title: Total NMR assignments of new [C7-O-C7'']-biflavones from leaves of the limonene-carvone chemotype of Lippia alba (Mill) N. E. Brown.
abstract: Phytochemical analysis of leaves of the limonene-carvone chemotype of Lippia alba led to the isolation of two biflavonoids with a new structural pattern with an ether linkage: 5,5''-dihydroxy-6,4',6'',3''',4'''-pentamethoxy-[C(7)--O--C(7'')]-biflavone (1) and 4',4,5,5''-tetrahydroxy-6,6'',3'''-trimethoxy-[C(7)--O--C(7'')]-biflavone (2). Structural elucidation of the new compounds was established on the basis of spectral data, through the use of 1D NMR and several 2D shift correlated NMR pulse sequences (COSY, HMQC, HMBC and NOESY).
authors.affiliation: Curso de Pós-Graduação em Química Orgânica, Departamento de Química Orgânica e Inorgânica, Centro de Ciências, Universidade Federal do Ceará, CP 12 200, 60451-970 Fortaleza, CE, Brazil.
authors.forename: Francisco Geraldo
authors.initials: FG
authors.lastname: Barbosa
authors.forename: Mary Anne Sousa
authors.initials: MA
authors.lastname: Lima
authors.forename: Edilberto Rocha
authors.initials: ER
authors.lastname: Silveira
mesh_terms: D044946:Biflavonoids / Q000737:chemistry* / Q000302:isolation & purification; D000081005:Cyclohexane Monoterpenes; D053138:Cyclohexenes; D000077222:Limonene; D032411:Lippia / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods* / Q000592:standards; D015394:Molecular Structure; D039821:Monoterpenes / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D012015:Reference Standards; D013729:Terpenes / Q000737:chemistry*
chemical_list: D044946:Biflavonoids; D000081005:Cyclohexane Monoterpenes; D053138:Cyclohexenes; D039821:Monoterpenes; D013729:Terpenes; C006923:carvone; D000077222:Limonene