Cocoa Flavanols and Platelet and Leukocyte Function: Recent In Vitro and Ex Vivo Studies in Healthy Adults

Cocoa procyanidins attenuate 4-hydroxynonenal-induced apoptosis of PC12 cells by directly inhibiting mitogen-activated protein kinase kinase 4 activity

Neurodegenerative disorders such as Alzheimer's disease (AD) are associated with oxidative stress, and it has been suggested that apoptosis is a crucial pathway in neuronal cell death in AD patients. 4-Hydroxynonenal (HNE), one of the aldehydic products of membrane lipid peroxidation, is reported to be elevated in the brains of AD patients and mediates the induction of neuronal apoptosis in the presence of oxidative stress. In this study, we investigated the HNE-induced apoptosis mechanism and the protective effects of the cocoa procyanidin fraction (CPF) and its major antioxidant procyanidin B2 against the apoptosis induced by HNE in rat pheochromocytoma (PC12) cells. HNE-induced nuclear condensation and increased sub-G1 fraction, both of which are markers of apoptotic cell death, were inhibited by CPF and procyanidin B2. Intracellular reactive oxygen species (ROS) accumulation was attenuated by pretreatment with CPF and procyanidin B2. CPF and procyanidin B2 also prevented HNE-induced poly(ADP-ribose) polymerase cleavage, antiapoptotic protein (Bcl-2 and Bcl-X(L)) down-regulation, and caspase-3 activation. Activation of c-Jun N-terminal protein kinase (JNK) and mitogen-activated protein kinase kinase 4 (MKK4) was attenuated by CPF and procyanidin B2. Moreover, CPF and procyanidin B2 bound directly to MKK4 and inhibited its activity. Data obtained with SP600125, a selective inhibitor of JNK, revealed that JNK is involved in HNE-induced apoptosis through the inhibition of PARP cleavage and caspase-3 activation in PC12 cells. Collectively, these results indicate that CPF and procyanidin B2 protect PC12 cells against HNE-induced apoptosis by blocking MKK4 activity as well as ROS accumulation.

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.

Cocoa: antioxidant and immunomodulator

Cocoa, a product consumed since 600 BC, is now a subject of increasing interest because of its antioxidant properties, which are mainly attributed to the content of flavonoids such as ( - )-epicatechin, catechin and procyanidins. Moreover, recent findings suggest a regulatory effect of cocoa on the immune cells implicated in innate and acquired immunity. Cocoa exerts regulatory activity on the secretion of inflammatory mediators from macrophages and other leucocytes in vitro. In addition, emerging data from in vivo studies support an immunomodulating effect. Long-term cocoa intake in rats affects both intestinal and systemic immune function. Studies in this line suggest that high-dose cocoa intake in young rats favours the T helper 1 (Th1) response and increases intestinal gammadelta T lymphocyte count, whereas the antibody-secreting response decreases. The mechanisms involved in this activity are uncertain; nonetheless, because redox-sensitive pathways control immune cell function, the action of cocoa flavonoids on modulating cell signalling and gene expression deserves investigation.

Immunomodulatory effect of Antrodia camphorata mycelia and culture filtrate

AIM OF THE STUDY

Antrodia camphorata, a precious folkloric medicinal mushroom, has been used to treat tumorigenic diseases in Taiwan. This study was to investigate the innate immunity augmentation effects of different fractions prepared from hot water extracts of submerged cultured Antrodia camphorata (AC).

MATERIALS AND METHODS

The cytokine induction potency of AC fraction in diluted peripheral blood culture was measured by ELISA. The effects of AC fraction on phagocytic activity and CD11b expression were measured by the ingestion of FITC-labeled Escherichia coli and by labeling with PE-labeled CD11b monoclonal antibody, respectively, using flow cytometry. The molecular mass of hot water-soluble polysaccharides and content of adenosine in AC fraction were determined by gel permeation chromatography (GPC) and HPLC, respectively.

RESULTS

The mycelia fraction, Fr. M II, and culture filtrate fractions, Fr. E II and Fr. E III, showed the strongest TNF-alpha and IL-6 induction effect as a function of their concentration. These fractions (20mug/ml) also showed marked activity in enhancing phagocytosis in human polymorphonuclear neutrophils (PMN) and monocytes. In parallel, the expression of CD11b, an early marker of PMN activation, was also up-regulated dose-dependently. Composition analysis suggested that immunomodulatory effect of mycelia is mainly attributed to the 10-20kDa polysaccharides and adenosine.

CONCLUSIONS

These results provide evidences that Antrodia camphorata can modulate innate immunity and may serve as an adjuvant for tumor treatment.

Short- and long-term effects of (-)-epicatechin on myocardial ischemia-reperfusion injury

Epidemiological studies have shown a correlation between flavonoid-rich diets and improved cardiovascular prognosis. Cocoa contains large amounts of flavonoids, in particular flavanols (mostly catechins and epicatechins). Flavonoids possess pleiotropic properties that may confer protective effects to tissues during injury. We examined the ability of epicatechin to reduce short-and long-term ischemia-reperfusion (I/R) myocardial injury. Epicatechin (1 mg.kg(-1).day(-1)) pretreatment (Tx) was administered daily via oral gavage to male rats for 2 or 10 days. Controls received water. Ischemia was induced via a 45-min coronary occlusion. Reperfusion was allowed until 48 h or 3 wk while Tx continued. We measured infarct (MI) size (%), hemodynamics, myeloperoxidase activity, tissue oxidative stress, and matrix metalloproteinase-9 (MMP-9) activity in 48-h groups. Cardiac morphometry was also evaluated in 3-wk groups. With 2 days of Tx, no reductions in MI size occurred. After 10 days, a significant approximately 50% reduction in MI size occurred. Epicatechin rats demonstrated no significant changes in hemodynamics. Tissue oxidative stress was reduced significantly in the epicatechin group vs. controls. MMP-9 activity demonstrated limited increases in the infarct region with epicatechin. By 3 wk, a significant 32% reduction in infarct size was observed with Tx, accompanied with sustained hemodynamics and preserved chamber morphometry. In conclusion, epicatechin Tx confers cardioprotection in the setting of I/R injury. The effects are independent of changes in hemodynamics, are sustained over time, and are accompanied by reduced levels of indicators of tissue injury. Results warrant the evaluation of cocoa flavanols as possible therapeutic agents to limit ischemic injury.

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.

Targeting platelets for prevention and treatment of cardiovascular disease

Platelets play an important role in the development of thrombosis, atherosclerosis, hypertension, heart attack and stroke. As a result, pharmacologic interventions that influence platelet functions, such as adhesion, aggregation and the release of different factors, are considered useful for the prevention and treatment of cardiovascular disease. Although classical anti-platelet agents have proven beneficial effects for the treatment of some specific cardiovascular diseases, there are limitations for their use as these drugs target platelet function directly. In contrast, newly developed anti-platelet agents have broad applications for the treatment of cardiovascular disease as they not only influence platelet function but are also considered to affect cardiac and vascular smooth muscle cell functions. Natural food products and nutraceutical agents also appear to modify cardiovascular abnormalities by affecting various platelet functions; however, the mechanisms of their actions remain to be investigated. Accordingly, this article is focused to discuss emerging pharmacologic, nutritional and nutraceutical interventions that may influence the prevention or progression of a broad range of cardiovascular diseases.

Immunomodulatory effect of exo-polysaccharides from submerged cultured Cordyceps sinensis: enhancement of cytokine synthesis, CD11b expression, and phagocytosis

Cordyceps sinensis is widely used as a traditional medicine for treatment of a wide variety of diseases or to maintain health. The immunomodulatory activity of polysaccharides prepared from submerged cultured C. sinensis BCRC36421 was investigated in human peripheral blood. Results demonstrated that Fr. A (exo-polysaccharides, 0.025 approximately 0.1 mg/ml) induced the production of tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-6, and IL-10 dose-dependently. Fr. A, as low as 0.025 mg/ml, could significantly augment surface expression of CD11b in monocytes and polymorphonuclear neutrophils. Functional assay revealed that Fr. A (0.05 mg/ml) also elevated phagocytosis in monocytes and PMN. On the other hand, Fr. B (intracellular polysaccharides) only moderately induced TNF-alpha release, CD11b expression, and phagocytosis at the same concentrations. Our results indicate that the immunomodulatory components of submerged cultured C. sinensis mainly reside in the culture filtrate.