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Anthocyanins (AC) are a group of water-soluble natural pigments found in various parts of higher plants. A very solid body of evidence indicates that these pigments possess properties potentially beneficial for human health thanks to different biological activities, and are able to protect against several human pathological conditions, including cardiovascular diseases. Many studies have highlighted that some health benefits of AC localize at the level of vessel endothelium, which contributes in multiple ways to vascular homeostasis, and also has an important functional role in the control of angiogenesis, inflammation, platelet aggregation, and vascular remodeling. Herein, we review the large existing literature concerning some of the molecular mechanisms that, beyond the antioxidant properties, may have a role in the effects of AC and AC-rich foods on vessel endothelium. For example, AC appears able to prevent peroxynitrite-mediated endothelial dysfunction in endothelial cells, not only due to their antioxidant activity, but also to their capability to regulate enzymes involved in NO activity. Furthermore, several evidences indicate that AC can prevent the expression of adhesion molecules and the adhesion of monocytes to ECs challenged by pro-inflammatory agents. Finally, the activity of AC on angiogenesis seems to involve their capability to modulate VEGF pathways. Dietary AC, despite their limited oral bioavailability and very low post-absorption plasma concentrations, may provide protection against oxidative stress-induced damage on vessel endothelium. However, the relationship between effective bioavailability and intracellular concentration of AC and their capability to protect vessel endothelium functions needs to be more deeply assessed.

This article focused on two methods to measure the activity of NF-kB. Both methods evalute "post-IkB phosphorylation" stages in the NF-kB activation cascade. In fact, EMSA performed with nuclear extracts provides an information only on NF-kB nuclear translocation and its ability to bind kB-DNA sequences. Likewise, the reporter gene assay is limited to assessing NF-kB-dependent gene expression no matter the mechanism that originally activated NF-kB. Nevertheless, the latter assay represents a more physiological and more reproducible way of measuring NF-kB activity in mammalian cells than the EMSA does. In order to obtain further insights into NF-kB signal transduction pathways, investigating IkB degradation and phosphorylation are recommended. The cloning and characterization of IkB kinases provided new testing possibilities based on measure of their activity.

Publisher Summary Several different epidemiological reports have indicated that consumption of foods rich in polyphenols is associated with a lower incidence of degenerative diseases, and experimental data is accumulating regarding phenolic compounds as natural phytochemical antioxidants important for human health. Polyphenols are attracting increasing interest as nutritional compounds recognized to positively affect human health. Flavonoids constitute a large class of polyphenolic compounds, ubiquitous in plants, containing a number of phenolic hydroxyl groups attached to ring structures conferring a strong antioxidant activity. Flavonoids often occur in nature as glycosidic derivatives, which have been reported to be more readily absorbed than the simple form. Flavonoids are normally ingested by consumption of fruits and vegetables, but some flavonoids, such as flavanols, catechin or epicatechin, and flavonol quercetin, are constituents of plant-derived beverages such as tea or red wine. Estimates of the total daily intake range from about 20 mg to 1 g depending on the characteristics of the diet. Complex mixtures of flavonoids have frequently been used in the past as the only possible remedy for various diseases, and currently, are widely used, even in affluent countries, both as an alternative and as a complement to “official” medical therapy. Study of the biological effects of phytochemicals is important for at least two different reasons: first to provide a biochemical and molecular background to the safe and proper use of these compounds; second, results obtained with these groups of compounds could be applied to a broader family of compounds, thus providing a basis for a better understanding of the biological activity of polyphenolic compounds as therapeutic agents in various human disorders.

Publisher Summary This chapter describes a quantitative assay procedure based on the use of radioisotope-labeled arginine for nitric oxide synthase inductive NOS (iNOS) enzyme activity, and summarizes the efficacy of either various purified flavonoids or the folk herbal medicines, Ginkgo biloba extract and Pinus rnarittima proprietary extract. iNOS—which tightly binds calmodulin even in the absence of calcium—is expressed by some cell types following stimulation with proinflammatory mediators such as cytokine or with the bacterial wall component lipopolysaccharide (LPS). Therefore, while the activity of the constitutive isoforms of NOS is mainly regulated by cytosolic calcium levels, iNOS activity depends on the amount of expressed enzyme essentially regulated at the transcriptional or posttranscriptional level. NO overproduction by iNOS is considered as a biological process potentially leading to opposite outcomes, either physiological or pathological, depending on the ability of cells or tissues to control both the expression of iNOS activity and the nonspecific effects of nitric oxide(NO).The chapter concludes with a discussion of the effects of flavonoids and natural plant extracts on iNOS activity.