Antidiabetic, antihyperlipidemic and antioxidant potential of methanol extract of Tectona grandis flowers in streptozotocin induced diabetic rats

Abstract

Objective To investigate antidiabetic, antihyperlipidemic and antioxidant activity of methanol extract of Tectona grandis ( T. grandis) flowers (METGF) in streptozotocin (STZ) induced diabetic rats to supports its traditional use. Methods Acute toxicity study of METGF was carried out in rat to determine its dose for the antidiabetic study. Oral glucose tolerance test (OGTT) was performed to evaluate METGF effect on elevated blood glucose level. Diabetes was induced in rats by administration of STZ (60 mg/kg, ip.) and it was confirmed 72 h after induction. METGF was orally given to the diabetic rats up to 28 days and blood glucose level were estimated each week. On 28 day of the experiment, diabetic rats were sacrificed after the blood collection for the biochemical parameters analysis and liver, kidney was collected to determine antioxidants levels. Results In acute toxicity, METGF did not show toxicity and death up to a dose 2 000 mg/kg in rats. Administration of METGF 100 and 200 mg/kg significantly ( P<0.001) reduced blood glucose levels in OGTT and STZ-induced diabetic rats. Both doses of METGF treatment significantly ( P<0.001, P<0.01 and P<0.05) increased body weight, serum insulin, haemoglobin (Hb) and total protein levels in diabetic rats. Also, MEGTF treatment reduced elevated glycosylated haemoglobin (HbA1c) and other biochemical parameters levels significantly ( P<0.001) in diabetic rats. Altered lipid profiles and antioxidants levels were reversed to near normal in diabetic rats treated with METGF. Conclusions These results concluded that METGF possesses antidiabetic, antihyperglycemic and antioxidant activity which supports its traditional use.