The beneficial effect of propolis on fat accumulation and lipid metabolism in rats fed a high-fat diet.

This study examined whether propolis, which had many biological activities, affected body fat and lipid metabolism. Four-week-old Wistar rats were fed a control or propolis diet for 8 wk. The control group was fed a high-fat diet, the low and the high group were fed a high-fat diet supplemented with 0.5% (w/w) and 0.05% (w/w) propolis, respectively. The weight of total white adipose tissue of the high group was lower than that of the control group. The level of PPARgamma protein in the adipose tissues of the high group was significantly lower than that of the control group. In plasma and the liver, the high group showed a significantly reduced level of cholesterol and triglyceride compared to the control group. The liver PPARalpha protein level of the high group was significantly higher than that of the control group. The liver HMG-CoA reductase protein in the high group was also significantly lower than that in the control group. Results from rats on an olive oil loading test were used to investigate whether propolis inhibited triglyceride absorption. The serum triglyceride level of the group, which received propolis corresponding to the daily dose of the high group, was significantly lower than that of the control group. It is possible that the administration of propolis improves the accumulation of body fat and dyslipidemia via the change of the expression of proteins involved in adipose depot and lipid metabolism.