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Jun
2003
Dietary flavanols and procyanidin oligomers from cocoa (Theobroma cacao) inhibit platelet function.

Am J Clin Nutr 2003, 77 (6), 1466-73.

BACKGROUND: Flavonoids may be partly responsible for some health benefits, including antiinflammatory action and a decreased tendency for the blood to clot. An acute dose of flavanols and oligomeric procyanidins from cocoa powder inhibits platelet activation and function over 6 h in humans. OBJECTIVE: This study sought to evaluate whether 28 d of supplementation with cocoa flavanols and relatedprocyanidin oligomers would modulate human...

Apr
2003
Chocolate intake increases urinary excretion of polyphenol-derived phenolic acids in healthy human subjects.

Am J Clin Nutr 2003, 77 (4), 912-8.

BACKGROUND: Proanthocyanidins, the most abundant polyphenols in chocolate, are not depolymerized in the stomach and reach the small intestine intact, where they are hardly absorbed because of their high molecular weight. In vitro and in vivo studies using pure compounds as substrates suggest that proanthocyanidins and the related catechin monomers may be degraded into more bioavailable low-molecular-weight phenolic acids by the microflora in...

Mar
2003
Studies in polyphenol chemistry and bioactivity. 4.(1) Synthesis of trimeric, tetrameric, pentameric, and higher oligomeric epicatechin-derived procyanidins having all-4beta,8-interflavan connectivity and their inhibition of cancer cell growth through cel

J Org Chem 2003, 68 (5), 1641-58.

We report an improved synthesis of bis(5,7,3',4'-tetra-O-benzyl)epicatechin 4beta,8-dimer (3) from 5,7,3',4'-tetra-O-benzylepicatechin (1) and 5,7,3',4'-tetra-O-benzyl-4-(2-hydroxyethoxy)epicatechin (2) by replacing the previously employed Lewis acid, titanium tetrachloride, with the clay mineral Bentonite K-10. Under the same conditions, the benzyl-protected all-4beta,8-trimer, -tetramer, and -pentamer were obtained regioselectively from their...

Mar
2003
Inhibition of 15-lipoxygenases by flavonoids: structure-activity relations and mode of action.

Biochem Pharmacol 2003, 65 (5), 773-81.

We have recently reported that flavonoids of cocoa inhibit the mammalian 15-lipoxygenase-1-a catalyst of enzymatic lipid peroxidation. To elucidate the structure-activity relationship of the inhibitory effect, we investigated the effects of 18 selected flavonoids of variable structure on pure rabbit reticulocyte and soybean 15-lipoxygenases using linoleic acid as substrate. Moreover, the inhibitionby quercetin was studied in detail to gain...

Feb
2003
Myeloperoxidase/nitrite-mediated lipid peroxidation of low-density lipoprotein as modulated by flavonoids.

FEBS Lett 2003, 537 (1-3), 146-50.

In the presence of a H(2)O(2)-generating system, myeloperoxidase (MPO) caused conjugated diene formation in low-density lipoprotein (LDL), indicating lipid peroxidation which was dependent on nitrite but not on chloride. The oxidation of LDL was inhibited by micromolar concentrations of flavonoidssuch as (-)-epicatechin, quercetin, rutin, taxifolin and luteolin, presumably via scavenging of the MPO-derived NO(2) radical. The flavonoids served as...

Feb
2003
Cocoa and chocolate flavonoids: implications for cardiovascular health.

J Am Diet Assoc 2003, 103 (2), 215-23.

This paper offers a review of current scientific research regarding the potential cardiovascular health benefits of flavonoids found in cocoa and chocolate. Recent reports indicate that the main flavonoids found in cocoa, flavan-3-ols and their oligomeric derivatives, procyanidins, have a variety of beneficial actions, including antioxidant protection and modulation of vascular homeostasis. These findings are supported by similar research on...

Jan
2003
Stabilizing effect of ascorbic acid on flavan-3-ols and dimeric procyanidins from cocoa.

J Agric Food Chem 2003, 51 (3), 828-33.

Cocoa flavanols and procyanidins have numerous biological activities. It is known that (-)-epicatechin, (+)-catechin, epicatechin-(4beta-8)-epicatechin (dimer B2), and epicatechin-(4beta-6)-epicatechin (dimer B5) are unstable at physiologic pH, degrading almost completely within several hours, whereas they are relatively stable at pH 5.0. The present study investigated the effects of ascorbic and citricacid on the stability of monomers and...

Jan
2003
Cocoa flavonols and procyanidins promote transforming growth factor-beta1 homeostasis in peripheral blood mononuclear cells.

Exp Biol Med (Maywood) 2003, 228 (1), 93-9.

Evidence suggests that certain flavan-3-ols and procyanidins (FP) can have a positive influence on cardiovascular health. It has been previously reported that FP isolated from cocoa can potentially modulate the level and production of several signaling molecules associated with immune function and inflammation, including several cytokines and eicosanoids. In the present study, we examined whether FP fractions monomers through decamers modulate...

Jan
2003
Flavan-3-ols and procyanidins protect liposomes against lipid oxidation and disruption of the bilayer structure.

Free Radic Biol Med 2003, 34 (1), 84-92.

The antioxidant activity and the membrane effects of the flavanols (-)-epicatechin, (+)-catechin, and their related oligomers, the procyanidins, were evaluated in liposomes composed by phosphatidylcholine:phosphatidylserine (60:40, molar ratio). When liposomes were oxidized with a steady source of free radicals, the flavanols and procyanidins (25 microM monomer equivalents) inhibited oxidation in a manner that was related to procyanidin chain...

Nov
2002
Cocoa procyanidin chain length does not determine ability to protect LDL from oxidation when monomer units are controlled.

J Nutr Biochem 2002, 13 (11), 645-652.

Cocoa flavan-3-ols (catechin, epicatechin and oligomeric procyanidins) were tested for their ability to decrease LDL oxidative susceptibility and spare alpha-tocopherol (alpha-toc) in vitro. Physiologic concentration (0.10-0.50 &mgr;M) of flavanols were used. The flavanols increased LDL conjugated diene lag times dose-dependently from 23-207% and 15-143% in response to copper and AAPH oxidation, respectively, and delayed alpha-toc consumption....

Nov
2002
Cocoa procyanidins are stable during gastric transit in humans.

Am J Clin Nutr 2002, 76 (5), 1106-10.

BACKGROUND: Polyphenolic procyanidins are abundant flavonoid polymers in Western diets. In vitro biological activity has been reported for these compounds, but activity in vivo depends on the amount and chemical nature of the flavonoids reaching the gastrointestinal tract. Degradation of procyanidinsunder simulated gastric conditions at pH 2.0 has been reported in vitro. OBJECTIVE: The objective was to examine whether depolymerization of...

Oct
2002
Influence of flavan-3-ols and procyanidins on UVC-mediated formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine in isolated DNA

Arch Biochem Biophys 2002, 406 (2), 203-8.

The flavan-3-ols (-)-epicatechin (epicatechin) and (+)-catechin (catechin) and their related oligomers (procyanidins) isolated from cocoa were assayed for their capacity to inhibit the UVC-mediatedformation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (oxo(8)dG) in calf thymus DNA. The above-mentioned compounds inhibited oxo(8)dG production in a concentration- and time-dependent manner. After 30 min of irradiation (30 kJ/m(2)), 0.1, 1.0, 10, and 100...

Oct
2002
Procyanidin dimer B2 [epicatechin-(4beta-8)-epicatechin] in human plasma after the consumption of a flavanol-rich cocoa.

Am J Clin Nutr 2002, 76 (4), 798-804.

BACKGROUND: Epidemiologic studies have linked flavonoid-rich foods with a reduced risk of cardiovascular mortality. Some cocoas are flavonoid-rich and contain the monomeric flavanols (-)-epicatechin and (+)-catechinand oligomeric procyanidins formed from these monomeric units. Both the monomers and the oligomers have shown potential in favorably influencing cardiovascular health in in vitro and preliminary clinical studies. Although previous...

Sep
2002
Modulation of TNF-alpha secretion in peripheral blood mononuclear cells by cocoa flavanols and procyanidins.

Dev Immunol 2002, 9 (3), 135-41.

Epidemiological reports have suggested that the consumption of foods rich in flavonoids is associated with a lower incidence of certain degenerative diseases, including cardiovascular disease.Flavanols and their related oligomers, the procyanidins CFP, isolated from cocoa can modulate the production and level of several signaling molecules associated with immune function and inflammation in vitro, including several cytokines and eicosanoids. To...

Aug
2002
Fractionation of polymeric procyanidins from lowbush blueberry and quantification of procyanidins in selected foods with an optimized normal-phase HPLC-MS fluorescent detection method.

J Agric Food Chem 2002, 50 (17), 4852-60.

The polymeric procyanidins were fractionated from lowbush blueberry on a Sephadex LH-20 column. The degree of polymerization (DP) for the polymers was determined by thiolysis to be in a range of 19.9 to 114.1. Normal-phase HPLC analysis indicated that the polymeric procyanidins did not contain oligomeric procyanidins with DP...

Jul
2002
Flavonoids of cocoa inhibit recombinant human 5-lipoxygenase.

J Nutr 2002, 132 (7), 1825-9.

(-)-Epicatechin and its related oligomers, the procyanidins, are present in sizable amounts in some cocoas and chocolates. Intake of flavonoid-rich chocolate in humans has been reported to increase the plasma level of (-)-epicatechin and concomitantly to significantly decrease the plasma level of proinflammatory cysteinyl leukotrienes. Because leukotrienes are formed via the 5-lipoxygenasepathway of arachidonic acid metabolism, we examined...

Jun
2002
(-)-Epicatechin effects in rat liver epithelial cells: stimulation of gap junctional communication and counteraction of its loss due to the tumor promoter 12-O-tetradecanoylphorbol-13-acetate.

Biochem Pharmacol 2002, 63 (12), 2145-9.

Gap junctional intercellular communication (GJIC) is a direct signaling pathway for neighboring cells. Disturbances in GJIC are suggested to play a role in carcinogenesis and may be involved in cardiac arrhythmia. Tumor promoters like 12-O-tetradecanoylphorbol-13-acetate (TPA) are capable of inhibiting GJIC, whereas GJIC is stimulated by several micronutrients like genistein, retinoids or carotenoids. (-)-Epicatechin (4-40 microM), a major...

May
2002
The effects of flavanol-rich cocoa and aspirin on ex vivo platelet function.

Thromb Res 2002, 106 (4-5), 191-7.

BACKGROUND: Flavanols modulate platelet function in vitro, but less is known of their in vivo effects and how they compare to pharmacological platelet inhibitors. We investigated the effect of a flavanol-rich cocoabeverage (897 mg/ml) in combination with and in comparison to aspirin on platelet function and activation in healthy subjects. METHODS AND RESULTS: On separate test days in a crossover design, 16 healthy adults consumed aspirin (...

May
2002
Chocolate Consumption and Platelet Functio

Jama 2002, 287 (17), 2212-3.

Flavonoid-rich foods and beverages have putative vascular health benefits, including protection against ischemic stroke and reductions in platelet reactivity.1- 5 Tea, grapes, apples, and cocoa contain a class of flavonoids known as the flavanols, which includes epicatechin and catechin. Flavanols can polymerize, producing theaflavins and thearubigins (found in tea) and procyanidins (found in grapes, apples, and cocoa). We previously reported...

May
2002
Chocolate: A Heart-healthy Food? Show Me the Science!

Nutr Today 2002, 37 (3), 103-109

Cocoa and chocolate foods produced by appropriate methods can contribute significant amounts ofheart-healthy flavanols to the diet. These flavanols may enhance cardiovascular health by delaying blood clotting, improving vascular endothelial function, and helping to moderate inflammation. The benefits of chocolate can be enjoyed without guilt as part of a healthful balanced diet.

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