Stachys sieboldii Miq. Root Attenuates Weight Gain and Dyslipidemia in Rats on a High-Fat and High-Cholesterol Diet

This study aimed at investigating the anti-obesity and anti-dyslipidemic effects of Stachys sieboldii Miq. root (SS) powder in rats following a high-fat and high-cholesterol (HFC) diet for 6 weeks. Thirty-two Sprague-Dawley rats were fed one of the following diets: a regular diet (RD), HFC, HFC supplemented with 3% SS (HFC + 3SS) or HFC supplemented with 5% SS (HFC + 5SS). Following an HFC diet increased body weight (BW) gain (p < 0.001) and the food efficiency ratio (FER; p < 0.001); however, SS consumption gradually prevented the HFC-induced BW gain (p < 0.001) and increase in FER (p < 0.01). The HFC diet resulted in increased liver size (p < 0.001) and total adipose tissue weight (p < 0.001), whereas the SS supplementation decreased hepatomegaly (p < 0.05) and body fat mass (p < 0.001). SS consumption prevented the increased activities of serum alanine aminotransferase (ALT; p < 0.001), aspartate aminotransferase (AST; p < 0.001), alkaline phosphatase (ALP; p < 0.01 in HFC + 5SS) and lactate dehydrogenase (LDH; p < 0.001 in HFC + 5SS) induced by the HFC diet (p < 0.001). The SS supplementation improved lipid profiles in the circulation by lowering triglyceride (TG; p < 0.01), total cholesterol (TC; p < 0.001) and non-HDL cholesterol (non-HDL-C; p < 0.001) levels, as well as the atherogenic index (p < 0.01) and cardiac risk factor (p < 0.01). The lipid distribution in the liver (p < 0.05) and white adipose tissues (WAT; p < 0.001) of the HFC + SS diet-consuming rats was remarkably lower than that of the HFC diet-consuming rats. The average size of the epididymal adipose tissue (p < 0.001) was significantly lower in the HFC + SS diet-fed rats than in the HFC diet-fed rats. The fecal lipid (>3% SS; p < 0.001) and cholesterol (5% SS; p < 0.001) efflux levels were significantly elevated by the SS supplementation compared to those measured in the RD or HFC diet-fed groups. In addition, the hepatic lipid and cholesterol metabolism-related gene expressions were affected by SS consumption, as the hepatic anabolic gene expression (Acc; p < 0.001, Fas; p < 0.001 and G6pdh; p < 0.01) was significantly attenuated. The HFC + 5SS diet-fed rats exhibited elevated hepatic Cyp7a1 (p < 0.001), Hmgcr (p < 0.001) and Ldlr (p < 0.001) mRNA expression levels compared to the HFC diet-fed rats. These results suggest that SS may possess anti-adipogenic and lipid-lowering effects by enhancing lipid and cholesterol efflux in mammals.

Keywords: Stachys sieboldii Miq; anti-obesity; cholesterol-lowering; high-fat and high-cholesterol (HFC) diet.