Assessment of the DPP‐IV inhibitory activity of a novel octapeptide derived from rapeseed using Caco‐2 cell monolayers and molecular docking analysis

Abstract

The Octapeptide ELHQEEPL, which was identified from the rapeseed protein napin showed prominent Dipeptidyl peptidase-IV (DPP-IV) inhibitory activity. The objective of this study was to investigate the DPP-IV inhibitory activity and transepithelial transport of ELHQEEPL in an approaching intestinal condition using Caco-2 cell monolayers. ELHQEEPL and its degraded fragments EL, HQEEP, and methylated ELHQEEPL were transported across Caco-2 cell monolayers through different pathways. Compared with the nonbiological enzyme inhibition test, the in vitro experiment on Caco-2 cell monolayers showed that the IC 50 value of DPP-IV inhibition increased by 43.11% for ELHQEEPL. There was no significant change in DPP-IV gene expression in the Caco-2 cell monolayers upon treatment with ELHQEEPL. Furthermore, molecular docking predicted that the weaker binding between inhibitory peptide and enzyme for the degradation products from ELHQEEPL during transepithelial transport greatly limited its role in inhibiting DPP-IV. Practical applications The DPP-IV inhibitory activity of ELHQEEPL was confirmed using Caco-2 cell monolayers as a novel assessment tool, although its potency was reduced by metabolic degradation. In general, this study reported the use of Caco-2 cell monolayers as a tool for comprehensively studying peptides as sources of DPP-IV inhibitors. A Caco-2 cell-based approach with molecular docking can be adapted for the investigation of intestinal absorption and activity attenuation of food peptides being considered for enzymatic action. Moreover, since the Caco-2 cells express a wide range of enzymes, this method can be used for screening for other active food peptides such as for the

Enhancement of DPP-IV inhibitory activity and the capacity for enabling GLP-1 secretion through RADA16-assisted molecular designed rapeseed peptide nanogels

“…They can be attached more firmly to the brush border of human small intestinal epithelial cells to inhibit the effect of the DPP-IV enzyme in the intestinal lumen. As we previously reported, 7 peptide nanogels with RAP1 and RAP2 functional structures could not change the expression of the DPP-IV gene, but decreased the activity of DPP-IV. In addition to degradation during gastrointestinal digestion, the original structure of most of the oligopeptides can also be altered and modified on the intestinal epithelial cells.…”

In Vivo and In Vitro Comparison of the DPP-IV Inhibitory Potential of Food Proteins from Different Origins after Gastrointestinal Digestion

“…Most studies measure DPP-IV-inhibitory activity using purified and recombinant DDP-IV in vitro. Recently, an in vitro approach involving live intestinal epithelial Caco-2 cells was developed by our team [ 42 ], and has since been used in several studies to assess DPP-IV-inhibitory activity [ 33 , 39 , 42 , 43 , 44 ]. DPP-IV-inhibitory activity has also been measured ex vivo in rat and human plasma [ 13 , 45 , 46 , 47 , 48 ].…”

Protease Inhibitors Purified from the Canola Meal Extracts of Two Genetically Diverse Genotypes Exhibit Antidiabetic and Antihypertension Properties

“…Moreover, neither the individual PIs nor their polymorphisms have been reported in detail. More recently, different oilseed proteins, including from rapeseed, have demonstrated the presence of ACE- and DPP-IV-inhibitory peptides [ 30 , 31 ]. In this study, canola meal from two genetically diverse genotypes was used to discover six protease inhibitors, which were evaluated for their potential antidiabetic and antihypertension potential.…”

“…The ACE inhibition IC 50 values of the purified PI preparations of two canola genotypes, purified in this study, were compared with the IC 50 values of compounds from different species. These compounds included in vitro digested dry fruit bodies of Pleurotus ostreatus (IC 50 510 μg/mL) [ 31 ], yeast hydrolyzates (26.13 μg/mL [ 32 ], and chickpea accession BDN-9-3 (IC 50 22430 μg/mL [ 33 ]. Considering these values, canola meal PIs in our studies showed significant potential for ACE inhibition.…”