Optimization of the conditions for microwave-assisted hot-water extraction of polysaccharides from Cordyceps militaris and analysis of their hypoglycemic activity

Cordyceps militaris is recognized for its health benefits in humans. In this study, we optimized the conditions required for microwave-assisted hot-water extraction of polysaccharides isolated from Cordyceps militaris (CM-P) using response surface methodology. The hypoglycemic effects of CM-P were evaluated in vitro and in vivo. The results showed that the optimal extraction conditions for CM-P were a microwave power of 430 W, a microwave time of 5 min, a solid–liquid ratio of 1:44, and three extractions. Under these conditions, we achieved an extraction rate for CM-P of 9.73% ± 0.16%. Within a concentration range of 1.0–10.0 mg/mL, the α-amylase and α-glucosidase inhibition rates of CM-P reached 63.82% ± 1.78% and 60.81% ± 0.94%, respectively, demonstrating the potent hypoglycemic activity of CM-P in vitro. In diabetic mice, CM-P treatment reduced blood glucose and insulin levels and improved insulin sensitivity and glucose tolerance in a dose-dependent manner. CM-P intervention also ameliorated lipid metabolism disorders and alleviated oxidative stress and inflammation. Histological analysis indicated that CM-P improved the organ index of the liver and kidney and reversed pancreatic, adipose, liver, and aortic injuries caused by diabetes. This study demonstrates that CM-P exhibits remarkable hypoglycemic effects and provides a theoretical basis for the development and utilization of polysaccharides from Cordyceps militaris.