Caffeic derivatives

N.A. Lycopus virginicus L. Phenolic acids, caffeic derivatives, chlorogenic derivatives, ellagic acids." Treat overactive thyroid gland, an astringent to reduce the production of mucus. 

The metabohtes and eonjugates of caffeic acid and caffeic derivatives identified in the different studies in humans and animals are summarized in Table 1. The majority of studies in hmnans and animals on absorption and metabolism of hydroxyeinnamates have been imdertaken with caffeic acid and its main natural conjugate, chlorogenie acid. The possession of a catechol moiety results in extensive metabohsm of caffeic acid, which leads to the formation of a number of metabohtes. The metabolic pathways of caffeic acid are schematically summarized in Figure 1 [6,16]. 

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

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. 

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. 

Reaction of [l,2,3]triazolo[1.5-c]pyrimidine with fuming nitric acid gives furoxan derivative 299 in low yield (Equation 65) <2001T10111>. Caffeic acid 300 reacts with acidic nitrite leading to a mixture of three products. The main product has been identified as the furoxan derivative 301 (Equation 66) <2001TL3303>. 

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). 

Simple phenolic compounds include (1) the phenylpropanoids, trans-cinnamic acid, p-coumaric acid and their derivatives (2) the phenylpropanoid lactones called coumarins (Fig. 3.4) and (3) benzoic acid derivatives in which two carbons have been cleaved from the three carbon side chain (Fig. 3.2). More complex molecules are elaborated by additions to these basic carbon skeletons. For example, the addition of quinic acid to caffeic acid produces chlorogenic acid, which accumulates in cut lettuce and contributes to tissue browning (Fig. 3.5). 

There is the often-overlooked group of polyphenols containing the derivatives of hydro-xycinnamic and hydroxybenzoic acids such as caffeic, chlorogenic, and gallic acids (Figure 29.8), which occur in food and exhibit certain antioxidant activity. For example, some caffeic acid esters isolated from propolis from honeybee hives showed antiinflammatory... 

Fig. 2.56. HPLC chromatogram of (a) Golden peel and (b) Golden pulp extracts at 280 nm. Peaks 1 = procyanidin B3 2 = procyanidin Bl 3 = ( + )-catechin 4 = procyanin B2 5 = chlorogenic acid 6 = ( — )-epicatechin 7 = caffeic acid 8 = phloretin derivative 9 = phloridzin 10 = rutin 11, 12 and 13 = flavonol glucosides. Reprinted with permission from A. Escarpa et al. [160].

The major pharmacological constituents of tea are the purine alkaloids caffeine (2.9-4.2%), theobromine (0.15-0.2%), and theophylline (0.02-0.04%). Also present are triterpene saponins (including barringtogenol C and Rl-barringenol), catechins (theaflavine, theaflavin acid, thearubigine), and caffeic acid derivatives (chlorogenic acid and theogallin). A cup of brewed tea contains approximately 20-100 mg of caffeine... 

Mate contains both caffeine (0.4-2.4%) and theobromine (0.3-0.5%). Also found are triterpene saponins and the caffeic acid derivatives—chlorogenic acid, neochlorogenic acid, and cryptochlorogenic acid. Flavonoids in mate are rutin, isoquercetin, and kaemferol glycosides. A nitrile glycoside, menisdaurin, is also present, which is noncyanogenic. 

Phenolic acids Benzoic acid derivatives OH Caffeic acid 1 Gentisic acid Benzoic acid 1 1 Vanllic acid Protocatechuic acid 1 /7-Hydroxybenzoic acid COOH Syringic acid Hydroxy-isochromans HO. l-phenyh6,7- dihydroxy-isochroman l-(3 -methoxy-4- hydroxyphenyh6,7- dihydroxydsochroman R1... 

Cinnamic acid OH derivatives H J> H Caffeic acid / -Coumaric acid o-Coumaric acid CH Ferulic acid Cinnamic acid Sinapinic acid COOH Flavonoids Flavones Apigenin q JT 11 Luteolin R2 Flavanonol 1 i IJ R3 V >r (+)-Taxifolin OH 0... 

Rechner, A.R., Spencer, J.P., Kuhnle, G., Hahn, U., and Rice-Evans, C.A., Novel biomarkers of the metabolism of caffeic acid derivatives in vivo, Free Radical Biol Med., 30, 1213, 2001. 

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