Water Extract of Liuwei Dihuang Reduces Weight Gain and Visceral Fat in Obese Rats

Abstract

The present study was conducted to determine the effect and mechanism of action of Liuwei Dihuang (LWDH) on weight gain and visceral fat deposition in male obese-prone CD rats. The rats were divided into three groups and fed a high-fat diet (60 kcal% from fat). Two treatment groups received 600 (WE600) or 1200 (WE1200) mg/kg/d LWDH water extract dissolved in water by gavage feeding once a day for 10 weeks. The control rats were gavaged with the vehicle. Daily food intake and weekly body weight were recorded. Energy metabolism was measured using an indirect calorimeter during week 8 of the treatment. At the end of the study, rats were sacrificed. Immediately, visceral fat pads were dissected and weighed. Serum was collected for the measurement of blood lipids and hormones. It was found that WE1200 lowered body weight after 3 weeks of treatment and the effect was maintained throughout the remaining study period. WE1200 also lowered visceral fat mass, serum leptin, plasma free fatty acids and cholesterol, respectively. The energy expenditure was increased by WE1200 in both the light and dark periods. Oxygen consumption, carbon dioxide production and fat oxidation were increased in both light and dark periods, whereas carbohydrate oxidation increased only in the light period in the WE1200 group. Rats in the WE600 showed lower serum free fatty acids and leptin levels, while showing no effect on the other parameters compared to the control. These results demonstrated potential of using LWDH water extract to treat obesity and its related complications. The effect may be attributable to the increase of energy expenditure, decrease of food intake and improvement of leptin sensitivity.