Abstract: Objective: To study the hypoglycemic and lipid-lowering effects of Dendrobium officinale polysaccharide (DOP) in type 2 diabetic mice in order to provide a pharmacological basis for full utilization of Dendrobium officinale. Methods: Mice were injected intraperitoneally (100 mg/kg mb) with tetraoxopyrimidine to construct a mouse model of type 2 diabetes mellitus (T2DM). The following six groups of mice were set up: high-dose (450 mg/kg mb), medium-dose (300 mg/kg mb), low-dose (150 mg/kg mb) DOP, normal control, positive control (metformin hydrochloride, 250 mg/kg mb), and model groups. All animals were gavaged for 4 consecutive weeks. Blood biochemistry (triglycerides and total cholesterol content), renal function indexes (serum creatinine and urea nitrogen content) and antioxidant capacity were tested on the test mice. The results showed that: 1) Compared with the model group, DOP had a significant hypoglycemic effect in T2DM mice, especially at the high dose (P < 0.01), and it could significantly increase glucose tolerance (P < 0.05), high-dose DOP being as effective as metformin hydrochloride. 2) Compared with the model group, DOP could significantly reduce the contents of total cholesterol, low-density liptein cholesterol, and triglyceride and increase (high-density liptein cholesterol) content (P < 0.05), indicating that DOP can improve lipid metabolism disorders in diabetic mice. 3) Compared with the model group, DOP could significantly reduce serum urea nitrogen and creatinine levels (P < 0.05), indicating that DOP can improve kidney damage in diabetic mice. 4) Compared with the model group, DOP could significantly increase insulin level and reduce insulin resistance (IR). 5) Compared with the model group, DOP could significantly increase total antioxidant capacity (T-AOC), and the activity of superoxide dismutase (SOD) and catalase (CAT) (P < 0.05). Conclusion: DOP can significantly improve the antioxidant capacity in the liver and pancreas in diabetic mice and repair oxidative damage in the liver and pancreas, thereby increasing insulin level and alleviating insulin resistance, and finally exerting a hypoglycemic effect. DOP also has the function of improving lipid metabolism disorders and kidney injury in diabetic mice.

Key words: Dendrobium officinale polysaccharide; hypoglycemic and lipid-lowering effect; lipid metabolism; type 2 diabetes