Antitumor potential of tricyclic pyridone analogues from an entomopathogenic fungus, Fusarium avenaceum SYKC02-P-1.

Two new tricyclic pyridone analogues, fusapyridons C (1) and D (2), were isolated along with structurally related known compounds 3 - 5 from the entomopathogenic fungus, F. avenaceum SYKC02-P-1. The structures of compounds 1 and 2 were elucidated by analyzing the spectral data of UV, 1 D and 2 D NMR as well as HRESIMS. The absolute configurations of fusapyridons C and D were established by means of single crystal X-ray diffraction and electronic circular dichroism calculation. And antitumor testing of all the isolates showed that compounds 4 and 5 exhibited significant inhibitory activity against the human prostate cancer cells (PC-3 cell lines) with IC50 values of 2.76 and 1.86 µM, respectively.