title: Essential oil from Xylopia frutescens Aubl. reduces cytosolic calcium levels on guinea pig ileum: mechanism underlying its spasmolytic potential.
abstract: BACKGROUND
  Xylopia frutescens Aubl. (embira, semente-de-embira or embira-vermelha), is used in folk medicine as antidiarrheal. The essential oil from its leaves (XF-EO) has been found to cause smooth muscle relaxation. Thus, the aim of this study was to investigate the spasmolytic action by which XF-EO acts on guinea pig ileum.
  
  
  METHODS
  The components of the XF-EO were identified by gas chromatography-mass spectrometry. Segments of guinea pig ileum were suspended in organ bath containing modified Krebs solution at 37 °C, bubbled with carbogen mixture under a resting tension of 1 g. Isotonic contractions were registered using kymographs and isometric contractions using force transducer coupled to an amplifier and computer. Fluorescence measurements were obtained with a microplate reader using Fluo-4.
  
  
  RESULTS
  Forty-three constituents were identified in XF-EO, mostly mono- and sesquiterpenes. XF-EO has been found to cause relaxation on guinea pig ileum. The essential oil inhibited in a concentration-dependent manner both CCh- and histamine-induced phasic contractions, being more potent on histamine-induced contractions as well as antagonized histamine-induced cumulative contractions in a non-competitive antagonism profile. XF-EO relaxed in a concentration-dependent manner the ileum pre-contracted with KCl and histamine. Since the potency was smaller in organ pre-contracted with KCl, it was hypothesized that XF-OE would be acting as a K(+) channel positive modulator. In the presence of CsCl (non-selective K(+) channel blocker), the relaxant potency of XF-OE was not altered, indicating a non-participation of these channels. Moreover, XF-EO inhibited CaCl2-induced cumulative contractions in a depolarizing medium nominally without Ca(2+) and relaxed the ileum pre-contracted with S-(-)-Bay K8644 in a concentration-dependent manner, thus, was confirmed the inhibition of Ca(2+) influx through Cav1 by XF-EO. In cellular experiments, the viability of longitudinal layer myocytes from guinea pig ileum was not altered in the presence of XF-OE and the Fluo-4-associated fluorescence intensity in these intestinal myocytes stimulated by histamine was reduced by the essential oil, indicating a [Ca(2+)]c reduction.
  
  
  CONCLUSIONS
  Spasmolytic action mechanism of XF-EO on guinea pig ileum can involve histaminergic receptor antagonism and Ca(2+) influx blockade, which results in [Ca(2+)]c reduction leading to smooth muscle relaxation.
authors.affiliation: Centro de Ciências da Saúde/Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil. iara@ltf.ufpb.br.
authors.forename: Iara Leão Luna de
authors.initials: IL
authors.lastname: Souza
authors.affiliation: Instituto de Ciências Biológicas e da Saúde/Universidade Federal de Alagoas, Maceió, Alagoas, Brazil. anacarolinacc@yahoo.com.br.
authors.forename: Ana Carolina de Carvalho
authors.initials: AC
authors.lastname: Correia
authors.affiliation: Centro de Ciências Exatas e da Natureza/Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil. lay_biomed@yahoo.com.br.
authors.forename: Layanne Cabral da Cunha
authors.initials: LC
authors.lastname: Araujo
authors.affiliation: Centro de Ciências da Saúde/Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil. henrique.luiz89@gmail.com.
authors.forename: Luiz Henrique César
authors.initials: LH
authors.lastname: Vasconcelos
authors.affiliation: Centro de Ciências da Saúde/Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil. ceicafarma@gmail.com.
authors.forename: Maria da Conceição Correia
authors.initials: Mda C
authors.lastname: Silva
authors.affiliation: Instituto de Pesquisa em Fármacos e Medicamentos/Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil. vicente@ltf.ufpb.br.
authors.forename: Vicente Carlos de Oliveira
authors.initials: VC
authors.lastname: Costa
authors.affiliation: Centro de Ciências da Saúde/Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil. josean@ltf.ufpb.br.|Instituto de Pesquisa em Fármacos e Medicamentos/Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil. josean@ltf.ufpb.br.
authors.forename: Josean Fechine
authors.initials: JF
authors.lastname: Tavares
authors.affiliation: Instituto Nacional de Farmacologia/Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil. edgar.gamero@unifesp.br.
authors.forename: Edgar Julian
authors.initials: EJ
authors.lastname: Paredes-Gamero
authors.affiliation: Centro de Ciências da Saúde/Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil. fabianacavalcante@ltf.ufpb.br.|Instituto de Pesquisa em Fármacos e Medicamentos/Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil. fabianacavalcante@ltf.ufpb.br.|Universidade Federal da Paraíba, Centro de Ciências da Saúde/Pós-Graduação em Produtos Naturais e Sintéticos Bioativos/Laboratório de Farmacologia Funcional Prof. George Thomas, Cidade, Universitária, P.O. Box 5009, 58051-970, João Pessoa, Paraíba, Brazil. fabianacavalcante@ltf.ufpb.br.
authors.forename: Fabiana de Andrade
authors.initials: Fde A
authors.lastname: Cavalcante
authors.affiliation: Centro de Ciências da Saúde/Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil. bagnolia@ltf.ufpb.br.|Instituto de Pesquisa em Fármacos e Medicamentos/Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil. bagnolia@ltf.ufpb.br.
authors.forename: Bagnólia Araújo da
authors.initials: BA
authors.lastname: Silva
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis*; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects*; D009822:Oils, Volatile / Q000494:pharmacology*; D010276:Parasympatholytics / Q000494:pharmacology*; D010938:Plant Oils / Q000494:pharmacology*; D054336:Xylopia / Q000737:chemistry*
chemical_list: D009822:Oils, Volatile; D010276:Parasympatholytics; D010938:Plant Oils; D002118:Calcium