A new isobenzofuranone from the mangrove endophytic fungus Penicillium sp. (ZH58).

A new isobenzofuranone, 4-(methoxymethyl)-7-methoxy-6-methyl-1(3H)-isobenzofuranone (1), together with seven known compounds, dilation (2), lumichrome (3), curvulari (4), 5,5'-oxy-dimethylene-bis(2-furaldehyde) (5), chromone (6), harman(1-methyl-β-carboline) (7), N9-methyl-1methyl-β-carboline (8), was isolated from the mangrove endophytic fungus, Penicillium sp. ZH58 obtained from the South China Sea coast. Their structures were determined by analysis of spectroscopic data. Compound 1 exhibited cytotoxicity against KB and KBV200 cells with IC50 values of 6 and 10 μg/mL, respectively.