Unremitting Problems With Chlorogenic Acid Nomenclature: A Review

Abstract

Recebido em 08/12/2015; aceito em 12/01/2016; publicado na web em 12/04/2016 This paper summarizes a problematic nomenclature of isomers belonging to chlorogenic acid family since its first occurrence until present. During decades, there have been a high number of articles dealing with the family. Unfortunately, researchers who want to get knowledge about this topic may be strongly confused after reading a few articles. Due to gradual discoveries and isolations of the individual isomers from plenty of matrices and because of the changing system of terminology after these discoveries, discrepancies among articles are common. The cause of this confusion is that the main compound of the family, 5-caffeoylquinic acid (also wellknown as chlorogenic acid), was truly called as 3-caffeoylquinic acid before 1976, when new rules for nomenclature were published. Many researchers and also chemicals suppliers, however, keep using the "pre-IUPAC" nomenclature and wrongly call 3-caffeoylquinic acid as chlorogenic acid, the main substituent of the family. Despite there have been some works struggling with this issue, the problem is still appearing. Therefore, the present work was written.

Chlorogenic acids and the acyl-quinic acids: discovery, biosynthesis, bioavailability and bioactivity

“…Unfortunately, papers are still published in which non-IUPAC numbering is used, the numbering system used is not stated, or worse, the numbering is IUPAC but the structure shown is not, or vice versa. Kremr et al 52 commented that some published structures make no attempt to depict the spatial arrangement of the substituents, and Clifford recorded that some authors discuss previously published data unaware that different numbering systems have been used, for example 3-CQA (non-IUPAC) and 3-CQA (IUPAC) are treated as the same compound. 34,53 Note that Wikipedia and many other online sources, plus many catalogues listing acyl-quinic acid preparations, use non-IUPAC nomenclature.…”

“…224,235,236 The data in Table 7 show that aer coffee consumption a total of 46.2 mmol of ferulic acid-based compounds (ferulic acid [3], FQAs [32][33][34], ferulic acid-4 0 -sulfate [36], FQA-O-glucuronides FQAsulfates) were present in the 0-24 h ileal uid. In healthy subjects these compounds would pass to the large intestine and the quantity of ferulic acid metabolites excreted in the urine of volunteers with a functioning colon (feruloylglycine [51], and dihydroferulic acid [35] and its 4 0 -sulfate [39] and 4 0 -O-glucuronide [52]) totalled 51.2 mmol (Table 8). This is not greatly in excess of the 46.2 mmol of ferulic acid-based compounds entering the large intestine (Table 8).…”

“…The data presented in Table 8, and that of Gomez-Juaristi et al 206 on urinary excretion of hydroxycinnamate metabolites aer the respective ingestion of coffee and maté by healthy volunteers clearly show that dihydrocaffeic acid-3 0 -sulfate (40) and feruloylglycine (51) would serve as very sensitive biomarkers for the consumption of relatively small amounts of acyl-quinic acids. A more detailed ngerprint for coffee could be obtained by the additional analysis of 3 0 ,4 0 -dimethoxycinnamic acid (26), dihydroferulic acid (35), dihydroferulic acid-4 0 -sulfate (39), ferulic acid-4 0 -sulfate (36) and dihydroferulic acid-4 0 -O-glucuronide (52). However, whether coffee and/or maté consumption can be accurately assessed in population studies from measurements of urinary biomarkers is doubtful.…”

Consumption of Chlorogenic Acids through Coffee and Health Implications

“…Later, CGA were found to be distinct from tannic acid, the latest only found in green coffee. In 1908, 5-caffeoylquinic acid (5-CQA) or chlorogenic acid, numbered according to the International Union of Pure and Applied Chemistry (IUPAC) recommendations [3], was first isolated from a cristaline potassium-caffeine chlorogenate complex by Gorter [2,4], who discovered that this compound was widely distributed in leaves and seeds of numerous plants [5] including phytotherapeutic ones. But at least until the early 1920s substances in coffee other than caffeine were considered to have no biological effects [6].…”

A Graphene‐based Electrochemical Sensor for the Individual, Selective and Simultaneous Determination of Total Chlorogenic Acids, Vanillin and Caffeine in Food and Beverage Samples

“…This compound is often inaccurately called CGA or 3‐CQA according to the pre‐IUPAC nomenclature. It should be underlined that a term CGA should be now used only to refer to the family of related quinic acid conjugates . Vanillin (VAN) (Figure ‐B), 4‐hydroxy‐3‐methoxybenzaldehyde), is a phenolic aldehyde which is the main aromatic compound in natural vanilla.…”