Lívia Noronha Coelho-de-Souza

Publications (2)3.95 Total impact

• Article: Vasorelaxation induced by the essential oil of Croton nepetaefolius and its constituents in rat aorta are partially mediated by the endothelium.

  Pedro Jorge Caldas Magalhães, Saad Lahlou, Davi Matthews Jucá, Lívia Noronha Coelho-de-Souza, Pedro Thiago Tibúrcio da Frota, Adriana Maria Gurgel da Costa, José Henrique Leal-Cardoso
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  ABSTRACT: Previously, we reported that essential oil of Croton nepetaefolius (EOCN) decreases blood pressure in normotensive rats, an effect that seems resulting from its vasodilatory action directly upon vascular smooth muscle. In the present study, we aimed to study the role of endothelium-nitric oxide pathway in the mediation of vasodilatory effects of EOCN and two of its constituents, methyleugenol and alpha-terpineol, using rat isolated thoracic aorta and mesenteric vascular bed preparations. EOCN (1-300 microg/mL), in a concentration-dependent manner, relaxed isolated endothelium-intact aortic rings precontracted with KCl 60 mM, with an IC(50) value of 26.7 (14.7-48.2) microg/mL. Either pretreatment of the tissue with L-NAME, a nitric oxide synthase inhibitor, or mechanical endothelium removal increased significantly the IC(50) value to 66.6 (52.7-84.1) or 105.6 (91.3-122.2) microg/mL, respectively. In endothelium-intact aortic rings precontracted with norepinephrine, EOCN (10-200 microg/mL) produced a vasorelaxant action which was decreased by the pretreatment of the aortic rings with methylene blue, a guanylate cyclase inhibitor. In mesenteric bed preparations perfused under constant pressure, EOCN reverted the reduction of mesenteric flow caused by KCl (60 mM), an effect that was attenuated by L-NAME. Vasodilator responses to EOCN in mesenteric bed preparations were mimicked by methyleugenol and alpha-terpineol, and were also significantly reduced in the presence of L-NAME. In conclusion, EOCN has vasorelaxant effects in both a resistance vascular bed and in a conduit artery. They seem attributed, at least in part, to the actions of its main constituents methyleugenol and alpha-terpineol and appear partially dependent upon the integrity of a functional vascular endothelium. Inhibition of other transduction pathways may be involved in the mediation of these effects.
  Fundamental and Clinical Pharmacology 05/2008; 22(2):169-77. · 1.80 Impact Factor
• Article: Relaxant effects of the essential oil of Eucalyptus tereticornis and its main constituent 1,8-cineole on guinea-pig tracheal smooth muscle.

  Lívia Noronha Coelho-de-Souza, José Henrique Leal-Cardoso, Francisco José de Abreu Matos, Saad Lahlou, Pedro Jorge Magalhães
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  ABSTRACT: The effects of the essential oil of Eucalyptus tereticornis Sm. (EOET) on guinea-pig tracheal smooth muscle were investigated. EOET (10 - 1000 microg/mL) relaxed the tracheal basal tonus with an EC (50) value of 125.3 [52.2 - 300.9] microg/mL. Its maximal relaxation (40 +/- 6 %) was significantly lower than that evoked by aminophylline (209 +/- 34 %). The K (+)-(60 mM)-induced contractions were significantly reduced by both EOET (200 - 1000 microg/mL) and its main constituent 1,8-cineole (600 - 1000 microg/mL). Acetylcholine (1 microgM)-induced contractions were significantly enhanced by 1,8-cineole (10 - 1000 microg/mL). However, they were significantly enhanced and reduced by lower (200 - 400 microg/mL) and higher (800 - 1000 microg/mL) concentrations of EOET, respectively. Electrical field stimulation-induced contractions were significantly increased by EOET (100 - 600 microg/mL). In conclusion, EOET produces myorelaxant effects on guinea-pig isolated trachea, an effect that seems to result from a complex interaction between its monoterpenoid constituents.
  Planta Medica 01/2006; 71(12):1173-5. · 2.15 Impact Factor