Antihyperglycemic and Antioxidative Stress Effects of Erythrophleum africanum (Fabaceae) Trunk Bark Powder Fractions on High-Calorie Diet-Induced Type 2 Diabetes in Rats

Abstract

Diabetes mellitus is a persistent and chronic metabolic disease characterized by high blood glucose levels. The aim of this work was to evaluate the antihyperglycemic and antioxidative stress effects of Erythrophyllum africanum trunk bark powder fractions in diabetes-induced rats. 30 male rats subdivided into 6 groups of five rats each received daily a sweetened hypercaloric diet supplemented with sucrose (4 g/kg bw), except for the normal control, which received a normal diet. Normal and diabetic controls subsequently received distilled water (10 mL/kg bw per os), the positive control received metformin (20 mg/kg bw per os) and the test rats received powder fractions (≤ 50 μm ≤ 50-120 μm) or unsieved powder of E. africanum (300 mg/kg bw per os) for 7 weeks. Dexamethasone (0.2 mg/kg) was administered intraperitoneally once a week from the third week, except for the normal control, which received saline. Fasting blood glucose, lipid profile, and biochemical parameters of oxidative stress were assessed during and at the end of treatment. Blood glucose levels of the animals at the 7th week were 0.92 ± 0.03, 1.52 ± 0.08, 0.78 ± 0.04, 0.77 ± 0.03, 1.13 ± 0.03, and 0.40 ± 0.01 g/L in the normal control, diabetic control, metformin-treated animals, ≤ 50 μm fraction, 50-120 μm fraction, and unsieved powder, respectively. Powder fraction ≤ 50 μm significantly improved (p < 0.01) the lipid profile (decrease in triglyceride and LDL cholesterol levels, an increase in HDL cholesterol levels) by reducing the atherogenic index. E. africanum has antihyperglycemic and antioxidative stress effects and would be less toxic to the liver and kidneys. The fine powder (≤ 50 μm) of E. africanum could be used as a food additive to prevent the occurrence of diabetes in vulnerable patients.

Keywords: Erythrophleum africanum; antihyperglycemic activity; antioxidant activity; high sugar diet.

FIGURE 1

Glycemia of rats during 7 weeks of treatment. Values were expressed as mean ± SEM, (n = 5). Significant differences (^α p ≤ 0.05; ^β p ≤ 0.01; ^δ p ≤ 0.001) compared to normal control (NC) and (^a p ≤ 0.05; ^b p ≤ 0.01; ^c p ≤ 0.001) compared to diabetic control (DC). EAPF, Erythrophleum africanum powder fractions; PC, Positive control.

FIGURE 2

Glycemia variation in rats during the oral glucose tolerance. Values were expressed as mean ± SEM, (n = 5). Significant differences (^α p ≤ 0.05; ^β p ≤ 0.01; ^δ p ≤ 0.001) compared to normal control (NC) and (^a p ≤ 0.05; ^b p ≤ 0.01; ^c p ≤ 0.001) compared to diabetic control (DC). EAPF, Erythrophleum africanum powder fractions; PC, Positive control.

FIGURE 3

Food intake of rats during treatment. Values were expressed as mean ± SEM, (n = 5). Significant differences (^α p ≤ 0.05; ^βp ≤ 0.01; ^δ p ≤ 0.001) compared to normal control (NC) and (^a p ≤ 0.05; ^b p ≤ 0.01; ^c p ≤ 0.001) compared to diabetic control (DC). EAPF, Erythrophleum africanum powder fractions; PC, Positive control.

FIGURE 4

Variation of body weight of rats during the 7 weeks of treatment. Values were expressed as mean ± SEM, (n = 5). Significant differences: ^α p ≤ 0.05; ^β p ≤ 0.01; ^δ p ≤ 0.001) compared to normal control (NC) and ^a p ≤ 0.05; ^b p ≤ 0.01; ^c p ≤ 0.001 compared to diabetic control (DC). EAPF, Erythrophleum africanum powder fractions; PC, Positive control.