Abstract

Scientific validation of pharmacological actions of 7 Senegalese plants used in traditional medicine for the treatment of respiratory illness was carried out. Changes in contractility of isolated rat trachea were assessed in organ chambers. Rings were allowed to equilibrate for 60 min before experiments were carried out, during which time the resting tension was adjusted, as required. Rings were first exposed to methanolic plants extracts (10^-2 and 10^-1 mg/ml) or solvent. After a 30 min incubation period, they were contracted with acetylcholine in a cumulative manner (10^-9 to 10^-3M). Extracts from leaves of Guiera senegalensis, Melaleuca leucodendron and Hymenocardia acida elicited a significant dose-dependant inhibition of the contractile agonist, suggesting further investigations on its chemical composition, the underlying mechanisms involvedand its potential health value. However, in rings pre-incubated with extracts fromCymbopogon giganteus leaves and Salvadora persica roots, effect of the contractile agonist was not affected. Moreover, a hypereactivity was observed with extracts from Gossypium barbadense leaves and Cassia occidentalisseeds. These results provide evidence that Senegalese herbals may be of interest as valuable source of information for the selection of plants for focused screening programmes and for therapeutically useful products.

Key words: Tracheal contractility, medicinal plants, respiratory illness.