Alkaloids isolated from the endophytic fungus Fusarium concentricum .

Endophytic fungi are an important resource for bioactive natural products. In this study, a new tryptophan derivative fusaconate A ( 1 ) and three pyridone alkaloids, including one new pyridone derivative 1'-methoxy-6'- epi -oxysporidinone ( 2 ) and two known ones ( 3 - 4 ), were identified from the endophytic fungus Fusarium concentricum which was isolated from the medicinal plant Anoectochilus roxburghii . Their structures were elucidated through extensive spectroscopic analysis, including HR-ESI-MS, 1 D and 2 D NMR. Compound 4 exhibited moderate cytotoxicities against HT29 and PC3 cells with IC 50 values of 7.60 and 4.99 μM, respectively.