Quantitative study and evaluation of the antioxidant potential of specialized metabolites, including glycosylated and aglycone forms, present in extracts of Nauclea latifolia, Bombax costatum and Vernonia cinerea, three medicinal plants of therapeutic importance widely distributed in Côte d'Ivoire

Abstract

Specialized plant metabolites play a crucial role in their survival, notably through their defensive properties against pathogens. These compounds are attracting increasing interest in scientific research. As part of the valorization of Ivorian flora, this study focused on the quantitative analysis and evaluation of the antioxidant activity of total phenols, total flavonoids, flavonic aglycones, and anthocyanins present in glycoside and aglycone extracts from three medicinal plants used in traditional medicine. The glycoside extracts were obtained by maceration in 80% methanol, while the aglycones were extracted through acid hydrolysis (2N). Phenolic compound content was determined using the Folin-Ciocalteu colorimetric method, with calibration curves based on gallic acid and catechin. Antioxidant potential was assessed using the DPPH free radical scavenging method. The results revealed yields of 19.50%, 18.75%, and 18.08% for the glycoside extracts, and 9.19%, 10.95%, and 6.78% for the aglycones. Quantifications confirmed significant richness in secondary metabolites. The IC50 values obtained were 0.056, 0.005, and 0.014 mg·mL⁻¹ for the glycoside extracts, and 0.040, 0.004, and 0.007 mg·mL⁻¹ for the aglycones. These findings suggest that the traditional use of these plants by traditional healers may be linked to their strong antioxidant activity, which is attributable to their high content of phenolic compounds.