sapogenins and Obesity

Obesity is one of the most important health problems worldwide. Panax ginseng has been reported to exert anti-obesity effect. However, the active constituents and the underlying mechanism remained uncertain. This study uncovered the anti-obesity effect of protopanaxadiol (PPD) and its potential mechanism. To investigate the anti-obesity effect of PPD, high-fat diet induced obesity (DIO) C57BL/6 mice were treated with PPD by both intraperitoneal injection (i.p.) and oral administration. Body weight and food intake were recorded. Energy expenditure was measured by CLAMS metabolic cages. For mechanism study, C-Fos in the hypothalamus of the mice was stained following the intracerebroventricular (i.c.v.) injection of PPD. Our results showed that with both injection and feeding, PPD reduced body weight, inhibited food intake, increased energy expenditure and improved liver damage in DIO mice. Mechanistically, i.c.v. injection of PPD inhibited feeding and increased C-Fos expression in paraventricular nucleus of the hypothalamus (PVH). The results suggest that PPD may reduce body weight of DIO mice via the activation of PVH neurons and PPD is a potential therapeutic candidate for the treatment of obesity.

Topics: Animals; Body Weight; Diet, High-Fat; Energy Metabolism; Liver; Mice; Mice, Inbred C57BL; Neurons; Obesity; Paraventricular Hypothalamic Nucleus; Sapogenins

Obesity is prevalent worldwide, and is highly associated with metabolic disorders, such as insulin resistance, hyperlipidemia and steatosis. Ginseng has been used as food and traditional herbal medicine for the treatment of various metabolic diseases. However, the molecular mechanisms how ginseng and its components participate in the regulation of lipogenesis are still largely unclear. Here, we identified that protopanaxatriol (PPT), a major ginseng constituent, inhibited rosiglitazone-supported adipocyte differentiation of 3T3-L1 cells by repressing the expression of lipogenesis-related gene expression. In high-fat diet-induced obesity (DIO) mice, PPT reduced body weight and serum lipid levels, improved insulin resistance, as well as morphology and lipid accumulation, particular macrovesicular steatosis, in the livers. These effects were confirmed with genetically obese ob/ob mice. A reporter gene assay showed that PPT specifically inhibited the transactivity of PPARγ, but not PPAR α, β/δ and LXR α, β. TR-FRET assay revealed that PPT was specifically bound to PPARγ LBD, which was further confirmed by the molecular docking study. Our data demonstrate that PPT is a novel PPARγ antagonist. The inhibition of PPARγ activity could be a promising therapy for obesity and steatosis. Our findings shed new light on the mechanism of ginseng in the treatment of metabolic syndrome.

Topics: 3T3-L1 Cells; Adipocytes; Adipogenesis; Animals; Cell Differentiation; Diet, High-Fat; Disease Models, Animal; Electron Transport; Fatty Liver; Female; Gene Expression Regulation; Inflammation; Liver; Mice; Mitochondria; Obesity; Panax; PPAR gamma; Sapogenins

Effects of protopanaxdiol (PDG) and protopanaxatriol (PTG) types of ginsenosides isolated from the leaves of American ginseng on porcine pancreatic lipase activity were determined in vitro. PDG inhibited the pancreatic lipase activity in a dose-dependent manner at the concentrations of 0.25-1mg/ml. It inhibited hydrolysis of about 83.2% of triolein at about 1mg/ml of PDG. However, PTG showed no inhibitory activity. Therefore, anti-obesity activity of PDG was evaluated in mice fed a high-fat diet. The results demonstrated that PDG was effective in preventing and healing obesity, fatty liver and hypertriglyceridemia in mice fed with a high-fat diet.

Topics: Animals; Anti-Obesity Agents; Dietary Fats; Female; Ginsenosides; Mice; Molecular Structure; Obesity; Panax; Plant Leaves; Sapogenins

A previous study demonstrated that ginseng crude saponins prevent obesity induced by a high-fat diet in rats. Ginseng crude saponins are known to contain a variety of bioactive saponins. The present study investigated and compared the antiobesity activity of protopanaxadiol (PD) and protopanaxatriol (PT) type saponins, major active compounds isolated from crude saponins. Male 4-week-old Sprague-Dawley rats were fed with normal diet (N) or high-fat diet (HF). After 5 weeks, the HF diet group was subdivided into the control HF diet, HF diet-PD and HF diet-PT group (50 mg/kg/day, 3 weeks, i.p.). Treatment with PD and PT in the HF diet group reduced the body weight, total food intake, fat contents, serum total cholesterol and leptin to levels equal to or below the N diet group. The hypothalamic expression of orexigenic neuropeptide Y was significantly decreased with PD or PT treatment, whereas that of anorexigenic cholecystokinin was increased, compared with the control HF diet group. In addition, PD type saponins had more potent antiobesity properties than PT saponins, indicating that PD-type saponins are the major components contributing to the antiobesity activities of ginseng crude saponins. The results suggest that the antiobesity activity of PD and PT type saponins may result from inhibiting energy gain, normalizing hypothalamic neuropeptides and serum biochemicals related to the control of obesity.

Topics: Animals; Anti-Obesity Agents; Body Weight; Cholecystokinin; Cholesterol; Eating; Hypothalamus; Leptin; Male; Neuropeptide Y; Obesity; Panax; Rats; Rats, Sprague-Dawley; Sapogenins; Triglycerides