α-Glucosidase inhibitory peptides screened from Trichosanthes kirilowii seed: Characterization, activity and potential mechanism

Trichosanthes kirilowii seeds (TKSs) represent an underutilized resource for generating bioactive peptides owing to high content of protein. However, the hypoglycemic properties of the peptides are unelucidated. To explore potential hypoglycemic peptides, TKSs proteins hydrolysates (TPHs) were prepared, fractionated and their anti-α-glucosidase activity were evaluated. The results indicated that < 3 kDa fraction from TPHs obtained by the hydrolysis of trypsin exhibited higher α-glucosidase inhibitory activity. Four candidate inhibitory peptides (HRQTWD, HANRLP, FGGVGER, SYAPEDR) were screened from this fraction using LC-MS/MS, showing a IC 50 in the range of 71.31 ± 1.19 to 1245.22 ± 147.3 μM. These peptides inhibited α-glucosidase by binding to its D203, D327, D443, F450, D542, and F575 through secondary interactions such as hydrogen bonding. This study demonstrates the efficacy of TPHs as dietary hypoglycemic agents and establishes a feasibility for their utilization in functional food development.