Chlorogenic acid isomer

LI M, CHEN Q and WANG H (1983) Separation and determination of chlorogenic acid isomers and relation between their contents and quality of tea , Tea Sci Res J, 1, 106-12. 

Rees, D. I., Theaker, P. D., High pressure liquid chromatography of chlorogenic acid isomers in coffee, Coll. Sc 1. Int. Cafe, 8, 79, 1977. (CA92 196458x)... 

Fig. 2.49. Profile of Hypericum perforatum extract with the H LC-MS attributions of the components detected. 1 = chlorogenic acid isomer 2 = 3-0- -coumaroylquinic acid 3 = chlorogenic acid 4 = rutin 5 = hyperoside 6 = isoquercitrin 7 = 3,3, , , 7-pentahydroxyflavanone 7-0-rhamnopyranoside 8 = quercitrin 9 = quercetin 10 = 13,118 tapigenin 11 = pSeudohypericin 12 = hypericin 13 = hyperforin analogue 14 = hyperform dialogue 15 = hyperforin 16 = adhyperforin. Reprinted with permission from M. Brolis eta. [ ].

Figure 6.6 HPLC chromatogram of the extract from Superior potato flesh (a) and of the same extract spiked with standards (b). Identification p.1, chlorogenic acid p.2, chlorogenic acid isomer p.3, caffeic acid p.4, p-coumaric acid p.5, ferulic acid p.6, t-cinnamic acid. Column, Inertsil ODS-3 V (5 p.m, 4.0 X 250 mm) flow rate, l.OmL/min column temperatures, 20°C mobile phase, acetonitrile 0.5% formic acid (gradient mode) detector, UV at 280 nm.

Figure 6.8 UV spectra of standard chlorogenic acid (a) trans-cinnamic acid (b) cafFeic acid (c) p-coumaric acid (d) and femlic acid (e). The spectra of peaks 1 (chlorogenic acid) (f), peak 2 (chlorogenic acid isomer) (g), and peak 3 (caffeic acid) (h) were determined with HPLC fractions isolated from extracts of Superior potato peel.

Figure 6.9 MS and MS/MS (negative ion mode) of peaks 1 and 2 (chlorogenic acid and its isomer), peak 3 (caffeic acid) and peak 4 (chlorogenic acid isomer) from isolated HPLC chromatograms of potato extracts.

Plant part Chlorogenic acid Chlorogenic acid isomer Caffeic acid Total... 

Potato variety Chlorogenic acid Chlorogenic acid isomer Caffe ic acid H2O in fresh tubers (%) Total pheno ics (mg/100 g)... 

K., Katagiri, K., and Mitani, T. 2000. Identification, quantitative determination, and antioxida-tive activities of chlorogenic acid isomers in prune (Prunus domestica L.). J. Agric. Food Chem. 48 5512-5516. 

SoNDHEiMER, E.. On the distribution of caffeic acid and the chlorogenic acid isomers in plants. Arch. Biochem. Biophysics 74, 131—138 (1958). 

Numerous organic acids iu coffee iuclude acids of metaboHc origin, eg, acetic lactic, citric, malic, and oxaUc free quiuic acid [77-95-2], and various chlorogenic acid (CGA) isomers that appear to be species specific. 

Polyphenolic compounds are present in mate. Flavanols, at least in significant quantities, are absent.9 The major phenolic compounds are chlorogenic acid and its oxidation products referred to as resinotanol , which are formed during the manufacturing process.10 The chlorogenic acid may be a mixture of three different isomers.11... 

Several studies reflect the widespread use of the LC-MSn for the characterization of phenolic acids, predominantly chlorogenic acids (Clifford and others 2003, 2005, 2006a,b,c). For example, using LC-MS3 it is possible to discriminate between different isomers of coumaroylquinic acid, caffeoylquinic acid, and feruloylquinic acid. In addition, a hierarchical key was proposed to facilitate the process of identification when standards are not available (Clifford and others 2003). 

Potato variety Potato section Chlorogenic acid Chlorogenic isomer Caffeic acid Total Ratio peel/flesh ... 

The phenolic compounds present in these three commodities fall into two general classifications, cinnamic acid derivatives and flavonoids. Included in the former are chlorogenic acid and its isomers, free cinnamic acids such as caffeic and p-coumaric acid and various esters of those two acids. Included among the flavonoids are the following ... 

In freshly harvested lettuce, the caffeic acid derivatives caffeoyltartaric, dicaffeoyltartaric, caffeoyl malate and chlorogenic acids have been identified, as they were in endive and chicory [63]. In the case of lettuce, the outer leaves contained 28 mg/kg caffeoyltartaric, 160 mg/kg dicaffeoyltartaric, 15 mg/kg caffeoylmalate and 55 mg/kg chlorogenic acid, while the inner leaves contained almost half these amounts. However, after minimal processing (wounding) or ethylene exposure, the phenolic metabolism is activated and other caffeic acid derivatives such as the isochlorogenic isomers (3,5-dicaffeoylquinic, 3,4-dicaffeoylquinic and 4,5-dicaffeoylquinic acids) accumulate, especially in the white tissue (midrib) [67 70-72]. 

In some fruits, PPOs use other phenolic substrates for example a relative of DOPA, 3,4-dihy-droxyphenylethylamine (dopamine), is the major substrate in bananas and DOPA is the natural substrate in the leaves of broad beans. The grape PPO acts on p-coumaryl and caffeoyl-tartaric (caftaric) acids while dates contain an unusual combination of diphenol oxidase substrates including a range of caffeoyl-shikimic acids these are analogous to the ubiquitous isomers of chlorogenic acid [45],... 

TABLE 1 Number of Theoretically Possible Isomers of Chlorogenic Acids... 

In the absence of other known inhibitory compounds we postulate that maysin and its derivatives and chlorogenic acid and its isomers are important factors contributing to the resistance to the fall armyworm in leaves of centipede grass, teosinte and corn. Potential variations of luteolin compounds similar to maysin are more numerous than chlorogenic acid and its two isomers. Therefore, the future emphasis is likely to be more concerned with the genetics of the luteolin compounds. 

The major phenolic compound in tobacco roots (Figure 1) is chlorogenic acid (CA), correctly termed 3-O-caffeoylquinic acid (3-O-CQA). Only minor to trace amounts of the 4- and 5-O-CQA isomers are found in the roots, but occur in larger quantities in the leaves. Two coumarin derivatives are found in major amounts in root tissue scopoletin (6-methoxy-7-hydroxycoumarin) and its glucoside, scopolin. Both CA and scopolin can reach levels of 1% of the dry weight of the root. Very little scopolin or scopoletin is found in the leaves. 

Artemisia scoparia MeOH extract contains only chlorogenic acid (peak 1) and one chlon enic acid isomer (peak 6). 

Chlorogenic acid (Fig. 6.3) and similar derivatives, e.g., positional isomers or dicaffeoylquinic acids, were found in Asteraceae, Apiaceae, Brassicaceae, Malaceae, Rosaceae, Saxifragaceae, but they are also conunon in Solanaceae, Convolvulaceae,... 

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