Antidiabetic potential of combinations of galactomannan and chlorogenic acid obtained from Ethiopian medicinal plants in streptozotocin-induced hyperglycemic mice

As the prevalence of diabetes has been increasing rapidly, finding therapeutic options with minimal side effects is important. Using functional foods as alternative bioactive molecule sources is preferable. Therefore, this study was conducted to evaluate the antidiabetic potential of combinations of chlorogenic acid and galactomannan obtained from the Ethiopian medicinal plants Trigonella foenum graecum L. and Coffee Arabica L. against streptozotocin-induced hyperglycemic mice. A randomized controlled trial was conducted for 28 days in streptozotocin-induced hyperglycemic mice. The mice were then treated with a mixture of galactomannan (GM) and chlorogenic acid (CGA) at a concentration of 100 mg/kg in three different proportions, namely, 25% to 75% (GMcga): 50% to 50% (GM-CGA) and 75% to 25% (CGAgm) (1:3, 1:1 and 3:1) daily. Fasting blood glucose (FBG), oral glucose tolerance test (OGTT) and histopathology of pancreatic beta cells were performed. The R statistical software package and GraphPad Prism V.20 were used for data analysis. The results are expressed as the mean ± SD, ANOVA, PWC "Bonferroni," and AUC at the 95% significance level. The mean fasting blood glucose level was found to be reduced by 235.8 (414 ±92.1–178.2 ± 23.87) and 130.8 (441.4 ± 58.7–310.6 ± 58.59) mmol/l (p≤ 0.05) with the CGAgm and GM-CGA combinations, respectively. The maximal blood glucose level, glucose peak time and AUC of the OGTT were significantly reduced in all combination treatments. Pathophysiologically, normal (GMcga), mild (GM-CGA) and moderate (CGAgm) atrophy of pancreatic beta cells was observed compared with severe degeneration in the diabetic control (DC), confirming the antidiabetic nature of the combinations. This study demonstrated that the combination of chlorogenic acid and galactomannan can improve fasting blood glucose, glucose tolerance and the number of pancreatic β-cells in STZ-induced diabetic mice, indicating their promising potential as nutraceuticals that might ameliorate hyperglycemia.