Phytochemical Evaluation and Determination of the Content of Some Natural Antioxidants (Polyphenols and Flavonoids) from Ficus Capensis, Newbouldia laevis and Carpolobia lutea

Abstract

Scientific interest in the search for natural antioxidants (secondary metabolites) from medicinal plants has increased considerably in recent years, due to the involvement of free radicals in the genesis of many diseases. The aim of the present study is to determine qualitatively and quantitatively the secondary metabolites of aqueous and hydroethanol extracts from the leaves of the medicinal plants under investigation. Qualitative determination is based on staining and/or precipitation reactions, while quantitative determination is based on the assay of secondary metabolites. The results of their qualitative determinations revealed an abundance of polyphenols and saponins, a significant presence of flavonoids and anthocyanins, and a moderate presence of alkaloids, terpenes and catechic tannins in the aqueous extract. In the hydroethanol extract, on the other hand, there is an abundance of flavonoids, a significant presence of polyphenols, saponins and anthocyanins, and a moderate presence of alkaloids, terpenes and catechic tannins. Gallic tannins and quinones are absent in both extracts. While their quantitative assay revealed an abundance of flavonoids (314.51±5.14 mgEAG/g extract) and total polyphenols (66.19±2.44 mgEQ/g extract). Thus, the high flavonoid and polyphenol content of the various extracts (aqueous and hydroethanolic) of the leaves of the plants studied would justify their use in traditional medicine in the care of sickle-cell patients.