Benzophenone O-glucoside, a biogenic precursor of 1,3,7-trioxygenated xanthones in Hypericum annulatum

Phytochemistry. 2001 Aug;57(8):1237-43. doi: 10.1016/s0031-9422(01)00194-7.

Abstract

Two benzophenones, hypericophenonoside (1) and annulatophenone (2) were isolated from the methanol extract of the herb of Hypericum annulatum. The structures of the benzophenones were established as 2'-O-beta-D-glucopyranosyl-2,4,5',6-tetrahydroxy benzophenone (1) and 2,3',5',6-tetrahydroxy-4-methoxybenzophenone (2) based on spectral and chemical evidence. Hypericophenonside is the second benzophenone O-glycoside found in nature. Acid and enzymatic hydrolysis of (1) led directly to the formation of 1,3,7-trihydroxyxanthone (gentisein). This fact confirmed the hypothesis that some xanthones could be formed in plants by dehydration of 2,2'-dihydroxybenzophenones, and the intermediate precursors appear to be benzophenone O-glycosides ortho to the carbonyl function.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Benzophenones / chemistry
  • Benzophenones / isolation & purification*
  • Glucosides / chemistry
  • Glucosides / isolation & purification*
  • Glycosides / chemistry
  • Glycosides / isolation & purification*
  • Hydrolysis
  • Magnetic Resonance Spectroscopy
  • Plants / chemistry*
  • Spectrophotometry, Infrared
  • Xanthenes / chemistry*
  • Xanthones*

Substances

  • Benzophenones
  • Glucosides
  • Glycosides
  • Xanthenes
  • Xanthones
  • annulatophenone
  • hypericophenonoside
  • gentisein