Production of Dipeptidyl Peptidase-IV Inhibitory Peptides from Germinated Jack Bean [Canavalia ensiformis (L.) DC.] Flour

Abstract

An alternate plant-based protein, jack bean sprout, was explored as a source of bioactive peptides. Germination to increase dipeptidyl peptidase-IV (DPP-IV) inhibitory peptide in jack bean sprout flour has yet to be reported. Therefore, this study aimed to investigate the optimal condition to maximize the content of bioactive peptides with maximum DPP-IV inhibitory activity. The relationship between germination and DPP-IV inhibitory activity was determined by analyzing the proteolytic activity, percentage of degree of hydrolysis (%DH), and peptide content. Peptide samples with the most potent DPP-IV inhibitory activity were subsequently fractionated, identified, and characterized. The 60-h germinated jack bean had the best DPP-IV inhibitory activity (41.57%; half maximal inhibitory concentration=2.24 mg/mL). Proteolytic activity (15.24 unit/g), %DH (11.43%), and peptide content (59.71 mg/g) supported this result. Furthermore, the <1.0 kDa peptide fraction of this sprouted flour had the highest molecular weight (MW) distribution (32.60%) and DPP-IV inhibitory activity (71.99%). Peptide sequences identified from MW <1.0 and 1.0∼3.5 kDa peptide fractions had valine, leucine, isoleucine, glycine, and tryptophan at the N-terminal and also had alanine at the penultimate N-terminal, verifying their presence as DPP-IV inhibitors. Furthermore, peptide sequences generated exhibited other biological activities, including angiotensin-converting enzyme, renin, and -glucosidase inhibitors.

Computational Screening for the Dipeptidyl Peptidase-IV Inhibitory Peptides from Putative Hemp Seed Hydrolyzed Peptidome as a Potential Antidiabetic Agent

“…From our hypothesis, hemp seed peptides might exhibit antidiabetic properties comparable to those of edible plant-derived peptides, as reported in previous studies. For example, short, low-molecular-weight peptides from Bambara bean (hydrolyzed by alcalase); soy, quinoa, and lupine (subjected to sequential hydrolysis with subtilisin–trypsin–flavourzyme); and jack bean (digested by pepsin–pancreatin) have been experimentally shown to possess DPPIV inhibitory properties through in vitro enzyme activity tests [ 18 , 29 , 60 , 61 ]. Currently, the idea of predicting and simulating the digestion of plant high-abundance proteins through gastrointestinal tract enzymes (pepsin, trypsin, pancreatin, and chymotrypsin) to represent the peptidome profile in the human gut after a meal has been applied to many edible plants [ 21 , 24 , 29 , 62 , 63 , 64 ].…”

“…This approach allows for the observation of not only the availability of these bioactive peptides but also their absorption potential using the everted gut sac method [ 29 ]. Through computer-aided analysis, in silico studies employing bioinformatics approaches have identified potential antidiabetic peptides in macadamia, soybean, black bean, and hemp [ 17 , 18 , 34 , 36 , 40 , 41 ]. Together with our virtual screening and validation results, these findings suggest that hemp seed peptides could play a therapeutic role in managing diabetes through DPPIV inhibition.…”

“…Most DPPIV inhibitory peptides are derived from plant-based sources, which cost less compared to animal-based proteins [ 16 ]. Peptides from plants such as macadamia and jack bean have been reported to have DPPIV inhibitory peptide properties [ 17 , 18 ], which is one of the curative methods for diabetic patients.…”