Phenolics phenolic acids

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). 

Food and plant phenolics are commonly detected using DAD detectors (Tan and others 2008). Photodiode array detection allows collection of the entire UV spectrum during the elution of a chromatographic peak, which makes it possible to identify a phenolic compound by its spectra. Simple phenols, phenolic acids, flavanones, benzophenones, isoflavones, and flavan-3-ols have maximum absorbance at 280 nm, hydroxycinnamic acids at 320 nm, flavonols, flavones, and dihydroflavonols at 365 nm, and anthocyanins at 520 nm (Ibern-G6mez and others 2002 Merken Hand Beecher 2000). Hydrolyzable tannins show a characteristic shoulder at 300 nm, suitable for identifying them (Arapitsas and others 2007). For stilbenes, maximum absorbance of trans-forms are at 306 nm and at 285 nm for cA-forms (Lamuela-Raventos and others 1995). 

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

Reversed-phase HPLC is used for the analysis of the different groups of phenols, phenolic acids, hydroxycinnamic acids, flavonoids, and procyanidins in grapes and wines (22,46,47,77-80). However, due to the presence of a large quantities of various compounds, wine analysis is difficult. Thus, different sample preparation procedures, including fractionation and extraction, are often applied when various groups of phenolic compounds are studied together. 

Phenolic compounds constitute one of the most numerous and widely distributed groups of phytochemicals in the plant kingdom. More than 8000 phenolic compounds have been described and this list continues to expand.49 Phenolic compounds exist as simple molecules, such as the phenolic acids, to highly polymerized structures, such as the proanthocyanidins. Harbome48 classified phenolics into 10 subclasses based upon their chemical structure these subclasses include the simple phenolics, phenolic acids, hydroxycinnamic acids, and flavonoids, among others. The flavonols represent one of the most commonly distributed classes of flavonoid compounds. 

Black cohosh Total phenolics, phenolic acids 60% methanol 2x5 min cycles, 50% flush volume, 90 s nitrogen purge, 40 °C, 6.8 MPa Mukhopadhyay et al., 2006... 

Xu, B. Chang, S.K.C. 2009. Total phenolic, phenolic acid, anthocyanin, flavan-3-ol, and flavonol profiles and antioxidant properties of pinto and black beans Phaseolus vulgaris. ) as affected by thermal processing. J. Agric. Food Chem. 57 4754 764. 

S12, S42), but it is now known that albumin is not the governing factor, nor is it the most important factor to be considered in the accumulation of abnormal collections of body fluids (H8). Furthermore, it is apparent from the existence of relatively healthy adults with no albumin in the blood (B5, Bll) that the protein is not essential for life. Notwithstanding these lately appreciated facts, an important if not unique physiological role of albumin is its capacity to act as a vehicular substance for a wide variety of ions with different structures. In addition to its ability to bind and transport fatty acids, certain hormones, steroids, peptides, and amino acids, it can hold and effectively isolate the ions of many different substances that may be undesirable or dangerous to cellular life, e.g., phenols, phenolic acids, poisonous metals, bilirubin. 

D19. Durant, J. A., A one-dimensional paper chromatographic technique for the separation of phenols, phenolic acids and their derivatives. Nature 169, 1062 (1952). 

In the following sections the synthesis of saturated monohydric, dihydric phenols, phenolic acids and their unsaturated constituents is described. 

In contrast to flue-cured, burley, and Maryland tobaccos, highly aromatic tobaccos such as Latakia were reported to contain significant levels of free simple phenols (1876, 1877a). As the complexity of the phenols increased, the likelihood of their presence in tobacco increased and many were found in smoke as a result of direct transfer, for example, the high molecular weight phenol, 3,4-dihydro-2,5,7,8-tetram-ethyl-2-(4,8,12-trimethyltridecyl)-l//-l-benzopyran-6-ol (a-tocopherol), first identified as a tobacco leaf component by Rowland (3347) and as a tobacco smoke component by Rodgman and Cook (3271), 6,7-dihydroxy-27/-l-benzopy-ran-6-one (esculetin) identified in tobacco and its smoke by Dieterman et al. (969). In the early 1960s, Herrmann (1625, 1626) reviewed various studies on the phenols, phenolic acids, and related compounds identified in tobacco and tobacco smoke. 

Herrmann, K. A review of literature on phenols, phenolic acids, and related compounds in green tobacco, cured tobacco, and tobacco smoke Deut. Apotheker Ztg. 101... 

Von Ebner (61, 187) long ago observed that certain phenols, phenolic acids and higher aldehydes exert a profound effect on collagen double refraction, reversing its sign. Kuntzel (130) demonstrated that the same effect is accomplished by treatment with several pyrogallic tanning... 

Carrasco-Pancorbo, A., G6mez-Caravaca, A. M., Cerretani, L., Bendini, A., Segura-Carretero, A., and Fern ndez-Gutierrez, A., A simple and rapid electrophoretic method to characterize simple phenols, ligands, complex phenols, phenolic acids, and flavonoids in extravirgin olive oil, J. Sep. Sci., 29,2221, 2006. 

Tryptophan, phenylalanine, tyrosine Aniline, chloroanlines, methylanilines, chloromethylanilines Nitrophenols, chlorinated phenols, phenolic acids (benzoic, p-hydroxybenzoic, vanillic, caffeic, p-coumaric, ferulic, salicylic, phenazine-1-carboxylic), aromatic anionic surfactants (alkylbenzenesulfonates)... 

SIMPLE PHENOLS, PHENOLIC ACIDS, AND RELATED COMPOUNDS... 

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. 

Chromosome aberrations CHO cells Onion root tips Simple phenols phenolic acids cinnamic acids Chlorogenic acid Several phenolics Stich et al. (1981a) Stich et al. (1981b) Levan and Tjio (1948)... 

Stich, H.F., Rosin, M.P., Wu, C.H., and Powrie, W.D., 1981a, The action of transition metals on the genotoxicity of simple phenols, phenolic acids and cinnamic acids. Cancer Lett., 14 251. 

A straightforward classification attempts to divide the broad category of phenolics into simple phenols and polyphenols, based exclusively on the number of phenol subunits present, but many plant phenolic compounds are polymerized into larger molecules. Thus, the term plant phenolics encompasses simple phenols, phenolic acids, coumarins, flavonoids, stilbenes, hydrolyzable and condensed tannins, lignans, and hgnins [4]. 

Polyphenols are a widespread group of secondary metabolites found in plants derived from phenylalanine and tyrosine, and they are characterized by the presence of several phenol groups (i.e., aromatic rings with hydroxyls) [1]. Plant phenolics include simple phenols, phenolic acids (benzoic and cinnamic acid derivatives), coumarins, flavonoids, stilbenes, hydrolysable and condensed tannins, lignans, and lignins [2, 3]. 

Monohydric phenols Polyhydric phenols Phenolic acids Phenolic antioxidants Phenols and the environment Phenols and beverages Metabolic studies Clinical studies Phenolic resins... 

Phenolic compounds present in natural products include simple phenols, phenolic acids, tocopherols, stilbenes, coumarins, flavonoids (flavonol, flavones, flavanols, antho-cyanidins, proanthocyanidins), tannins, lignans, and lignins (Naczk and Shahidi, 2006 Folmer et ah, 2014). Phenolic compounds are secondary plant metabolites that are synthesized in response to stress conditions, such as UV irradiation, nutrient deficiencies, infection, and wounding (Naczk and Shahidi, 2006 Ramakrishna and Ravishankar, 2011). 

Phenolic compounds that act as antioxidants are widespread in the plant kingdom. Plant phenolics can be classified as simple phenolics, phenolic acids, hydroxycin-namic acid derivatives, and flavonoids. In addition to the basic hydroxylated aromatic ring structure of these compounds, plant phenolics are often associated with sugars and organic acids. The consumption of natural plant phenolics have been estimated to be up to 1 g per day. Overall, the presence of phenolics in the diet has been positively... 

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