Flavone C-glycosides from leaves of Oxalis triangularis

J Agric Food Chem. 2005 Dec 28;53(26):10057-60. doi: 10.1021/jf051626h.

Abstract

The flavone C-glycosides luteolin 6-C-(2''-O-beta-xylopyranosyl-beta-glucopyranoside) (1), apigenin 6-C-(2''-O-alpha-rhamnopyranosyl-beta-glucopyranoside) (2), apigenin 6-C-(2''-O-beta-xylopyranosyl-beta-glucopyranoside) (3), apigenin 6-C-(2''-O-(6'''-(E)-caffeoylglucoside)-beta-glucopyranoside) (4), and apigenin 6-C-(2''-O-(6'''-(E)-p-coumaroylglucoside)-beta-glucopyranoside) (5) have been isolated from the purple leaves of Oxalis triangularis. Compound 4 is new, while 5 has previously been isolated from Cucumis sativus after treatment with silicon and infection with Sphaerotheca fuliginea. Signal duplication in the NMR spectra of 2, 4, and 5 revealed the presence of rotameric conformers, created by rotational hindrance at the C(sp3) -C(sp2) glucosyl-flavone linkage in these flavone C-glycosides.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Chromatography, High Pressure Liquid
  • Glycosides / chemistry*
  • Glycosides / isolation & purification
  • Molecular Sequence Data
  • Plant Leaves / chemistry
  • Plants / chemistry*
  • Spectrophotometry, Ultraviolet

Substances

  • Glycosides