Phytochemical study and dosage of polyphenols and flavonoids of the methanolic extract of the leaves and stem bark of Gardenia ternifolia

Gardenia ternifolia is a medicinal plant used in Senegal and in several African countries for the treatment of many pathologies. According to the results of the bibliography, the four parts of the plant, mainly used for medicinal purposes, are recommended. Therefore, the chemical studies made on the extracts of the leaves, roots, seeds and fruits show that they are rich sources of secondary metabolites. The phytochemical study carried out on the hexane, ethyl acetate, methanolic and aqueous extracts of the leaves and stem bark of the Gardenia ternifolia plant reveals the presence of polyphenols, flavonoids, alkaloids, gallic and catechin tannins, sterols, polyterpenes, coumarins, mucilages, catechols and Leucoanthocyanins in the two different organs of this plant. The successive extracts obtained with hexane, ethyl acetate, methanol and water gave yields varying respectively from 0.14 to 3.94% for the four leaves extracts and 0.08 to 1.62% for the four stem bark extracts. The determination of the total polyphenols of the methanolic extracts respectively gave variable contents between 1.57 ± 0.05 and 7.00 ± 0.044 μg EAG/mg for the leaves and the bark of the stems. Compared to flavonoids, the levels vary respectively between 1.57 ± 0.05 and 15.45 ± 0.066 μg EQ/mg for stem bark and leaves. In general, the methanolic extract and the aqueous extract are the richest in secondary metabolites, polyphenols and flavonoids. This suggests that these families of compounds are responsible for the biological activity of the plant in the treatment of certain types of diseases. However, in-depth tests on the antioxidant, antidiabetic and antimicrobial activities are necessary in order to identify the full therapeutic potential of this plant.