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Dec
2011
Structurally related (-)-epicatechin metabolites in humans: assessment using de novo chemically synthesized authentic standards.

Free Radic Biol Med 2012, 52 (8), 1403-12. Free Radic Biol Med. 2012 Apr 15;52(8):1403-12. doi: 10.1016/j.freeradbiomed.2011.12.010. Epub 2011 Dec 23.

Accumulating data suggest that diets rich in flavanols and procyanidins are beneficial for human health. In this context, there has been a great interest in elucidating the systemic levels and metabolic profiles at which these compounds occur in humans. Although recent progress has been made, there still exist considerable differences and various disagreements with regard to the mammalian metabolites of these compounds, which in turn are largely...

Sep
2011
Selective removal of the violet color produced by anthocyanins in procyanidin-rich unfermented cocoa extracts.

J Food Sci 2011, 76 (7), C1010-7. J Food Sci. 2011 Sep;76(7):C1010-7. doi: 10.1111/j.1750-3841.2011.02322.x.

Cacao (Theobroma cacao L.) is rich in procyanidins, a large portion of which degrades during the natural fermentation process of producing cocoa powder. Recent advances in technology have enabled scientists to produce unfermented cocoa powder, preserving the original profile of procyanidins present in cocoa and allowing for the development of highly concentrated procyanidin-rich extracts. During this process, the anthocyanins naturally present...

Jun
2011
Physicochemical properties of acidified skim milk gels containing cocoa flavanols.

J Agric Food Chem 2011, 59 (12), 6740-7. J Agric Food Chem. 2011 Jun 22;59(12):6740-7. doi: 10.1021/jf200993f. Epub 2011 May 23.

The physicochemical properties of acidified milk gels after the addition of cocoa flavanols were studied. As the flavanol level increased (from 0 to 2.5 mg/g), syneresis and gel elasticity (tan δ) were found to significantly increase and decrease, respectively. Flavanol addition reduced the stress at fracture, with no changes in fracture strain, suggesting that the bond type (i.e., covalent vs noncovalent) was the underlying factor explaining...

Jan
2011
The stereochemical configuration of flavanols influences the level and metabolism of flavanols in humans and their biological activity in vivo.

Free Radic Biol Med 2011, 50 (2), 237-44.

Extensive epidemiological and clinical evidence associates diets high in flavanol-containing foods with cardiovascular health benefits in humans. Catechin and epicatechin, the most common flavanolsin foods, are present in the diet in different enantiomeric forms. This study investigated the influence of the stereochemical configuration of flavanols on their absorption, metabolism, and biologicalactivity. Healthy adult males were asked to consume...

Jan
2011
Prebiotic evaluation of cocoa-derived flavanols in healthy humans by using a randomized, controlled, double-blind, crossover intervention study.

Am J Clin Nutr 2011, 93 (1), 62-72. Am J Clin Nutr. 2011 Jan;93(1):62-72. doi: 10.3945/ajcn.110.000075. Epub 2010 Nov 10.

BACKGROUND: The absorption of cocoa flavanols in the small intestine is limited, and the majority of the flavanols reach the large intestine where they may be metabolized by resident microbiota. OBJECTIVE: We assessed the prebiotic potential of cocoa flavanols in a randomized, double-blind, crossover, controlled intervention study. DESIGN: Twenty-two healthy human volunteers were randomly assigned to either a high-cocoa flavanol (HCF)...

Dec
2010
Recommending flavanols and procyanidins for cardiovascular health: current knowledge and future needs.

Mol Aspects Med 2010, 31 (6), 546-57

Data on the potential health benefits of dietary flavanols and procyanidins, especially in the context of cardiovascular health, are considerable and continue to accumulate. Significant progress has been made in flavanol analytics and the creation of phytonutrient-content food databases, and novel data emanated from epidemiological investigations as well as dietary intervention studies. However, a comprehensive understanding of the...

Dec
2010
The flavanol (-)-epicatechin prevents stroke damage through the Nrf2/HO1 pathway.

Journal of Cerebral Blood Flow and Metabolism 2010, 30 (12), 1951-1961.

Epidemiologic studies have shown that foods rich in polyphenols, such as flavanols, can lower the risk of ischemic heart disease; however, the mechanism of protection has not been clearly established. In this study, we investigated whether epicatechin (EC), a flavanol in cocoa and tea, is protective against brain ischemic damage in mice. Wild-type mice pretreated orally with 5, 15, or 30 mg/kg EC before middle cerebral artery occlusion (MCAO)...

Oct
2010
Consumption of cocoa flavanols results in acute improvements in mood and cognitive performance during sustained mental effort.

J Psychopharmacol 2010, 24 (10), 1505-14.

Cocoa flavanols (CF) positively influence physiological processes in ways that suggest theirconsumption may improve aspects of cognitive function. This study investigated the acute cognitiveand subjective effects of CF consumption during sustained mental demand. In this randomized, controlled, double-blinded, balanced, three period crossover trial 30 healthy adults consumed drinks containing 520 mg, 994 mg CF and a matched control, with a three-...

Sep
2010
Dose-related effects of flavanol-rich cocoa on blood pressure.

J Hum Hypertens 2010, 24 (9), 568-76.

Consumption of flavanol-containing cocoa products has been shown to lower blood pressure (BP), but the minimum dose required to reduce BP is not known. This study aimed to examine the effect of three different doses of cocoa flavanols (CF) on 24-h mean arterial BP. Twenty four hour ambulatory BP (24-ABP) monitoring was performed in 32 men and 20 postmenopausal women with untreated mild hypertension (seated clinic BP >130/85 and

Aug
2010
Enantioselective syntheses of sulfur analogues of flavan-3-Ols.

Molecules 2010, 15 (8), 5595-619.

The first enantioselective syntheses of sulfur flavan-3-ol analogues 1-8 have been accomplished, whereby the oxygen atom of the pyran ring has been replaced by a sulfur atom. The key steps were: (a) Pd(0) catalyzed introduction of -S t-butyl group, (b) Sharpless enantioselective dihydroxylation of the alkene, (c) acid catalyzed ring closure to produce the thiopyran ring, and (d) removal of benzyl groups using N,N-dimethylaniline and AlCl(3). The...

Jul
2010
Synthesis of [2-13C, 4-13C]-(2R,3S)-catechin and [2-13C, 4-13C]-(2R,3R)-epicatechin

Journal of Labelled Compounds & Radiopharmaceuticals 2010, 53 (10), 605-612.

The first synthesis of doubly labeled, [2-13C, 4-13C]-(2R,3S)-catechin 15 and [2-13C, 4-13C]-(2R,3R)-epicatechin 18 starting from labeled 2-hydroxy-4, 6-bis(benzyloxy)acetophenone 3 and labeled 3, 4-bis(benzyloxy)-benzaldehyde 7 are described.

Jul
2010
Improvement of endothelial function with dietary flavanols is associated with mobilization of circulating angiogenic cells in patients with coronary artery disease.

J Am Coll Cardiol 2010, 56 (3), 218-24.

OBJECTIVES: In patients with coronary artery disease (CAD) medically managed according to currently accepted guidelines, we tested whether a 1-month dietary intervention with flavanol-containing cocoa leads to an improvement of endothelial dysfunction and whether this is associated with an enhanced number and function of circulating angiogenic cells (CACs). BACKGROUND: Dietary flavanols can improve endothelial dysfunction. The CACs, also...

May
2010
Impact of cocoa flavanol consumption on blood pressure responsiveness to exercise.

Br J Nutr 2010, 103 (10), 1480-4.

Impaired endothelial vasodilatation may contribute to the exaggerated blood pressure (BP) responses to exercise in individuals who are overweight/obese. The present study investigated whether consumption of cocoa flavanols, which improve endothelium-dependent flow-mediated dilatation (FMD), can modify BP responsiveness to exercise. Twenty-one volunteers (eight females and thirteen males, 54.9 (se 2.2) years, BMI 31.6 (se 0.8) kg/m2, systolic BP...

Jan
2010
Dietary factors and the risk for acute infant leukemia: evaluating the effects of cocoa-derived flavanols on DNA topoisomerase activity.

Exp Biol Med (Maywood) 2010, 235 (1), 77-89.

There is cumulative strong evidence that diets rich in flavanols can provide certain positive health benefits, particularly with respect to the cardiovascular system. Consequently, it has been suggested that increasing one's dietary intake of flavanols may be of benefit. Complicating this idea, there are reports that high intakes of certain flavonoids during pregnancy are associated with an increased riskfor acute infant leukemia due to a poison...

Nov
2009
Dimeric procyanidins are inhibitors of NF-kappaB-DNA binding.

Biochem Pharmacol 2009, 78 (9), 1252-62

Given the central role of the transcription factor NF-kappaB in inflammation, molecules that can inhibit NF-kappaB are being actively investigated. The present work characterize potential interactions between dimeric procyanidins [B-type (B1 and B2) and A-type (A1 and A2)] and NF-kappaB proteins. B1 and B2, inhibited tumor necrosis factor alpha (TNFalpha)- and phorbol 12-myristate 13-acetate (PMA)-induced transactivation of NF-kappaB-driven...

Jun
2009
Method performance and multi-laboratory assessment of a normal phase high pressure liquid chromatography-fluorescence detection method for the quantitation of flavanols and procyanidins in cocoa and chocolate containing samples.

J Chromatogr A 2009, 1216 (24), 4831-40.

The quantitative parameters and method performance for a normal-phase HPLC separation offlavanols and procyanidins in chocolate and cocoa-containing food products were optimized and assessed. Single laboratory method performance was examined over three months using three separate secondary standards. RSD(r) ranged from 1.9%, 4.5% to 9.0% for cocoa powder, liquor andchocolate samples containing 74.39, 15.47 and 1.87 mg/g flavanols and...

Feb
2009
Cocoa flavanols and procyanidins can modulate the lipopolysaccharide activation of polymorphonuclear cells in vitro.

J Med Food 2009, 12 (1), 1-7.

Flavanols and procyanidins isolated from cocoa have been reported to possess multiple activities potentially relevant to oxidant defenses, vascular function, and immune function. In a combination of in vivo and in vitro studies, we and others have observed that cocoa can be an anti-inflammatory modulator and that compounds in cocoa are capable of modulating eicosanoid production, platelet aggregation, and the pool size of nitric oxide. The...

Dec
2008
Cytotoxic effects of digalloyl dimer procyanidins in human cancer cell lines.

J Nutr Biochem 2008, 19 (12), 797-808.

Flavanols, a class of polyphenols present in certain plant-based foods, have received increasing attention for their putative anticancer activity. In vitro and in vivo studies, which have compared the effectiveness of various monomer flavanols, indicate that the presence of a galloyl residue on the 3 position on the C-ring enhances the cytotoxicity of these compounds. Procyanidins, oligomerized flavanols, have been reported to be more cytotoxic...

Aug
2008
TNFalpha-induced NF-kappaB activation and cell oxidant production are modulated by hexameric procyanidins in Caco-2 cells.

Aug 15 2008

Hexameric procyanidins inhibit TNFalpha-induced NF-kappaB activation in Caco-2 cells. Most of the physiological actions of high molecular weight procyanidins could be limited to the gut lumen. Transcription factor NF-kappaB plays a central role in inflammation including human intestinal bowel disease. We investigated the capacity of a hexameric procyanidin fraction (Hex) to prevent tumor necrosis factor alpha (TNFalpha)-induced NF-kappaB...

Aug
2008
Cocoa flavanols lower vascular arginase activity in human endothelial cells in vitro and in erythrocytes in vivo.

Arch Biochem Biophys 2008, 476 (2), 211-5.

The availability of l-arginine can be a rate-limiting factor for cellular NO production by nitric oxide synthases (NOS). Arginase competes with NOS for l-arginine as the common substrate. Increasedarginase activity has been linked to low NO levels, and an inhibition of arginase activity has been reported to improve endothelium-dependent vasorelaxation. Based on the above, we hypothesized that an increase in the circulating NO pool following...

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Cardiovascular Publications

Aug
2006
Aging and vascular responses to flavanol-rich cocoa.

J Hypertens 2006, 24 (8), 1575-80.

OBJECTIVES: Strong evidence has secured aging as a powerful predictor of both cardiovascular risk and endothelial dysfunction, yet specific treatment is not available. We tested the hypothesis thatvascular responsiveness to flavanol-rich cocoa increases with advancing age. We have previously shown that flavanol-rich cocoa induced peripheral vasodilation, improving endothelial function via a nitric oxide (NO)-dependent mechanism. METHODS: We...

Aug
2006
Inhibitory effects of procyanidin B(2) dimer on lipid-laden macrophage formation.

J Cardiovasc Pharmacol 2006, 48 (2), 54-70.

A proteomic analysis of procyanidin B(2) isolated from cocoa against oxidized low-density lipoprotein-induced lipid-laden macrophage formation was performed. Of approximately 400 detected proteins, 12 were differentially expressed as a result of B(2) treatment. They were subsequently identified by liquid chromatography-electrospray ionization-tandem mass spectrometry and the SWISS-PROT database. Further reverse transcriptase-polymerase chain...

Aug
2006
The effect of cocoa polyphenols on the growth, metabolism, and biofilm formation by Streptococcus mutans and Streptococcus sanguinis.

Eur J Oral Sci 2006, 114 (4), 343-8.

The aim of this study was to determine if cocoa polyphenols could interfere with biofilm formation byStreptococcus mutans or Streptococcus sanguinis, and reduce acid production from sucrose by S.mutans. The antimicrobial activity of cocoa polyphenols was assessed against cariogenic (S. mutans) and health-associated (S. sanguinis) species by minimum inhibitory concentration assays. Cocoapolyphenol dimer, tetramer, and pentamer inhibited the...

Jul
2006
Flavanols and cardiovascular health: effects on the circulating NO pool in humans.

J Cardiovasc Pharmacol 2006, 47 Suppl 2, S122-7; discussion S172-6.

Atherosclerosis is the major cause for chronic vascular diseases. The key event in the pathogenesis of atherosclerosis is believed to be dysfunction of the endothelium and disruption of endothelial homeostasis, leading to vasoconstriction, inflammation, leukocyte adhesion, thrombosis, and proliferation of vascular smooth muscle cells. Endothelium-derived nitric oxide (NO) plays a major role in vascular homeostasis and a decrease in NO-...

Jun
2006
Procyanidin dimer B2 [epicatechin-(4beta-8)-epicatechin] suppresses the expression of cyclooxygenase-2 in endotoxin-treated monocytic cells.

Biochem Biophys Res Commun 2006, 345 (1), 508-15.

The anti-inflammatory activity of the predominant procyanidin dimer in cocoa, dimer B2, was investigated in this study. Pretreatment of the reduced COX-2 expression induced by the endotoxin lipopolysaccharide (LPS) in differentiated human monocytic cells (THP-1) in culture. To further elucidate the underlying mechanism of COX-2 inhibition by procyanidin, we examined their effects on the activation of extracellular signal-regulated protein kinase...

Jan
2006
(-)-Epicatechin mediates beneficial effects of flavanol-rich cocoa on vascular function in humans.

Proc Natl Acad Sci U S A 2006, 103 (4), 1024-9.

Epidemiological and medical anthropological investigations suggest that flavanol-rich foods exert cardiovascular health benefits. Endothelial dysfunction, a prognostically relevant key event in atherosclerosis, is characterized by a decreased bioactivity of nitric oxide (NO) and impaired flow-mediated vasodilation (FMD). We show in healthy male adults that the ingestion of flavanol-rich cocoawas associated with acute elevations in levels of...

Jan
2006
Endothelial function, nitric oxide, and cocoa flavanols.

J Cardiovasc Pharmacol 2006, 47 Suppl 2, S128-35; discussion S172-6.

Endothelial dysfunction is the pathophysiologic principle involved in the initiation and progression of arteriosclerosis, thus endothelial function serves as a "barometer" for cardiovascular health that can be used for the evaluation of new therapeutic strategies. This review provides an introduction to the concept of endothelial dysfunction, and it explores the importance of this prognostic marker in the context of clinical, dietary...

Jan
2006
The anti-inflammatory properties of cocoa flavanols.

J Cardiovasc Pharmacol 2006, 47 Suppl 2, S163-71; discussion S172-6.

Signs of chronic or acute inflammation have been demonstrated in most cardiovascular diseases of multifactorial pathogenesis, including atherosclerosis and chronic heart failure. The triggers and mechanisms leading to inflammation may vary between clinical conditions but they share many common mediators, including specific patterns of eicosanoid and cytokine production. Certain cocoa-based products can be rich in a subclass of flavonoids known...

Jan
2006
Dietary flavanols and platelet reactivity.

J Cardiovasc Pharmacol 2006, 47 Suppl 2, S187-96; discussion S206-9.

Epidemiology studies suggest that the consumption of diets rich in flavonoids is associated with reduced risk of cardiovascular disease. Plant-derived foods and beverages, such as red wine, tea, grape and grape juice, cocoa and chocolate, can be rich in 1 particular class of flavonoid, the flavan-3-ols. There is now an increasing body of research that suggests that consuming flavanol-rich foods can positively affect hemostasis, through...

Jan
2006
Chronic consumption of flavanol-rich cocoa improves endothelial function and decreases vascular cell adhesion molecule in hypercholesterolemic postmenopausal women.

J Cardiovasc Pharmacol 2006, 47 Suppl 2, S177-86; discussion S206-9.

Endothelial dysfunction characterizes many disease states including subclinical atherosclerosis. Theconsumption of flavanol-rich cocoa and cocoa-based products has been shown to improveendothelial function in both compromised and otherwise normal, healthy individuals when administered either acutely or over a period of several days, or weeks. Women experience increased risk for cardiovascular disease after menopause, which can be associated with...

Jan
2006
Vascular action of cocoa flavanols in humans: the roots of the story.

Journal of Cardiovascular Pharmacology 2006, 47, S99-S102.

Diet patterns are widely recognized as contributors to hypertension. Widely studied potential contributors include intake of sodium, potassium, magnesium, calcium, soluble fiber, omega-3 fatty acids, alcohol, protein, and calories. We add to that list the effect of dietary flavanols present in certain cocoas, which have sufficient activity on vascular nitric oxide to influence blood pressure control. Kuna Indians who live on islands near Panama...

Jan
2006
Hypertension, the Kuna, and the epidemiology of flavanols.

J Cardiovasc Pharmacol 2006, 47 Suppl 2, S103-9; discussion 119-21.

A low sodium diet has often been implicated in the protection of low blood pressure populations fromhypertension, but several other dietary factors, including those as yet unidentified, may also be involved. The Kuna Indians of Panama are free of hypertension and cardiovascular disease, but this is changing with migration to urban areas. We compared the indigenous diet of Kuna Indians living on remote islands in Panama (Ailigandi), whose...

Jan
2006
Cocoa flavanols and platelet and leukocyte function: recent in vitro and ex vivo studies in healthy adults.

J Cardiovasc Pharmacol 2006, 47 Suppl 2, S197-205; discussion S206-9.

There is growing interest in possible beneficial effects of specific dietary components on cardiovascular health. Platelets and leukocytes contribute to arterial thrombosis and to inflammatory processes. Previous studies performed in vitro have demonstrated inhibition of platelet function by (-)-epicatechin and (+)-catechin, flavan-3-ols (flavanols) that are present in several foods including some cocoas. Also, some modest inhibition of platelet...

Oct
2005
Acute consumption of flavanol-rich cocoa and the reversal of endothelial dysfunction in smokers.

J Am Coll Cardiol 2005, 46 (7), 1276-83.

OBJECTIVES: This study was designed to assess the effect of flavanol-rich food on the circulating pool of bioactive nitric oxide (NO) and endothelial dysfunction in smokers. BACKGROUND: Studies suggest that smoking-related vascular disease is caused by impaired NO synthesis and that diets rich in flavanols can increase bioactive NO in plasma. METHODS: In smokers (n = 11), the effects of flavanol-rich cocoa on circulating NO species in...

Aug
2005
Flavanols for cardiovascular health: the science behind the sweetness.

J Hypertens 2005, 23 (8), 1453-9.

PURPOSE OF REVIEW: Cardiovascular benefits for cocoa are being claimed in the scientific literature with growing intensity. To date, excitement over the potential health benefits of flavonoids has been driven mostly by epidemiological studies of tea and red wine, but raw cocoa contains specific flavonoids in concentrations far exceeding those from most other sources. Early evidence supports cocoa's enhancement of endothelial function via...

Mar
2005
Influence of cocoa flavanols and procyanidins on free radical-induced human erythrocyte hemolysis.

Clin Dev Immunol 2005, 12 (1), 27-34.

Cocoa can be a rich source of antioxidants including the flavan-3-ols, epicatechin and catechin, and their oligomers (procyanidins). While these flavonoids have been reported to reduce the rate of freeradical-induced erythrocyte hemolysis in experimental animal models, little is known about their effect on human erythrocyte hemolysis. The major objective of this work was to study the effect of a flavonoid-rich cocoa beverage on the resistance of...

Mar
2005
Regular consumption of a flavanol-rich chocolate can improve oxidant stress in young soccer players.

Clin Dev Immunol 2005, 12 (1), 11-7.

The consumption of a diet rich in certain flavonoids, including the flavanol sub-class, has been associated with a reduced risk for vascular disease. We evaluated the effects of the regularconsumption (14 d) of a flavanol-containing milk chocolate (FCMC) or cocoa butter chocolate (CBC) on variables related to vascular disease risk, oxidative stress and physical activity. Twenty-eight free-living, young (18-20 years old) male soccer players...

Mar
2005
Flavanols and platelet reactivity

Clin Dev Immunol 2005, 12 (1), 1-9.

Platelet activity and platelet-endothelial cell interactions are important in the acute development of thrombosis, as well as in the pathogenesis of cardiovascular disease. An increasing number of foods have been reported to have platelet-inhibitory actions, and research with a number of flavanol-rich foods, including, grape juice, cocoa and chocolate, suggests that these foods may provide some protection against thrombosis. In the present...

Mar
2005
Flavonoid-membrane interactions: a protective role of flavonoids at the membrane surface?

Clin Dev Immunol 2005, 12 (1), 19-25.

Flavonoids can exert beneficial health effects through multiple mechanisms. In this paper, we address the important, although not fully understood, capacity of flavonoids to interact with cellmembranes. The interactions of polyphenols with bilayers include: (a) the partition of the more non-polar compounds in the hydrophobic interior of the membrane, and (b) the formation of hydrogen bonds between the polar head groups of lipids and the more...

Jan
2005
Cocoa polyphenols and inflammatory mediators.

Am J Clin Nutr 2005, 81 (1 Suppl), 304S-312S.

Cocoa products are sources of flavan-3-ols, which have attracted interest regarding cardiovascular health. This review provides a survey of our research on the effects of cocoa polyphenols on leukotriene and nitric oxide (NO) metabolism and on myeloperoxidase-induced modification of LDL. Because intake of flavonoid-rich chocolate by human subjects was reported to decrease the plasma concentrations of proinflammatory cysteinyl leukotrienes, we...

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There are currently no Brain Health publications in this category.

Biological Effects Publications

Aug
2006
Aging and vascular responses to flavanol-rich cocoa.

J Hypertens 2006, 24 (8), 1575-80.

OBJECTIVES: Strong evidence has secured aging as a powerful predictor of both cardiovascular risk and endothelial dysfunction, yet specific treatment is not available. We tested the hypothesis thatvascular responsiveness to flavanol-rich cocoa increases with advancing age. We have previously shown that flavanol-rich cocoa induced peripheral vasodilation, improving endothelial function via a nitric oxide (NO)-dependent mechanism. METHODS: We...

Jun
2006
Long-term ingestion of high flavanol cocoa provides photoprotection against UV-induced erythema and improves skin condition in women.

J Nutr 2006, 136 (6), 1565-9.

Dietary antioxidants contribute to endogenous photoprotection and are important for the maintenance of skin health. In the present study, 2 groups of women consumed either a highflavanol (326 mg/d) or low flavanol (27 mg/d) cocoa powder dissolved in 100 mL water for 12 wk. Epicatechin (61 mg/d) and catechin (20 mg/d) were the major flavanol monomers in the high flavanoldrink, whereas the low flavanol drink contained 6.6 mg epicatechin and 1.6 mg...

Jan
2006
Cocoa flavanols and brain perfusion.

J Cardiovasc Pharmacol 2006, 47 Suppl 2, S210-4.

Foods and beverages rich in flavonoids are being heralded as potential preventive agents for a range of pathologic conditions, ranging from hypertension to coronary heart disease to stroke and dementia. We and others have demonstrated that short-term ingestion of cocoa, particularly rich in the subclass of flavonoids known as flavanols, induced a consistent and striking peripheral vasodilation in healthy people, improving endothelial function in...

Apr
2005
Pentameric procyanidin from Theobroma cacao selectively inhibits growth of human breast cancer cells.

Mol Cancer Ther 2005, 4 (4), 537-46.

A naturally occurring, cocoa-derived pentameric procyanidin (pentamer) was previously shown to cause G0/G1 cell cycle arrest in human breast cancer cells by an unknown molecular mechanism. Here, we show that pentamer selectively inhibits the proliferation of human breast cancer cells (MDA MB-231, MDA MB-436, MDA MB-468, SKBR-3, and MCF-7) and benzo(a)pyrene-immortalized 184A1N4 and 184B5 cells. In contrast, normal human mammary epithelial cells...

Mar
2005
Regular consumption of a flavanol-rich chocolate can improve oxidant stress in young soccer players.

Clin Dev Immunol 2005, 12 (1), 11-7.

The consumption of a diet rich in certain flavonoids, including the flavanol sub-class, has been associated with a reduced risk for vascular disease. We evaluated the effects of the regularconsumption (14 d) of a flavanol-containing milk chocolate (FCMC) or cocoa butter chocolate (CBC) on variables related to vascular disease risk, oxidative stress and physical activity. Twenty-eight free-living, young (18-20 years old) male soccer players...

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...

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...

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...

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...

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Chemistry Publications

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...

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...

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...

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...

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...

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...

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
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
Epicatechin in human plasma: in vivo determination and effect of chocolate consumption on plasma oxidation status.

J Nutr 2000, 130 (8S Suppl), 2109S-14S.

Diets that are rich in plant foods have been associated with a decreased risk for specific disease processes and certain chronic diseases. In addition to essential macronutrients and micronutrients, the flavonoids in a variety of plant foods may have health-enhancing properties. Chocolate is a food that is known to be rich in the flavan-3-ol epicatechin and procyanidin oligomers. However, the bioavailability and the biological effects of the...

Aug
2000
Studies in polyphenol chemistry and bioactivity. 2. Establishment of interflavan linkage regio- and stereochemistry by oxidative degradation of an O-alkylated derivative of procyanidin B2 to (R)-(-)-2,4-diphenylbutyric acid.

Org Chem 2000, 65 (17), 5371-81.

The assignment of interflavan bond regio- and stereochemistry in oligomeric proanthocyanidins has in the past relied on empirical spectroscopic techniques which are influenced by the conformation of the C rings. Only recently was the 4,8-regiochemistry of procyanidin B2 (3b) firmly established by 2-dimensional NMR methods. We describe herein the proof of 4beta-stereochemistry in 3b by oxidativedegradation of the derivative 3d bearing...

Nov
1999
Protection against peroxynitrite by cocoa polyphenol oligomers

FEBS Lett 1999, 462 (1-2), 167-70.

Flavonoids, natural plant constituents, protect against peroxynitrite and can thereby play a role in defense against this mediator of inflammation. Procyanidin oligomers of different size (monomer through nonamer), isolated from the seeds of Theobroma cacao, were examined for their ability to protect against peroxynitrite-dependent oxidation of dihydrorhodamine 123 and nitration of tyrosine. By molarity, oligomers were more effective than the...

Aug
1999
Studies in Polyphenol Chemistry and Bioactivity. 1. Preparation of Building Blocks from (+)-Catechin. Procyanidin Formation. Synthesis of the Cancer Cell Growth Inhibitor, 3-O-Galloyl-(2R,3R)-epicatechin-4β,8-[3-O-galloyl-(2R,3R)-epicatechin]

J Amer Chem Soc 1999, 121 (51), 12073-12081.

A project has been initiated to synthesize proanthocyanidin oligomers found in cocoa. Natural, readily available (+)-catechin was transformed into 5,7,3‘,4‘-tetra-O-benzyl-(−)-epicatechin (14) by (a) benzylation of the phenolic oxygens; (b) oxidation of the 3-alcohol to ketone by the Dess−Martin periodinane; and (c) reduction with lithium tri-sec-butylborohydride (l-Selectride) in the presence of LiBr. The additive diminishes the extent of...

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Analytical Methods Publications

Nov
1999
Protection against peroxynitrite by cocoa polyphenol oligomers

FEBS Lett 1999, 462 (1-2), 167-70.

Flavonoids, natural plant constituents, protect against peroxynitrite and can thereby play a role in defense against this mediator of inflammation. Procyanidin oligomers of different size (monomer through nonamer), isolated from the seeds of Theobroma cacao, were examined for their ability to protect against peroxynitrite-dependent oxidation of dihydrorhodamine 123 and nitration of tyrosine. By molarity, oligomers were more effective than the...

Nov
1999
Chocolate contains additional flavonoids not found in tea

Lancet 1999, 354 (9192), 1825.

Ilya Arts and colleagues (Aug 7, p 488) report that chocolate and tea may contribute significantly to total dietary catechin intake (20% and 55%, respectively). However, their methods only took into account the monomeric catechins and neglected the more abundant oligomers found in chocolate,Anchor which are present in only minor concentrations in tea. Indeed, Arts and colleagues' method to determine catechin content illustrates a commonly...

Oct
1999
HPLC method for the quantification of procyanidins in cocoa and chocolate samples and correlation to total antioxidant capacity.

J Agric Food Chem. 1999 Oct;47(10):4184-8.

Monomeric and oligomeric procyanidins present in cocoa liquors and chocolates were separated and quantified in four different laboratories using a normal-phase high-performance liquid chromatography (HPLC) method with fluorescence detection. Procyanidin standards through decamers were obtained by extraction from cocoa beans, enrichment by Sephadex LH-20 gel permeation chromatography, and final purification by preparative normal-phase HPLC. The...

Sep
1999
High-performance liquid Chromatography/Mass spectrometry analysis of proanthocyanidins in foods and beverages.

J Agric Food Chem 1999, 47 (9), 3693-701.

Monomeric and oligomeric proanthocyanidins present in a range of plant-derived foods andbeverages were separated by degree of polymerization and identified using a modified normal-phasehigh-performance liquid chromatography (HPLC) method coupled with on-line mass spectrometry (MS)analysis using an atmospheric pressure ionization electrospray chamber. In addition, ultraviolet (UV) and fluorescence detection were used to monitor the separation of...

Feb
1999
Identification of procyanidins in cocoa (Theobroma cacao) and chocolate using high-performance liquid chromatography/mass spectrometry.
Monomeric and oligomeric procyanidins present in cocoa and chocolate were separated and identified using a modified normal-phase high-performance liquid chromatography (HPLC) method coupled with on-line mass spectrometry (MS) analysis using an atmospheric pressure ionization electrospray chamber. The chromatographic separation was achieved using a silica stationary phase in combination with a gradient ascending in polarity. This qualitative...

Jan
1999
Recent advances in the analysis of procyanidins in cocoa and chocolate.

Leatherhead Food RA 1999, 2 (4), 335-345

Significant technical advances have enabled us to separate and identify the procyanidin oligomers present in cocoa and chocolate. These advances have allowed for the development of a new method for the quantification of procyanidins in cocoa, chocolate and several other foods and beverages, and have facilitated research to explore the health benefits of specific procyanidins.

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Absorption and Metabolism Publications

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...

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...

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...

Aug
2000
Cocoa and chocolate: Composition, bioavailability, and health implications.

J Med Food 2000, 3 (2), 77-105.

Chocolate and cocoa are extensively used in many cultures. Although their composition has been studied, the functional significance of the components has not been as well defined. There are indications that cocoa constituents exert beneficial effects on human health, and therefore cocoa and chocolate may be considered functional foods. The use of functional foods to modulate human health has gained greater significance in recent years, and...

Aug
2000
Epicatechin in human plasma: in vivo determination and effect of chocolate consumption on plasma oxidation status.

J Nutr 2000, 130 (8S Suppl), 2109S-14S.

Diets that are rich in plant foods have been associated with a decreased risk for specific disease processes and certain chronic diseases. In addition to essential macronutrients and micronutrients, the flavonoids in a variety of plant foods may have health-enhancing properties. Chocolate is a food that is known to be rich in the flavan-3-ol epicatechin and procyanidin oligomers. However, the bioavailability and the biological effects of the...

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....

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