title: New diarylheptanoids from Alnus japonica and their antioxidative activity.
abstract: In the course of research on the bioactive constituents of woody plants in the Cyugoku area of Japan, a methanol extract of the leaves of Alnus japonica were found to have strong antioxidative activity. Ethyl acetate soluble and n-buthanol soluble fractions of the methanol extract had a potent antioxidative effect. Both fractions were purified by silica gel column chromatography and HPLC using an ODS column to give four new diarylheptanoids along with known diarylheptanoids and flavonoids. These new compounds were elucidated to be 7-(3,4-dihydroxyphenyl)-5-hydroxy-1-(4-hydroxyphenyl)-3-heptanone-5-O-beta-D-xylopyranoside (1), 1-(3,4-dihydroxyphenyl)-5-hydroxy-7-(4-hydroxyphenyl)-3-heptanone-5-O-beta-D-xylopyranoside (2), 1,7-bis-(3,4-dihydroxyphenyl)-5-hydroxy-3-heptanone-5-O-[2-(2-methylbutenoyl)]-beta-D-xylopyranoside (3) and 1,7-bis-(3,4-dihydroxyphenyl)-5-methoxy-3-heptanone (4) using spectral methods and especially 1H-, 13C-NMR and 2D-NMR measurements. The isolated compounds including their main constituent, oregonin (5), were tested for antioxidative activity. Some of these compounds having two catechol structures showed potent antioxidative activity. Compounds having one catechol structure showed moderate antioxidative activity, but a peracetate of 5 having no catechol structure exhibited no antioxidative activity. Thus the catechol structure of the diarylheptanoids is indispensable for antioxidative activity.
authors.affiliation: School of Bioresources, Hiroshima Prefectural University, Nanatsuka, Shobara, Japan. kuroyang@pu-hiroshima.ac.jp
authors.forename: Masanori
authors.initials: M
authors.lastname: Kuroyanagi
authors.forename: Mari
authors.initials: M
authors.lastname: Shimomae
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Nagashima
authors.forename: Norio
authors.initials: N
authors.lastname: Muto
authors.forename: Takuro
authors.initials: T
authors.lastname: Okuda
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kawahara
authors.forename: Takahisa
authors.initials: T
authors.lastname: Nakane
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Sano
mesh_terms: D020001:1-Butanol; D000085:Acetates; D029661:Alnus / Q000737:chemistry*; D000975:Antioxidants / Q000737:chemistry* / Q000302:isolation & purification*; D001713:Biphenyl Compounds; D002851:Chromatography, High Pressure Liquid; D036381:Diarylheptanoids / Q000737:chemistry* / Q000302:isolation & purification; D000431:Ethanol; D047309:Flavones / Q000737:chemistry / Q000302:isolation & purification; D016166:Free Radical Scavengers / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D000432:Methanol; D016877:Oxidants / Q000737:chemistry; D010084:Oxidation-Reduction; D010851:Picrates / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry; D012997:Solvents; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013481:Superoxides / Q000737:chemistry
chemical_list: D000085:Acetates; D000975:Antioxidants; D001713:Biphenyl Compounds; D036381:Diarylheptanoids; D047309:Flavones; D016166:Free Radical Scavengers; D016877:Oxidants; D010851:Picrates; D010936:Plant Extracts; D012997:Solvents; D013481:Superoxides; D000431:Ethanol; C007650:ethyl acetate; D020001:1-Butanol; C004931:1,1-diphenyl-2-picrylhydrazyl; D000432:Methanol