The investigation of α-amylase inhibitory activity of selected Pinto bean peptides via preclinical study using AR42J cell

- BPs successfully inhibited the activity of α-amylase which secreted from AR42J cell.
- The inhibitory activity was dose-dependent and achieved up to 97.9%
- PBP9 is the most potent α-amylase inhibitor with IC50 value of 0.31 mM.
- MTT assay showed that PBP induced dose dependent effect on the cell viability.
- Different inhibition modes were found among the PBPs.

The current work investigated the α-amylase inhibitory activity of five selected Pinto bean peptides (PBPs) using AR42J cell. The objectives were: (a) to prove the potential of PBPs as α-amylase inhibitor in living cells, and (b) to investigate the inhibition mode of PBPs. Results showed that PBP9 obtained the lowest IC50 value of 0.31 mM followed by PBP7 (5.92 mM), PBP1 (6.08 mM), PBP6 (6.14 mM) and PBP3 (6.64 mM). In the MTT assay, all PBP showed a dose-dependent trend, whereby lower concentration of PBP demonstrated a higher cell viability. By using PBP concentrations of 0.33-8.3 mM, Michaelis-Menten kinetic parameters and Lineweaver-Burk plots revealed that Km and Vmax values were ranged from 38.52-794.38 mM and 0.72-1.15 mM/min, respectively, resulting in uncompetitive (PBP3, PBP6 and PBP7) and unusual (PBP1 and PBP9) α-amylase inhibition modes. It was suggested that PBP could be considered as new agents for the diabetes treatment.