Fatty Acid Synthase Inhibitors Separated from Oiltea Camellia by High-Speed Counter-Current Chromatography

Abstract

The inhibitory effects of oiltea camellia extracts (OCEs) and its active components on fatty acid synthase (FAS) were investigated. OCE potently inhibited the activity of FAS with an half-maximal inhibitory concentration (IC 50) value of 2.30 μg/mL. The inhibition kinetic results showed that OCE and acetyl-CoA competitively inhibited FAS but these compounds exhibited mixed inhibition against malonyl-CoA and NADPH. Further study uncovered that the active components of OCE, ellagic acid (EA) and 3-O-methylellagic acid 4'-O-β-D-glucopyranoside (MEAG), which were isolated and purified by high-speed counter-current chromatography (HSCCC) using a 2-phase solvent system of chloroform-ethanol-water-acetic acid (4:3:2:0.01, v/v/v/v), inhibited FAS with IC 50 of 2.50 and 37.73 μg/mL, respectively. Their inhibition kinetics were different from that of OCE. Both of them exhibited uncompetitive inhibition for nicotinamide adenine dinucleotide phosphate (NADPH) and decreased the FAS activity through inactivation of acetyl/malonyl transferase on FAS. These results suggest that OCE could be a valuable resource for bioactive substances. © 2011 Institute of Food Technologists ®.