[Yacon root extract improves lipid metabolism in hyperlipidemic rats by inhibiting HMGCR expression and activating the PPAR/CYP7A1/CPT-1 pathway].

Objective: To investigate the effect of yacon root extract on lipid metabolism in rats with hyperlipidemia (HLP) and its underlying mechanisms.

Methods: SD rat models of HLP induced by high- fat diet feeding for 8 weeks were randomized into the model group, fenofibrate treatment group (27 mg/kg), and yacon extract treatment groups at doses of 5, 2.5 and 1.25 g/kg (=10). The rats were given corresponding drug treatments via gavage for 8 weeks. After the treatments, the rats were observed for body weight changes, liver coefficient, liver pathology, and serum levels of triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C). The mRNA and protein expressions of HMGCR, PPAR, CYP7A1, and CPT-1 in the liver were detected using RT-qPCR and Western blotting.

Results: Compared with those in the model group, the rats treated with fenofibrate and 5 g/kg yacon root extract showed significantly slower body weight gain and lower liver coefficient ( < 0.05) with lower serum levels of TG, TC, and LDL- C ( < 0.05) but higher HDL- C level ( < 0.05). The HLP rat models showed obvious fatty degeneration and vacuolar changes in the liver, which were significantly alleviated by fenofibrate treatment and by treatment with yacon root extract in a dose-dependent manner. Both fenofibrate and 5 g/kg yacon root extract significantly lowered the mRNA and protein expression levels of HMGCR ( < 0.001) and increased the expressions of PPAR, CYP7A1, and CPT-1 in the liver of HLP rats ( < 0.001).

Conclusion: Yacon root extract can reduce serum TG and TC levels in HLP rats possibly by inhibiting HMGCR expression and activating the PPAR/CYP7A1/CPT-1 signaling pathway, thereby promoting fatty acid β oxidation and bile acid metabolism.