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Mechanisms underlying the biological effects of coffee and its constituents are incompletely understood. Many effects have been attributed solely to caffeine, neglecting that coffee is a mixture of many chemical substances. Some authors suggest that the main mechanism of action of caffeine is to antagonize adenosine receptors (AR); a second effect is the inhibition of phosphodiesterases with the subsequent accumulation of cAMP and an intensification of the effects of catecholamines. Although the inhibition of phosphodiesterases may contribute to the actions of caffeine, there is growing evidence that most pharmacological effects of this xanthine result from antagonism of AR. One of the main objectives of this work was to investigate whether substances other than caffeine in coffee may influence the homeostasis of intracellular cyclic nucleotides in vitro and in vivo. The influence of selected coffee compounds, extracts and brews on key elements involved in the adenosine receptor-mediated signaling pathway have been investigated. A further aim of this work was also to determine if coffee or some coffee constituents may have a stimulatory effect on the cellular heme oxygenase activity (HO-activity). Two coffee extracts, a slightly (AB1) and an intensively roasted coffee (AB2), were studied along with selected individual compounds. Caffeine and low substituted pyrazines showed no effect on the HO-activity, while NMP, pyrazines with a greater substitution pattern such as Tetramethylpyrazine (TMP) and 2-Ethyl-3,5(6)-dimethylpyrazine (2-E-3,5-DMP) and both coffee extracts significantly induced the HO-activity in liver hepatocellular carcinoma (HepG2), intestinal colo-rectal adenocarcinoma (Caco-2) and in some instances in monocytic leukemia (MM6) cells. It was found that caffeine, theophylline, coffee extracts from conventional or functional coffees, pyrazines (2,3-DE-6-MP, 2-Isobutyl-3-methoxyP), 5-CQA and caffeic acid all significantly inhibited the basal cytoplasmatic PDE activity in lysates of lung tumour xenograft cells (LXFL529L) and human platelets. To a somewhat lesser extent, PDE inhibition was also found in experiments performed with paraxanthine and other pyrazines (2-E-3,5-DMP, TMP and 2-E-5-MP). Thus the degree of roasting has a considerable impact on constituents of influence for PDE activity. Caffeine, coffee polyphenols and some pyrazines and further, as yet unknown roasting products appear to represent the main modulating constituents. In two coffee intervention studies, a short-term (8 weeks) and a long-term study (24 weeks), comprising 8 and 84 healthy volunteers respectively, we examined extracellular key elements of the adenosine pathway including plasma adenosine levels and adenosine deaminase activity. Additionally, we studied the intracellular cAMP concentration and the PDE activity in platelets as surrogate biomarkers of adipocytes. Results of in vitro experiments had suggested that the concentrations of caffeine and coffee extracts required to obtain a half maximal inhibition were in the upper range of physiological conditions. Yet, it was demonstrated for the first time in vivo that moderate consumption of coffee can modulate the activity of platelet phosphodiesterases in humans in long and short term. In both studies, the first exposure to coffee showed a strong inhibition (p

Los fitoquímicos y algunos componentes bioactivos despiertan especial interés en la comunidad científica, por ser sustancias con efectos benéficos en la salud, evidenciado por estudios que involucran efectos, acciones y prevención de riesgo en ciertas enfermedades. Las razones de interés de los consumidores por estas sustancias radica en obtener bienestar por medio de la dieta, por ello demandan información sobre los efectos de estas sustancias y de los alimentos funcionales. Este artículo de revisión proporciona un marco de las investigaciones que evalúan la relación entre la dieta y la salud, en especial de los componentes biológicos que aportan la connotación de funcionales a los alimentos. Aunque no se consideran nutrientes esenciales algunos de esos componentes, proporcionan una importante protección para la salud junto a una adecuada nutrición. Cada compuesto revisado en este documento, muestra la relación con la salud y posibles efectos en el tratamiento de enfermedades. Phytochemical substances are bioactive compounds that have special interest for scientist because of the health-promoting properties that have been demonstrated in scientific studies. Some consumers are interested to eat these products to be healthier; therefore they are requiring information about of the nutritional properties in functional foods which could be placed in the product advertising label. This review focuses on researches about bioactive compounds and the relevance of functional foods for nutrition and health, bringing an overview of what is published about bioactive compounds and the relationship between diet and health. Although these compounds are not considered essential nutrients, this article discusses the biological activity of those compounds, in particular their properties and the resulting health benefits.