Blood glucose lowering effects of leaf extracts of cleome gynandra, amaranthus cruentus and their mixture in normoglycaemic and hyperglycaemic rats

Abstract

In healthy persons, blood glucose is maintained in the range 3.5 – 8.0 mmol/L. However, in Diabetes Mellitus (DM) chronic hyperglycemia is observed due to defects in insulin secretion, insulin action or both. This study investigated glucose lowering effects of ethanolic leaf extracts of Cleome gynandra (CG), Amaranthus cruentus (AC) and their mixture (1:1 ratio) in Normoglycaemic and hyperglycemic rats. The study was an in vivo experimental study conducted in the pharmacology laboratory at the University of Zambia, School of Medicine. The ethanolic leaf extracts was obtained from the leaves of AC and CG by maceration and formulated into 3 dose levels (200, 400 and 600 mg/Kg BW). Normal saline (0.9%) and Glibenclamide (5 mg/kg BW) were used as controls. Male Albino rats (n =55) of species Rattus norvegicus weighing 120-300 grams, with Random Blood Glucose (RBG) ranging 4.7 – 7.5 mmol/L were used in the study. We tested glucose lowering effect of the ethanolic leaf extracts to Normolglycemic and hyperglycemic rats allocated in 11 groups comprising 5 rats per group. After 12 hour fast with access to drinking water, single doses of crude drug of AC, CG and Mixture using a gavage needle were administered to the Rats. We then measured Fasting Blood Glucose (FBG) at times 0, 1, 2, 4, 6, 8, 16 and 24 hours. Diabetes was induced by a single intraperitoneal injection of 140 mg/kg BW with Alloxan monohydrate to overnight fasted rat. For Sub-acute studies of 10 days, treatments were given orally and we measured RBG every alternate day. Standard euthanasia procedure was performed afterwards. Data was analyzed by Students `t’ test and one way ANOVA. Results were expressed as mean ± standard deviation and Statistical significance was set at p < 0.05. Extracts of AC, CG and their mixture produced reduction in FBG of 30% (2.8 ± 0.09 to 1.6 ± 0.03 mmol/L), 35.4% (2.9 ± 0.07 to 2.0 ± 0.05 mmol/L) and 26.1 % (2.9 ± 0.05 to 2.2 ± 0.06 mmol/L) respectively in normolglycemic rats after 6 hours. Similarly in hyperglycemic rats extracts of AC, CG and their mixture produced maximum reduction in FBG of 23.8% (25.5 ± 1.57 to 20.1 ± 1.66 mmol/L), 31.7 % (25.8± 0.13 to 19.30 ± 1.74 mmol/L) and 26.9 % (24.74 ± 2.26 to 14.2 ± 1.01 mmol/) respectively after 6 hours.Mean RBG was lower in the experimental compared to Hyperglycemic control group at day 10 (17.6±1.61 Vs. 28.8 ± 0.23 mmol/L, p = 0.004). The leaf extracts seem to act via extra-pancreatic mechanisms because there was no statistical difference when the glucose lowering effect of the Extracts on the normolglycemic and hyperglycemic were compared (p > 0.05) Therefore in normolglycemic and hyperglycemic (diabetic) rats, ethanolic leaf extracts had glucose lowering effects. The Leaf extracts seem to act via extra pancreatic mechanisms. Key words: Diabetes, Alloxan, Ethanolic Leaf Extracts, Amaranthus cruentus (AC), Cleome gynandra (CG), rats, Glucometer, hypoglycemia, hyperglycemia.