Effect of methylated tea catechins from Chinese oolong tea on the proliferation and differentiation of 3T3-L1 preadipocyte

As the important component of tea catechins in oolong tea, (-)-epigallocatechin 3-O-(3-O-methyl) gallate (EGCG3Me) has exhibited various beneficial effects, however, little attention about its obesity prevention effect is available. In this study, the inhibitory effects of tea catechin monomers, including their methylated forms on the proliferation and differentiation of 3T3-L1 preadipocyte were studied. The major methylated tea catechins in oolong tea were identified as EGCG3Me and ECG3Me. The accumulation of triglyceride was significantly reduced in a concentration-dependent manner in groups treated with EGCG3Me at concentrations of 20,40 and 80 mu g/mL, and the accumulation of lipid was decreased to 89.42 +/- 2.66%, 64.36 +/- 3.13% and 39.37 +/- 2.79%, respectively. Both EGCG3Me and EGCG treatments showed a significant inhibitory effect on adipogenesis, while EGCG3Me showed a relatively higher effect than EGCG, which was contrary to the results of cytotoxic activity. For ECG and ECG3Me, ECG3Me also showed a relatively higher antiobesity effect and lower cytotoxic activity. The results of activity screening showed that methylated tea catechins, including EGCG3Me and ECG3Me inhibited the proliferation and differentiation of 3T3-L1 preadipocyte. The difference of inhibitory effects for tested compounds may be due to their structural difference (the hydroxyl group at C-3 in D ring substituted by methoxy group). (C) 2015 Elsevier B.V. All rights reserved.