Pancreatic lipase inhibitory gallotannins from galla rhois with inhibitory effects on adipocyte differentiation in 3T3-L1 cells

Activity-guided isolation of a methanolic extract of Galla Rhois using pancreatic lipase and 3T3-L1 adipocytes led to the isolation of seven phenolic compounds: protoaphin-fb (1), 2-O-digalloyl-1,3,4,6-tetra-O-galloyl-β-D- glucose (2), 1,2,3,4,6-penta-O-galloyl-β-D-glucose (3), 1,2,4,6-tetra-O-galloyl-β-D-glucose (4), 3-hydroxy-5-methoxy-phenol 1-O-β-D-glucoside (5), methylgallate (6), and gallic acid (7). Their structures were established on the basis of NMR and MS spectroscopic data interpretation. All isolates were evaluated for their inhibitory effects on pancreatic lipase, and compounds 1-5 exhibited potent inhibitory effects on this enzyme, with IC50 values ranging from 30.6 ± 2.4 to 3.5 ± 0.5 μM. In addition, the highly galloylated compound 2 was also found to induce potent inhibition of adipocyte differentiation in 3T3-L1 cells.