Hepatoprotective constituents of the seeds of Combretum quadrangulare

Hepatoprotective effect of MeOH, MeOH-H2O (1:1) and H2O extracts of Combret um quadrangulare seeds were examined on D-galactosamine (D-GalN)/tumor necr osis factor-alpha (TNF-alpha)-induced cell death in primary cultured mouse hepatocytes. The MeOH extract showed the strongest inhibitory effect on o-G alN/TNF-alpha -induced cell death (IC50, 56.4 mug/ml). Moreover, the MeOH e xtract also significantly lowered the serum glutamic pyruvic transaminase ( sGPT) level on D-GalN/lipopolysaccharide (LPS)-induced liver injury in mice . Bioguided separation of the MeOH extract led to the isolation of 38 compo unds of various classes including triterpene glucosides, lignans and catech in derivatives. Among the isolated triterpene glucosides, lupane-type (1-3; IC50, 63.1, 59.8 and 76.2 muM, respectively) and ursane-type (11, mixture of 12 and 14; IC50, 30.2 and 33.6 muM, respectively) compounds exhibited st rong hepatoprotective activity. 1-O-Galloyl-6-O-(4-hydroxy-3,5-dimethoxy)be nzoyl-beta -D-glucose (26; IC50, 7.2 muM), methyl gallate (28: IC50, 19.9 m uM), and (-)-epicatechin (31; IC50, 71.2 muM) also had a potent hepatoprote ctive effect on D-GalN/TNF-alpha -induced cell death in primary cultured mo use hepatocytes.