Insulin secretory actions of ethanolic extract of Acacia arabica bark in high fat-fed diet-induced obese Type 2 diabetic rats

Acacia arabica commonly known as 'babul' has been widely used for the treatment of nu-merous diseases, including diabetes due to their potential pharmacological actions. The aim of the present study was to investigate the insulinotropic and antidiabetic properties of ethanol extract of Acacia arabica (EEAA) bark through in vitro and in vivo studies in high fat-fed (HFF) rats. EEAA at 40-5000 & mu;g/ml significantly increased (P<0.05-0.001) insulin secretion with 5.6 and 16.7 mM glucose, respectively, from clonal pancreatic BRIN BD11 ⠂-cells. Similarly, EEAA at 10-40 & mu;g/ml demonstrated a substantial (P<0.05-0.001) insulin secretory effect with 16.7 mM glucose from isolated mouse islets, with a magnitude com-parable to 1 & mu;M glucagon-like peptide-1 (GLP-1). Diazoxide, verapamil, and calcium-free conditions decreased insulin secretion by 25-26%. The insulin secretory effect was further potentiated (P<0.05-0.01) with 200 & mu;M isobutylmethylxanthine (IBMX; 1.5-fold), 200 & mu;M tolbutamide (1.4-fold), and 30 mM KCl (1.4-fold). EEAA at 40 & mu;g/ml, induced membrane de-polarization and elevated intracellular Ca2+ as well as increased (P<0.05-0.001) glucose up-take in 3T3L1 cells and inhibited starch digestion, glucose diffusion, dipeptidyl peptidase-IV (DPP-IV) enzyme activity, and protein glycation by 15-38%, 11-29%, 15-64%, and 21-38% (P<0.05, 0.001), respectively. In HFF rats, EEAA (250 mg/5 ml/kg) improved glucose toler-ance, plasma insulin, and GLP-1 levels, and lowered DPP-IV enzyme activity. Phytochemical screening of EEAA revealed the presence of flavonoids, tannins and anthraquinone. These naturally occurring phytoconstituents may contribute to the potential antidiabetic actions of EEAA. Thus, our finding suggests that EEAA, as a good source of antidiabetic constituents, would be beneficial for Type 2 diabetes patients.

Automated summary

The aim of this study was to investigate the insulinotropic and antidiabetic properties of ethanol extract of Acacia arabica (EEAA) bark through in vitro and in vivo studies. The results showed that EEAA significantly increased insulin secretion, regulated blood glucose levels, and improved insulin resistance. These findings suggest that EEAA has potential antidiabetic effects.