Spasmolytic activity of Artemisia copa aqueous extract and isolated compounds.

Artemisia copaPhil. (Compositae) is used in popular medicine as a digestive and for gastric pains. The effects ofA. copaaqueous extract and its isolated compounds were evaluated on isolated rat jejunum. The extract inhibited non-competitively the cumulative concentration–response curves induced by acetylcholine and CaCl2. The tonic jejunum contractions induced by 80 mM KCl were inhibited byA. copa. Relaxant effects ofA. copaon the tonic contraction induced by 25 mM KCl, [EC50: 0.94 mg mL−1(0.64–1.39)], was not inhibited by glibenclamide, TEA, l-NAME or methylene blue. Chrysoeriol, spinacetin and luteolin (30 µg mL−1), produced an antagonism on the CaCl2concentration–response curve, showing an inhibition of the maximum contractions (70.0% ± 5.0%, 49.1% ± 4.5% and 77.0% ± 3.5% ofEmax, respectively), whereas tricin did not inhibit when the same concentration was used.A. copaexerts spasmolytic activity by blocking calcium channels and three isolated compounds could be, at least partly, responsible for the effect. [ABSTRACT FROM PUBLISHER]