Bioactive Peptides from African Yam (AVIAIMF and GPADPF) and Taro (NGDF and NGNW) Reveal Multifunctional Antidiabetic Effects Using Biochemical and Cellular Models

The multifactorial nature of type 2 diabetes mellitus (T2DM) has driven a need to discover multifunctional antidiabetic peptides preferably from functional food sources for possible application as antidiabetic supplements. Herein, the antidiabetic effects of bioactive peptides previously identified in yam (AVIAIMF & GPADPF) and taro (NGDF & NGNW) were investigated. The peptides showed significantly ( p < 0.05) higher dipeptidyl peptidase IV inhibitory activities than vildagliptin with NGDF having the best activity. AVIAIMF, GPADPF, and NGNW significantly inhibited the formation of methylglyoxal-induced advanced glycosylated end products (AGEs) while AVIAIMF and NGNW showed oxygen radical scavenging (ORAC) activities. The peptides also showed significant ( p < 0.05) nitric oxide (NO) scavenging activities in murine macrophage (RAW 264.7) cells and were not cytotoxic to the RAW 264.7 cells in the presence and absence of lipopolysaccharide. The peptides did not show a biologically significant inhibition of lipid formation in 3T3-LI adipocytes and were not cytotoxic to human colon adenocarcinoma (Caco-2) cells, suggesting safety. The ORAC negatively correlated (− 0.40) with % AGEs formed and positively correlated (0.53 and 0.41) with the viability of LPS + and LPS- RAW 264.7 cells respectively. AVIAIMF, GPADPF and NGNW have shown promising multifunctional anti-T2DM activities that could be considered as potential antidiabetic peptides for application in functional antidiabetic foods.