From Linden Flower to Linden Honey. Part 2 : Glycosidic Precursors of Cyclohexa-1,3-diene-1-carboxylic Acids
✍ Scribed by Eric Frérot; Alain Velluz; Erik Decorzant; Regula Naef
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 71 KB
- Volume
- 3
- Category
- Article
- ISSN
- 1612-1872
No coin nor oath required. For personal study only.
✦ Synopsis
The presence of two unusual, recently identified terpene acids, i.e., 4-(1-hydroxy-1-methylethyl)cyclohexa-1,3-diene-1-carboxylic acid (1) and 4-(1-methylethenyl)cyclohexa-1,3-diene-1-carboxylic acid (2), was now also confirmed in (Swiss) linden honey, after solid-phase extraction and HPLC purification. NMR Spectroscopy, in combination with UPLC/MS analysis, showed the presence of several glycosides of 1, which accounted for ca. 0.6 weight-% of the honey, as quantified by UPLC-UV. The major -glycoside× of 1, compound 5, could be isolated and identified by 2D-NMR experiments as the corresponding b-gentiobiosyl ester (rather than the classical compound with a glycosidic bond between an aglycone OH group and the sugar). The same diglycosides found in linden honey were also detected in linden nectar; also, chestnut and fir honeys contained these glycosides in minor quantities, but not colza, acacia, or dandelion honeys (Table 2).