Abstract
This study was aimed to investigate the efficacy of aqueous extract of neem (Azadirachta indica), nayantara leaves (Catharanthus roseus), garlic (Allium sativum) and to compare their efficacy with a patent drug (Comet) Metformin hydrochloride (MetHCL) against healthy and Streptozotocin (STZ) induced diabetic rats. Effects of herbal extracts on body weight (bwt), biochemical and haematological changes were observed. Male rats (Rattus norvagicus; n = 324) were divided into 18 equal groups. Extracts of neem, nayantara and garlic @ 300 & 600 mg/kg bwt and MetforminHCI @ 250 & 500 mg/kg bwt were administered daily orally to eight groups of STZ induced diabetic rats and eight groups of healthy rats for 180 days, keeping one group as diabetic control (DC) and another as normal control (NC). The rats were sacrificed at 30 days interval. The body weight significantly (P<0.05) increased in treatments groups with highest (33.8%) increment following neem (600mg/kg bwt). The fasting blood glucose (FBG), glycozylated Hb (HbA1c) and serum creatinine increased significantly (P<0.05) in STZ induced diabetic rats. Values decreased significantly (P<0.05) in all treated groups with a highest reduction observed following neem (600 mg/kg bwt; FBG- 70.8%, HbAcl-62%) and creatinine (75%) with nayantara extract. AST, ALT, ALP and bilirubin increased significantly (P<0.05) in STZ induced diabetic and DC rats, and decreased significantly (P<0.05) in all treated groups. Serum triglyceride (TG), total cholesterol (Tch), low density lipoprotein (LDLch) and very low density lipoprotein (VLDLch) increased in STZ induced diabetic and DC rats. These values decreased significantly (P<0.05) in all treated rats with highest reduction following neem (TG-41%, Tch-46%, LDLch-48% and VLDLch-60%) treatment. Serum insulin and high density liporotein (HDLch) decreased significantly (P<0.05) in STZ induced diabetic and DC rats, which were reversed in diabetic treated (DT) groups significantly (P<0.05) with highest increment following nayantara (insulin-144.9%) and MetHCL (HDL-68%) dosing. RBC, Hb, PCV, ESR, lymphocyte, monocyte, MCHC and MCH reduced significantly (P<0.05) and increased in all treatment groups but best responses were evident with neem extracts. Neutrophil, extracts. Neutrophil, MCV, WBC and Eosinophil increased significantly (P<0.05) in DC rats and MetHCl. Neem extract showed better efficacy. The overall efficacy of neem was better than MetHCl, however, nayantara and garlic were similar to MetHCL and may be used as promising antidiabetic agents.