title: Mechanism of action of relaxant effect of Agastache mexicana ssp.mexicana essential oil in guinea-pig trachea smooth muscle.
abstract: BACKGROUND
  Agastache mexicana ssp. mexicana (Kunth) Lint & Epling (Lamiaceae), popularly known as 'toronjil morado', is used in Mexican traditional medicine for the treatment of several diseases such as hypertension, anxiety and respiratory disorders.
  
  
  OBJECTIVE
  This study investigates the relaxant action mechanism of A. mexicana ssp. mexicana essential oil (AMEO) in guinea-pig isolated trachea model.
  
  
  METHODS
  AMEO was analyzed by GC/MS. The relaxant effect of AMEO (5-50 μg/mL) was tested in guinea-pig trachea pre-contracted with carbachol (3 × 10-6M) or histamine (3 × 10-5M) in the presence or absence of glibenclamide (10-5M), propranolol (3 × 10-6M) or 2',5'-dideoxyadenosine (10-5M). The antagonist effect of AMEO (10-300 μg/mL) against contractions elicited by carbachol (10-15-10-3M), histamine (10-15-10-3M) or calcium (10-300 μg/mL) was evaluated.
  
  
  RESULTS
  Essential oil composition was estragole, d-limonene and linalyl anthranilate. AMEO relaxed the carbachol (EC50=18.25 ± 1.03 μg/mL) and histamine (EC50=13.3 ± 1.02 μg/mL)-induced contractions. The relaxant effect of AMEO was not modified by the presence of propranolol, glibenclamide or 2',5'-dideoxyadenosine, suggesting that effect of AMEO is not related to β2-adrenergic receptors, ATP-sensitive potassium channels or adenylate cyclase activation. AMEO was more potent to antagonize histamine (pA2' = -1.507 ± 0.122) than carbachol (pA2' = -2.180 ± 0.357). Also, AMEO antagonized the calcium chloride-induced contractions.
  
  
  CONCLUSIONS
  The results suggest that relaxant effect of AMEO might be due to blockade of calcium influx in guinea-pig trachea smooth muscle. It is possible that estragole and d-limonene could contribute majority in the relaxant effect of AMEO.
authors.affiliation: a Departamento de Farmacia, Facultad de Química , Universidad Nacional Autónoma de México Ciudad Universitaria , Coyoacán , Ciudad de México , México.
authors.forename: Andrés
authors.initials: A
authors.lastname: Navarrete
authors.affiliation: a Departamento de Farmacia, Facultad de Química , Universidad Nacional Autónoma de México Ciudad Universitaria , Coyoacán , Ciudad de México , México.
authors.forename: Natalia
authors.initials: N
authors.lastname: Ávila-Rosas
authors.affiliation: a Departamento de Farmacia, Facultad de Química , Universidad Nacional Autónoma de México Ciudad Universitaria , Coyoacán , Ciudad de México , México.
authors.forename: Mateo
authors.initials: M
authors.lastname: Majín-León
authors.affiliation: a Departamento de Farmacia, Facultad de Química , Universidad Nacional Autónoma de México Ciudad Universitaria , Coyoacán , Ciudad de México , México.
authors.forename: José Luis
authors.initials: JL
authors.lastname: Balderas-López
authors.affiliation: a Departamento de Farmacia, Facultad de Química , Universidad Nacional Autónoma de México Ciudad Universitaria , Coyoacán , Ciudad de México , México.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Alfaro-Romero
authors.affiliation: b Laboratório de Pesquisa em Fármacos, Curso de Farmácia, Departamento de Ciências Biológicas e da Saúde , Universidade Federal do Amapá , Macapá , AP , Brazil.
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Tavares-Carvalho
mesh_terms: D031327:Agastache / Q000737:chemistry*; D000818:Animals; D016084:Bronchoconstriction / Q000187:drug effects*; D001993:Bronchodilator Agents / Q000302:isolation & purification / Q000494:pharmacology*; D020013:Calcium Signaling / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D008401:Gas Chromatography-Mass Spectrometry; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D009822:Oils, Volatile / Q000302:isolation & purification / Q000494:pharmacology*; D008517:Phytotherapy; D035261:Plant Components, Aerial; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal; D014132:Trachea / Q000187:drug effects* / Q000378:metabolism
chemical_list: D001993:Bronchodilator Agents; D009822:Oils, Volatile; D010936:Plant Extracts
keywords: Estragole; airways; asthma; d-limonene; pA2′