Natural Compound α-PGG and Its Synthetic Derivative 6Cl-TGQ Alter Insulin Secretion: Evidence for Diminishing Glucose Uptake as a Mechanism.

Purpose: Previously we showed that natural compound α-penta-galloyl-glucose (α-PGG) and its synthetic derivative 6-chloro-6-deoxy-1,2,3,4-tetra-O-galloyl-α-D-glucopyranose (6Cl-TGQ) act to improve insulin signaling in adipocytes by increasing glucose transport. In this study, we investigated the mechanism of actions of α-PGG and 6Cl-TGQ on insulin secretion.

Methods: Mouse islets and/or INS-1832/13 beta-cells were used to test the effects of our compounds on glucose-stimulated insulin secretion (GSIS), intracellular calcium [Ca] using fura-2AM, glucose transport activity via a radioactive glucose uptake assay, intracellular ATP/ADP, and extracellular acidification (ECAR) and mitochondrial oxygen consumption rates (OCAR) using Seahorse metabolic analysis.