Phenolic acids derivatives

Simple phenols, phenolic acids derived from benzoic acid, and phenolic acids derived from cinnamic acid have been the most commonly identified... 

The determination of the antioxidant activity and phenolic profile of various tea and herbal infusions were recently reported. Atoui et al. [67] applied TEAC and luminol PCL assays to assess the antioxidant activity, and positive-ion LC-DAD-ESI-MS to assess the phenolic profile in 9 different teas, including Greek mountain tea, mint, chamomile, black Ceylon, and Chinese green tea. About 60 different flavonoid and phenolic acid derivatives were identified. 

Anthocyanin (cyanidin) pigmentation can be observed in some cultivars, although its nature has not been fully determined. 3 -Caffeoylquinic is the principal phenolic acid derivative, although 4 - and 5 -caffeoylquinic acids are also present. A concentration of 167 mg caffeic acid per kg has been reported in apricots [19]. The presence of the corresponding p-coumaroyl-and feruloyl quinic acid derivatives has also been reported [16], as have p-coumaroylglucose and feruloyl glucose. 

Among the phenolic acid derivatives, 3 -caffeoylquinic is the main compound in both species, although other p-coumaroyl-, caffeoyl-, and feroulyl quinic derivatives have also been reported in minor amounts. 

Among the phenolic acid derivatives, the most abundant and characteristic is caffeoyltartaric acid. p-Coumaroyl tartaric and... 

In addition, the phenolic acid derivatives include chlorogenic acid, caffeoylglucose and verbascoside. The flavonol rutin and the flavones luteolin 7-glucoside and apigenin 7-glucoside have also been reported. 

The main phenolic acid derivative is chlorogenic acid, although 3 -caffeoylquinic and 4 -cafFeoylquinic acids, and p-coumaroyl- and feruloyl-quinic acid derivatives have also been reported [16]. Up to 128mg caffeic acid per kg fresh peaches have been reported [19]. 

Among the phenolic acid derivatives, 4-hydroxybenzoic gucoside is the main compound, although gallic, p-coumaric, caffeic and ferulic acid derivatives have also been recorded in much smaller amounts [32]. 

The main phenolic acid derivative is chlorogenic acid (575-632 mg/kg f.w.), although neochlorogenic (trace) and cryptochlorogenic acids (8-11 mg/kg), 5 -feruloyl quinic acid (15-17 mg/kg), and caffeoyl, feruloyl and sinapoylglucose have also been reported [63]. 

Bell peppers, both green and red, contain low amounts of phenolic acid derivatives p-Coumaric (< 4 mg/kg), caffeic (< 10 mg/kg), ferulic (<15 mg/kg), sinapic (<5 mg/kg) and vanillic (10 mg/kg) acids [77]. Caffeoyl glucose, feruloyl glucose and sinapoyl glucose are the main hydroxycinnamic acid derivatives found, while no quinic acid derivatives have been detected [63]. Feruloyl glucose may accumulate up to 11 mg/kg f.w. and sinapoyl glucose up to 5 mg/kg in some red cultivars. 

As regards phenolic acid derivatives, potato tubers contain mainly caffeic acid derivatives, although ferulic, p-coumaric, sinapic and vanillic acids are also present [64]. The caffeic acid derivatives are mainly located in a thin 1-2 mm thick layer on the outer part of the tuber. The caffeic acid content ranges from 163 to 280 mg/kg f.w. depending on the cultivar. Ferulic acid (from 13 to 28 mg/kg), p-coumaric (from 0.5 to 4 mg/kg), sinapic (from 0.5 to 8 mg/kg) and vanillic acid (from 5 to 16 mg/kg) are present in much smaller amounts [64]. 

An HPLC study of the individual phenolic acid derivatives showed chlorogenic acid to be the predominant compound in potato (22-71 mg/kg). Cryptochlorogenic acid (11 mg/kg), neochlorogenic acid (7 mg/kg) and isochlorogenic acid (4,5-dicaffeoyl quinic acid) (Fig. 4) (3 mg/kg) were also present in smaller amounts [80]. It was also demonstrated that caffeic acid compounds are not distributed uniformly in the tuber, but occur in strongly decreasing concentrations from the outer to the inner section. About 50% of the compounds as a whole are located in the potato peel and adjoining tissue. 

Phenolic acid derivatives (cinnamic acids) and degradation products of flavonoids (phenylpropionic and phenylacetic acids) suffer transformations by caecal bacteria. The following transformations have been observed dehydroxylation of 3,4-dihydroxy derivatives to give 3-hydroxy compounds, demethylation of o-hydroxy-methoxyphenolic acids, reduction of the double bonds of cinnamic acids to yield the corresponding phenylpropionic acids, decarboxylation of cinnamic and phenylacetic acids (only when 4-hydroxyl is present), hydroxylation of... 

Phenolic acids (derivatives of benzoic and cinnamic acids)... 

Salicylates are phenolic acids derived from salicylic acid, and include salicin (in Salix species), populin (in Populus... 

Phenolic acids are found predominantly and widely distributed in almost all fruits. There are two classes of phenolic acids derivatives of benzoic acid... 

Nonflavonoid compounds comprise simple phenols, phenolic acids, coumarins, xanthones, stilbenes, lignins, and lignans. Phenolic acids are further divided into benzoic acid derivatives, based on a C6-C1 skeleton and cinnamic acid derivatives, which are based on a C6-C3 skeleton [6], The conmarins are phenolic acid derivatives composed of a benzene ring fnsed with an oxygen heterocycle. Xanthones consist of a C6-C1-C6 basic structure, and stilbenes are composed of a C6-C2-C6 skeleton with various hydroxylation patterns [13], Lignins are polymers of C6-C3 units, whereas lignans are made up of two phenylpropane units [13]. The structures of each of these classes are shown in Table 16.1. 

Monagas M, Khan N, Andres-Lacueva C, et al. Dihydroxylated phenolic acids derived from microbial metabolism reduce lipopolysaccharide-stimulated cytokine secretion by human peripheral blood mononuclear cells. Br Nutr. 2009 102(2) 201 —206. 

In the literature, there are a large number of different flavanols found in many different plants worldwide. Their structures differ from each other in the stereochemistry of the asymmetric carbons, the hydroxylation pattern of the aromatic rings, type and number of ester-linked substituents (e.g., methyl, glucosyl derivatives) or ester-linked substituents (e.g., phenolic acid derivatives), degree of polymerization, etc. 

Niemeyer HM, Pesel ES, Capaja SV, Bravo HR, Franke S, Francke W (1989) Changes in hydroxamic acid levels of wheat plants induced by aphid feeding. Phytochemistry 28 447-449 Nilsson MC (1994) Separation of allelopathy and resource competition by the boreal dwarf shrub Empetrum hermaphwditum Hagerap. Oecologia 98 1-7 Ohno T (2001) Oxidation of phenolic acid derivatives by soil and its relevance to allelopathic activity. J Environ Qual 30 1631-1635... 

Phenolic acid derivatives Apple Pear Grape Tomato Cherry Plum Peach Apricot Straw- berry Black- berry Black currant Blueberry Loquat... 

Asakawa, Y., and E. Wollenweber A novel phenolic acid derivative from buds of Populus lasiocarpa. Phytochemistry 15, 811—812 (1976). 

Challice, J. S., and A. H. Williams Phenolic compounds of the genus Pyrus. I. The occurrence of flavones and phenolic acid derivatives of 3,4-dihydroxybenzyl alcohol 4-glucoside in Pyrus calleryana. Phytochemistry 7, 119—130 (1968). 

Once absorbed, flavanoids and phenolic acid derivatives undergo extensive metabolism. 

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