Bio-guided Fractionation of the Ethanolic Extract from Leaves of Trema orientalis Blume (Cannabaceae), a Presumed Antihypertensive Plant from Congo-Brazzaville
Résumé
Hypertension is a risk factor for cardiovascular disease, which is currently a real public health problem. This disease affects about one billion people worldwide and is responsible for more than 70% of cardiovascular related deaths. Recently, the World Health Organization reported that of the hypertensive cases detected in Congo, only 7% were controlled. Today, there is no lifetime treatment and existing drugs are less accessible by the African population. To treat the disease, the Congolese population uses more the medicinal plants. However, the majority of compounds responsible for the biological activity of these plants are not known. In order to bring out Congolese plants with antihypertensive properties, we focus our interest on Trema orientalis Blume (Canabaceae). An ethanolic extract of the leaves of Trema orientalis was prepared after successive depletion of the organic solvents. Thereafter, a bio-guided fractionation on silica gel of the ethanol extract was carried out. Fractionation monitoring was done by TLC and the results of vasodilating activity measured. The fractions exhibiting the best biological activity allowed a second fractionation process to obtain five fractions which are characteristic of polyphenols, in particular flavonoids, and which exhibited good vasodilating activity on the isolated aorta of rats. Our future work will focus on the identification of these biologically active compounds.