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

Cocoa flavanols: effects on vascular nitric oxide and blood pressure

Diets rich in fruits and vegetables have been associated with benefits for human health. Those effects have been partially ascribed to their content in flavonoids, compounds that are present in many edible plants and its derived foods. In humans, a significant number of studies has been developed analyzing the effect of foods and beverages rich in flavonoids on the presence and progression of risk factors associated to cardiovascular diseases, including hypertension. Cocoa derived products, rich in flavanols, have been thoroughly studied and demonstrated to be efficient improving endothelial function and decreasing blood pressure in humans and animals. However, the final chemical species and the mechanism/s responsible for these effects have not been completely defined. In this paper we present data supporting the hypothesis that flavanols could define superoxide anion production and then, establish optimal nitric oxide levels and blood pressure.

Polyphenols and human health: prevention of disease and mechanisms of action

Polyphenols are found ubiquitously in plants and their regular consumption has been associated with a reduced risk of a number of chronic diseases, including cancer, cardiovascular disease (CVD) and neurodegenerative disorders. Rather than exerting direct antioxidant effects, the mechanisms by which polyphenols express these beneficial properties appear to involve their interaction with cellular signaling pathways and related machinery that mediate cell function under both normal and pathological conditions. We illustrate that their interactions with two such pathways, the MAP kinase (ERK, JNK, p38) and PI3 kinase/Akt signaling cascades, allow them to impact upon normal and abnormal cell function, thus influencing the cellular processes involved in the initiation and progression of cancer, CVD and neurodegeneration. For example, their ability to activate ERK in neurons leads to a promotion of neuronal survival and cognitive enhancements, both of which influence the progression of Alzheimer’s disease, whilst ERK activation by polyphenols in vascular endothelial cells influences nitric oxide production, blood pressure and ultimately CVD risk. The main focus of this review is to provide an overview of the role that polyphenols play in the prevention of cancer, cardiovascular disease and neurodegeneration. We present epidemiological data, human intervention study findings, as well as animal and in vitro studies in support of these actions and in each case we consider how their actions at the cellular level may underpin their physiological effects.

Antioxidant effects of cocoa and cocoa products ex vivo and in vivo: is there evidence from controlled intervention studies?

PURPOSE OF REVIEW

There is strong epidemiological evidence that the consumption of flavanol-rich cocoa products contributes to the prevention of cardiovascular diseases mediated partly by their strong antioxidant effects. We reviewed the recent literature to answer the question whether this antioxidant action can be confirmed by intervention studies in healthy study participants and specific patient groups.

RECENT FINDINGS

In 19 controlled intervention studies (two in patients with cardiovascular diseases), markers of plasma antioxidant capacity and oxidative stress were analyzed after bolus and/or regular cocoa consumption. In both, healthy study participants and patients, total plasma antioxidant capacity as well as most markers of oxidative stress were not influenced by the intervention. Low-density lipoprotein oxidation ex vivo and in vivo decreased probably due to a direct beneficial effect of cocoa flavanols on lipid and protein oxidation.

SUMMARY

Recent clinical trials do not provide sufficient evidence for an essential contribution of cocoa products to the overall antioxidant defense. Any recommendations for cocoa intake within preventive and therapeutic measures are presently not reasonable.

Plant phenolics: extraction, analysis and their antioxidant and anticancer properties

Phenolics are broadly distributed in the plant kingdom and are the most abundant secondary metabolites of plants. Plant polyphenols have drawn increasing attention due to their potent antioxidant properties and their marked effects in the prevention of various oxidative stress associated diseases such as cancer. In the last few years, the identification and development of phenolic compounds or extracts from different plants has become a major area of health- and medical-related research. This review provides an updated and comprehensive overview on phenolic extraction, purification, analysis and quantification as well as their antioxidant properties. Furthermore, the anticancer effects of phenolics in-vitro and in-vivo animal models are viewed, including recent human intervention studies. Finally, possible mechanisms of action involving antioxidant and pro-oxidant activity as well as interference with cellular functions are discussed.

Biological Evaluation of Polyherbal Ayurvedic Cardiotonic Preparation "Mahamrutyunjaya rasa"

Mahamrutyunjaya rasa (MHR), an Ayurvedic formulation, used as cardiotonic, contains potentially toxic compounds like aconitine, which are detoxified during preparation using traditional methods. Comparative toxicological evaluation of laboratory prepared formulation (F1) and two marketed formulations (F2 and F3) were performed based on their effects on viability of H9c2 cells and after single oral dose administration in mice. Cardioprotective effect of formulations at 25 and 50 mg/kg doses were studied in isoproterenol- (ISO-) induced myocardial infarcted rats. F1 and F2 did not affect the cell viability, while F3 decreased the cell viability in concentration and time-dependent manner. Rats administered with ISO showed significant increase in the serum levels of glutamate oxaloacetate transaminase, alkaline phosphotase, creatinine kinase isoenzymes, lactate dehydrogenase, and uric acid, while F1 and F2 treatment showed significant reduction in the same. F3 showed further increase in the serum levels of enzymes and uric acid in ISO-challenged rats. High pressure liquid chromatographic analysis of formulations showed higher concentration of aconitine in F3. Study shows that F1 and F2 possess cardioprotective property with higher safety, while formulation F3 cannot be used as cardioprotective due to its cytotoxic effects. Thus, proper quality assessment methods are required during preparation of traditional formulations.

Does chocolate intake during pregnancy reduce the risks of preeclampsia and gestational hypertension?

PURPOSE

Chocolate consumption is associated with favorable levels of blood pressure and other cardiovascular disease risk markers. We analyzed a prospective cohort study to determine whether regular chocolate intake during pregnancy is associated with reduced risks of preeclampsia and gestational hypertension (GH).

METHODS

Subjects were recruited from 13 prenatal care practices in Connecticut (1988-1991). In-person interviews were administered at <16 weeks' gestation to ascertain risk factors for adverse pregnancy outcomes. Hospital delivery and prenatal records were abstracted to classify preeclampsia (n = 58), GH (n = 158), and normotensive pregnancies (n = 2351). Chocolate consumption (servings/week) during the first and third trimesters was ascertained at initial interview and immediately postpartum, respectively. Consumers of less than 1 serving/week comprised the referent group. Adjusted odds ratios (aORs) were estimated by the use of logistic regression.

RESULTS

Chocolate intake was more frequent among normotensive (80.7%) than preeclamptic (62.5%) or GH women (75.8%), and associated with reduced odds of preeclampsia (first trimester: aOR, 0.55; 95% confidence interval [95% CI], 0.32-0.95; third trimester: aOR, 0.56; 95% CI, 0.32-0.97). Only first trimester intake was associated with reduced odds of GH (aOR,0.65; 95% CI, 0.45-0.87).

CONCLUSIONS

These findings provide additional evidence of the benefits of chocolate. Prospective studies are needed to confirm and delineate protective effects of chocolate intake on risk of preeclampsia.

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

Cocoa flavanols (CF) positively influence physiological processes in ways that suggest their consumption may improve aspects of cognitive function. This study investigated the acute cognitive and 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-day washout between drinks. Assessments included the state anxiety inventory and repeated 10-min cycles of a Cognitive Demand Battery comprising of two serial subtraction tasks (Serial Threes and Serial Sevens), a Rapid Visual Information Processing (RVIP) task and a 'mental fatigue' scale, over the course of 1 h. Consumption of both 520 mg and 994 mg CF significantly improved Serial Threes performance. The 994 mg CF beverage significantly speeded RVIP responses but also resulted in more errors during Serial Sevens. Increases in self-reported 'mental fatigue' were significantly attenuated by the consumption of the 520 mg CF beverage only. This is the first report of acute cognitive improvements following CF consumption in healthy adults. While the mechanisms underlying the effects are unknown they may be related to known effects of CF on endothelial function and blood flow.

Basic biochemical mechanisms behind the health benefits of polyphenols

Polyphenols and consequently many flavonoids have several beneficial actions on human health. However, the actual molecular interactions of polyphenols with biological systems remain mostly speculative. This review addresses the potential mechanisms of action that have been so far identified, as well as the feasibility that they could occur in vivo. Those mechanisms include: i) non specific actions, based on chemical features common to most polyphenols, e.g. the presence of a phenol group to scavenge free radicals; and ii) specific mechanisms; based on particular structural and conformational characteristics of select polyphenols and the biological target, e.g. proteins, or defined membrane domains. A better knowledge about the nature and biological consequences of polyphenol interactions with cell components will certainly contribute to develop nutritional and pharmacological strategies oriented to prevent the onset and/or the consequences of human disease.

Phytoceuticals: the new 'physic garden' for asthma and chronic obstructive pulmonary disease

Phytoceuticals (non-nutritional but beneficial plant chemicals) merit investigation as pharmacotherapy for asthma and chronic obstructive pulmonary disease (COPD). Although asthma is mostly treated adequately, COPD is not. Thus, there is a need for new drugs with improved therapeutic benefit, especially in COPD. Recent interest in herbal remedies has redirected attention towards plants as sources of improved treatments for lung disease. Phytoceuticals from a variety of plants and plant products, including butterbur, English ivy, apples, chocolate, green tea and red wine, demonstrate broad-spectrum pharmacotherapeutic activities that could be exploited in the clinic. Well-designed clinical trials are required to determine whether these beneficial activities are reproduced in patients, with the prospect that phytoceuticals are the new physic garden for asthma and COPD.

Healthy properties of proanthocyanidins

Proanthocyanidins, also named condensed tannins, are the result of flavanols condensation. Oligomers and polymers of proanthocyanidins can widely be found in the plant kingdom, as in fruits and berries, seeds, flowers, and leaves. They have a putative role as antioxidants, and they affect the inflammatory process via calcium-dependent release of nitric oxide and protect against H(2)O(2)-induced lipid peroxidation. They also demonstrated a role in cardiovascular diseases via vessel relaxation and LDL oxidation inhibition. These condensed tannins have also shown activities that improve diabetic complications, such as neuropathy, retinopathy, or nephropathy, including a decrease in serum glucose and advanced glycation end products. Furthermore, proanthocyanidins have evidenced anticancer properties by mitigating tumor development through induction of apoptosis or inhibition of cell proliferation. Finally, they are able to produce antiadhesive actions against bacteria in urinary and dental infections, including Escherichia coli and Streptococcus mutans. Hence, proanthocyanidins are considered as beneficial molecules in preventing or treating many diseases and pathological conditions. Therefore, finding out more about condensed tannins bioavailability, and understanding the regulatory genes and pathways involved in their effects should be aimed in future research.

Cocoa, chocolate, and cardiovascular disease

A significant body of evidence demonstrates that diets rich in fruits and vegetables promote health and attenuate, or delay, the onset of various diseases, including cardiovascular disease, diabetes, certain cancers, and several other age-related degenerative disorders. The concept that moderate chocolate consumption could be part of a healthy diet has gained acceptance in past years based on the health benefits ascribed to selected cocoa components. Specifically, cocoa as a plant and chocolate as food contain a series of chemicals that can interact with cell and tissue components, providing protection against the development and amelioration of pathological conditions. The most relevant effects of cocoa and chocolate have been related to cardiovascular disease. The mechanisms behind these effects are still under investigation. However, the maintenance or restoration of vascular NO production and bioavailability and the antioxidant effects are the mechanisms most consistently supported by experimental data. This review will summarize the most recent research on the cardiovascular effects of cocoa flavanols and related compounds.

(-)-epicatechin activation of endothelial cell endothelial nitric oxide synthase, nitric oxide, and related signaling pathways

Recent reports indicate that (-)-epicatechin can exert cardioprotective actions, which may involve endothelial nitric oxide synthase (eNOS)-mediated nitric oxide production in endothelial cells. However, the mechanism by which (-)-epicatechin activates eNOS remains unclear. In this study, we proposed to identify the intracellular pathways involved in (-)-epicatechin-induced effects on eNOS, using human coronary artery endothelial cells in culture. Treatment of cells with (-)-epicatechin led to time- and dose-dependent effects that peaked at 10 minutes at 1 mumol/L. (-)-Epicatechin treatment activates eNOS via serine 633 and serine 1177 phosphorylation and threonine 495 dephosphorylation. Using specific inhibitors, we have established the participation of the phosphatidylinositol 3-kinase pathway in eNOS activation. (-)-Epicatechin induces eNOS uncoupling from caveolin-1 and its association with calmodulin-1, suggesting the involvement of intracellular calcium. These results allowed us to propose that (-)-epicatechin effects may be dependent on actions exerted at the cell membrane level. To test this hypothesis, cells were treated with the phospholipase C inhibitor U73122, which blocked (-)-epicatechin-induced eNOS activation. We also demonstrated inositol phosphate accumulation in (-)-epicatechin-treated cells. The inhibitory effects of the preincubation of cells with the calmodulin-dependent kinase II (CaMKII) inhibitor KN-93 indicate that (-)-epicatechin-induced eNOS activation is at least partially mediated via the Ca(2+)/CaMKII pathway. The (-)-epicatechin stereoisomer catechin was only partially able to stimulate nitric oxide production in cells. Together, these results strongly suggest the presence of a cell surface acceptor-effector for the cacao flavanol (-)-epicatechin, which may mediate its cardiovascular effects.

Comparative study of eight well-known polyphenolic antioxidants

Eight antioxidants from five different polyphenolic classes (cinnamic acids, benzoic acids, flavonoids, proanthocyanidins and stilbenes), and the water-soluble vitamin E derivative trolox were examined for their antioxidant activity in-vitro. In addition, the compounds were tested for their cytotoxicity on growing fibroblasts and their inhibition of the classical pathway of the complement system. Procyanidin C1 was shown to be a good scavenger of both DPPH* and HO*, and a strong inhibitor of lipid peroxidation and the classical pathway of the complement system. Consequently, procyanidin C1 was classified as the most promising antioxidant in-vitro of all compounds tested. In contrast, genistein exhibited a very low antioxidant activity in both the lipid peroxidation and the DPPH* scavenging assay, a high cytotoxicity and a low complement-inhibiting activity.

Changes in arterial blood pressure of a soluble cocoa fiber product in spontaneously hypertensive rats

The effect produced by long-term intake of a soluble cocoa fiber product (SCFP) on the development of hypertension of spontaneously hypertensive rats (SHR) was evaluated. Twenty male 3-week-old SHR were divided into two groups of 10 animals that drank either tap water (control) or a solution of SCFP (0.75 g/day SCFP) until the 20th week of life. Five 20-week-old rats of each group were sacrificed. Tap water as drinking fluid was given to all the animals from the 20th to 24th week of life. The 24-week-old rats were also sacrificed. Body weight, liquid and dry food intake, and arterial blood pressure (tail cuff) were recorded weekly. Malondialdehyde (MDA), glucose and angiotensin converting enzyme (ACE) activity in the plasma from the sacrificed rats were also obtained, and we evaluated the relaxation caused by acetylcholine in the aorta from these animals. SCFP attenuated the development of hypertension in SHR; however, the withdrawal of SCFP caused an increase in blood pressure in the rats. Body weight gain was slower in the group treated with SCFP. SCFP increased liquid intake but decreased dry food intake in the rats. SCFP decreased plasma MDA concentrations and slightly decreased plasma ACE activity, but no differences were observed in plasma glucose and in the aorta responses to acetylcholine in both groups of 20-week-old SHR. We have demonstrated the antihypertensive and antioxidant properties of SCFP. The control of body weight and the control of increased angiotensin II may be involved in the antihypertensive effect of this product.

Cancer protective properties of cocoa: a review of the epidemiologic evidence

Due to their high concentration of catechins and procyanidins, bioactive compounds with distinct properties, cocoa and chocolate products may have beneficial health effects against oxidative stress and chronic inflammation, risk factors for cancer and other chronic diseases. This review focuses on the epidemiologic evidence for protective effects against cancer and overall mortality. The very small number of observational epidemiologic studies offers weak support for a reduction in mortality and little data related to cancer, whereas several intervention studies, despite their short duration, have reported some favorable changes in biomarkers assessing antioxidant status but very few findings related to inflammatory markers. In moderation, cocoa products may offer strong antioxidant effects in combination with a pleasurable eating experience. The benign profile of its fatty acids in combination with the low content of sugar of dark chocolate should lessen concerns about the adverse effects of cocoa products. Future nutritional trials need to assess a larger number of biomarkers that may be relevant for cancer risk, whereas epidemiologic studies require valid dietary assessment methods to examine the association of cocoa products with cancer risk in larger populations and to distinguish possible cancer protective effects of cocoa products from those due to other polyphenolic compounds.

Natural cocoa as diet-mediated antimalarial prophylaxis

BACKGROUND

The Maya of Central America are credited with the first consumption of cocoa and maintaining its ancient Olmec name kakawa translated in English as "God Food", in recognition of its multiple health benefits. The legend of cocoa is receiving renewed attention in recent years, on account of epidemiological and scientific studies that support its cardiovascular health benefits. Increasing numbers of scientific reports corroborating cocoa's antiquated reputation as health food persuaded this author to promote regular consumption of cocoa in Ghana since 2004. Cocoa is readily available in Ghana; the country is the second largest producer accounting for 14% of the world's output. Numerous anecdotal reports of reduced episodic malaria in people who daily drink natural unsweetened cocoa beverage prompted a search for scientific mechanisms that possibly account for cocoa's antimalarial effects. This paper presents the outcome as a hypothesis.

METHODS

Internet search for literature on effects of cocoa's ingredients on malaria parasites and illness using a variety of search tools.

RESULTS

Evidential literature suggests five mechanisms that possibly underpin cocoa's anecdotal antimalarial effects. (i) Increased availability of antioxidants in plasma, (ii) membrane effects in general and erythrocyte membrane in particular, (iii) increased plasma levels of nitric oxide, (iv) antimalarial activity of cocoa flavanoids and their derivatives, and (v) boosted immune system mediated by components of cocoa including cocoa butter, polyphenols, magnesium, and zinc.

CONCLUSION

A hypothesis is formulated that cocoa offers a diet-mediated antimalarial prophylaxis; and an additional novel tool in the fight against the legendary scourge.

Bioavailability of procyanidin dimers and trimers and matrix food effects in in vitro and in vivo models

Among procyanidins (PC), monomers, such as catechin and epicatechin, have been widely studied, whereas dimer and trimer oligomers have received much less attention, despite their abundance in our diet. Recent studies have showed that as dimers and trimers could be important in determining the biological effects of procyanidin-rich food, understanding their bioavailability and metabolism is fundamental. The purpose of the present work is to study the stability of PC under digestion conditions, the metabolism and the bioavailability by using a combination of in vitro and in vivo models. Simultaneously, the matrix effect of a carbohydrate-rich food on the digestibility and bioavailability of PC is investigated. The results show a high level of stability of PC under gastric and duodenal digestion conditions. However, the pharmacokinetic study revealed limited absorption. Free forms of dimers and trimers have been detected in rat plasma, reaching the maximum concentration 1 h after oral intake of a grape seed extract.

Polyphenols from cocoa and vascular health-a critical review

Cocoa is a rich source of dietary polyphenols. In vitro as well as cell culture data indicate that cocoa polyphenols may exhibit antioxidant and anti-inflammatory, as well as anti-atherogenic activity. Several molecular targets (e.g., nuclear factor kappa B, endothelial nitric oxide synthase, angiotensin converting enzyme) have been recently identified which may partly explain potential beneficial cardiovascular effects of cocoa polyphenols. However cocoa polyphenol concentrations, as used in many cell culture studies, are not physiologically achievable. Bioavailability studies indicate that plasma concentrations of cocoa polyphenols following dietary intake are low and in the nanomolar range. Human studies regarding the effect of cocoa polyphenols on vascular health are often underpowered and lack a rigorous study design. If dietary cocoa polyphenol intake is due to chocolate its high energy content needs to be taken into account. In order to determine potential health benefits of cocoa polyphenols large scale, long term, randomized, placebo controlled studies, (ideally with a cross-over design) as well as prospective studies are warranted.

Effect of dark chocolate on plasma epicatechin levels, DNA resistance to oxidative stress and total antioxidant activity in healthy subjects

Dark chocolate (DC) may be cardioprotective by antioxidant properties of flavonoids. We investigated the effect of DC (860 mg polyphenols, of which 58 mg epicatechin) compared with white chocolate (WC; 5 mg polyphenols, undetectable epicatechin) on plasma epicatechin levels, mononuclear blood cells (MNBC) DNA damage and plasma total antioxidant activity (TAA). Twenty healthy subjects followed a balanced diet (55 % of energy from carbohydrates, 30 % from fat and 1 g protein/kg body weight) for 4 weeks. Since the 14th day until the 27th day, they introduced daily 45 g of either WC (n 10) or DC (n 10). Whole experimental period was standardised in antioxidant intake. Blood samples were collected at T0, after 2 weeks (T14), 2 h and 22 h after the first chocolate intake (T14+2 h and T14+22 h), and at 27th day, before chocolate intake (T27), 2 h and 22 h after (T27+2 h and T27+22 h). Samples, except for T14+2 h and T27+2 h, were fasting collected. Detectable epicatechin levels were observed exclusively 2 h after DC intake (T14+2 h = 0·362 (se 0·052) μmol/l and T27+2 h = 0·369 (se 0·041) μmol/l); at the same times corresponded lower MNBC DNA damages (T14+2 h = − 19·4 (se 3·4) % v. T14, P < 0·05; T27+2 h = − 24 (se 7·4) % v. T27, P < 0·05; T14+2 hv. T27+2 h, P = 0·7). Both effects were no longer evident after 22 h. No effect was observed on TAA. WC did not affect any variable. DC may transiently improve DNA resistance to oxidative stress, probably for flavonoid kinetics.

Epicatechin induces NF-κB, activator protein-1 (AP-1) and nuclear transcription factor erythroid 2p45-related factor-2 (Nrf2) via phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) and extracellular regulated kinase (ERK) signalling in HepG2 cells

The dietary flavonoid epicatechin has been reported to exhibit a wide range of biological activities. The objective of the present study was to investigate the time-dependent regulation by epicatechin on the activity of the main transcription factors (NF-κB, activator protein-1 (AP-1) and nuclear transcription factor erythroid 2p45-related factor (Nrf2)) related to antioxidant defence and survival and proliferation pathways in HepG2 cells. Treatment of cells with 10 μm-epicatechin induced the NF-κB pathway in a time-dependent manner characterised by increased levels of IκB kinase (IKK) and phosphorylated inhibitor of κB subunit-α (p-IκBα) and proteolytic degradation of IκB, which was consistent with an up-regulation of the NF-κB-binding activity. Time-dependent activation of the AP-1 pathway, in concert with enhanced c-Jun nuclear levels and induction of Nrf2 translocation and phosphorylation were also demonstrated. Additionally, epicatechin-induced NF-κB and Nrf2 were connected to reactive oxygen species intracellular levels and to the activation of cell survival and proliferation pathways, being phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) and extracellular regulated kinase (ERK) associated to Nrf2 modulation and ERK to NF-κB induction. These data suggest that the epicatechin-induced survival effect occurs by the induction of redox-sensitive transcription factors through a tight regulation of survival and proliferation pathways.

Antihypertensive effect of a polyphenol-rich cocoa powder industrially processed to preserve the original flavonoids of the cocoa beans

A natural flavonoid-enriched cocoa powder, commercially named CocoanOX and developed via a patented industrial process, was characterized and tested for a possible antihypertensive effect. The bioavailability of this polyphenol-rich cocoa powder developed at pilot scale was previously demonstrated in humans. The present results showed that this product was very rich in total procyanidins (128.9 mg/g), especially monomers, dimers, and trimers (54.1 mg/g), and mainly (-)-epicatechin (19.36 mg/g). The effect of a single oral administration of CocoanOX in spontaneously hypertensive rats (SHR) was evaluated at different doses (50, 100, 300, and 600 mg/kg). This product produced a clear antihypertensive effect in these animals, but these doses did not modify the arterial blood pressure in the normotensive Wistar-Kyoto rats. Paradoxically, the maximum effect in the systolic blood pressure (SBP) of SHR was caused by 300 mg/kg of CocoanOX. This dose brought about a decrease in this variable very similar to that caused by 50 mg/kg Captopril. It was also surprising that the maximum effect in the diastolic blood pressure (DBP) was caused by 100 mg/kg CocoanOX. The initial values of DBP and SBP were recovered in SHR, respectively, 24 and 48 h postadministration of the different doses of CocoanOX or Captopril. These results suggest that CocoanOX could be used as a functional ingredient with antihypertensive effect, although it would be also necessary to carry out bioavailability and clinical studies to demonstrate its long-term antihypertensive efficiency in humans.

Acute effect of nut consumption on plasma total polyphenols, antioxidant capacity and lipid peroxidation

BACKGROUND

Nuts have been shown to have beneficial effects on human health due to the healthy fat content; however, the effect of antioxidants (i.e. polyphenols) in nuts have not been fully investigated. The present study aimed to assess the immediate effect of a polyphenol-rich meal (75% of energy from nuts: walnuts or almonds) and a polyphenol-free meal on plasma polyphenol content, antioxidant capacity and lipid peroxidation in healthy volunteers.

METHODS

Thirteen subjects participated in a randomized, crossover, intervention study. After an overnight fast, walnuts, almonds or a control meal in the form of smoothies were consumed by study subjects. Each subject participated on three occasions, 1 week apart, consuming one of the smoothies each time. Blood samples were obtained at fasting and then at intervals up to 3.5 h after consumption of the smoothies.

RESULTS

There was a significant increase in plasma polyphenol concentration following both nut meals, with peak concentrations being achieved at 90 min, and with a walnut meal having a more sustained higher concentration than an almond meal. The plasma total antioxidant capacity reached its highest point at 150 min postconsumption of the nut meals, and was higher after the almond compared to walnut meal. A gradual significant (P < 0.05) reduction in the susceptibility of plasma to lipid peroxidation was observed 90 min after ingestion of the nut meals. No changes were observed following consumption of control meal.

CONCLUSIONS

Consumption of both nuts increased plasma polyphenol concentrations, increased the total antioxidant capacity and reduced plasma lipid peroxidation.

Chocolate, lifestyle, and health

Interest in the biological activities of cocoa polyphenols is increasing steadily. In fact, the high polyphenol content of cocoa, coupled with its widespread presence in many food items, render this food of particular interest from the nutritional and "pharmacological" viewpoints. This paper summarizes the new findings and developments regarding the effects of cocoa and chocolate consumption on human health as presented at the International Conference "Chocolate, Lifestyle, and Health" (Milan, Italy, March 2, 2007) regarding the effects of cocoa and chocolate consumption on human health.

Antioxidant activity of blueberry fruit is impaired by association with milk

The antioxidant properties of dietary phenolics are believed to be reduced in vivo because of their affinity for proteins. In this study we assessed the bioavailability of phenolics and the in vivo plasma antioxidant capacity after the consumption of blueberries (Vaccinium corymbosum L.) with and without milk. In a crossover design, 11 healthy human volunteers consumed either (a) 200 g of blueberries plus 200 ml of water or (b) 200 g of blueberries plus 200 ml of whole milk. Venous samples were collected at baseline and at 1, 2, and 5 h postconsumption. Ingestion of blueberries increased plasma levels of reducing and chain-breaking potential (+6.1%, p<0.001; +11.1%, p<0.05) and enhanced plasma concentrations of caffeic and ferulic acid. When blueberries and milk were ingested there was no increase in plasma antioxidant capacity. There was a reduction in the peak plasma concentrations of caffeic and ferulic acid (-49.7%, p<0.001, and -19.8%, p<0.05, respectively) as well as the overall absorption (AUC) of caffeic acid (p<0.001). The ingestion of blueberries in association with milk, thus, impairs the in vivo antioxidant properties of blueberries and reduces the absorption of caffeic acid.

Liquid chromatography tandem mass spectrometry identification of proanthocyanidins in rat plasma after oral administration of grape seed extract

Proanthocyanidin rich plant extracts derived from grape seed extract (GSE), hawthorn and cranberry are on markets for their preventive effects against cardiovascular diseases and uroinfections in woman. However, the importance of these health beneficial effects of these botanicals remains elusive due to incomplete understanding of uptake, metabolism and bioavailability of proanthocyanidins in vivo. In the present study rats were given GSE orally (300 mg/kg, twice a day) and blood and urine were collected over a 24 h period. Monomeric catechins and their methylated metabolites, and proanthocyanidins up to trimers were detected in blood samples treated with GSE using LC-MS/MS operating in the multiple reaction monitoring (MRM) mode. A new tetramethylated metabolite of dimeric proanthocyanidin (m/z 633) in GSE-treated urine was tentatively identified. Using LC-MS/MS, (+)-catechin and (-)-epicatechin were identified in the brain conclusively. These data suggested that GSE catechins cross the blood brain barrier and may be responsible for the neuroprotective effects of GSE.

Effects of cacao liquor polyphenols on cardiovascular and autonomic nervous functions in hypercholesterolaemic rabbits

Many epidemiological studies have shown that polyphenols can reduce the risk of mortality from cardiovascular diseases. This study tested the hypothesis that cacao liquor polyphenols have the properties to restore the cardiovascular and autonomic nervous function in an animal model of familial hypercholesterolaemia. Male Kurosawa and Kusanagi-hypercholesterolaemic rabbits were housed in individual cages in a room where a 12-hr light:dark cycle (lights-on at 8:00 and lights-off at 20:00) was maintained. At 3 months of age, they were divided into two groups (standard diet and cacao liquor polyphenol) and the animals received 100 g of the respective diets per day and were provided with tap water ad libitum. Heart rate and blood pressure were measured by a telemetry system. To clarify the autonomic nervous function, power spectral analysis of heart rate variability, baroreflex sensitivity and autonomic nervous tone were measured. After 6 months of dietary administration of cacao liquor polyphenols, heart rate and blood pressure were lowered but plasma lipid concentrations were unchanged. The area of atherosclerotic lesions in the aorta in the cacao liquor polyphenol group was significantly smaller than that in the standard diet group. The high-frequency power of heart rate variability in the rabbits in the standard diet group was significantly decreased with ageing, but that in the cacao liquor polyphenol group was not different between short-term and long-term treatment. Moreover, cacao liquor polyphenols preserved parasympathetic nervous tone, although that in the standard diet group was significantly decreased with ageing. We conclude that cacao liquor polyphenols may play an important role to protect cardiovascular and autonomic nervous functions.

Dark chocolate effect on platelet activity, C-reactive protein and lipid profile: a pilot study

BACKGROUND

Dark chocolate (DC) is one of the richest sources of flavonoids. Since DC has been demonstrated to have beneficial effects on the cardiovascular system, our study examined its effect on platelet reactivity, inflammation, and lipid levels in healthy subjects.

METHODS

In 28 healthy volunteers, we analyzed the effect of one week of DC (providing 700 mg of flavonoids/day). The primary outcome was to determine the effects of DC consumption on platelet activity measured by flow cytometry (adenosine diphosphate [ADP]- and arachidonic acid [AA]-induced total and activated glycoprotein (GP) IIb/IIIa as well as P-selectin expression). In addition to this, we measured the effect of DC on high-sensitivity C-reactive protein (hsCRP), high-density lipid cholesterol (HDL) and low-density lipid cholesterol (LDL) levels.

RESULTS

Following seven days of regular DC ingestion, LDL fell by 6% (120 +/- 38 vs 112 +/- 37 mg/dL, P < 0.018) and HDL rose by 9% (66 +/- 23 vs 72 +/- 26 mg/dL, P < 0.0019). ADP- and AA-induced activated GPIIb/IIIa expression was reduced by DC [27.3 +/- 27.8 vs 17.4 +/- 20.5 mean fluorescence intensity (MFI), P < 0.006; and 9.2 +/- 6.5 vs. 6.1 +/- 2.2 MFI, P < 0.005, respectively]. DC reduced hsCRP levels in women (1.8 +/- 2.1 vs. 1.4 +/- 1.7 mg/dL, P < 0.04).

CONCLUSIONS

One week of DC ingestion improved lipid profiles and decreased platelet reactivity within the total group while reducing inflammation only in women. Regular dark chocolate ingestion may have cardioprotective properties. Further long-term research is warranted to evaluate the effect of flavonoids on cardiovascular health and to determine whether DC's beneficial effects are related to flavonoids or some yet unknown component. This research is based on a larger study which was presented at the American Heart Association Scientific Sessions 2007.

Bioavailability issues in studying the health effects of plant polyphenolic compounds

Polyphenolic compounds are common in the diet and have been suggested to have a number of beneficial health effects including prevention of cancer, cardiovascular disease, diabetes, and others. For some dietary polyphenols, certain benficial effects are suggested by epidemiological studies, some are supported by studies in animal models, and still others are extrapolated from studies in vitro. Because of the relatively poor bioavailability of many of these compounds, the molecular basis of these beneficial effects is not clear. In the present review, we discuss the potential health benefits of dietary polyphenols from the point of view of bioavailability. Tea catechins, curcumin, and proanthocyanidins are used as examples to illustrate some of the problems that need to be resolved. Further research on both the biological activity and bioavailability of dietary polyphenols is needed to properly assess their usefulness for the prevention and treatment of disease.

Polyphenols in cocoa and cocoa products: is there a link between antioxidant properties and health?

Cocoa and cocoa products have received much attention due to their significant polyphenol contents. Cocoa and cocoa products, namely cocoa liquor, cocoa powder and chocolates (milk and dark chocolates) may present varied polyphenol contents and possess different levels of antioxidant potentials. For the past ten years, at least 28 human studies have been conducted utilizing one of these cocoa products. However, questions arise on which of these products would deliver the best polyphenol contents and antioxidant effects. Moreover, the presence of methylxanthines, peptides, and minerals could synergistically enhance or reduce antioxidant properties of cocoa and cocoa products. To a greater extent, cocoa beans from different countries of origins and the methods of preparation (primary and secondary) could also partially influence the antioxidant polyphenols of cocoa products. Hence, comprehensive studies on the aforementioned factors could provide the understanding of health-promoting activities of cocoa or cocoa products components.

Protection of human HepG2 cells against oxidative stress by cocoa phenolic extract

Cocoa is a rich source of flavanols and procyanidin oligomers with antioxidative properties, providing protection against oxidation and nitration. The present study investigated the potential protective effect of a polyphenolic extract from cocoa on cell viability and antioxidant defenses of cultured human HepG2 cells submitted to oxidative stress induced by tert-butylhydroperoxide (t-BOOH). Pretreatment of cells with 0.05-50 microg/mL of cocoa polyphenolic extract (CPE) for 2 or 20 h completely prevented cell damage and enhanced activity of antioxidant enzymes induced by a treatment with t-BOOH. Moreover, lower levels of GSH caused by t-BOOH in HepG2 cells were partly recovered by a pretreatment with CPE. Increased reactive oxygen species (ROS) induced by t-BOOH was dose-dependently prevented when cells were pretreated for 2 or 20 h with CPE. These results show that treatment of HepG2 in culture with CPE (within the physiological range of concentrations) confers a significant protection against oxidation to the cells.

Acute dark chocolate and cocoa ingestion and endothelial function: a randomized controlled crossover trial

BACKGROUND

Studies suggest cardioprotective benefits of dark chocolate containing cocoa.

OBJECTIVE

This study examines the acute effects of solid dark chocolate and liquid cocoa intake on endothelial function and blood pressure in overweight adults.

DESIGN

Randomized, placebo-controlled, single-blind crossover trial of 45 healthy adults [mean age: 53 y; mean body mass index (in kg/m(2)): 30]. In phase 1, subjects were randomly assigned to consume a solid dark chocolate bar (containing 22 g cocoa powder) or a cocoa-free placebo bar (containing 0 g cocoa powder). In phase 2, subjects were randomly assigned to consume sugar-free cocoa (containing 22 g cocoa powder), sugared cocoa (containing 22 g cocoa powder), or a placebo (containing 0 g cocoa powder).

RESULTS

Solid dark chocolate and liquid cocoa ingestion improved endothelial function (measured as flow-mediated dilatation) compared with placebo (dark chocolate: 4.3 +/- 3.4% compared with -1.8 +/- 3.3%; P < 0.001; sugar-free and sugared cocoa: 5.7 +/- 2.6% and 2.0 +/- 1.8% compared with -1.5 +/- 2.8%; P < 0.001). Blood pressure decreased after the ingestion of dark chocolate and sugar-free cocoa compared with placebo (dark chocolate: systolic, -3.2 +/- 5.8 mm Hg compared with 2.7 +/- 6.6 mm Hg; P < 0.001; and diastolic, -1.4 +/- 3.9 mm Hg compared with 2.7 +/- 6.4 mm Hg; P = 0.01; sugar-free cocoa: systolic, -2.1 +/- 7.0 mm Hg compared with 3.2 +/- 5.6 mm Hg; P < 0.001; and diastolic: -1.2 +/- 8.7 mm Hg compared with 2.8 +/- 5.6 mm Hg; P = 0.014). Endothelial function improved significantly more with sugar-free than with regular cocoa (5.7 +/- 2.6% compared with 2.0 +/- 1.8%; P < 0.001).

CONCLUSIONS

The acute ingestion of both solid dark chocolate and liquid cocoa improved endothelial function and lowered blood pressure in overweight adults. Sugar content may attenuate these effects, and sugar-free preparations may augment them.

Platelet reactivity in male smokers following the acute consumption of a flavanol-rich grapeseed extract

Epidemiological studies suggest that a high dietary intake of flavanols, a subclass of flavonoids, is associated with reduced risk of vascular disease. Clinical studies have also shown that the consumption of certain flavanol-rich foods (e.g., cocoa, tea, red wine), as well as intake of the individual flavanol (-)-epicatechin, can result in improvement in a number of parameters associated with vascular disease, including improved endothelial function, reduced platelet reactivity, and reduced oxidative stress. The present study assessed the effects of a flavanol-rich supplement on platelet reactivity and plasma oxidant defense in a group of smokers, a population at an elevated risk for vascular disease. Male smokers were randomly assigned to a placebo (n = 10) or a flavanol-rich grapeseed extract (FRGSE; n = 13) group, and after an overnight fast, blood samples were collected before and at 1, 2, and 6 hours following consumption of the placebo or supplement. The FRGSE supplement, but not the placebo, significantly decreased ADP-stimulated platelet reactivity at 1, 2, and 6 hours following intake (P < .05) compared to baseline levels. Similarly, the supplement, but not the placebo, decreased epinephrine-stimulated platelet reactivity 2 hours following consumption. Plasma antioxidant capacity (total radical trapping antioxidant potential), lipid oxidation (plasma thiobarbituric acid-reactive substances), and serum uric acid concentrations were not affected in either group. Thus smokers may obtain some health benefits from the consumption of certain flavanol-rich foods, beverages, and supplements.

Flavan-3-ols: nature, occurrence and biological activity

Representing the most common flavonoid consumed in the American diet, the flavan-3-ols and their polymeric condensation products, the proanthocyanidins, are regarded as functional ingredients in various beverages, whole and processed foods, herbal remedies and supplements. Their presence in food affects food quality parameters such as astringency, bitterness, sourness, sweetness, salivary viscosity, aroma, and color formation. The ability of flavan-3-ols to aid food functionality has also been established in terms of microbial stability, foamability, oxidative stability, and heat stability. While some foods only contain monomeric flavan-3-ols [(-)-epicatechin predominates] and dimeric proanthocyanidins, most foods contain oligomers of degree of polymerization values ranging from 1-10 or greater than 10. Flavan-3-ols have been reported to exhibit several health beneficial effects by acting as antioxidant, anticarcinogen, cardiopreventive, antimicrobial, anti-viral, and neuro-protective agents. This review summarizes the distribution and health effects of these compounds.

Modulation of palmitic acid-induced cell death by ergothioneine: evidence of an anti-inflammatory action

Inflammation and reactive oxygen species have been implicated in pathogenesis of vascular diabetic complications. However, treatment with classic free-radical scavengers and antioxidants has not been yet proved to reduce the risk of developing such complications. In search of more effective treatment we have tested the protective role of Ergothioneine (EGT), in vitro, on C2C12 cells model on FFA-induced lipotoxicity. Cells were incubated for 24 h in the presence of palmitic acid (PA) (250, 500, 750, 1000 microM), added as pro-oxidant compound, with or without 24-h pre-treatment with EGT. Cells were assessed for cell viability and MAPKs expression by Western Blot. Pre-treatment with EGT resulted in greater cell viability at each PA concentration (EGT 500 microM: 5, 16, 17, 23% and EGT 1000 microM: 9, 18, 21 and 25%). In response to PA exposure, p38 and JNK activity increased significantly while EGT prevented such activation. Moreover the analysis of the IL-6 production reveal that EGT is also able to exert anti-inflammatory action inhibiting the PA IL-6 modulation (P < 0.001). In conclusion, these results indicate that 1. EGT has a protective role on PA-induced cell death, possibly via 2. reduced activity of MAPKs cascade having also 3. an anti-inflammatory action exerted on the IL-6 modulation.

Dark Chocolate Improves Coronary Vasomotion and Reduces Platelet Reactivity

Background— Dark chocolate has potent antioxidant properties. Coronary atherosclerosis is promoted by impaired endothelial function and increased platelet activation. Traditional risk factors, high oxidative stress, and reduced antioxidant defenses play a crucial role in the pathogenesis of atherosclerosis, particularly in transplanted hearts. Thus, flavonoid-rich dark chocolate holds the potential to have a beneficial impact on graft atherosclerosis.

Methods and Results— We assessed the effect of flavonoid-rich dark chocolate compared with cocoa-free control chocolate on coronary vascular and platelet function in 22 heart transplant recipients in a double-blind, randomized study. Coronary vasomotion was assessed with quantitative coronary angiography and cold pressor testing before and 2 hours after ingestion of 40 g of dark (70% cocoa) chocolate or control chocolate, respectively. Two hours after ingestion of flavonoid-rich dark chocolate, coronary artery diameter was increased significantly (from 2.36±0.51 to 2.51±0.59 mm, P <0.01), whereas it remained unchanged after control chocolate. Endothelium-dependent coronary vasomotion improved significantly after dark chocolate (4.5±11.4% versus −4.3±11.7% in the placebo group, P =0.01). Platelet adhesion decreased from 4.9±1.1% to 3.8±0.8% ( P =0.04) in the dark chocolate group but remained unchanged in the control group.

Conclusions— Dark chocolate induces coronary vasodilation, improves coronary vascular function, and decreases platelet adhesion 2 hours after consumption. These immediate beneficial effects were paralleled by a significant reduction of serum oxidative stress and were positively correlated with changes in serum epicatechin concentration.

Repeated red wine consumption and changes on plasma antioxidant capacity and endogenous antioxidants (uric acid and protein thiol groups)

This study aims to ascertain the in vivo antioxidant properties of red wine by determining how it affects antioxidant biomarkers (plasma antioxidant capacity (PAC) and endogenous antioxidants such as uric acid or protein thiol groups). Antioxidant biomarkers have been assessed in eight healthy human volunteers after repeated intakes of 300 mL of red wine every day for a week. During this intervention period, volunteers followed a low phenolic diet designed to prevent the phenolic compounds in wine from interfering with the phenolics from other foods or beverages. This diet was followed throughout the week that the volunteers drank wine and for another control week when they drank water. Biomarkers were determined before the subjects taking part in the study started the intervention period with red wine (Monastrell variety) and 1, 3, and 7 days after. PAC was evaluated by the Ferric Reducing Ability of Plasma assay (FRAP), and the Oxygen Radical Absorbance Capacity assay using fluorescein (ORAC-FL). In addition, the concentrations of endogenous antioxidants such as uric acid, albumin, bilirubin, and protein thiol groups were analyzed. The FRAP method shows that PAC increased after the week of wine consumption but decreased after the week without wine consumption. The uric acid concentration did not show any changes that were significantly different from our results in acute wine intake studies. Protein thiol groups decreased significantly (p < 0.05) with the low phenolic diet, but this decrease was not statistically significant if the diet was taken with red wine (p < 0.05).

Cocoa and health: a decade of research

It has been over 10 years since the first mention in a medical journal about cocoa and chocolate as potential sources of antioxidants for health. During this time, cocoa has been found to improve antioxidant status, reduce inflammation and correlate with reduced heart disease risk; with these results, and its popularity, it has received wide coverage in the press. However, after 10 years of research, what is known about the potential health benefits of cocoa and what are the important next steps in understanding this decadent source of antioxidants?

Antidepressant-like effect of Cecropia glazioui Sneth and its constituents - in vivo and in vitro characterization of the underlying mechanism

The present study aimed to characterize the antidepressant-like effect of a standardized aqueous extract (AE) of Cecropia glazioui Sneth and its purified fractions on in vivo (forced swimming test), ex vivo (hippocampal monoamines levels) and in vitro (serotonin, noradrenaline and dopamine uptake) tests, searching for the active principles and the underlying mechanisms of action. Treatment with AE, or with its butanolic fraction (BuF), the latter rich in catechins, procyanidins and flavonoids, reduced the immobility of rats in the forced swimming test indicating an antidepressant-like effect. Biochemical analysis of the hippocampal neurotransmitters in BuF-treated rats showed significant increase in monoamines levels. BuF and six of its purified constituents inhibited the uptake of [(3)H]-serotonin, [(3)H]-dopamine and [(3)H]-noradrenaline by synaptosomes of different brain regions. Catechin, catechin (4alpha-->8) ent-catechin (Procyanidin B3 isomer) and epicatechin (4beta-->8) epicatechin (Procyanidin B2) were the most active compounds. Comparatively, the uptake of [(3)H]-noradrenaline was the most affected. These results show that the antidepressant-like effect promoted by C. glazioui extract is most likely due to the blockade of the monoamines uptake in the CNS.