Purpose: To investigate the effect of Amaranthus tricolor leaf extract on some biochemical parameters in diabetic and normal rats.
Methods: A. tricolor aqueous extract was assayed for antioxidant properties using ferric reducing ability of plasma (FRAP) assay, 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and phosphomolybdenum assay. The effect of the leaf extract on serum glucose and triglyceride, total cholesterol, low density lipoprotein (LDL), very low density lipoprotein (VLDL), elevated high density lipoprotein (HDL), body weight and hematological parameters were assessed in diabetic and normal rats. The extract doses used were 200 and 400 mg/kg body weight. Acute toxicity studies were also carried out.
Results: In the extract doses, 200 and 400 mg/kg, reduced blood glucose levels in a dose-dependant manner, from 168.0 ± 18.5 mg/dl at 0 h to 43.0 ± 9.3 mg/dl at the 12th hour and from 146.50 ± 22.1 mg/dl at 0 h to 37.250 ± 6.3 mg/dl at the 12th hour, respectively. Oral administration of 400 mg/kg of the extract for 21 days significantly reduced (p <0.001) serum glucose, serum triglyceride, total cholesterol, low density lipoprotein, and very low density lipoprotein, but elevated (p <0.05) high density lipoprotein in diabetic experimental rats, compared to diabetic control. The extract prevented a decrease in body weight in treated diabetic rats and promoted an improvement in haemoglobin levels. Total antioxidant activity assay revealed that 1 g of dry leaf powder was equivalent to 0.035g/ml of ascorbic acid. The extract showed no toxicity up to 2 g/kg body weight.
Conclusions: This study shows that the aqueous extract of Amaranthus tricolor possesses some beneficial antidiabetic properties that warrant further research.