A new xanthone derivative from mangrove endophytic fungus No. ZSU-H16.

A new xanthone derivative, 3,5,8-trihydroxy-2,2-dimethyl-3,4,4-trihydro-2 H,6 H-pyrano[3,2- b]-xanthen-6one ( 1), together with three known compounds, 5,8-dihydroxy-2,2-dimethyl-2 H,6 H-pyrano[3,2- b]xanthen6-one ( 2), cyclo-( N- O-methyl-L-Trp-L-Ile-D-Pip-L-2-amino-8-oxo-decanoyl) ( 3), and cyclo-(Phe-Tyr) ( 4), was isolated from the mangrove endophytic fungus No. ZSU-H16 obtained from the South China Sea coast. Their structures were elucidated by spectroscopic methods, mainly 1D and 2D NMR spectroscopic techniques. Compound 1 exhibited cytotoxicity against KB and KBV 200 cells with IC50 values greater than 50 μg/mL, respectively. [ABSTRACT FROM AUTHOR]