Evaluation of Antidiabetic Activity of the Leaf Latex of Aloe pulcherrima Gilbert and Sebsebe (Aloaceae)

Abstract

The leaf latex of Aloe pulcherrima has been used as remedy for diabetes mellitus. This was carried out to determine in vitro and in vivo antidiabetic activities of the leaf latex of Aloe pulcherrima. Methods. Sucrase and maltase inhibitory activity of the leaf latex of A. pulcherrima was determined in glucose oxidase assay, and α-amylase inhibitory activity was determined in dinitrosalicylic acid assay. Normoglycemic, glucose-loaded, and streptozotocin-induced diabetic mice were treated orally to determine blood glucose lowering activity of the latex. Effect of the latex on serum lipid level and body weight was measured in streptozotocin-induced diabetic mice. Additionally, DPPH assay was used to determine free radical scavenging capacity of the latex. Results. Antioxidant activity of the latex was concentration dependent; the strongest inhibition was measured at 800 μg/ml (80.57%). The leaf latex of A. pulcherrima inhibited sucrase (IC50 = 2.92 μg/ml), maltase (IC50 = 11.81 μg/ml) and α-amylase (IC50 = 14.92 μg/ml) enzymes. All doses of the leaf latex induced hypoglycemic effect after 4 h in normal mice, and low dose of the latex did not show significant effect after 6 h. Glucose reduction of the leaf latex of A. pulcherrima was significant (p<0.05) in oral glucose-loaded mice compared to the vehicle control. Blood glucose level of diabetic mice was significantly (p<0.05) reduced on week one and weak two in a streptozotocin-induced diabetic mouse model. Glucose reduction increased with increasing the doses of the leaf latex of A. pulcherrima on week one (p<0.05 (200 mg/kg), p<0.01 (400 mg/kg), and p<0.001 (600 mg/kg)). Administration of the leaf latex of A. pulcherrima for two weeks significantly (p<0.05) improved diabetic dyslipidemia and body weight of diabetic mice. Conclusion. The study confirmed that the leaf latex of the plant showed a significant antidiabetic activity justifying the traditional uses of the plant.