Actions of Artemisia vulgaris extracts and isolated sesquiterpene lactones against receptors mediating contraction of guinea pig ileum and trachea

The present study evaluates the Philippine medicinal plant Artemisia vulgaris for antagonistic activity at selected biogenic amine receptors on smooth muscle of the airways and gastrointestinal tract in order to explain its traditional use in asthma and hyperactive gut. The antagonistic activity of chloroform crude extract (AV-CHCl3) and methanol crude extract (AV-MeOH) of Artemisia vulgaris was studied against concentration–response curves for contractions of the guinea pig ileum and trachea to 5-hydroxytrptamine (5-HT2 receptors), methacholine (M3 muscarinic receptors), histamine (H1 receptors) and β-phenylethylamine (trace amine-associated receptors, TAAR1). The Artemisia vulgaris chloroform (AV-CHCl3) and methanol (AV-MeOH) extract showed histamine H1 antagonism in the ileum and trachea. Further analysis of AV-CHCl3 isolated two major components, yomogin and 1,2,3,4-diepoxy-11(13)-eudesmen-12,8-olide. Yomogin, a sesquiterpene lactone, exhibited a novel histamine H1 receptor antagonism in the ileum. The presence of a specific, competitive histamine receptor antagonist and smooth muscle relaxant activity in Artemisia vulgaris extracts on the smooth muscle in ileum and trachea explains its traditional use in the treatment of asthma and hyperactive gut.