title: Bronchodilator activity of an aqueous fraction of an ethanol extract of the leaves of Cissampelos sympodialis Eichl. (Menispermaceae) in the guinea pig.
abstract: The bronchodilator activity of an aqueous fraction (AF) of a 70% hydroalcoholic extract of the leaves of Cissampelos sympodialis Eichl. was evaluated in the guinea-pig. The AF inhibited the spontaneous tone of the trachea (IC(50), 13.9 μg/ml), which was potentiated (IC(50), 4.6 μg/ml) by 3-isobutyl-l-methylxanthine, blocked by β(2) adrenoceptor blocking agent timolol, but unaffected by removal of epithelium or addition of NG-Nitro-L-arginine methyl ester or methylene blue. The AF also antagonized contractions induced by carbachol, capsaicin and arachidonic acid in normal trachea and by ovalbumin in trachea obtained from sensitized guinea-pigs. The IC(50)-values in these experiments varied from 34.1-70.5 μg/ml. Further, the AF (100 mg/kg) by the more effective i.p. route increased the preconvulsive time of animals exposed to an aerosol of histamine to 63.5 ± 5 s 1 h after administration compared to 28 ± 1 s in the untreated group. In addition, the AF at 100 mg/kg i.p. or i.G. protected the sensitized guinea-pigs against anaphylactic shock induced by ovalbumin aerosol by 78.6 and 86.7% respectively.
authors.affiliation: Laboratório de Tecnologia Farmacêutica Universidade Federal da Paraíba, Caixa João Pessoa, PB, Brazil.
authors.forename: G
authors.initials: G
authors.lastname: Thomas
authors.forename: C C
authors.initials: CC
authors.lastname: Araújo
authors.forename: J C
authors.initials: JC
authors.lastname: Duarte
authors.forename: D P
authors.initials: DP
authors.lastname: De Souza