title: Comparison of antioxidative properties of carbazole alkaloids from Murraya koenigii leaves.
abstract: A new dimeric carbazole alkaloid, 8,10'-[3,3',11,11'-tetrahydro-9,9'-dihydroxy-3,3',5,8'-tetramethyl-3,3'-bis(4-methyl-3-pentenyl)]bipyrano[3,2-a]carbazole (12), was isolated from the CH(2)Cl(2) extract of Murraya koenigii together with six known carbazole alkaloids, koenimbine (6), O-methylmurrayamine A (7), O-methylmahanine (8), isomahanine (9), bismahanine (10), and bispyrayafoline (11). Their structures were determined on the basis of (1)H and (13)C NMR spectroscopic and mass spectrometric (MS) data. The antioxidative properties of 12 carbazole alkaloids isolated from leaves of M. koenigii were evaluated on the basis of the oil stability index together with their radical scavenging ability against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. On the basis of the lag time to reach a steady state, the 12 carbazoles were classified into three groups. It is suggested that an aryl hydroxyl substituent on the carbazole rings plays a role in stabilizing the thermal oxidation and rate of reaction against DPPH radical.
authors.affiliation: Department of Home Economics, Kenmei Women's Junior College, Honmachi, Himeji, Hyogo 670-0012, Japan. nakatani@life.osaka-cu.ac.jp
authors.forename: Yukari
authors.initials: Y
authors.lastname: Tachibana
authors.forename: Hiroe
authors.initials: H
authors.lastname: Kikuzaki
authors.forename: Nordin Hj
authors.initials: NH
authors.lastname: Lajis
authors.forename: Nobuji
authors.initials: N
authors.lastname: Nakatani
mesh_terms: D000470:Alkaloids / Q000737:chemistry / Q000302:isolation & purification*; D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification*; D001713:Biphenyl Compounds; D002227:Carbazoles / Q000737:chemistry / Q000302:isolation & purification*; D004355:Drug Stability; D016166:Free Radical Scavengers / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D032101:Murraya / Q000737:chemistry*; D010851:Picrates / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry*
chemical_list: D000470:Alkaloids; D000975:Antioxidants; D001713:Biphenyl Compounds; D002227:Carbazoles; D016166:Free Radical Scavengers; D010851:Picrates; D010936:Plant Extracts; C004931:1,1-diphenyl-2-picrylhydrazyl