Comparative Phytochemical Analysis and Antiradical Activity of Five Plants Used for the Treatment of Type 2 Diabetes in Benin

Background: Diabetes remains a real public health problem in the world today. Although considered a disease of rich countries, today diabetes is increasingly a major concern in developing countries and particularly in sub-Saharan Africa. In Benin, its prevalence in 2015 was 12.4%. Objective: This work aimed to compare the secondary metabolites, the content of phenolic compounds (total phenol, flavonoid) and the antiradical power of five plants (Bambusa vulgaris Schrad. Ex Wendel; Parkia biglobosa (Jacq.) R. Br. Ex G. Don; Mangifera indica L.; Saccharum officinarum L.; and Annona muricata L.) used in Benin by traditional healers to treat type 2 diabetes. Materials and Methods: Secondary metabolites were identified by coloration and precipitation reactions specific to each family of metabolites. Total phenols were determined by Folin Ciocalteu method. The aluminum trichloride method has been used to quantify total flavonoids. The antiradical capacity was evaluated by 2,2-diphenyl-l-picrylhydrazyl (DPPH). Results: Plants which leaves were higher in total phenols were Mangifera indica, Parkia biglobosa and Bambusa vulgaris while Annona muricata and Parkia biglobosa were the richest plants in flavonoids. The hydroethanolic extract of leaves of Bambusa vulgaris (IC50=0.28mg/mL), Parkia biglobosa (IC50=0.3mg/mL) and Mangifera indica (IC50=2.5mg/mL) showed more pronounced antiradical activity than vitamin C (IC50=3.2 mg/mL) which were synthetic antioxidant. Conclusion: Our results showed that among the five plants studied Mangifera indica, Parkia biglobosa and Bambusa vulgaris were the richest in total phenols and also those whose leaf extracts had the highest antiradical activities. These three plants could therefore be considered as potential remedies for type 2 diabetes and its complications.