Effect of tea leaf catechin, (-)-epigallocatechin gallate, on plasma cholesterol level in rats.

Previously we observed the fact that crude tea catechins (tannins) extracted from green tea leaf have a hypocholesterolemic effect. To further investigate the findings we isolated the main component of green tea catechins, (-) -epigallocatechin gallate (EGCg), and studied its effects on lipids metabolism in rats fed a 25% casein diet containing 15% lard and 1% cholesterol (a high-fat cholesterol diet). The diets were supplemented with 0.5% and 1.0% EGCg. Feeding period was 4 weeks in all experiments. The EGCg supplemented diets did not affect the body weight gain and food consumption. Rats fed the high-fat cholesterol diet increased plasma and liver cholesterol concentrations compared to rats fed a 25% casein diet (basal diet). EGCg supplementation decreased plasma total cholesterol and low density lipoprotein (LDL) cholesterol levels and increased high density lipoprotein (HDL) cholesterol concentration. The liver total lipids, total cholesterol and triglyceride concentration were increased in rats fed the high-fat cholesterol diet, but the addition of EGCg decreased those parameters. EGCg feeding increased the fecal excretion of total lipids and cholesterol. Supplementation of 1.0% EGCg to the 25% casein diet had no effect on plasma and liver cholesterol concentrations. These results demonstrate that EGCg exerts hypocholesterolemic effects in cholesterol-fed rats.