 4 and 6 – 8 that possess no acetyl group showed no inhibitory activity (IC 50  > 50 μM), indicating that the acetyl group at 10- or 12- are essential for their cytotoxic activities. The structure-activity relationships of these phomones were also reported.