Tehran University of Medical Sciences Traditional and Integrative Medicine 2476-5104 8 1 2023 02 28 40 47 Yabré Zakaline Institute of Research in Health Science (IRSS), Ouagadougou 03, Burkina Faso AND Laboratory of Drug Development (LADME), Center for Training, Research, and Expertise in Pharmaceutical Sciences (CEA-CFOREM), Doctoral School of Sciences and Health, University Joseph KI-ZERBO, Ouagadougou 03, Burkina Faso Boly Rainatou Institute of Research in Health Science (IRSS), Ouagadougou 03, Burkina Faso Nitiéma Mathieu Institute of Research in Health Science (IRSS), Ouagadougou 03, Burkina Faso Belemnaba Lazare Institute of Research in Health Science (IRSS), Ouagadougou 03, Burkina Faso Youl Estelle Laboratory of Drug Development (LADME), Center for Training, Research, and Expertise in Pharmaceutical Sciences (CEA-CFOREM), Doctoral School of Sciences and Health, University Joseph KI-ZERBO, Ouagadougou 03, Burkina Faso Guissou Pierre University of Saint Thomas D’Aquin, Ouagadougou 06, Burkina Faso Ouédraogo Sylvin Institute of Research in Health Science (IRSS), Ouagadougou 03, Burkina Faso 2022 06 30 2022 12 17 A previous study has reported the interesting relaxant effect of the hydroalcoholic extract from Waltheria indica L. (Malvaceae) leafy stems, a plant with several therapeutic uses. The present study aimed to investigate the preventive effect of this plant using an ex vivo model of the rat trachea. Two agonists, acetylcholine (10-6 - 1.5×10-5 M) and barium chloride (10-5- 10-1 M) were used to induce contractions. The preventive effect was assessed on rat tracheal rings pretreated with hydroalcoholic extract (1.92 mg/mL), glibenclamide, atropine, and papaverine, all at 10 µM. Acetylcholine and barium chloride provoke contractions in a concentration-dependent manner, with a maximum contractile response of 3.953 ± 0.692 g and 2.999 ± 0.326 g, respectively. The EC50 values were 3.711 ± 0.823 µM and 9.502 ± 12.354 mM, respectively, for acetylcholine- and barium chloride-induced contraction. Glibenclamide caused a rightward shift of the acetylcholine-response curve, followed by a reduction of the maximum contraction (from 3.953 ± 0.692 g to 3. 116 ± 0.244 g). The hydroalcoholic extract, atropine, papaverine, and their combinations induced a complete suppression of the contractile response to acetylcholine (p < 0.0001) and barium chloride (p < 0.0001). The hydroalcoholic extract exhibited a potent relaxant effect comparable to that of atropine and papaverine. It can be concluded that the hydroalcoholic extract of W. indica can potently prevent acetylcholine-and barium chloride-induced contractions. The possible mechanisms by which the extract exerts its relaxant effect may involve the blockade of muscarinic receptors, the inhibition of phosphodiesterase activity, and/or the calcium channel. https://jtim.tums.ac.ir/index.php/jtim/article/view/747