title: Solving the confusion of gnaphaliin structure: gnaphaliin A and gnaphaliin B identified as active principles of Gnaphalium liebmannii with tracheal smooth muscle relaxant properties.
abstract: Inflorescences of Gnaphalium liebmannii, commonly known as "Gordolobo", is the most important remedy in Mexican traditional medicine to treat respiratory diseases, including asthma. By a bioguided fractionation of the n-hexane extract of this plant, following the relaxant effect on guinea pig tracheal smooth muscle, the flavones 5,7-dihydroxy-3,8-dimethoxyflavone (1) and 3,5-dihydroxy-7,8-dimethoxyflavone (2) were identified as the active relaxant compounds. Compounds 1 and 2 showed more potent relaxant properties than aminophylline in this model. Both 1 and 2 have been described as gnaphaliin in the past; here EIMS data, NMR experiments for both compounds, and X-ray diffraction analysis for 1 provided structural information to suggest that 1 and 2 should be named gnaphaliins A and B, respectively.
authors.affiliation: Facultad de Química, Departamento de Farmacia, Universidad Nacional Autónoma de México, Ciudad Universitaria Coyoacán, México DF, Mexico.
authors.forename: Fernando
authors.initials: F
authors.lastname: Rodríguez-Ramos
authors.forename: Andrés
authors.initials: A
authors.lastname: Navarrete
mesh_terms: D000628:Aminophylline / Q000494:pharmacology; D000818:Animals; D004195:Disease Models, Animal; D005419:Flavonoids / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D036622:Gnaphalium / Q000737:chemistry*; D006168:Guinea Pigs; D015394:Molecular Structure; D009126:Muscle Relaxation / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D010276:Parasympatholytics / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010946:Plants, Medicinal / Q000737:chemistry*; D014132:Trachea / Q000187:drug effects
chemical_list: D005419:Flavonoids; D010276:Parasympatholytics; C542036:gnaphaliin A; C542037:gnaphaliin B; C121845:gnaphalin; D000628:Aminophylline