Fatty acid synthase inhibitors from Geum japonicum Thunb. var. chinense.

Bioassay-guided fractionation of the MeOH extract of Geum japonicum Thunb. var. chinense using the fatty acid synthase inhibition assay led to the isolation of a new dimeric ellagitannin, gemin G (1), together with six known compounds, gemin A (2), casuarinin (3), pedunculagin (4), potentillin (5) , tellimagrandin II (6), and ellagic acid (7). Their structures were determined on the basis of spectroscopic analyses. Compounds 1-7 displayed strong inhibitory activities on fatty acid synthase with IC(50) values in the range of 0.21-41.4 microM. Compounds 1-4 exhibited significant antioxidant activities higher than vitamin C in the ORAC assay. Compounds 1 and 2 also showed weak cytotoxic effects on BGC-823 cell.