Evaluation of the antihyperlipidemic and antioxidant properties of the aqueous leaf extract of camellia sinensis in oil-induced hyperlipidemic rats

Abstract

Camellia sinensis (Green Tea) has been reported to have numerous health benefits. The present study investigated the lipid-lowering effect and the antioxidant activity of the leaf of Camellia sinensis (CS). Palm oil (PO) and groundnut oil (GO) (ratio 2:1; 8 mL/kg) were administered to Sprague-Dawley rats orally for 5 wk to induce hyperlipidemia. Rats, which showed high plasma levels of total cholesterol (TC), triglyceride (TG) and low-density lipoprotein (LDL-C) were selected for the study. Rats in the treatment groups received CS (250 and 500 mg/kg) while the control groups received distilled water and atorvastatin (10 mg/kg). All animals were treated for 7 wk and blood samples were collected after 10 h fast. Antioxidant activity was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging and ferric-reducing antioxidant power (FRAP) assays. The extract significantly (p ≤ 0.05) attenuated the elevated plasma TC, TG and LDL-cholesterol, while the plasma level of HDL-cholesterol was significantly (p ≤ 0.05) increased. The atherogenic index and plasma level of malondialdehyde (MDA) was also attenuated by the extract. The extract showed effective antioxidant properties by its ability to scavenge free radical of DPPH and conversion of Fe3+ to Fe2+ in the FRAP assay. Direct correlation was observed between DPPH and FRAP. Similarly, there were positive correlations between MDA and lipid profiles except HDL-cholesterol which showed a negative correlation. This study suggests that Camellia sinensis may be effective in lowering blood lipid level through the regulation of cholesterol and inhibition of lipid peroxidation.