Evaluation of Antidiabetic Activity of Methanolic Leaf Extract of Nephelium lappaceum L. against Streptozotocin-Nicotinamide Induced Type-II Diabetes in Wistar Albino Rats

Abstract

Leaves of Nephelium lappaceum L. Family Sapindaceae has been traditionally used in many Asian countries for several therapeutic purposes. However, the antidiabetic activity of leaf has not been scientifically investigated so far. The aim of this study therefore, was to evaluate the antidiabetic activity of methanolic leaf extract of Nephelium lappaceum (MLEN) against streptozotocin (STZ) - nicotinamide (NIC) induced type II diabetes in albino rats. Non-insulin dependent diabetes mellitus was induced in overnight fasted rats by a single intraperitoneal injection of 60mg/kg streptozotocin 15min after the i.p administration of 120mg/kg of nicotinamide. The diabetic rats were treated with 28 days by the oral administration of methanolic leaf extract of Nephelium lappaceum L. (400 and 800mg/kg/b.w). In glucose to tolerance test, MLEN markedly reduced the external glucose load. Fasting blood glucose level, body weight were monitored every 7 days during the treatment. At the end of the study fasting blood glucose level, haemoglobin, HbA1c, kidney (urea, creatinine) functional test, liver (SGOT, SGPT) functional test and in vivo antioxidant markers (GSH, CAT, SOD, Vitamin C and LPO) were estimated. Histopathology of pancreas was carried out to assess antidiabetic effect of MLEN. After treatment with MLEN fasting blood glucose, HbA1c levels, SGOT, SGPT and LPO were significantly decreased in diabetic rats. However, haemoglobin, CAT and GSH levels were significantly increased in MLEN treated diabetic rats. The histopathological study of the pancreas in extract treated diabetic group’s revealed regeneration of beta cells. The methanolic leaf extract of Nephelium lappaceum L. was evaluated for its effect on blood sugar, against the STZ –NIC induced diabetic rats and compared it with standard drug metformin. The result of this experimental study concluded that MLEN of Nephelium lappaceum L. leaves possess safe and strong antidiabetic activity against STZ-NIC induced diabetic rats.