title: Effects of the water soluble fraction from leaves of Ageratum conyzoides on smooth muscle.
abstract: The water soluble fraction of Ageratum conyzoides L. (WSF) was studied in isolated rat uterus and intestinal smooth muscles in order to evaluate its popular use as a spasmolytic. WSF (0.2 and 0.4 mg/mL) increased EC(50) values and decreased maximum responses to acetylcholine and calcium chloride. WSF (0.5-3.3 mg/mL) also produced direct myorelaxant effect on smooth muscle preparations. Theophylline (10(-3) M) potentiated the relaxant action of WSF. Theophylline also prevented the decrease in maximum response promoted by WSF in acetylcholine concentration-effect curves. These results seem to be partially linked to calcium mobilization. The data also suggest that WSF could act synergistically with theophylline in the inhibition of cyclic AMP phosphodiesterase. The results give support to the popular medicinal indications of the plant.
authors.affiliation: Department of Biology, Center of Sciences, Federal University of Ceará (UFC), Fortaleza, Ceará, Brazil.
authors.forename: M J
authors.initials: MJ
authors.lastname: Silva
authors.forename: F R
authors.initials: FR
authors.lastname: Capaz
authors.forename: M R
authors.initials: MR
authors.lastname: Vale
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D019659:Asteraceae; D002122:Calcium Chloride / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004386:Duodenum / Q000187:drug effects; D005260:Female; D066298:In Vitro Techniques; D007583:Jejunum / Q000187:drug effects; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D010121:Oxytocin / Q000494:pharmacology; D010276:Parasympatholytics / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar; D012995:Solubility; D013806:Theophylline / Q000494:pharmacology; D014590:Uterine Contraction / Q000187:drug effects; D014599:Uterus / Q000187:drug effects
chemical_list: D010276:Parasympatholytics; D010936:Plant Extracts; D010121:Oxytocin; D013806:Theophylline; D002122:Calcium Chloride; D000109:Acetylcholine