Polysaccharides from Laminaria japonica show hypoglycemic and hypolipidemic activities in mice with experimentally induced diabetes

Diabetes mellitus (DM) is a chronic metabolic disorder of the endocrine system. The rapid increase in the incidence of DM is a serious public health concern worldwide. The treatment of DM and its complications mainly involves the use of chemically or biochemically synthesized drugs, but these drugs also have adverse side effects. Therefore, there is an urgent need to search for drugs from natural sources that would cause fewer side effects. This study aimed to determine whether polysaccharides from Laminaria japonica (LJP) exert hypoglycemic and hypolipidemic effects in mice with alloxan-induced diabetes. To this end, diabetes was induced by alloxan injection (200 mg/kg body weight [bw], intraperitoneal [ip]). After induction of diabetes, diabetic mice were randomly divided into five groups: diabetic control (DC) group, glibenclamide-treated (DG) group, low-dose LJP-treated (DLL) group, moderate-dose LJP-treated (DML) group, and high-dose LJP-treated (DHL) group, with normal mice used as the control group (NC group). After treatment for 28 days, body weight, fasting blood glucose (FBG), serum insulin, total cholesterol (TC), triglyceride (TG), high-density lipoprotein-cholesterol (HDL-C), and low-density lipoprotein-cholesterol (LDL-C) levels were measured. The results revealed that LJP administration prevented body-weight loss, decreased FBG levels, and increased serum insulin levels in diabetic mice. Furthermore, it decreased TC, TG, and LDL-C levels, and increased HDL-C levels in these mice. Thus, the results indicate that LJP possesses hypoglycemic and hypolipidemic activities and polysaccharides from LJP may hold promise for the development of a drug of natural origin for the treatment of DM.