Phytochemical Screening, Antioxidant Activity and Cytotoxicity of four Medicinal Plants for Antidiabetic Purposes Used in the Ivorian Pharmacopoeia

Abstract

Aims: This study aims to investigate the phytochemical profile, antioxidant activity and cytotoxicity of aqueous extracts from four plants used in the Yamoussoukro district (Côte d'Ivoire) for the treatment of diabetes. Methodology: Secondary metabolites of four plants (Alchornea cordifolia, Ocimum gratissimum, Tetrapleura tetraptera and Vernonia colorata) were carried out by phytochemical screening using appropriate reagents. Polyphenol and tannin contents were determined using the Folin- ciocalteu colorimetric method. The antioxidant activity of the various extracts was then assessed in vitro using the DPPH (1,1-diphenyl-2-picryl-hydrazyl) assay. Acute toxicity was also assessed by administering extracts orally to mice in single increasing doses. Hypoglycemic and antihyperglycemic activities were determined by monitoring blood glucose levels in mice after administration of the extracts. Results: Phytochemical screening revealed the presence of polyphenols, particularly flavonoids, as well as alkaloids, saponosides, terpenes and sterols in all extracts. The highest total flavonoid content was obtained with the V. colorata extract (58.10 mg/g QE). The A. cordifolia extract had the highest content of total polyphenols (57.56 ± 2.34 mg/g GAE) and total tannins (0.84 ± 0.02 mg/g TAE). Also, the highest antioxidant capacity (0.4190 mg/mL) was observed with the A. cordifolia extract, as well as good hypoglycemic activity at a dose of 300 mg/kg BW. In addition, all the extracts studied had a lethal dose greater than 5000 mg/kg BW. Conclusion and Outlook: These results show that the plant extracts studied contain several secondary metabolites responsible for their good antioxidant capacities. What's more, the plants studied have good anti-diabetic activity and are non-toxic by the oral route. This could justify their use in traditional medicine to combat diabetes.