Flavonoids extracted from Linaria vulgaris protect against hyperlipidemia and hepatic steatosis induced by western-type diet in mice.

Previous studies have shown that flavonoids (Fs) present in Linaria vulgaris inhibit lipid accumulation in vitro. This study was designed to evaluate the effects of Fs extracted from Linaria vulgaris ssp. sinensis (Bebeaux) Hong, on hyperlipidemia and hepatic steatosis induced by a western-type diet in mice. The major constituents of Fs were analyzed by LC-MS analysis. C57BL/6 mice were fed a western-type diet for 8 weeks to induce hyperlipidemia (model group), or fed a western-type diet followed by Fs treatment (90, 30 or 10 mg/kg/day) or atorvastatin treatment (1.0 mg/kg/day), for 8 weeks. It was found that Fs treatment resulted in significant reductions in serum levels of AST, ALT, TC, TG, LDL-C, free fatty acid and hepatic TC, and TG compared to those in model mice with hyperlipidemia (P < 0.05). The mice treated with Fs showed a relatively normal hepatic architecture compared to the hepatic steatosis shown in the model group. Moreover, the expressions of mature forms of sterol regulatory element-binding proteins (nuclear form of srebps, n-SREBPs) and 3-hydroxy-3-methylglutaryl coenzyme reductase (HMGCR) involved in lipid metabolism, were suppressed in the Fs-treated groups. Taken together, these results suggest Fs exert protective effects against hyperlipidemia and hepatic steatosis, which may involve the inhibition of mature SREBPs expressions.