An Unambiguous Nomenclature for the Acyl-quinic Acids Commonly Known as Chlorogenic Acids

Abstract

The history of the acyl-quinic acids is briefly reviewed, the merits and limitations of the various nomenclature systems applicable are critically compared, and their limitations are highlighted, in particular their inability to provide an unambiguous description of all quinic acid enantiomers and diastereoisomers and associated acyl-quinic acids. Recommendations are made for a nomenclature system that in combination with IUPAC numbering achieves this objective. A comprehensive set of structures for the quinic acid enantiomers and diastereoisomers is presented. The Supporting Information provides an explanation of trivial names and a decision tree to determine which quinic acid isomer a structure represents.

Consumption of Chlorogenic Acids through Coffee and Health Implications

“…Discovered and isolated in the 80s [9], quinic acid lactones or quinides formed by dehydration of the quinic acid moiety during roasting ( Figure 2) also gained physiological importance in the 90s [10][11][12][13][14]. Currently, more than 300 major and compounds such as dicaffeoylquinic acids (diCQA), diferuloylquinic acids, caffeoylferuloylquinic acids, dimethoxycinnamoylquinic acids, caffeoyldimethoxycinnamoylquinic acids, trimetoxycinnamoylcaffeoylquinic acids; feruloyldimethoxycinnamoylquinic acid, sinapoylquinic acids, sinapoylcaffeoylquinic acids, sinapoylferuloylquinic acids, and related compounds, in addition to a number of new minor p-coumaric acid-containing compounds have been described both in coffee [15][16][17][18][19][20][21][22][23][24] and in other plant materials [25,26], and a number of potential beneficial effects of CGA have been revealed in vitro and in animal studies, corroborating results of epidemiological studies. The aim of this review was to raise the awareness of coffee consumers and not consumers for the high intake of CGA through coffee and for their potential beneficial health effects on health.…”

“…When citing other authors, their numbering has been changed for consistency. Numbering follows the International Union of Pure and Applied Chemistry (IUPAC) numbering system [3], which has been recently discussed, in other reviews [23,24]. Figure 2.…”

13C-1H coupling constants as a conformational tool for structural assignment of quinic and octulosonic acid

“…The carbon atoms are numbered starting from the carbon that carries the COOH group. Note that this is the same numbering as that used by Abrankó and Clifford [13]. Figure 2 shows the optimized structures of the quinic acid isomers.…”

“…Solvent effects were included using the polarizable continuum model (PCM) [22] using the integral equation formalism (IEFPCM [23]) variant and methanol as the solvent. As mentioned above, each stereoisomer has two separate chair conformations, with the COOH group either axial or equatorial [13]. We have chosen the conformers following Ref.…”

“…All eight quinic acid stereoisomers occur in two different chair conformations, which can be converted into each other by a Bchair flip^ [13]. These two chair conformations have opposite axial/equatorial positions of the carbonyl and hydroxyl groups.…”