Two new stereoisomers of neolignan and lignan from the flower buds of Magnolia fargesii

Chem Pharm Bull (Tokyo). 2009 Mar;57(3):298-301. doi: 10.1248/cpb.57.298.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldehyde Reductase / antagonists & inhibitors
  • Animals
  • Circular Dichroism
  • Flowers / chemistry*
  • Free Radical Scavengers / chemistry
  • Free Radical Scavengers / isolation & purification
  • Free Radical Scavengers / pharmacology
  • Lignans / chemistry*
  • Lignans / isolation & purification
  • Lignans / pharmacology
  • Magnolia / chemistry*
  • Rats
  • Stereoisomerism

Substances

  • Free Radical Scavengers
  • Lignans
  • Aldehyde Reductase