Cocos nucifera and metformin combination for modulation of diabetic symptoms in streptozotocin induced diabetic rats

BACKGROUND: Cocos nucifera, belonging to Arecaceae family, holds quite an importance in the Indian traditional medicinal system. C.nucifera inflorescence (CnI) has been reported in the literature to be useful in the treatment of diarrhoea, dysentery, diabetes, and dyspepsia. In this study, we aimed to evaluate the efficacy of CnI as an adjuvant with metformin in ameliorating Type-2 diabetes mellitus (T2-DM). OBJECTIVES: To evaluate antidiabetic activity of CnI in combination with metformin in Streptozotocin (STZ) induced diabetic rats. MATERIALS AND METHODS: Diabetes was induced in male Wistar rats using streptozotocin (45 mg/kg; i.p.). Plasma glucose level (PGL) was estimated after 72 h of STZ injection. Ethanolic extract of CnI (250 mg/kg and 500 mg/kg) per se and in combination with metformin (22.5 mg/kg) was administered orally once daily to rats for a period of 28 days. PGL level was estimated on 7(th), 14(th) and 21(st) day followed by Oral Glucose Tolerance Test (OGTT) and PGL both on the 28(th) day of treatment. DPPH assay was performed to evaluate antioxidant activity of CnI extract. RESULTS: Extract of CnI (250 mg/kg and 500 mg/kg alone and the combination of extract (250 mg/kg) along with metformin (22.5 mg/kg) significantly decreased PGL (p < 0.0001) on 7(th), 14(th), 21(st) and 28(th) days. Histopathological analysis of pancreatic tissue showed that treatment with CnI extract per se and in combination with metformin improved the damaged architecture of pancreas. CONCLUSION: The combination therapy of CnI and metformin produced a significant antidiabetic effect than that of the extract alone and provides a scientific rationale for their use in antidiabetic therapy as an adjuvant.