Antidiabetic and insulinotropic properties of bark of Heritiera fomes: inhibits starch digestion, protein glycation, DPP-IV activity, and glucose absorption in gut.

Heritiera fomes (Sundari) have been accepted as a supplement for the treatment of pre and post diabetes. The present study investigated the effects of ethanol extract of H. fomes (EEHF) on insulin release from clonal pancreatic β-cells and mouse islets and protein glycation, starch digestion, glucose diffusion, DPP-IV enzyme activity in vitro and glucose homeostasis in type 2 diabetic rats. EEHF, significantly stimulated insulin release in concentration-dependent manner from BRIN-BD11 cells and isolated mouse islets with stimulatory effects equivalent in magnitude to 1µM GLP-1. Insulinotropic effects of H. fomes (200µg/ml) on BRIN-BD11 cells were partly inhibited by verapamil, diazoxide and calcium free conditions showing importance of ion channels and Ca²⁺in mechanism of action. Secretion was further potentiated by activation of augmentation pathways revealed using IBMX, tolbutamide and

KCl. At 200µg/ml, EEHF induced membrane depolarization and increased intracellular Ca²⁺. Extract significantly inhibited starch digestion, DPP-IV activity, and decreased protein glycation. To investigate the possible effects on carbohydrate digestion, the sucrose content of the gastrointestinal tract was observed in 24h fasted rats after an oral sucrose load (2·5g/kg bw). The extract significantly inhibited postprandial hyperglycaemia after sucrose load and inversely increased unabsorbed sucrose content throughout the gut. The extract also significantly suppressed the absorption of glucose during in situ gut perfusion with glucose. Furthermore, the extract improved glucose tolerance and gut motility. This investigation hypothesized insulin release is the mechanism of action to control diabetes indeed and reassures to carry on to establish the plant for diabetes treatment.

Publication History

Article published online:
13 December 2021