Ferulic acid derivatives

Main actives Water-soluble polysaccharides and glycoproteins, volatile oil (up to 2%), caffeic and ferulic acid derivatives including cichoric acid (0.6-2.1%), alkamides (0.01-0.04%), polyynes and pyrrolizidine alkaloids. 

In addition to their direct antioxidant activity, ferulic acid and its ester derivatives have also been shown to act as indirect antioxidants, that is, to induce cytoprotective (phase 2) enzymes [Dinkova-Kostova et al., 1998 Dinkova-Kostova, 2002], Similarly to curumin, ferulic acid derivatives also... 

Table 1 Selected ferulic acid derivatives evaluated as antineurodegenerative agents. Only Entry 1 was effective in improving learning and memory retention. 1H NMR data for all derivatives supplied by author...

Biomimetic conversion of ferulic acid derivatives to phenylcoumarans was carried out by using a variety of oxidants, of which the oxidation system (H2O2-HRP) gave the best results. However, the enzyme did not effect any stereocontrol. To overcome this difficultly, enantiopure ferulic acid derivatives such a A-ferulyl (S)-alaninate (308) were synthesized. The substrate 308 was dissolved in dioxane and phosphate/citric acid buffer (pH 3.5) was added. Aqueous H2O2 and HRP were added over 20 min. The mixture was stirred at room temperature for 2.5 h to yield a mixture of two phenylcoumarans 309 and 310 (70%) with a 1 4 ratio (Scheme 66). In the case of a camphor sultan derivative 311, a mixture of two phenylcoumarans was also obtained in 40% yield (312/313 = 1 9). Furthermore, oxidation of 311 with Ag20 in CH2CI2 (room temp., 24 h) yielded the same phenylcoumarans (35%) in a 1 12 ratio. The observed enantioselectivity in the oxidation... 

The phenolic acids detected are characteristic, and include vanillic acid, and glucosides of />-hydroxybenzoic, protocatechuic, vanillic, syringic and salicylic acids. 3 -Caffeoylquinic is the principal phenolic acid derivative (63-218 mg caffeic acid per kg fresh weight) [19], although other p-coumaric and ferulic acid derivatives have also been reported [16]. 

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]. 

In carrots, the principal phenolics are the hydroxycinnamic acid derivatives. Of these, caffeic acid derivatives are the main components (20-100 mg/kg fw. depending on the cultivar), while ferulic acid derivatives are accumulated in intermediate quantities (10-20 mg/kg) and p-coumaric derivatives, 4-hydroxybenzoic acid derivatives and vanillic acid are present in trace amounts [38]. The main compound in carrots is chlorogenic acid, which has been estimated as between 23 and 121 mg/kg f w. depending on the cultivar. However, in carrot tops, this compound can reach 375-400 mg/kg [40], while cryptochlorogenic, neochlorogenic and 5-feruloylquinic acids have also been detected. 

The principal phenolic acids in these vegetables are ferulic and p-coumaric acid derivatives, the green parts of chives and leeks containing more than in the white part. In leek, the white tissue contains 6-7 mg ferulic acid per kg f.w., while this compound reaches concentrations of 23-39 mg/kg in the green parts [64]. In the case of chive, p-coumaric acid derivatives reach 21-51 mg/kg and ferulic acid derivatives 32-76 mg/kg. In garlic a different pattern of phenolic metabolite accumulation is observed in skins and internal tissues. The external tissues contain 49-58 mg/kg p-coumaric acid, 27-31 mg/kg ferulic acid and 27-25 mg/kg sinapic acid, whereas the internal tissues only contain 2mg, 6-8 mg and 2 mg/kg, respectively. In addition, the internal tissues contain 12-13 mg/kg p-hydroxybenzoic acid [64]. 

Feruloyl Esterases. Psychrophilic feruloyl esterases are employed in industry for biomass degradation, biotransformation, and isolation of ferulic acid derivatives useful as antioxidant, antimicrobial, and photoprotectant properties. For instance, one studied feruloyl esterase from the psychrophilic bacterium, P. haloplanktis TAG 125, is a family 1 carbohydrate esterase and displays significant activity toward pNP-acetate, a- and yS-naphthyl acetate, and 4-methylumbelliferyl p-trimethylammonio cinnamate chloride (a model substrate for determining ferulolyl esterase activity) (23). 

Hosoda A, Ozaki Y, Kashiwada A, Mutoh M, Wakabayashi K, Mizuno K, Nomura E, Taniguchi H (2002) Syntheses of ferulic acid derivatives and their suppressive effects on cyclooxygenase-2 promoter activity. Bioorg Med Chem 10 1189... 

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). 

Recent scientific investigations of natural polyphenols have demonstrated their powerful antioxidant property (Niki et al, 1995). Several classes of polyphenols have been chemically identified. Some of these are grape polyphenols, tea polyphenols, soy polyphenols, oligomeric proanthocyanidines (OPA) and other natural polyphenols of the flavone class. Rice bran polyphenols are different from the above in that they are p-hydroxy cinnamic acid derivatives such as p-coumaric acid, ferulic acid and p-sinapic acid. Tricin, a flavone derivative, has also been isolated from rice bran. 

Studies by Hudson et al, (2000) have demonstrated the presence of eight polyphenols in rice bran by using high-pressure liquid chromatography. They are protocatechuic acid, p-coumaric acid, ferulic acid, sinapic aci vanillic acid, caffeic acid, which is a methoxycirmamic acid derivative, and tricin. The effect of these polyphenols on cell viability and on the colony-forming ability of human-derived MDA MB 468 and HBL 100 breast cells, colon-derived SW 480 and human colonic epithelial cells was assessed. These authors concluded that rice bran polyphenols have putative cancer chemopreventive properties. 

HIRAGA Y, NAKATA N, JIN H, ITO S, SATO R, YOSHIDA A, MORI T, OZEKI M, IKEDA Y (1993) Effect of the rice bran-derived ph)itosterol cycloartenol ferulic acid ester on the central nervous system. Arzneimittel-Forschung, 43(7) 715-21. 

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. 

The most common hydroxycinnamic acid derivatives are p-coumaric (4-hydroxy-cinnamic), caffeic (3,4-dyhydroxycinnamic), ferulic (4-hydroxy-3-methoxycinnamic), and sinapic (4-hydroxy-3,5-dimethoxycinnamic) acids, which frequently occur in foods as simple esters with quinic acid or glucose (Mattila and Kumpulainen 2002). 

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