Puerariae flos alleviates metabolic diseases in Western diet-loaded, spontaneously obese type 2 diabetic model mice

Puerariae flos extract (PFE) has been reported to have many effects, including preventing the development of hangovers, liver protective effects, and an estrogenic effect. In addition, some papers reported that PFE is effective against metabolic diseases, with hypolipidemic and hypoglycemic effects. However, the mechanism underlying such effects remains unclear. For the purpose of clarifying the effect of PFE on metabolic diseases related to the accumulation of visceral fat and to determine the mechanism of such action, TSOD mice, a multifactorial genetic disease animal model that spontaneously develops various metabolic diseases such as obesity and type 2 diabetes, were given a Western diet (WTD) as an environmental factor to prepare a disease model (TSOD-WTD). When TSOD mice were loaded with WTD, it was confirmed that metabolic diseases such as obesity and abnormal glucose/lipid metabolism are aggravated. In contrast, PFE treatment to TSOD-WTD mice was shown to suppress body weight gain and visceral fat accumulation, alleviated the abnormal glucose tolerance and hyperinsulinemia, as well as causing an increase in blood adiponectin. Furthermore, the suppression of liver enlargement was observed in PFE-treated mice, with suppression of fatty degeneration and anti-inflammatory effect. In addition, to clarify the mechanism of the hyperlipidemia-alleviating effects in the liver, we investigated the effect of PFE on the expression of genes involved in cholesterol homeostasis. PFE was associated with a significant increase in gene expression for cholesterol synthesis rate-limiting enzyme HMG-CoA reductase, cholesterol catabolization enzyme Cyp7A1, bile salt export pump adenosine triphosphate-binding cassette transporter B11, and low-density lipoprotein receptor involved in cholesterol uptake. The above results suggest that PFE acts to alleviate the effects of various metabolic diseases based on the accumulation of visceral adipose tissue, including obesity, diabetes, and hyperlipidemia, with the promotion of catabolization/excretion of cholesterol in the liver being a key mechanism of action.