Incorporation of ferulic

A more general response, and particularly in plants that do not normally make tyramine ferulate (such as poplar and arabidopsis) appears to be the direct incorporation of ferulic acid itself into lignins. In sharp contrast with claims in another report [381], we readily detected thioacidolysis marker compounds for 4-0-etherihed fernlic acid, as well as for a novel fcA-(P-0-4-ether) that derives from fernlic acid radical coupling reactions, in natnral grasses and in CCR-dehcient plant materials decarboxylation truncates the sidechain providing a pathway for a second P-O-4-conpling reaction [97,104]. Both types of strnctures are evidenced in NMR spectra [97,104]. 

Ralph, J., Grabber, J. H., and Hatfield, R. D. (1995) Lignin-ferulate crosslinks in grasses Active incorporation of ferulate polysaccharide esters into ryegrass lignins. Carbohydr. Res. 275(1), 167-178. 

Incorporation of [1-13C] Ferulic Acid. [1-13C] ferulic acid 5a, synthesized as previously described (26), was administered for 21-28 days to seedlings of L. leucocephala and T. aestivum following germination. The solid state C-13 spectra so obtained are shown in Figs. 2a and 2b, respectively. Note that these are difference spectra, obtained by subtraction of natural abundance resonances from that of the C-13 enriched samples, i.e., only C-13 enhanced resonances are evident. 

Incorporation of [2-13C] Ferulic Acid. Figs. 3a and 3b show the results obtained when [2-13C] ferulic acid 5b was administered to L. leucocephala (25) and T. aestivum L. (24), respectively. In the case of L. leucocephala, the dominant resonance observed at 82.7 ppm was coincident to that of... 

Incorporation of [3-13C] Ferulic Acid 5c. Figs. 4a and 4b show the results obtained following uptake of [3-13C] ferulic acid 5c to L. leucocephala and T. aestivum L., respectively the spectrum shown in Fig. 4c corresponds to a synthetic DHP polymer from [2-13C] coniferyl alcohol 2c. 

S units by quantitative NMR spectroscopy (Quantitative C NMR of Lignins section) or from 2D HSQC spectra (Quantification in 2D NMR section). Other differences between GS lignins are frequently the presence of unique entities, such as incorporated hydroxycinnamates (Ferulates in Lignins Cell Wall Cross-Linking in Grasses by Ferulates section), and y-acylated units (p-Hydroxybenzoates in Various Flardwoods section) [309]. 

Preparation of Ferulic Acid Incorporated Starch-Chitosan Blend Film.199... 

Mathew, S. and Abraham, T. E. 2008. Characterisation of ferulic acid incorporated starch-chitosan blend films. Food Hydrocolloids, 22(5) 826-835. 

Phenylalanine and p-coumaric acid, but not 3,4-dihydrox-ycinnamic (caffeic) acid or acetate, were incorporated into podophyllotoxin (51). In Podophyllum hexandrwn (Berberi-daceae), both cinnamic and ferulic acids are incorporated into both halves of the molecule. The carbon of the 0-methyl group of ferulic acid is distributed into both rings A and C. Sinapic and 3,4,5-trimethoxycinnamic acids are not incorporated. This suggests that other oxidation and methylation occurs after the initial dimerization reaction (Jackson and Dewick, 1984 Pelter, 1986 Poulton, 1981). 

The incorporation of several phenolic compounds into humified organic matter, and into the microbial biomass of soil, was studied by Kassim et all, They found that substantial proportions of the intact molecules of phenolic compounds, such as ferulic acid and catechol, were stabilised by incorporation into existing humus. Incorporation into the microbial biomass was greatest during the first two to four weeks of incubation, after which the amount declined with a corresponding increase in the proportion evolved as CO2. 

A study of the biosynthesis of curcumin (130) has produced unexpected results. Administration of labelled acetate, malonate, and phenylalanine to Curcuma longa plants revealed that all of these substrates were implicated in the biosynthetic route. Previous biosynthetic proposals suggested that the most plausible biosynthesis of curcumin (130) would involve condensation of two cinnamate or ferulate (128) units (derived from phenylalanine) and one acetate or malonate unit However, the recent studies have shown that the majority of radioactivity from acetate and malonate was not confined to the central methine carbon atom of curcumin (130). Since [l- C]phenylalanine was incorporated specifically, the high incorporation of activity from acetate/malonate into the aromatic regions of curcumin has been rationalized in terms of a biosynthetic route (Scheme 22) in which a P-pentaketo-acid derivative (132) is postulated as an intermediate. Further experimental evidence in support of these proposals is anticipated. 

Figure 15.9 SEM micrographs of the surface and cross section of blend films (a) surface of 0.5 1 starch-chitosan blend film (b) cross section of control blend film (c) cross section of ferulic acid incorporated blend film. Reprinted from Mathew and Abraham, 2008, with permission from Eisevier.

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. 

How the aliphatic monomers are incorporated into the suberin polymer is not known. Presumably, activated co-hydroxy acids and dicarboxylic acids are ester-ified to the hydroxyl groups as found in cutin biosynthesis. The long chain fatty alcohols might be incorporated into suberin via esterification with phenylpro-panoic acids such as ferulic acid, followed by peroxidase-catalyzed polymerization of the phenolic derivative. This suggestion is based on the finding that ferulic acid esters of very long chain fatty alcohols are frequently found in sub-erin-associated waxes. The recently cloned hydroxycinnamoyl-CoA tyramine N-(hydroxycinnamoyl) transferase [77] may produce a tyramide derivative of the phenolic compound that may then be incorporated into the polymer by a peroxidase. The glycerol triester composed of a fatty acid, caffeic acid and a>-hydroxy acid found in the suberin associated wax [40] may also be incorporated into the polymer by a peroxidase. 

Both and nmR showed the presence of aromatic and aliphatic components. In l C-NMR, resonances at =58 ppm indicate the presence of many OCH3 groups, such as those occurring in syringic, vanillic, and ferulic acids. Spectra clearly show the presence of palmitic and stearic acids by GC/MS, IR, and NMR data. The fulvic and humic acids are predominantly made up of phenolic and fatty acid units. These are highly aromatic because lignin residues have been incorporated in the humification process. 

Synthesis of podophyllotoxin (3.86) in cell culture of Linum album results in yields comparable to those of the most efficient tissue cultures of Podophyllum hexandrum. In order to further improve L. album cultures, Seidel et al. (2002) investigated the biosynthesis of podophyllotoxin (3.86). They fed a number of labeled compounds that to L. album cell cultures to identify which of these compounds could be used as precursors to podophyllotoxin. They determined that the substitution pattern on the benzene ring is critical. The substitution has to be either 3-methoxy, 4-hydroxy, as in ferulic acid (3.33), or, alternatively, 3,4-methylenedioxycinnamic acid (3.90) can serve as precursor. The precursor of podophyllotoxin in L. album appears to be deoxypodophyllotoxin (3.83), based on the higher level of isotope incorporation in the latter compound. This means that 7-hydroxymatairesinol, the precursors of 5-methoxypodophyllotoxin in L. flavum (Xia et al., 2000), is not a precursor of podophyllotoxin in L. album. 

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