Emma Ramiro-Puig

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.

Clinical benefit and preservation of flavonols in dark chocolate manufacturing.

The consumption of high-cacao-content chocolate has been associated with positive health benefits ascribed to flavanol [corrected] antioxidants derived from the ground, fermented cocoa seeds of Theobroma cacao. However, flavanols [corrected] impart a bitter, astringent flavor to foodstuffs, frequently masked in chocolates and confections by aggressive processing and adulteration with other flavors. Recent reports have implied that not all varieties of dark chocolate are created equally, and significant caveats exist regarding its potential health benefits. It is perhaps not surprising that extensive processing, dilution, and the addition of flavor modifiers may improve the palatability of chocolate, but could have negative nutritional and clinical benefits. This article examines the chemical composition of chocolate and the clinical data associated with the consumption of flavonoid-rich cocoa. We review the steps in chocolate manufacturing that directly affect the antioxidant levels in chocolate products, and the caveats associated with claims of health benefits from the consumption of dark chocolate.

Spleen lymphocyte function modulated by a cocoa-enriched diet

Previous studies have shown the down‐regulating in vitro effect of cocoa flavonoids on lymphocyte and macrophage activation. In the present paper, we report the capacity of a long‐term rich cocoa diet to modulate macrophage cytokine secretion and lymphocyte function in young rats. Weaned rats received natural cocoa (4% or 10% food intake), containing 32 mg flavonoids/g, for 3 weeks. Spleen immune function was then evaluated through the analysis of lymphocyte composition, their proliferative response and their ability to secrete cytokines and Ig. In addition, the status of activated peritoneal macrophages was established through tumour necrosis factor (TNF)‐α secretion. The richest cocoa diet (10%) caused a reduction of TNF‐α secretion by peritoneal macrophages showing anti‐inflammatory activity. Similarly, although a 10% cocoa diet increased lymphocyte proliferation rate, it down‐regulated T helper 2 (Th2)‐related cytokines and decreased Ig secretion. These changes were accompanied by an increase in spleen B cell proportion and a decrease in Th cell percentage. In summary, these results demonstrate the functional activity of a cocoa‐high dosage in down‐regulating the immune response that might be beneficial in hypersensitivity and autoimmunity.

Neuroprotective effect of cocoa flavonids on in vitro oxidative stress

BackgroundCocoa is a rich source of flavonoids that, among other functions, can act as antioxidants. In living systems, the production of reactive oxygen species (ROS) activate an array of intracellular cascades, including mitogen-activated protein kinases (MAPK), that are closely associated with cell death or survival pathways.Aim of the studyTo ascertain the role of a cocoa extract and its main flavonoid, (-)-epicatechin, in an in vitro model of oxidative stress induced in a neuronal cell line.MethodsWe analyzed ROS production by fluorometry (dichlorofluorescein assay), and activation of MAPK pathways including extracellular signal-regulated kinases 1/2 (ERK 1/2), c-Jun N-terminal kinase (JNK), and p-38, by Western blot analysis.ResultsCells incubated with cocoa extract or (-)-epicatechin, reduced ROS production in a dose-dependent manner, reaching 35% inhibition. pJNK and p38, involved in apoptosis, were down-modulated by cocoa extract and (-)-epicatechin with p38 inhibition reaching up to 70%.ConclusionsOur results show that cocoa extract and (-)-epicatechin may exert a neuroprotective action by reducing ROS production and modulating MAPK activation.

Influence of a cocoa‐enriched diet on specific immune response in ovalbumin‐sensitized rats

Previous studies in young rats have reported the impact of 3 weeks of high cocoa intake on healthy immune status. The present article describes the effects of a longer-term cocoa-enriched diet (9 weeks) on the specific immune response to ovalbumin (OVA) in adult Wistar rats. At 4 weeks after immunization, control rats produced anti-OVA antibodies, which, according their amount and isotype, were arranged as follows: IgG1 > IgG2a > IgM > IgG2b > IgG2c. Both cocoa diets studied (4% and 10%) down-modulated OVA-specific antibody levels of IgG1 (main subclass associated with the Th2 immune response in rats), IgG2a, IgG2c and IgM isotypes. Conversely, cocoa-fed rats presented equal or higher levels of anti-OVA IgG2b antibodies (subclass linked to the Th1 response). Spleen and lymph node cells from OVA-immunized control and cocoa-fed animals proliferated similarly under OVA stimulation. However, spleen cells from cocoa-fed animals showed decreased interleukin-4 secretion (main Th2 cytokine), and lymph node cells from the same rats displayed higher interferon-gamma secretion (main Th1 cytokine). These changes were accompanied by a reduction in the number of anti-OVA IgG-secreting cells in spleen. In conclusion, cocoa diets induced attenuation of antibody synthesis that may be attributable to specific down-regulation of the Th2 immune response.

Distribution of epicatechin metabolites in lymphoid tissues and testes of young rats with a cocoa-enriched diet

An increasing number of scientific studies support that flavanol-rich foods and beverages such as cocoa can promote human health, and are beneficial agents for the prevention of some diseases. Our previous studies showed that long-term cocoa intake enhances the antioxidant status in lymphoid organs and also modulates lymphocyte functionality in healthy young rats. Cocoa polyphenolic antioxidants seem to be the best candidates for those effects. However, data regarding polyphenol metabolites in tissues after a long-term cocoa intake are scarce. In the present study we mainly focus on the uptake and accumulation of epicatechin metabolites in lymphoid organs, including the thymus, spleen and mesenteric lymphoid nodes, as well as in the liver and testes after a diet rich in cocoa. Ten young weaned Wistar rats were fed randomly with a 10 % (w/w) cocoa diet or a control diet for 3 weeks, corresponding to their infancy and youth. Tissues were treated with a solid-phase extraction and analysed by liquid chromatography-tandem MS. The major compounds recovered in these tissues were glucuronide derivatives of epicatechin and methylepicatechin. The highest concentration of these metabolites was found in the thymus, testicles and liver, followed by lymphatic nodes and spleen. The high amount of epicatechin metabolites found in the thymus supports our previous findings showing its high antioxidant capacity compared with other tissues such as the spleen. Moreover, this is the first time that epicatechin metabolites have been found in high concentrations in the testes, confirming other studies that have suggested the testes as an important site of oxidation.

Cocoa intake attenuates oxidative stress associated with rat adjuvant arthritis

Cocoa contains flavonoids with antioxidant properties. The aim of this study was to ascertain the effect of cocoa intake on oxidative stress associated with a model of chronic inflammation such as adjuvant arthritis. Female Wistar rats were fed with a 5% or 10% cocoa-enriched diet or were given p.o. a quercetin suspension every other day for 10 days. Arthritis was induced by a heat-killed Mycobacterium butyricum suspension. Reactive oxygen species (ROS) produced by macrophages, and splenic superoxide dismutase (total, cytoplasmic and mitochondrial) and catalase activities were determined. Clinically, joint swelling in arthritic rats was not reduced by antioxidants; however, the 5% cocoa diet and quercetin administration reduced ROS production. Moreover, the 5% cocoa diet normalized the activities of superoxide dismutase and catalase. In conclusion, a cocoa diet reduces the oxidative stress associated with a chronic inflammatory pathology, although it was not enough to attenuate joint swelling.

El intestino: pieza clave del sistema inmunitario

The gut is constantly exposed to a high antigenic load coming from the diet and commensal bacteria. The Gut-Associated Lymphoid Tissue (GALT) constitutes the most extensive and complex part of the immune system and is capable of efficiently distinguishing invasive pathogens from innocuous antigens. The knowledge of its unique structure consisting on organised tissue, inductor of the immune response (Peyers patches and mesenteric lymph nodes), and diffused tissue, effector of the immune response (intraepithelial lymphocytes and lamina propria lymphocytes), allow us to understand the development and regulation of the immune response in the gut and how this one can be extended to the rest of the organism.