Abstract: Objective: In vitro and in vivo methods were used to explore the hypolipidemic effect of Undaria pinnatifida polysaccharide (PUP). Methods: In a simulating gastrointestinal environment, the taurocholate-binding capability of PUP and its inhibitory effect on pancreatic lipase were determined. C57BL/6J mice were fed a high-fat diet (HFD) to induce hyperlipidemia. The hyperlipidemic mice were gavaged with simvastatin, physiological saline or PUP at low and high doses. Body mass, four serum lipid parameters, serum antioxidant indices and serum and liver marker enzyme activities as well as hepatic pathological changes in the PUP groups and the hyperlipidemia group were measured and compared with each other. Results: At a concentration of 10 mg/mL, the binding rate of PUP to taurocholate was 52.3%, and the inhibition rate of pancrelipase by PUP at 1.0 mg/mL was 31.9%. In addition, PUP alleviated body mass gain in HFD-fed mice, suppressed the increase in total triglycerides (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), increased the level of high density lipoprotein cholesterol (HDL-C), and improved the antioxidant status. PUP also reduced the content of malondialdehyde (MDA), the activity of serum and liver marker enzymes and liver damage caused by HFD. Conclusion: PUP has a significant hypolipidemic effect in vitro and in vivo.

Key words: Undaria pinnatifida polysaccharide; in vitro simulation; animal experiment; hypolipidemia; liver damage