Caffeic acid

Soybeans contain only 1—25 ppm of phenofic acids (33) whereas defatted sunflower meal contains 2.7% chlorogenic acid, 0.38% quinic acid, and 0.2% caffeic acid (34). Chlorogenic acid turns from yellow to green and finally to brown as the pH is raised from 7 to 11. Interaction of chlorogenic acid... 

Of these, the CGA isomers are the principal acids and result from the esterification of the 3, 4, and 5 position hydroxyls of quinic acid with the carboxyls of several phenoHc acids, including caffeic acid (C) [331-39-5], ferruHc acid (F) [1135-24-6], andT -coumaric acid (Cm) [501 -98 ]. 

Fig. 2.77 Compounds 246-249, caffeic-acid derivatives from Echinacea angustifolia. Compounds 250 and 251, sweet principals from Lippia dulcis...

NARDINI M, SCACCINI c, PACKER L and VIRGILI F (2000) In vivo inhibition of the activity of phosphorylase kinase, protein kinase C and protein kinase A by caffeic acid and a procyanidin rich pine bark (Pinus maritima) extract Biochimica Biophysica Acta 1474, 219-25. 

For some toxins it is possible to demonstrate an apparent improvement in functional response at levels of exposure which are below a threshold. This effect, which has been termed hormesis , is most effectively demonstrated in the consistently improved longevity of animals whose caloric intake is restricted rather than allowing them to feed ad lib (Tannenbaum, 1942). Clearly in this instance, the observed effects are the result of exposure to a complex mixture of chemicals whose metabolism determines the total amount of energy available to the organism. But it is also possible to show similar effects when single chemicals such as alcohol (Maclure, 1993), or caffeic acid (Lutz et al., 1997) are administered, as well as for more toxic chemicals such as arsenic (Pisciotto and Graziano, 1980) or even tetrachloro-p-dibenzodioxin (TCDD) ( Huff et al., 1994) when administered at very low doses. It is possible that there are toxins that effect a modest, reversible disruption in homeostasis which results in an over-compensation, and that this is the mechanism of the beneficial effect observed. These effects would not be observed in the animal bioassays since to show them it would be necessary to have at least three dose groups below the NOAEL. In addition, the strain of animal used would have to have a very low incidence of disease to show any effect. 

LUTZ u, LUGLI s, BITSCH A, SCLATTER J and LUTZ w K (1997) Dose response for the stimulation of cell division by caffeic acid in forestomach and kidney of the male F344 rat. Fund Appl Toxicol. 39 131-7. 

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. 

Most of the anthocyanins acylated with caffeic acid have this cinnamyl moiety linked to a glucosyl position 6, as in gooseberries, some grape cultivars, ° " ° black carrots, red cabbage,red radishes," and sweet potatoes. Some anthocyanins isolated from species of potatoes have a caffeyl group located at position 4 of the rhamnosyl unit of the rutinose disaccharide. " ... 

The effects of catechin, epicatechin, procyanidin B2, caffeic acid, / -coumaric acid, myricetrin, and quercetrin on the color intensity and stability of malvidin 3-glucoside at a molar ratio of 1 1 under conditions similar to red wine were evaluated. " Flavan 3-ols appeared to have the lowest protective effects and flavonols the highest strong color changes were visually perceptible. " In the complexation of malvin chloride and natural polyphenols, flavonol glycosides by far exerted the best protector effect. ... 

As alkaloids contain a nitrogen atom, they react mostly alkahne and are able to form soluble salts in aqueous environments. In plants, however, they can occur in the free state, as a salt, or as an N-oxide, and accumulate in the plant vacuole as a reservoir or often coupled to phenoUc acids Uke chloro-genic acid or caffeic acid [2]. 

N form in nutrient solution pH of the nutrient solution after 10 h Reducing substances in the nutrient solution (nmol caffeic acid equivalents 10 h g root fresh weight] ... 

Nutrient availability also plays a major role in exudation, with deficiencies in N, P, or K often increasing the rate of exudation (218). It is believed that nutrient deficiency may trigger the release of substances such as organic acids or nonproteinogenic amino acids (phytosiderophores), which may enhance the acquisition of the limiting nutrient (219,220). An example here might be the release of phenolic acids such as caffeic acid in response to iron deficiency, which results in an increase in uptake of the cation (221). 

V. Solinas, S. Deiana, C. Gessa, C. Pistidda, and R. Rausa, Reduction of the Felll-desferrioxamine-B complexes by caffeic acid a reduction mechanism of biochemical significance. Soil. Biol. Biochem. 275 649 (1996). 

Lapierre, C. Pollet, B. Petit-Conil, M. Toval, G. Romero, J. Pilate, G. Leple, J. C. Boerjan, W. Ferret, V. De Nadai, V. Jouanin, L. Stmctural alterations of lignins in transgenic poplars with depressed cinnamyl alcohol dehydrogenase or caffeic acid... 

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