Quinic acid esters

Other Phenolic Compounds. There are several phenolic acids important to tea chemistry. GaUic acid (3) and its quinic acid ester, theogallin (4), have been identified in tea (17,18) and have been detected by hplc (19,20). 

Gentry EJ, Jampani HB, Keshavarz-Shokri A, Morton MD, Velde DV, Telikepalli H, Mitscher LA, Shawar R, Humble D, Baker W. (1998) Antitubercular natural products Berberine from the roots of commercial Hydrastis canadensis powder. Isolation of inactive 8-oxotetrahydrothalifen-dine, canadine, beta-hydrastine, and two new quinic acid esters, hycandinic acid esters-1 and -2. J Nat Prod 61 1187-1193. 

ABSTRACT Chlorogenic acids are polyphenolic compounds that occur ubiquitously in foods of plant origin. They are quinic acid esters of hydroxycinnamic acid. Recently, naturally occurring plant phenolics have attracted considerable attention in relation to their physiological potential. Depending upon the conditions, phenolic compounds can be either beneficial or detrimental to biological processes. 

Moller, B. and Herrmann, K. 1983. Quinic acid esters of hydroxycinnamic acids in stone and pome fruit Phytochemistry 22 477-481. 

Polyphenolic phytochemicals are classified into three major groups phenolic acids, fla-vonoids, and tannins. Phenolic acids include hydroxybenzoic, hydroxyphenylacetic, and hydroxycinnamic acids (Figure 11.3.3). Hy-droxycinnamic acids are the most widely distributed of the phenolic acids in plant tissues. The important hydroxycinnamic acids are p-coumaric, caffeic, ferulic, and sinapic acids. Most hydroxycinnamic acids are rarely encountered in the free state in nature. They occur as glucose esters and, more frequently, as quinic acid esters (Herrmann, 1989). Phenolic acids are usually detected at wavelengths between 210 and 320 nm. In general, the polarity of phenolic acids is increased mainly by the hy-... 

The FAB-MS/MS of chlorogenic acid resulted in daughter ions of 191, 179, 161, and 135 m/z. Chlorogenic acid is a quinic acid ester of caffeic acid, thus, one would expect the loss of a caffeoyl unit or caffeic acid. The ion at 191 m/z represents the loss of caffeic acid from chlorogenic acid to give quinic acid. The presence of the 179, 161, and 135 m/z ions are related to the caffeic residue. Minor ions at 309 and 147 m/z are indicative of a loss of carbon dioxide (44 m/z units) from chlorogenic acid and quinic acid, respectively. For further discussion on MS analysis of CAD, see Facino et al. (1993). Using the same rationale, MS data from other CAD can be interpreted and used to support other analytical data. 

CGA chemistry is defined by isomerism. Quinic acid possesses four distinct hydroxyl groups, which can all be acylated to provide four regioisomeric monoacyl quinic acid esters. With 2 acyl groups being identical, 6 distinct... 

Some relatively nonspecific enzymatic formation of caffeic (12), ferulic (13), and synapic (14) acids has been noted (Davin et al., 1992). Monooxygenases of microsomal fractions appear to be involved. For example, a specific p-coum-arate-3-hydroxylase has been isolated from mung beans. However, other work suggests that the carboxyl group of p-coumaric acid must be esterified as a quinic acid ester before... 

Hydroxycinnamoyl quinic acid esters and flavonol glycosides. Nucleosil 120 C18 reversed phase column (250 x 1% formic acid in deionized Water-acetonitrile DAD 280, 360 nm [12]... 

Teramachi F, Koyano T, Kowithayakorn T, Hayashi M, Komiyama K, Ishibashi M (2005) Collagenase inhibitory quinic acid esters from Ipomoea pes-caprae. J Nat Prod 68 794-796 Terahara N, Shimizu T, Kato Y, Nakamura M, Maitani T, Yamaguchi M, Goda Y (1999) Six acylated anthocyanins from the storage roots of purple sweet potato, Ipomoea batatas. Biosci Biotechnol Biochem 63 1420-1424... 

Green and roasted coffees, for example, contain more than 50 esters of cinnamic acids. Their level in green coffee beans ranges from 4 to 14%. The main groups are caffeoylquinic, dicaffeoylquinic, feruloylquinic, p-coumaroylquinic and caffeoyl-feruloylquinic acids. Moreover, all esters and diesters of quinic acid are found in three types of positional isomers that include 3-0-esters, 4-0-esters and 5-0-esters. The main component is chlorogenic acid, that is 3-0-caffeoyl-L-quinic acid, but this name also refers to all the natural quinic acid esters. The structures of the basic esters and diesters of caffeoylquinic acids are given in formulae 8-82. 

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