Antioxidant and Hypoglycemic Activities of Mulberry Leaves Extract,Tea Polyphenols and Their Compounds

To investigate the antioxidant and hypoglycemic activities of mulberry leaf extract(MLE),tea polyphenols(TP)and their compounds,the DPPH and ABTS⁺ free radicals scavenging activities and inhibitory effects on key enzymes linked to diabetes(porcine pancreatic α-amylase,rat intestinal sucrase and maltase)were applied. The results showed that the antioxidant capacity of TP was the strongest,followed by MLE-TP compounds and MLE. And the MLE-TP compounds showed antagonistic effect in terms of the antioxidant activity. The MLE-TP compounds showed stronger inhibitory effects on the key enzymes of diabetes than MLE and TP. The Combination Index(CI)of MLE-TP compound with the mass ratio of 2:1 to α-amylase was 0.531,and the CI values of MLE-TP compound with the mass ratio of 1:1 to sucrose and maltase were 0.429 and 0.452,respectively. The MLE-TP compounds could enhance the inhibitory effects on the key enzymes linked to diabetes indicating synergistic hypoglycemic effects,which provided a theoretical basis for developing safe and effective natural functional products and related drugs for alleviating the diabetes.