title: 2-(4'-aminobenzenamine)-pyrimidine, a new alpha-antagonist from Autonoë madeirensis.
abstract: A new natural pyrimidine derivative, 2-(4'-aminobenzenamine)-pyrimidine (1), was isolated from the bulbs of Autonoë madeirensis, a Hyacinthaceae of the Madeira Archipelago (Portugal) and the structure determined on the basis of spectroscopic data. As some pyrimidine compounds are important alpha1-adrenergic antagonists, we investigated the effect of 1 on rat vas deferens contractility induced by the alpha1-agonist phenylephrine. In concentrations virtually devoid of effect on the rat vas deferens contractility, 1 shifted to the right the concentration-response curves of phenylephrine without changing the maximal effect. These results provide evidence that 1 acts as an alpha1-adrenoceptor antagonist and suggest a competitive mechanism of action.
authors.affiliation: CECF, Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal.
authors.forename: Catarina
authors.initials: C
authors.lastname: Dias
authors.forename: Alexandra
authors.initials: A
authors.lastname: Paulo
authors.forename: José
authors.initials: J
authors.lastname: Nascimento
authors.forename: Peter
authors.initials: P
authors.lastname: Houghton
authors.forename: Jane E
authors.initials: JE
authors.lastname: Hawkes
authors.forename: M Lurdes
authors.initials: ML
authors.lastname: Gonçalves
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D019668:Liliaceae; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D010656:Phenylephrine; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D011743:Pyrimidines / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D014649:Vas Deferens / Q000187:drug effects
chemical_list: D000317:Adrenergic alpha-Antagonists; D010936:Plant Extracts; D011743:Pyrimidines; D010656:Phenylephrine