title: Two new stereoisomers of neolignan and lignan from the flower buds of Magnolia fargesii.
abstract: A new stereoisomer of 8-O-4' system neolignan, (7R,8S)-1-(3,4-dimethoxyphenyl)-2-[4-(3-hydroxy-1-propenyl)-2-methoxyphenoxy]-propane-1,3-diol (1) and a new stereoisomer of tetrahydrofuranoid lignan, (7R,8S,7'S,8'R)-(3,4,5,3',4')-pentamethoxy-9,7'-dihydroxy-8.8',7.O.9'-lignan (2) along with seven known lignans and neolignans (3-9) were isolated from the methanol extracts of the flower buds of Magnolia fargesii. The structures of these compounds (1-9) were elucidated by spectroscopic methods including 1D- and 2D-NMR as well as by comparison with reported values. Absolute configurations of new stereoisomers 1 and 2 were determined by circular dichroism (CD) spectra. The absolute configuration of (7S,8S,10S)-[tetrahydro-4-hydroxy-2-(3,4,5-trimethoxyphenyl)furan-3-yl]methyl 3,4-dimethoxy benzoate (3) was determined by Mosher's esterification method for the first time in this study. Three lignans, tanegool (4), (+)-dehydrodiconiferyl alcohol (5), and epieudes-min (6), were isolated from this plant for the first time. Superoxide radical scavenging activities of the isolates (1-9) were measured by irradiated riboflavin/ethylenediaminetetraacetic acid (EDTA)/Nitroblue tetrazolium (NBT) system, and their in vitro rat lens aldose reductase (RLAR) inhibitory activities were also evaluated.
authors.affiliation: Diabetes Research Center, Division of Traditional Korean Medicine (TKM) Integrated Research, Korea Institute of Oriental Medicine (KIOM), Daejeon 305-811, Korea.
authors.forename: Jun
authors.initials: J
authors.lastname: Lee
authors.forename: Eun-Kyoung
authors.initials: EK
authors.lastname: Seo
authors.forename: Dae Sik
authors.initials: DS
authors.lastname: Jang
authors.forename: Tae Joung
authors.initials: TJ
authors.lastname: Ha
authors.forename: Jong-Pyung
authors.initials: JP
authors.lastname: Kim
authors.forename: Joo-Won
authors.initials: JW
authors.lastname: Nam
authors.forename: Green
authors.initials: G
authors.lastname: Bae
authors.forename: Yun Mi
authors.initials: YM
authors.lastname: Lee
authors.forename: Min Suk
authors.initials: MS
authors.lastname: Yang
authors.forename: Jin Sook
authors.initials: JS
authors.lastname: Kim
mesh_terms: D000449:Aldehyde Reductase / Q000037:antagonists & inhibitors; D000818:Animals; D002942:Circular Dichroism; D035264:Flowers / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D017705:Lignans / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D031566:Magnolia / Q000737:chemistry*; D051381:Rats; D013237:Stereoisomerism
chemical_list: D016166:Free Radical Scavengers; D017705:Lignans; D000449:Aldehyde Reductase