title: Novel flavonol glycoside, 7-O-methyl mearnsitrin, from Sageretia theezans and its antioxidant effect.
abstract: A novel flavonol glycoside, 7-O-methylmearnsitrin (7,4'-O-dimethylmyricetin 3-O-alpha-L-rhamnopyranoside), and myricetrin, kaempferol 3-O-alpha-L-rhamnopyranoside, europetin 3-O-alpha-L-rhamnoside, and 7-O-methyl quercetin 3-O-alpha-L-rhamnopyranoside were isolated from the leaves of Sageretia theezans, and their chemical structures were identified by spectroscopic analyses including two-dimensional NMR (HSQC, HMBC). Whereas myricetrin, europetin 3-O-alpha-L-rhamnoside, and 7-O-methylquercetin 3-O-alpha-L-rhamnopyranoside showed stronger activities than ascorbic acid and alpha-tocopherol, 7-O-methylmearnsitrin showed very weak antioxidant activities by ESR and LDL oxidation inhibition tests.
authors.affiliation: Department of Food Science and Technology, Kyungpook National University, Taegu 702-701, Korea. kchung@knu.ac.kr
authors.forename: Shin-Kyo
authors.initials: SK
authors.lastname: Chung
authors.forename: Young-Chan
authors.initials: YC
authors.lastname: Kim
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Takaya
authors.forename: Kenji
authors.initials: K
authors.lastname: Terashima
authors.forename: Masatake
authors.initials: M
authors.lastname: Niwa
mesh_terms: D000975:Antioxidants / Q000302:isolation & purification* / Q000494:pharmacology; D004578:Electron Spin Resonance Spectroscopy; D005419:Flavonoids / Q000302:isolation & purification* / Q000494:pharmacology; D044948:Flavonols / Q000302:isolation & purification* / Q000494:pharmacology; D015227:Lipid Peroxidation / Q000187:drug effects; D008074:Lipoproteins / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D018515:Plant Leaves / Q000737:chemistry*; D027823:Rhamnaceae / Q000737:chemistry*
chemical_list: C489343:7-O-methyl mearnsitrin; D000975:Antioxidants; D005419:Flavonoids; D044948:Flavonols; D008074:Lipoproteins