Investigation on hypoglycemic effects of ethanol extract of Alpinia nigra (Gaertn.) in animal model.

BACKGROUND Our study aims at exploring the hypoglycemic effect, efficacy, and possible mode of action of ethanol extract of Alpinia nigra (EEAN) as an antidiabetic agent in an animal model. METHODS Oral glucose tolerance test (OGTT) was used to identify primary hypoglycemic effect in mice. Three tests (glucose absorption, sucrose absorption, and disaccharidase activity) were carried out by gut perfusion and six segments studies to assess carbohydrate absorption and glucose utilization. RESULTS In OGTT, at 400 mg/kg and 800 mg/kg dose of EEAN extract significantly improved oral glucose tolerance among normal mice at 60 min and 90 min with compared to control. Both doses of extract significantly (P < 0.01) reduced blood glucose level and showed the hypoglycemic effect by retarding 11.43% and 20.82% of blood glucose level after 2 h of administration in glucose-induced mice, respectively. In situ perfused rat intestinal model demonstrated reduced glucose absorption at a 500 mg/kg dose. Inhibition of intestinal disaccharidase was also found by the extract. This was confirmed, yet again, via the six segment study. Throughout the length of the gastrointestinal tract, sucrose digestion was found to be inhibited which is also evident in the six segment study. CONCLUSIONS This study suggests that the EEAN has hypoglycemic effects in a dose-dependent manner by inhibiting intestinal glucose absorption, and these may be effective in the treatment of diabetes. Further study is required to explicate the effect this extract or the active compounds have on the individual glucose transporters and the precise mechanism.