Traditional medicine uses many plants in the preparation of medicinal recipes for the treatment of human pathologies. These plants are thus indispensable to the existence of all living beings, because they provide all the necessary elements for their survival. Man, to ensure a daily well-being, uses plants in various fields including traditional medicine. The purpose of this work is to determine some toxicological parameters of the decocté of the leaves of Vernonia colorata (Asteraceae) and Crescentia cujete (Bignoniaceae) in order to control the dosage and prevent poisoning in the therapeutic use of these plants. The acute toxicity of aqueous decoction of these species was assessed following a process of orally administering raw decoctions to mice at increasing doses ranging from 6000 to 7500 mg/kg body weight (bw). Phytomedicines were used orally at different doses. The results obtained the solubility limit dose corresponding to the maximum tolerated dose or DTM of 6000 mg/kg and 7500 mg/kg respectively for Vernonia colorata and Crescentia cujete. This toxicological endpoint (maximum tolerated dose) is far greater than 21.04 and 100.33 mg/kg body weight of the daily doses recommended by traditional healers. Therefore, the doses prescribed by traditional healers are not toxic. The use of these plants under traditional conditions of preparation and oral administration against diabetes may be scientifically justified.

In the search for plants that can fight against hypertension, we have initiated an ethnopharmacological survey on the markets of the city of Abidjan in Côte d’Ivoire. The markets of three districts in the city were visited for this purpose: Yopougon, Abobo and adjamé. In yopougon, we visited the Wassakara market. The central market and the Gouro market were respectively chosen for the communes of Abobo and Adjamé. This choice is justified by an impressive number of sellers of medicinal plants in these markets. The survey made it possible to interview 90 herbalists on the basis of a questionnaire sheet. These investigations revealed 21 species of plants used in traditional medicine, in the treatment of hypertension. The modes of administration of these herbal medicines are decocted to drink and pastes to purge. In comparison with the calculated citation frequencies, two plants are very frequent. They are: Nymphaea lotus (Fc = 9.01%) and Phyllantus amarus (Fc = 8.02%). These two plants are found in all the sellers of medicinal plants visited during our surveys. A phytochemical screening was performed to assess the scientific basis for the empirical use of these two most common plants. These tests revealed that these plants contain sterols, polyterpenes, polyphenols, flavonoids, saponosides and alkaloids with a strong presence of flavonoids and alkaloids in the species Nymphaea lotus. The hypotensive effect could be related to the strong presence of alkaloids and flavonoids. These two plants could be of interest scientific world in the fight against hypertension.