Effects of hydroxycitrate, conjugated linoleic acid, and guar gum on food intake, body weight regain, and metabolism after body weight loss in male rats

Garcinia cambogia Extract Increased Hepatic Levels of Lipolysis-Stimulated Lipoprotein Receptor and Lipids in Mice on Normal Diet

Garcinia cambogia extract (GCE) is a popular weight-loss supplement that also lowers plasma triglyceride (TG) levels. We hypothesized that GCE-mediated inhibition of ATP citrate lyase and thereby hepatic TG production could lead to compensatory mechanisms, including increased hepatic TG uptake via lipoprotein receptors. GCE (20 mg/day) administered 40 days orally to female C57BL/6Rj mice on a standard chow diet led to a decrease in both plasma fasting and post-prandial TG-rich lipoprotein levels, but with no significant change in body weight gain. Lipolysis stimulated lipoprotein receptor (LSR) protein levels, but not those of LDL-receptor, were increased as compared to controls. Mouse Hepa1-6 cells treated with the GCE active ingredient, hydroxycitrate, also led to increased LSR protein levels. Hepatic total cholesterol, TG, and muscle TG contents were higher in GCE-treated animals as compared to controls, whereas adipose TG levels were unchanged. LSR and LDL-receptor protein levels were correlated with liver total cholesterol, but only LDL-receptor was associated with liver TG. These results show that GCE treatment in mice on a standard chow diet led to significantly increased liver and muscle lipids, with no significant change in adipose tissue TG levels, which should be considered in the long-term use of GCE.

Antiobesity and Cholesterol-Lowering Effects of Dendropanax morbifera Water Extracts in Mouse 3T3-L1 Cells

Obesity is the most common metabolic disease in developed countries and has become a global epidemic in recent years. Obesity is associated with various metabolic abnormalities, including glucose intolerance, insulin resistance, type 2 diabetes, dyslipidemia, and hypertension. Leaves from the plant Dendropanax morbiferus are beneficial to health as they contain high levels of vitamin C and tannin. There have been seminal studies on the anticancer, antimicrobial, antidiabetes, and antihyperglycemic effects of treatments with D. morbiferus trees. Herein, we investigated the toxicity of D. morbiferus water (DLW) extracts in vitro, and demonstrated no toxicity at 5-500 μg/mL in 24-72-h experiments with 3T3-L1 cells. The DLW increased cell viability at 48 h and inhibited adipogenesis in 3T3-L1 cells by reducing intracellular triglyceride levels and glucose uptake. In addition, mRNA and protein expression levels of adipogenesis-related genes were lowered by DLW, suggesting antiobesity effects in mouse 3T3-L1 cells. Because few studies have demonstrated cholesterol-lowering effects of D. morbiferus, we investigated the activities of adipogenic transcriptional factors following treatments of 3T3-L1 cells with D. morbiferus and observed increased CEBPα, CEBPβ, PPARγ, and SREBP1 activities in the cells, indicating that DLW extracts inhibit adipogenesis.

Effect of dietary Garcinia cambogia extract on serum essential minerals (calcium, phosphorus, magnesium) and trace elements (iron, copper, zinc) in rats fed with high-lipid diet

The aim of the study was to investigate the effect of Garcinia cambogia extract on serum calcium (Ca), phosphorus (P), magnesium (Mg), iron (Fe), zinc (Zn) and copper (Cu) concentrations in rats fed with the normal or the high-lipid and -cholesterol diet. Thirty 1-year-old female Sprague-Dawley rats (pathogen-free), weighing an average of 229 g, were randomly assigned to three experimental groups of ten animals each. Diets and tap water were given ad libitum for 75 days. Group 1 (control group) was fed with basal diet (2 % liquid vegetable oil, 0 % cholesterol), while the diets of groups 2 and 3 contained vegetable oil (2 % liquid vegetable oil and 5 % hydrogenated vegetable oil) and cholesterol (3 %) in high levels. 4,5 % G. cambogia extract containing 65 % HCA was added to the diet of group 3 as from day 45. Blood samples were withdrawn on days 0, 45 and 75. Serum mineral levels were analyzed using standard enzymatic colorimetric methods with a spectrophotometer. All significant differences were p<0.05. Serum Ca levels were not significantly different between all groups on days 45 and 75. Serum P level was significantly higher in the group fed with high-lipid diet and G. cambogia extract than in the control group on day 45. Serum Mg level was significantly higher in group 2 than in the control group on day 45. Serum Fe levels were significantly lower in the control group than in the other groups on days 45 and 75. Serum Zn level of the group fed with high-lipid diet and G. cambogia extract was significantly higher than in the control group on day 75. Serum Cu levels were significantly higher in group 2 than in the control group, and in group 3 than in group 2 on day 75. In conclusion, a diet containing the high fat amounts may lead to the increase in circular levels of some minerals due to the short-chain fatty acid production lowering the luminal pH which increases mineral solubility, or serving as a fuel for mucosal cells and stimulating cell proliferation in the large intestine. G. cambogia extract may be used in the P and Cu deficiencies due to increases resulting in the present P and Cu amounts in G. cambogia extract, or the use of phytate P in diet. It was hoped that with further evidence-based study this product will enter to mainstream medicines.

Beneficial and deleterious effects of hydroxycitrate in rats fed a high-fructose diet

OBJECTIVE

The present study assessed whether long-term supplementation of a high-fructose diet with hydroxycitrate (HCA), an inhibitor of de novo lipogenesis that is widely used as a non-prescription dietary aid, decreases food intake, visceral fat accumulation, hypertriglyceridemia, and hyperinsulinemia in rats.

METHODS

We examined the effects of HCA (1.8% of diet) on food intake, body weight gain, visceral fat accumulation, hypertriglyceridemia, and hyperinsulinemia in rats during a 4-wk period of ad libitum access to a 50% fructose diet after a 3-wk period of food restriction in which they lost about 20% of their body weight.

RESULTS

HCA decreased food intake and weight gain throughout the test and reduced visceral fat accumulation compared with control rats fed ad libitum (CON). Rats that were pair-fed (PF) to the HCA rats showed similar decreases in weight gain and visceral fat. HCA did not ameliorate the hypertriglyceridemia induced by high-fructose feeding. HCA improved insulin sensitivity on day 10 in comparison with CON rats, but by day 27 insulin levels were similarly higher and liver glycogen levels were similarly lower in HCA and CON rats in comparison with PF rats. Liver lipid content was elevated in HCA rats compared with CON and PF rats.

CONCLUSION

These findings indicate that, although HCA attenuates body weight gain and visceral fat accumulation by reducing food intake under these conditions, it has no lasting beneficial effects on hypertriglyceridemia and hyperinsulinemia and leads to the accumulation of liver lipids.