Identification and target of action of cholecystokinin-releasing peptides from simulated digestion hydrolysate of wheat protein

BACKGROUND

Wheat protein intake leads to improved appetite control. However, the active components causing appetite in wheat have not been fully clarified. Gut cholecystokinin (CCK) plays a vital role in appetite control. This study aimed to investigate the ability of wheat protein digest (WPD) to stimulate CCK secretion and clarify the active components and target of action.

RESULTS

WPD was prepared by a simulated gastrointestinal digestion model. WPD treatment with a concentration of 5 mg mL-1 significantly stimulated CCK secretion in enteroendocrine STC-1 cells (P < 0.05). Furthermore, oral gavage with WPD in mice significantly increased plasma CCK level at 60 min (P < 0.01). Preparative C18 column separation was used to isolate peptide fractions associated with CCK secretion and peptide sequences were identified by liquid chromatography-tandem mass spectrometry. A new CCK-releasing peptide, RYIVPL, that potently stimulated CCK secretion was successfully identified. After pretreatment with a specific calcium-sensing receptor (CaSR) antagonist, NPS 2143, CCK secretion induced by WPD or RYIVPL was greatly suppressed, suggesting that CaSR was involved in WPD- or RYIVPL-induced CCK secretion.

CONCLUSION

The present study demonstrated that WPD has an ability to stimulate CCK secretion in vitro and in vivo, and determined that peptide RYIVPL in WPD could stimulate CCK secretion through CaSR. © 2023 Society of Chemical Industry.

Banxia Xiexin decoction ameliorates dextran sulfate sodium (DSS)-induced ulcerative colitis via inhibiting serine-threonine protein kinase (Akt)/mitogen-activated protein kinase (MAPK) signaling pathway

Banxia Xiexin decoction (BXD), a traditional Chinese medicine, was widely used in treating ulcerative colitis (UC). However, the active components of BXD and its mechanism in UC remain elusive. Therefore, we used network pharmacology in vivo experiments, molecular docking, and surface plasmon resonance strategy (SPR) to uncover BXD's potential mechanism. A UC rat model was established by orally administering 7% dextran sulfate sodium (DSS) in drinking water, BXD and palmatine were orally administered for 7 days. Network pharmacology was used to investigate the main bioactive components and crucial targets of BXD in treating UC. Molecular docking was used to investigate interactions between components and crucial targets, verifying the results by SPR. By network pharmacology predicting, 20 active components and 44 candidate anti-UC targets of BXD were identified, and the crucial proteins were screeded from PPI network, including extracellular regulated protein kinases (ERK), AKT1, and tumor necrosis factor-α (TNF). In addition, some key active components (palmatine, sexangularetin, and skullcapflavone II) were screened out from the active components-targets network. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment and in vivo experiments showed that protein-serine-threonine kinase (Akt)/MAPK pathway was involved in BXD treatment for UC; BXD and palmatine significantly ameliorated the severity of DSS-induced UC in rats. Our study might assist in further investigation of the active components in Chinese medicine.