New Diarylheptanoids from Alnus japonica and Their Antioxidative Activity

• Published in: Chemical & pharmaceutical bulletin Vol. 53; no. 12; pp. 1519 - 1523
• Main Authors: Kuroyanagi, Masanori, Shimomae, Mari, Nagashima, Yasuo, Muto, Norio, Okuda, Takuro, Kawahara, Nobuo, Nakane, Takahisa, Sano, Toshikazu
• Format: Journal Article
• Language: English
• Published: TOKYO The Pharmaceutical Society of Japan 01.12.2005; Pharmaceutical Soc Japan; Japan Science and Technology Agency
• Subjects: 1-Butanol; Acetates; Alnus - chemistry; Alnus japonica; antioxidant; Antioxidants - chemistry; Antioxidants - isolation & purification; Betulaceae; Biphenyl Compounds; Chemistry; Chemistry, Medicinal; Chemistry, Multidisciplinary; Chromatography, High Pressure Liquid; diarylheptanoid; Diarylheptanoids - chemistry; Diarylheptanoids - isolation & purification; Ethanol; Flavones - chemistry; Flavones - isolation & purification; Free Radical Scavengers - chemistry; Life Sciences & Biomedicine; Magnetic Resonance Spectroscopy; Methanol; oregonin; Oxidants - chemistry; Oxidation-Reduction; Pharmacology & Pharmacy; Physical Sciences; Picrates - chemistry; Plant Extracts - chemistry; Plant Leaves - chemistry; Science & Technology; Solvents; Spectrometry, Mass, Fast Atom Bombardment; Superoxides - chemistry; GLYCOSIDES; SERRULATOIDES; antioxidant; diarytheptanoid; TRITERPENOIDS; CURCUMIN; BARK; oregonin; Alnus japonica; CYCLOOXYGENASE-2 EXPRESSION; ZINGIBER-OFFICINALE; Betulaceae; FLOWERS; CONSTITUENTS; RHIZOMES
• ISSN: 0009-2363; 1347-5223
• DOI: 10.1248/cpb.53.1519

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-β-D-xylopyranoside (1), 1-(3,4-dihydroxyphenyl)-5-hydroxy-7-(4-hydroxyphenyl)-3-heptanone-5-O-β-D-xylopyranoside (2), 1,7-bis-(3,4-dihydroxyphenyl)-5-hydroxy-3-heptanone-5-O-[2-(2-methylbutenoyl)]-β-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.