Rabbit Anti-Human TAS2R5 (internal) Polyclonal antibody

Qing-Hua Granule (QHG), the modified formulation of a classical Chinese prescription named Gegen Qinlian Decoction, was clinically employed to treat type 2 diabetes mellitus (T2DM) through regulation of glucagon-like peptide-1 (GLP-1). However, the potential mechanism is unknown. We investigate whether QHG induces GLP-1 secretion via activation of bitter taste receptor (TAS2R) pathway in the gastrointestinal tract of db/db mice. The db/db mice were intragastrically (i.g.) administered QHG (low/medium/high dose) once daily for 8 weeks. GLP-1 secretion was evaluated. The bitter receptor signaling pathway, which regulates GLP-1 secretion, including TAS2R5 (a subtype of TAS2R), a-gustducin (Gagust), 1-phosphatidylinositol-4, 5-bisphosphate phosphodiesterase beta-2 (PLCb2), transient receptor potential cation channel subfamily M member 5 (TRPM5), was assessed by quantitative real-time polymerase chain reaction (qRT-PCR), Western blot and immunohistochemistry (IHC). The biochemical observations of ileum and pancreas tissue were detected histopathologically. Acquity Ultra Performance LCTM - Micromass ZQ 2000 (UPLC-MS) was used for the phytochemical analysis. QHG exhibited significant and dose-dependent effect on GLP-1 secretion in db/db mice, along with significant up-regulation of TAS2R5 mRNA level and activation of TAS2R pathway (p < 0.05). In addition, QHG improved the histopathological structure of ileum and pancreatic tissue. Seventeen compounds were identified in QHG. In conclusion, QHG induces GLP-1 secretion in db/db mice, most likely through the bitter taste receptor pathway. (C) 2017 Elsevier Masson SAS. All rights reserved.

Polyphenols may contribute directly to plant-based foodstuffs flavor, in particular to astringency and bitterness. In this work, the bitterness of a small library of polyphenols from different classes [procyanidin dimers type B, ellagitannins (punicalagin, castalagin, and vescalagin) and phenolic acid ethyl esters (protocatechuic, ferulic, and vanillic acid ethyl esters] was studied by a cell-based assay. The bitter taste receptors (TAS2Rs) activated by these polyphenols and the half-maximum effective concentrations (EC50) of each agonist-TAS2Rs pair were determined. Computational methodologies were used to understand the polyphenol molecular region responsible for receptor activation and to get insights into the type of bonds established in the agonist-TAS2Rs pairs. The results show the combinatorial pattern of TAS2Rs activation. TAS2R5 seems to be the only receptor exhibiting a bias toward the activation by condensed tannins, while TAS2R7 seems more tuned for hydrolyzable (ellagi)tannins. Additionally, at the concentrations usually found for these compounds in foodstuffs, they can actively contribute to bitter taste, especially ellagitannins.