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May
2002
Inhibitory effects of cocoa flavanols and procyanidin oligomers on free radical-induced erythrocyte hemolysis.

Exp Biol Med (Maywood) 2002, 227 (5), 321-9.

Excessive peroxidation of biomembranes is thought to contribute to the initiation and progression of numerous degenerative diseases. The present study examined the inhibitory effects of a cocoaextract, individual cocoa flavanols (-)-epicatechin and (+)-catechin, and procyanidin oligomers (dimer to decamer) isolated from cocoa on rat erythrocyte hemolysis. In vitro, the flavanols and theprocyanidin oligomers exhibited dose-dependent protection...

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...

Mar
2002
Stability of the flavan-3-ols epicatechin and catechin and related dimeric procyanidins derived from cocoa.

J Agric Food Chem 2002, 50 (6), 1700-5.

Cocoa flavanols and procyanidins possess wide-ranging biological activities. The present study investigated the stability of the cocoa monomers, (-)-epicatechin and (+)-catechin, and the dimers,epicatechin-(4beta-8)-epicatechin (Dimer B2) and epicatechin-(4beta- 6)-epicatechin (Dimer B5), in simulated gastric and intestinal juice and at different pH values. The dimers were less stable than the monomers at both acidic and alkaline pH. Incubation...

Mar
2002
Effect of cocoa flavanols and their related oligomers on the secretion of interleukin-5 in peripheral blood mononuclear cells.

J Med Food 2002, 5 (1), 17-22.

We previously showed that flavanols and their related oligomers (FLO) isolated from cocoa can have immunomodulatory effects on production of the cytokines interleukin-1beta (IL-1beta), IL-2, and IL-4. In the present study, we examined whether selected FLO fractions isolated from cocoa (monomer through decamer) modulate IL-5 protein secretion from resting and phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC). Although...

Feb
2002
Evidence that the antioxidant flavonoids in tea and cocoa are beneficial for cardiovascular health.

Curr Opin Lipidol 2002, 13 (1), 41-9.

Epidemiologic studies suggest an inverse association of tea consumption with cardiovasculardisease. The antioxidant effects of flavonoids in tea (including preventing oxidative damage to LDL) are among the potential mechanisms that could underlie the protective effects. Other possible mechanisms include attenuating the inflammatory process in atherosclerosis, reducing thrombosis, promoting normal endothelial function, and blocking expression of...

Jan
2002
Flavanols and procyanidins of cocoa and chocolate inhibit growth and polyamine biosynthesis of human colonic cancer cells.

Cancer Lett 2002, 175 (2), 147-55.

The effects of cocoa powder and extracts with different amounts of flavanols and related procyanidin oligomers were investigated on the growth of Caco-2 cells. Treatment of the cells with 50 microg/ml of procyanidin-enriched (PE) extracts caused a 70% growth inhibition with a blockade of the cell cycle at the G2/M phase. PE extracts caused a significant decrease of ornithine decarboxylase and S-adenosylmethionine decarboxylase activities, two...

Dec
2001
(-)-Epicatechin inhibits nitration and dimerization of tyrosine in hydrophilic as well as hydrophobic environments.

Biochem Biophys Res Commun 2001, 289 (5), 1334-8.

The flavanol (-)-epicatechin is known to protect against peroxynitrite-induced nitration and oxidation reactions. This study investigated the protection afforded by (-)-epicatechin against both these reaction types on one target molecule, the aminoacid tyrosine, in a hydrophilic milieu as well as with a lipophilic tyrosine derivative, N-t-BOC l-tyrosine tert-butyl ester (BTBE), bound to liposomes. The flavanol efficiently attenuated both...

Dec
2001
Polyphenols of cocoa: inhibition of mammalian 15-lipoxygenase.

Biol Chem 2001, 382 (12), 1687-96.

Some cocoas and chocolates are rich in (-)-epicatechin and its related oligomers, the procyanidins. Fractions of these compounds, isolated from the seeds of Theobroma cacao, caused dose-dependent inhibition of isolated rabbit 15-lipoxygenase-1 with the larger oligomers being more active; the decamer fraction revealed an IC50 of 0.8 microM. Among the monomeric flavanols, epigallocatechin gallate (IC50 = 4 microM) and epicatechin gallate (5 microM...

Nov
2001
Effects of cocoa powder and dark chocolate on LDL oxidative susceptibility and prostaglandin concentrations in humans.

Am J Clin Nutr 2001, 74 (5), 596-602.

BACKGROUND: Flavonoids are polyphenolic compounds of plant origin with antioxidant effects. Flavonoids inhibitLDL oxidation and reduce thrombotic tendency in vitro. Little is known about how cocoa powder anddark chocolate, rich sources of polyphenols, affect these cardiovascular disease risk factors. OBJECTIVE: We evaluated the effects of a diet high in cocoa powder and dark chocolate (CP-DC diet) on LDLoxidative susceptibility, serum total...

Jul
2001
Epicatechin selectively prevents nitration but not oxidation reactions of peroxynitrite.

Biochem Biophys Res Commun 2001, 285 (3), 782-7.

The flavanol (-)-epicatechin has been found to protect against damage inflicted by peroxynitrite, an inflammatory intermediate. Here, epicatechin was tested in systems of increasing complexity. The compound efficiently protected against nitration of protein tyrosine residues by peroxynitrite (IC(50) approximately 0.02 mol epicatechin/mol peroxynitrite). However, at epicatechin concentrations completely preventing nitration of tyrosine by...

Mar
2001
Identification of procyanidins and anthocyanins in blueberries and cranberries (Vaccinium spp.) using high-performance liquid chromatography/mass spectrometry.

J Agric Food Chem 2001, 49 (3), 1270-6.

Blueberries and cranberries were analyzed for procyanidins using normal-phase HPLC/MS. Monomers, identified as (+)-catechin and (-)-epicatechin, and a series of oligomers were detected inblueberries, and MS data confirmed that the oligomers consisted of (epi)catechin units that were exclusively singly linked (B-type). The procyanidin "fingerprints" were similar for Tifblue and Rubel but higher than that for lowbush blueberries. In whole...

Feb
2001
Studies in polyphenol chemistry and bioactivity. 3.(1,2) stereocontrolled synthesis of epicatechin-4alpha,8-epicatechin, an unnatural isomer of the B-type procyanidins.

J Org Chem 2001, 66 (4), 1287-96.

Oligomeric procyanidins containing 4alpha-linked epicatechin units are rare in nature and have hitherto not been accessible through stereoselective synthesis. We report herein the preparation of the prototypical dimer, epicatechin-4alpha,8-epicatechin (6), by reaction of the protected 4-ketones 11a,b with aryllithium reagents derived by halogen/metal exchange from the aryl bromides 26a,b. Removal of the 4-hydroxyl group from the resulting...

Jan
2001
Proximate, Mineral and Procyanidin Content of Certain Foods and Beverages Consumed by the Kuna Amerinds of Panama

J Food Comp Anal 2001, 14 (6), 553-563.

The Kuna Amerinds reside chiefly in the San Blas islands (Kuna Yala) on the Caribbean coast of Panama. The diet of this population has not previously been described in detail and composition data for certain foods consumed by this population does not exist or is lacking for certain important nutrients. The protein, fat, moisture, fiber, sugar, mineral and procyanidin content was determined in foods selected because of the frequency with which...

Jan
2001
Inhibition of in Vitro low-density lipoprotein oxidation by oligomeric procyanidins present in chocolate and cocoas

Methods Enzymol 2001, 335, 350-60.

Introduction Flavonoids, including the procyanidins, are an integral part of the human diet, being found in a wide variety of plant foods, including vegetables, fruits, and their juices, herbs, wine, tea, and legumes. Intense research interest has focuesd on the potential role of flavonoids as physiologically active antioxidants, particularlrly with regard to cardiovascular disease. Dietary flavonoid intake has bee associated with a lower...

Jan
2001
Chocolate procyanidins decrease the leukotriene-prostacyclin ratio in humans and human aortic endothelial cells.

Am J Clin Nutr 2001, 73 (1), 36-40.

BACKGROUND: Polyphenolic phytochemicals inhibit vascular and inflammatory processes that contribute to disease. These effects are hypothesized to result from polyphenol-mediated alterations in cellular eicosanoid synthesis. OBJECTIVE: The objective was to determine and compare the ability of cocoa procyanidins to alter eicosanoid synthesis in human subjects and cultured human aortic endothelial cells. DESIGN: After an overnight fast, 10...

Oct
2000
Influence of oligomer chain length on the antioxidant activity of procyanidins.

Biochem Biophys Res Commun 2000, 276 (3), 945-51.

The antioxidant activity of catechin monomers and procyanidin (dimers to hexamers) fractions purified from cocoa was studied in two in vitro systems: liposomes and human LDL. Liposome oxidation (evaluated as formation of 2-thiobarbituric acid reactive substances) was initiated with 2,2'-azobis (2-amidinopropane) hydrochloride (AAPH), 2,2'-azobis (2,4-dimethylvaleronitrile) (AMVN), iron/ascorbate, or UV-C; LDL oxidation (evaluated as formation of...

Aug
2000
Cocoa procyanidins and human cytokine transcription and secretion.

J Nutr 2000, 130 (8S Suppl), 2093S-9S.

We examined whether cocoa, in its isolated procyanidin fractions (monomer through decamer), would modulate cytokine production at the levels of transcription and protein secretion in both resting and phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC). In resting cells, interleukin (IL)-1beta and IL-4 gene expression from cocoa-treated cells varied markedly among the subjects tested. However, at the protein level, the...

Aug
2000
Reactions of peroxynitrite with cocoa procyanidin oligomers.

J Nutr 2000, 130 (8S Suppl), 2100S-4S.

Peroxynitrite is a mediator molecule in inflammation, and its biological properties are being studied extensively. Flavonoids, which are natural plant constituents, protect against peroxynitrite and thereby could play an anti-inflammatory role. Procyanidin oligomers of different sizes (monomer through nonamer), isolated from the seeds of Theobroma cacao, were recently examined for their ability to protect against peroxynitrite-dependent...

Aug
2000
A dose-response effect from chocolate consumption on plasma epicatechin and oxidative damage.

J Nutr 2000, 130 (8S Suppl), 2115S-9S.

Evidence from epidemiological studies suggests that a diet high in plant foods and rich in polyphenols is inversely associated with a risk for cardiovascular and other chronic diseases.Chocolate, like red wine and green tea, is a polyphenol-rich food, primarily containing procyanidin polyphenols. These polyphenols are hypothesized to provide cardioprotective effects due to their ability to scavenge free radicals and inhibit lipid oxidation....

Aug
2000
Effects of cocoa extracts on endothelium-dependent relaxation.

J Nutr 2000, 130 (8S Suppl), 2105S-8S.

The aim of this study was to examine the effects of procyanidins derived from cocoa on vascular smooth muscle. Two hypotheses were tested: 1) extracts of cocoa, which are rich in procyanidins, cause endothelium-dependent relaxation (EDR), and 2) extracts of cocoa activate endothelial nitric oxide synthase (NOS). The experiments were carried out on aortic rings obtained from New Zealand White rabbits. The polymeric procyanidins (tetramer through...

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