Ferulic acid structure

The yellow color of wheat straw, attributed at least in part to ferulic acid structures associated with the lignin, is not bleached by alkaline peroxide treatment [73]. 

Phytosterols have been demonstrated as being anti-cancer components in the diet (Awad and Fink 2000). Scientific studies indicate that phytosterols may offer profection against colon, breast and prostate cancers (Vanderhaeghe and Bouic, 2000). The possible mechanisms, as reported by these authors, include the effect of phytosterols on membrane structure and function and on the signal transduction pathways that regulate tumor growth and apoptosis. The rice bran derived phytosterol-cycloartenol-ferulic acid ester on the central nervous system has been studied by Hiraga et al. (1993). 

Ralph, J. Kim, H. Lu, F. Grabber, J. H. Boerjan, W. Leple, J.-C. Berrio Sierra, J. Mir Derikvand, M. Jouanin, L. Lapierre, C. Identification of the structure and origin of a thioacidolysis marker compound for ferulic acid incorporation into angiosperm lignins (and an indicator for cinnamoyl-CoA reductase deficiency). Plant J. 2008, 53, 368-379. 

The alternative structure of ferulic acid was excluded by spectral comparison with an authentic sample of ferulic acid. 

Hydroxy cinnamic acids are included in the phenylpropanoid group (C6-C3). They are formed with an aromatic ring and a three-carbon chain. There are four basic structures the coumaric acids, caffeic acids, ferulic acids, and sinapic acids. In nature, they are usually associated with other compounds such as chlorogenic acid, which is the link between caffeic acid and quinic acid. 

Fig. 6. Mechanisms for the reduction of compounds I and II of HRP C by ferulic acid, after Henriksen et al. 195). This scheme is based on new information from the 1.45 A resolution crystal structure of the ternary complex of ferulic acid and cyanide-ligated HRP C 195). The direction of proton transfer is indicated by the dotted arrows. The mechanism is discussed in Section IV,B,2, and the crystal structure data in Section IV,F,4. Note that a distal site water molecule makes an important hydrogen bond with the backbone carbonyl group of Prol39 (a residue conserved in all members of the plant peroxidase superfamily).

The crystal structures of two ferulic acid complexes of HRP C have been solved, one with resting state enzyme (to 2.0 A resolution) and the other with the cyanide-ligated enzyme (to 1.45 A resolution) 195). These represent a major achievement for the crystallography of peroxidase complexes. The binary complex is heterogenous, according to the 2Fo-Fc omit difference electron density map of the active site. The disordered density observed has been interpreted in terms of three... 

Attachment of Hydroxycinnamic Acids to Structural Cell Wall Polymers. Peroxidase mediation may also result in binding the hydroxycinnamic acids to the plant cell wall polymers (66,67). For example, it was reported that peroxidases isolated from the cell walls of Pinus elliottii catalyze the formation of alkali-stable linkages between [2-14C] ferulic acid 1 and pine cell walls (66). Presumably this is a consequence of free-radical coupling of the phenoxy radical species (from ferulic acid 1) with other free-radical moieties on the lignin polymer. There is some additional indirect support for this hypothesis, since we have established that E-ferulic acid 1 is a good substrate for horseradish peroxidase with an apparent Km (77 /tM), which is approximately one fifth of that for E-coniferyl alcohol (400 /iM) (unpublished data). 

Figure 1. Chemical structure of ferulic acid (left) and / -fluoroferulic acid (right).

In the case of ferulic acid, dimers are known one of these has a difuran structure and another a benzofuran structure. 

Another interesting example of C-C bond formation can be found in reports from Li and co-workers who, in 2004, described the preparation of an MIP with peroxidase-like activity capable of dimerising the homovanillic acid (HVA) (73) [49]. In this case a polymer was prepared by using the HVA substrate, instead of a TSA, as a template and a haemin unit as catalytic centre (74). The polymerisation was carried out in the presence of acrylamide and vinyl-pyridine in order to add extra functionalities aiding substrate recognition. The imprinted polymer showed an enzyme-like activity, as confirmed by adherence to the Michaelis-Menten saturation model, and it was inhibited by ferulic acid (75), a structural analogue of the substrate, which is also capable of inhibiting the natural peroxidase. 

Kanski J, Aksenova M, Stoyanova A, Butterfield DA. 2002. Ferulic acid antioxidant protection against hydroxyl and peroxyl radical oxidation in synaptosomal and neuronal cell culture systems in vitro Structure-activity studies. J Nutr Biochem 13 273-281. 

Plant foods contain a variety of PPs that are regarded as active agents and particularly as antioxidants. The chemical structures are quite complex and there are relatively small molecules such as hydrocinnamic acids (caffeic acid and ferulic acid) and also extremely large molecules like the proantho-... 

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