Pentamethylquercetin reduces fat deposition via Sirt1-mediated pathways in male obese mice induced by a high fat diet.

Pentamethylquercetin (PMQ) is a natural quercetin derivative found in a variety of edible herb. Although PMQ has potential as anti-diabetic agent, there have been no reports on its anti-adipogenic effects in the obese animals. This study investigated whether PMQ attenuates high-fat diet (HFD)-induced adipogenesis in the epididymal fat tissues of mice and explored its underlying mechanisms. In comparison with HFD-fed mice, mice fed with PMQ showed significantly lower body weight gain, adipose tissue mass, and plasma levels of triglyceride, total cholesterol, low-density lipoprotein cholesterol, and glucose, but higher plasma levels of high-density lipoprotein cholesterol. PMQ significantly reversed the HFD-induced regulation of Sirt1/mTOR signaling genes (Sirt1, mTOR, 4EBP1, and S6K1), and key adipogenic genes (PPARγ, SREBP1, FAS, ATGL, HSL, and Perilipin) in the epididymal adipose tissues of obese mice. However, nicotinamide appeared to partly inhibit PMQ-mediated anti-adipogenic effects involved in this attenuation. These results suggested that PMQ inhibited visceral adipogenesis by suppressing the Sirt1-mediated mTOR and adipogenesis signaling cascades. It might be a potential candidate for the treatment of obesity.

Hypolipidemic and antioxidant activities of polysaccharides from Rosae Laevigatae Fructus in rats.

Two major fractions (RLP-1 and RLP-2) were obtained by purifying the crude polysaccharides extracted from a traditional Chinese herb Rosae Laevigatae Fructus. The average molecular weight of RLP-1 and RLP-2 was 21.5 kDa and 16.1 kDa, respectively. Monosaccharide analysis indicated that RLP-1 was composed of xylose, mannose and galactose in the molar ratio of 1:11:8, while RLP-2 was only a glucan. Oral administration of RLP-1 could significantly decrease levels of serum total cholesterol (TC), triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C), inhibit hepatic lipid accumulation, increase antioxidant lipids and up-regulate expressions of peroxisome proliferator-activated receptor-γ (PPAR-γ) and lipoprotein lipase (LPL) in hyperlipidemia rats. These results suggest that RLP-1 improve hyperlipidemia possibly through regulating PPAR-mediated lipid metabolism. Therefore, could be explored as a possible agent for hyperlipidemia.

Dietary quercetin ameliorates nonalcoholic steatohepatitis induced by a high-fat diet in gerbils.

Dietary quercetin is highly abundant in edible plants, which possesses a wide range of pharmacological properties. This study was to investigate hepatoprotective effects of quercetin in the nonalcoholic steatohepatitis (NASH) gerbils induced by a high-fat diet (HFD), and to evaluate its regulatory mechanism on hepatic inflammatory response. The gerbils were fed with HFD for 28 days to induce NASH. From 15th day to 28th day, the treated drugs were given daily to each animal, respectively. The lipid profiles and biochemical markers were determined at the end of the experiment. The expressions of Sirt1, NF-κB p65 and iNOS were detected by immunohistochemistry and Western blot analysis. The results showed that oral administration of quercetin at doses of 30-60 mg/kg to hyperlipidemia rats for 14 days were highly effective in decreasing the levels of serum total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), alanine aminotransferase (ALT) and aspartate aminotransferase (AST). It could decrease lipid accumulation in the hepatocytes, and reduce serum levels of pro-inflammatory cytokines TNF-α and IL-6 via regulating the expressions of Sirt1, NF-κB p65 and iNOS. Thus, dietary quercetin had significant therapeutic benefits and could be explored as a potential promising candidate for the prevention of NASH.