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 IC50 values of 7.60 and 4.99 μM, respectively.
Keywords: Fusarium concentricum; cytotoxicity; endophytic fungi; pyridone alkaloids.