Phenol, cinnamic acid

El-Basyouni, S.Z., A. C. Neish, andG. H. N. Towers The Phenolic Acids in Wlxeat III. Insoluble Derivatives of Phenolic Cinnamic Acids as Natural Intermediates in Lignin Biosynthesis. Phytochem. 3, 627—640 (1964). 

Keywords phenol, cinnamic acid, phenylpropiolic acid, KlO-clay, microwave irradiation, 4-phenylcoumarin, 3,4-dihydro-4-phenylcoumarin... 

Martin AK. The origin or urinary aromatic compounds excreted by ruminants. II. The metabolism of phenolic cinnamic acids to benzoic acid. Br J Nutr 1982 47 155-164. 

EL-BASYOUNI S.Z., NEISK A.C. and TOWERS G.H.N. 1964. The phenolic acids in wheat. III. Insoluble derivatives of phenolic cinnamic acids as natural intermediates in lignin biosynthesis. Phytochemistry, 3, 627-639. 

Monohydric alcohols, aldehydes (including chloral hydrate), ketones, cinnamic acid, amines (2-naphthylaminc is odourless), nitrophenols (resemble both phenol and nitro-compound),... 

The chemical formulae for a variety of plant phenols are given in Fig. 16.2, including examples of simpler phenols, such as cinnamic acid derivative, and of tocopherols, flavonoids, flavonoid glycosides and anthocyanidins. The flavonoids include the following subclasses flavanones (taxifolin), flavones (luteolin), flavonols (quercetin) and flavanols (catechin/epicatechin). The... 

Wine and by-products Cinnamic acid derivatives, anthocyanins and flavanols dominate (10 to 20 J,M gallic acid equivalents) Oil-in-water emulsion (dressing model) Red wine yields better protection, but phenols in white and rose wine seem more efficient on a molar basis Sanchez-Moreno et al., 2000... 

The total phenolic content in XRPP was 1.10%. The major components were found to be p-hydroxybenzoic acid (0.44%), vanillin (0.19%), syringic acid (0.13%), and syringaldehyde (0.13%). The contents of p-hydroybenzaldehyde, vanillic acid and ferulic acid were 0.032, 0.015 and 0.020%, respectively. Gallic acid, protocatechuic acid and cinnamic acid were detected in trace amounts. 

The pure enzyme was tested for activity against several methylated phenolic and cinnamic acids (Table 2). The enzyme was active on methyl esters of cinnamic acids caffeio p-coumaric> ferulic, and is therefore termed a cinnamoyl esterase (CinnAE). 

Arcmatic compounds phenols, phenolic acids, cinnamic acid derivatives, coumarins, flavonoids, quinones, and tannins, all of which are aromatic compounds, comprise the largest group of secondary plant products. They are often referred to as "phenolics" and have been identified as allelopathic agents in more instances than all of the other classes of compounds combined 5). 

Two hypotheses have been proposed to explain how phenolic acids directly increase membrane permeability. The first is that the compounds solubilize into cellular membranes, and thus cause a "loosening" of the membrane structure so that minerals can leak across the membrane (28-30, 42). Support for this hypothesis comes from the fact that the extent of inhibition of electrical potentials correlates with the log P (partition coefficient of a compound between octanol and water) for various benzoic and cinnamic acid derivatives (Figure 5). 

Simple phenolic compounds include (1) the phenylpropanoids, trans-cinnamic acid, p-coumaric acid and their derivatives (2) the phenylpropanoid lactones called coumarins (Fig. 3.4) and (3) benzoic acid derivatives in which two carbons have been cleaved from the three carbon side chain (Fig. 3.2). More complex molecules are elaborated by additions to these basic carbon skeletons. For example, the addition of quinic acid to caffeic acid produces chlorogenic acid, which accumulates in cut lettuce and contributes to tissue browning (Fig. 3.5). 

Landete and others (2009) reported that Lactobacillus plantarum have the ability to metabolize phenolic compounds found in olive products (such as oleuropein, hydroxytyrosol, and tyrosol, as well as vanillic, p-hydroxybenzoic, sinapic, syringic, protocatechuic, and cinnamic acids). For example, oleuropein was metabolized mainly to hydroxytyrosol, whereas protocatechuic acid was decarboxylated to catechol by the enzymatic actions. 

Cinnamic acid may also be hydrogenated catalytically (p. 377). If the sodium amalgam method is chosen, the catalytic method should be practised with phenol. 

This limitation is well Illustrated by the failure of those methods to uncover the presence of another important group, the flavanoid, coumarin and cinnamic acid phenols (85 - 117). On the other hand, some 32 of these compounds were identified when isolation procedures specific for these types of compounds were employed. Using isolation and identification techniques which are particularly useful for alkaloids, it would be possible to determine whether any representatives of this class are present and, if so, to conduct subsequent studies for structure determination. 

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