Synergistic effect of ethanol extracts of Vernonia amygdalina and Croton zambesicus in alloxan-induced diabetic rats

Introduction: Therapeutic application of medicinal plants is Therapeutic application of medicinal plants is largely based on their chemical contents which synergistically work together in the same or different plants. Aims: This research assessed the synergistic antidiabetic and hypolipidemic potential of ethanol leaf extract of Vernonia amygdalina (VAMG) and Croton zambesicus (CZMG) in alloxan-induced diabetic male Wistar rats in other to justify the traditional medicinal application of the extracts as antidiabetic agents. Materials and Methods: The plants were collected, air-dried, and extracted separately in ethanol to produce the respective extracts (VAMG and CZMG). Secondary metabolites in each extract were screened using standard methods. The acute toxicity tests were carried out to determine the median lethal dose (LD50) of the respective extracts. The animals were induced with diabetics using alloxan monohydrate and the ones showing fasting blood glucose of 250 mg/ dL were used for the study. The blood sugar levels and body weights of the diabetic rats were observed after the administration of the different extracts and the combined extracts for 28 days. The effects of the different extracts on lipid profile and hepatic enzymes of the diabetic rats were also studied. Results: The blood sugar levels and body weights of the diabetic rats were observed after the administration of the different extracts and the combined extracts for 28 days. The effects of the different extracts on lipid profile and hepatic enzymes of the diabetic rats were also studied. The extracts contained tannins, flavonoids, saponins, phenolics and glycosides. Moreover, the exposure of the alloxan-induced diabetic rats to the combined plant extract (VACZ) caused a significantly (P < .05) reduced fasting blood sugar concentration, serum ALT, ALP, AST, total cholesterol, triglycerides, LDL cholesterol, and VLDL cholesterol, and an increased body weight, total protein and HDL cholesterol. The activity was comparable with the glibenclamide. Conclusion: Thus, the tested leaf extracts contained bioactive components whose synergistic activity could trigger a significant reduction of the blood sugar concentration and regulates the activity of hepatic indices in alloxan-induced diabetic rats than during a single administration. The extracts’ biological activity was comparable to the glibenclamide, and could be used in the development of antidiabetic candidate. The results confirmed the scientific basis of the traditional application of these medicinal plants.