Antidiabetic activities of aqueous and ethanolic extracts of Piper betle leaves in rats

Leaves of Piper betle (Piperaceae) possess several bioactivities and are used in traditional medicinal systems. However, its antidiabetic activity has not been scientifically investigated so far. The aim of this study therefore, was to investigate the antidiabetic activity of Piper betle leaves. This was tested in normoglycaemic and strepozotocin (STZ)-induced diabetic rats using oral administration of hot water extract (HWE) and cold ethanolic extract (CEE). In normoglycaemic rats, both HWE and CEE significantly lowered the blood glucose level in a dose-dependent manner. In glucose tolerance test, both extracts markedly reduced the external glucose load. The antidiabetic activity of HWE is comparable to that of CEE. Moreover, HWE failed to inhibit the glucose absorption from the small intestine of rats. Both extracts were found to be non-toxic and well tolerated after following chronic oral administration (no overt signs of toxicity, hepatotoxicity or renotoxicity). However, the weight of the spleen had increased in treated groups possibly indicating lymphoproliferative activity. It is concluded that HWE and CEE of Piper betle leaves possess safe and strong antidiabetic activity.