Of -caffeic acid

Morreel, K. Ralph, J. Lu, F Goeminne, G. Busson, R. Herdewijn, P. Goeman, J. L. Van der Eycken, J. Boeijan, W. Messens, E. Phenolic profiling of caffeic acid O-methyltransferase-dehcient poplar reveals novel benzodioxane oligolignols. Plant Physiol. 2004, 136, 4023 1036. 

Nakayama, T., Protective effects of caffeic acid esters against hydrogen peroxide-induced cell damage, Colloq. Sci. Int. Cafe, 16th(Vol.l), 372, 1995. (CA124 134741e)... 

Caffeic acid is generally the most abundant hydroxycinnamic acid in fruit and vegetables. The richest sources are coffee (drink), lettuce, carrots, blueberries, blackberries, cranberries, sweet potatoes (whole, cooked, and raw) and potatoes (Table 2.2). Prunes, peaches, orange juice, apples, tomatoes, grapes, and grape products (Bet6s-Saura and others 1996) also contain small quantities of caffeic acid. 

Gonthier MP, Remesy C, Scalbert A, Cheynier V, Souquet JM, Poutanen K and Aura AM. 2006. Microbial metabolism of caffeic acid and its sters chlorogenic and caftaric acid by human faecal microbiota in vitro. Biomed Pharmacother 60 536-540. 

Ceschel GC, Maffei P, Sforzini A, Lombardi Borgia S, Yasin A, Ronchi C (2002) In vitro permeation through porcine buccal mucosa of caffeic acid phenetyl ester (CAPE) from a topical mucoadhesive gel containing propolis. Fitoterapia 73 Suppl. 1 S44—S52... 

Lignans of another type, dicarboxylic acid lignans (p-hydroxycinnamate dimers), were isolated from liverworts (Hepaticopsida) and some vascular plants [11, 64]. Little is known about the biosynthesis of this class of lignans, but a feeding experiment demonstrated the conversion of caffeic acid to optically pure epiphyllic acid in a liyerwoTt Lophocolea heterophylla (Fig. 12.9) [65]. 

Yilmaz HR, Uz E, Yucel N, Altuntas I, OzceUk N. (2004) Protective effect of caffeic acid phenethyl ester (CAPE) on lipid peroxidation and antioxidant enzymes in diabetic rat Uver. J Biochem Mol Toxicol 18 234-238. 

Correlation Between Total Phenols Expressed as Percent Caffeic Acid Equivalents and Ozone Injury. Twelve cultivars of peanuts ranging from low to high ozone sensitivity were examined. Foliage of each of the cultivars was evaluated for content of total phenols before and after ozone treatment. Because of the relatively high concentrations of caffeic acid in peanut foliage, values are expressed as percent caffeic equivalents in the total phenol assay. Experimental results used in establishing the correlation between caffeic acid and ozone injury are shown in Table I. 

Mason (30) and Pierpoint (31) have described the involvement of o-diphenols in plants and how they contribute to abnormal plant pigmentation. o-Diphenols are oxidized to o-quinones by enzymes of the phenolase complex (o-diphenol O2 oxidoreductase, E.C. 1.10.3.1) and by peroxidase (E.C. 1.11.1.7). o-Quinones react with amino acids, proteins, amines and thiol groups of proteins to polymerize and from reddish-brown pigments. Concentrations of caffeic acid are doubled in both bean (8) and peanut... 

DC245 Herrmann, K. On the occurrence of caffeic acid and chlorogenic acid in fruits and vegetables. Naturwissen-schaften 1956 43 109. DC257... 

Hapiot, P. et al.. Oxidation of caffeic acid and related hydroxycinnamic acids. J. Electroanal. Chem. 405, 169, 1996. 

Fulcrand, H. et al.. Characterization of compounds obtained by chemical oxidation of caffeic acid in acidic conditions. Phytochemistry 35, 499, 1994. 

Rechner, A.R., Spencer, J.P., Kuhnle, G., Hahn, U., and Rice-Evans, C.A., Novel biomarkers of the metabolism of caffeic acid derivatives in vivo, Free Radical Biol Med., 30, 1213, 2001. 

Depending on the identity, number and position of the acyl residues, these acids may be divided into the following groups mono-esters of caffeic, p-coumaric and ferulic acid di-, tri- and tetra-esters of caffeic acid [14,15] mixed di-esters of caffeic and ferulic acid or caffeic and sinapic acid [16] mixed esters of caffeic acid with dibasic aliphatic acids (e.g., oxalic, succinic) [17]. 

Hirose, M., Fukushima, S., Shirai, T., Hasegawa, R., Kato, T., Tanaka, H., Asakawa, E. Ito, N. (1990) Stomach carcinogeiucity of caffeic acid, sesamol and catechol in rats and mice. Jpn. 

Hanham, A.F., Dunn, B.P. Stich, H.F. (1983) Clastogenic activity of caffeic acid and its relationship to hydrogen peroxide generated during autooxidation. Mutat. Res., 116, 333-339... 

The oxidation of DOPA and adrenaline to dopachrome and adrenochrome, respectively, by a horse radish peroxidase-H202 system has been reported by Herzmann.29,30 The oxidation process was activated by trace quantities of caffeic acid, its esters, and related compounds.30 Ascorbic acid inhibited the oxidation of adrenaline by this enzyme in the initial stages of the reaction, but later had a stimulatory effect.30... 

Table X illustrates the successful application of formaldehyde precipitation as a means of estimating the flavonoid and nonflavonoid contents in a mixture. The mixture consisted of catechin as the flavonoid and caffeic, vanillic, and syringic acids as the nonflavonoids. The catechin was 86% precipitated (lower than usual because of the low level), but the other substances were not significantly precipitated. The slight apparent loss of caffeic acid is attributable to experimental variation since in many other experiments the lack of reaction and precipitation or co-precipitation of caffeic acid or chlorgenic acid has been demonstrated. Allowing for the same slight solubility of the catechin-formalde-hyde product in the mixtures as in the single component solution, the analysis of the mixtures gave 95.7-107.6% of the calculated value. This indicates no significant co-precipitation or entrainment of the nonflavonoids as the flavonoid was removed. This result has been verified a number of times with different substances added to model solutions and wines (21, 22).

The term chlorogenic acid was introduced in 1846 [1] to describe a coffee bean component that was later characterized as 5-0-caffeoylquinic acid [2], which is an ester of caffeic acid with quinic acid. Such esters are known as depsides, and the term chlorogenic acids is now often used to refer to the range of depsides that have been found in plants and it is in this sense that this term will be employed throughout this paper. 

Enzymatic Transformations of Caffeic Acid in Body Tissues... 

Within the body tissues the changes of caffeic acid are methylation of the hydroxyl group in the 3 position, p-oxidation of side chain and conjugation with glycine or glucuronic acid. 

After oral administration of caffeic acid to rats, small amounts of vanillic acid and vanilloylglycine are excreted. The conversion of p-hydroxycinnamic acid into /7-hydroxybenzoic acid is found in rat liver mitochondria [18], Studies with /7-hydroxy[U-14C]cinnamic acid have showed that 14C02 is released during reaction, indicating that reaction probably followed the p-oxidation type reactions, the two carbon being first removed as acetyl-CoA, and then oxidized to C02. It is assumed that conversion of ferulic acid formed by methylation of caffeic acid into vanillic acid occurs in rat liver mitochondria. 

Vanilloylglycine, feruloylglycine and /w-coumaric acid glucuronide are identified after oral administration of caffeic acid to humans [15], Intraperitoneal injection of the sodium salt of caffeic acid to rats also produces these conjugates. Thus, conjugation with glycine or glucuronic acid in body tissues is demonstrated. 

Caffeic acid is metabolized by liver enzymes to give ferulic, vanillic acids and their glycine conjugates, which may be excreted into urine. In addition, dihydroferulic acid is produced by catechol o-methyltransferase in the liver. Because of the specificity of this enzyme, only ortho hydroxy-methoxy metabolites may be formed. These reactions may occur in rats as well in humans [15]. Fig. (2) shows the metabolic reactions of caffeic acid in body tissues. 

Fig. (2) Metabolic reactions of caffeic acid in body tissues...

A pure culture of the organism was inoculated into a basal medium with the addition of 0.025% caffeic acid. After 7 days incubation at 25°C under conditions of reduced oxygen tension, the caffeic acid was completely metabolized. Metabolites of caffeic acid are identified as dihydrocaffeic acid and ethyl catechol, respectively. In the 1960s, it has been reported that a constitutive enzyme present in strains of Aerobacter decarboxylates caffeic acid to 4-vinylcatechol nonoxidatively [20], Several cinnamic acids have been tested and the decarboxylation product from /7-coumaric acid has been identified as 4-vinylphenol. Thus, the bacterial enzyme activity requires a relatively unhindered 4-hydroxy group on the aromatic ring and an acrylic acid side chain. 

The principal transformations of caffeic acid mediated by microorganisms are reduction of the unsaturated aliphatic side chain, dehydroxylation, and decarboxylation. 

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