Bioactive metabolites from Chaetomium globosum L18, an endophytic fungus in the medicinal plant Curcuma wenyujin.

An endophytic fungus, strain L18, isolated from the medicinal plant Curcuma wenyujin Y.H. Chen et C. Ling was identified as Chaetomium globosum Kunze based on morphological characteristics and sequence data for the internal transcribed spacer (ITS-5.8S-ITS2) of the nuclear ribosomal DNA. A new metabolite named chaetoglobosin X (1), together with three known compounds erogosterol (2), ergosterol 5α,8-peroside (3) and 2-methyl-3-hydroxy indole (4), were isolated from C. globosum L18. Their structures were elucidated by spectroscopic methods including NMR, UV, IR and MS data and comparison with published data. Chaetoglobosin X (1) is hitherto unknown, whereas 2-methyl-3-hydroxy indole (4) is reported for the first time as a fungal metabolite, and erogosterol (2) and ergosterol 5α,8-peroside (3) are known fungal metabolites previously identified in other genera. Chaetoglobosin X (1) exhibited a broader antifungal spectrum and showed the strongest cytotoxic activity against H22 and MFC cancer cell lines.