Two new stereoisomers of neolignan and lignan from the flower buds of Magnolia fargesii.
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.
Lee
Jun
J
Diabetes Research Center, Division of Traditional Korean Medicine (TKM) Integrated Research, Korea Institute of Oriental Medicine (KIOM), Daejeon 305-811, Korea.
Seo
Eun-Kyoung
EK
Jang
Dae Sik
DS
Ha
Tae Joung
TJ
Kim
Jong-Pyung
JP
Nam
Joo-Won
JW
Bae
Green
G
Lee
Yun Mi
YM
Yang
Min Suk
MS
Kim
Jin Sook
JS
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
D016166:Free Radical Scavengers; D017705:Lignans; D000449:Aldehyde Reductase