| In the pastoral zone of Gaongho in Burkina Faso, the main disease of ruminants is the African Animal Trypanosomiasis (AAT) which is very often controlled by herders with the aqueous extracts of five plants whose present study proposes to evaluate the potential trypanocidal activities. To this end, a parasitological field survey in ruminants was carried out followed by an in vitro trypanocidal test of five plant extracts using three concentrations (25, 50 and 100 mg / ml) in triplicate in comparison with negative (PBS) and positive (Veriben) controls in the laboratory. The field survey revealed an overall prevalence rate of 4.14% for trypanosomes, including 4.54% for cattle and sheep and 3.33% for goats, with no significant difference (P ˃ 0. 05) was recorded between the three ruminant species. Among the latter, the sex effect showed a significant difference in goats where males were more infested (P = 0.0015) than females. On the other hand, the age of the animals presented no significant difference (P = 0.8218) between the three species. All ruminants tested were more infested with Trypanosoma brucei brucei (66.67%) than T. congolense (33.33%). The in vitro test was conducted with aqueous extracts of five plants (Balanites aegyptiaca, Capparis sepiaria, Guiera senegalensis, Mitragyna inermis, and Vitellaria paradoxa) on Trypanosoma brucei brucei. Concentrations of 50 and 100 mg / ml of G. senegalensis leaf extracts and V. paradoxa bark caused high mortality of T. brucei brucei and were comparable to Veriben, the standard reference product. The results obtained with the extracts of G. senegalensis and V. paradoxa showed that these plantsmay be the potential source of trypanocidal drugs. Keywords

Aqueous decoction of Guiera senegalensis leaves was studied orally and intraperitoneally for its antitrypanosomal activity on mice infected experimentally with Trypanosoma brucei brucei. After a phytochemical screening followed by an acute toxicity study on mice, the extract of plant was administered once daily for 2 days at doses of 60, 120 and 240 mg / kg orally and 15, 30 and 60 mg / kg intraperitoneally after infection. Then, parameters of parasitaemia, packed cell volume (PCV), mean survival time and body weight of the mice treated with the extract were measured and compared with positive (diminazene aceturate) and negative (distilled water) controls for 7 days in a row. Results indicate that the aqueous extract of G. senegalensis leaves contains tannins, flavonoids, saponosides, reducing compounds and anthocyanosides, alkaloids and coumarins. LD50 of the extract are 1264.49 mg / kg by oral route and 316.22 mg / kg by intraperitoneal route. The doses of 240 mg / kg by oral route and 15 and 60 mg / kg by intraperitoneal route of aqueous extract showed a mean survival time (5 days) comparable to the positive control. Parasitaemia level increased in all mice tested except in mice treated with diminazene aceturate during the post-infestation period. During this period, PCV and body weight of all mice decreased by both routes of administration. These results of the study show the pharmacological utility of G. senegalensis leaves in the control of TAA by herders / pastoralists and suggest continuing further bio-guided studies to isolate the active components of the plant in order to improve their efficiency. Keywords: In vivo test; Trypanosoma brucei brucei; Guiera senegalensis leaves; phytochemical screening; acute toxicity.