Fucoidan ameliorates steatohepatitis and insulin resistance by suppressing oxidative stress and inflammatory cytokines in experimental non-alcoholic fatty liver disease

Fucoidan, a sulfated polysaccharide derived from brown seaweeds, possesses a wide range of pharmacological properties. In the present study, we investigated the therapeutic effect of fucoidan on non-alcoholic fatty liver disease (NAFLD) in rats. Rats were fed a high-fat diet (HFD) for 12 weeks to induce NAFLD. Oral administrations of fucoidan (100 mg/kg, orally), metformin (200 mg/kg, orally) or the vehicle were started in the last four weeks. Results showed that administration of fucoidan for 4 weeks attenuated the development of NAFLD as evidenced by the significant decrease in liver index, serum liver enzymes activities, serum total cholesterol and triglycerides, fasting serum glucose, insulin, insulin resistance, and body composition index. Further, fucoidan decreased hepatic malondialdehyde as well as nitric oxide concentrations, and concomitantly increased hepatic reduced glutathione level. In addition, the effect of fucoidan was accompanied with significant decrease in hepatic mRNA expressions of tumor necrosis factor-α, interleukins-1β and matrix metalloproteinase-2. Furthermore, histopathological examination confirmed the effect of fucoidan. In conclusion, fucoidan ameliorated the development of HFD-induced NAFLD in rats that may be, at least partly, related to its hypolipidemic, insulin sensitizing, antioxidant and anti-inflammatory mechanisms.