Chemical composition of shallot (Allium ascalonicum Hort.)

J Agric Food Chem. 2002 Sep 25;50(20):5686-90. doi: 10.1021/jf020396t.

Abstract

An extensive phytochemical analysis of the polar extracts from bulbs of shallot, Allium ascalonicum Hort., led to the isolation of two new furostanol saponins, named ascalonicoside A1/A2 (1a/1b) and ascalonicoside B (4), respectively, along with compounds 2a and 2b, most likely extraction artifacts. On the basis of 2D NMR and mass spectrometry data, the structures of the novel compounds were elucidated as furost-5(6)-en-3beta,22alpha-diol 1beta-O-beta-D-galactopyranosyl 26-O-[alpha-L-rhamnopyranosyl-(1-->2)-O-beta-D-glucopyranoside] (1a), its epimer at position 22 (1b), and furost-5(6),20(22)-dien-3beta-ol 1beta-O-beta-D-galactopyranosyl 26-O-[alpha-L-rhamnopyranosyl-(1-->2)-O-beta-D-glucopyranoside] (4). This is the first report of furostanol saponins in A. ascalonicum. High concentrations of quercetin, isorhamnetin, and their glycosides were also isolated and described.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allium / chemistry*
  • Flavonols*
  • Glycosides / analysis
  • Magnetic Resonance Spectroscopy
  • Mass Spectrometry
  • Molecular Structure
  • Plant Extracts / chemistry*
  • Quercetin / analogs & derivatives*
  • Quercetin / analysis
  • Saponins / analysis
  • Spectrometry, Mass, Fast Atom Bombardment

Substances

  • Flavonols
  • Glycosides
  • Plant Extracts
  • Saponins
  • 3-methylquercetin
  • Quercetin