In vitro modulation of glucagon-like peptide release by DPP-IV inhibitory polyphenol-polysaccharide conjugates of sprouted quinoa yoghurt

Abstract

Glucagon-like peptide-1 (GLP-1) is an important signal in the peripheral and neural systems, which contributes to the maintenance of glucose and energy homeostasis. In this study, 1H NMR validated polyphenols and polysaccharides extracted from sprouted quinoa yoghurt were used as isolates and conjugates to upregulate the stimulation of GLP-1 release in NCI-H716 cells. In addition, we explored their effect on proglucagon and prohormone convertase 3 mRNA expressions, HNF-3γ and CCK-2R gene protein expression, as well as cytosolic calcium release. Variations in concentration showed a dose-dependent GLP-1 stimulation, and were significantly optimized by germination. Proglucagon mRNA expression in NCI-H716 cells was upregulated, and was relatively highest with QYPSP1 treatments in a 2.68 fold. The results suggested that the conjugates had greater potential to stimulate GLP-1 release than their isolates. Sprouted quinoa yoghurt could therefore be a potential functional food useful to regulate glucose and energy homeostasis.