Xanthone constituents of Hypericum subsessile

Cytotoxicity screening of the extracts of Hypericum subsessile N.Robson as carried out by L1210 cells.Isolation of chemical constituents as carried out from the effective parts of H. subsessile by column chromatography. The chemical structures were identified by physico-chemical properties and spectral data.Six xanthone constituents have been isolated and elucidated as 2,3-dimethoxyxanthone(1),1,3-dihydroxy-5,6-dimethoxyxanthone(2),toxyloxanthone B(3),kielcorin(4),candensin D(Hypericorin)(5)and subalatin(6). Compounds 1～6 were obtained from H. subsessile for the first time.In addition,CHCl3 and EtOAc fractions possess cytotoxic activities and the IC50 are 8.8 and 14.6 μg/mL for L1210 cells,respectively.