Purification and identification of a novel antidiabetic peptide from Chinese giant salamander (Andrias davidianus) protein hydrolysate against α-amylase and α-glucosidase

This study aimed to purify and identify a novel antidiabetic peptides from Chinese giant salamander (Andrias davidianus) protein hydrolysate and to evaluate its anti-diabetic properties against -amylase and -glucosidase. The isolation was done by gel filtration, reverse phase chromatography (RF-HLPC), and finally peptide and amino acid sequences were identified by LC/MS/MS system. Our results revealed five novel peptides that strongly inhibited -amylase and -glucosidase. The peptides' amino acid sequences were Cys-Ser-Ser-Val (MW=393.99Da), Tyr-Ser-Phe-Arg (MW=570.99Da), Ser-Ala-Ala-Pro (MW=343.89Da), Pro-Gly-Gly-Pro (MW=325.99Da) and Leu-Gly-Gly-Gly-Asn (MW=415.99Da) possessing -amylase inhibitory activity IC50 of 13.76x10(3), 10.82x10(3), 4.46x10(3), 4.23x10(3), and 2.86x10(3)mu g/mL, respectively; and for -glucosidase with IC50 of 206.00, 162.00, 66.90, 63.50, and 42.93 mu g/mL, respectively. Intriguingly, the peptide LGGGN showed higher inhibition on both -amylase and -glucosidase and could be considered as a potential anti-diabetic inhibitor.