Numerous studies have demonstrated the importance of naturally occurring dietary polyphenols in promoting cardiovascular health and emphasized the significant role these compounds play in limiting the effects of cellular aging. Polyphenols such as resveratrol, epigallocatechin gallate (EGCG), and curcumin have been acknowledged for having beneficial effects on cardiovascular health, while some have also been shown to be protective in aging. This review highlights the literature surrounding this topic on the prominently studied and documented polyphenols as pertaining to cardiovascular health and aging.

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To investigate the beneficial properties associated with polyphenols, we screened 12 polyphenols for their ability to increase the viability of PC12 cells subjected to oxidative stress via CoCl2 and H2O2. Cell viability data demonstrate that 50 micromol/L methyl gallate and 50 micromol/L fisetin significantly increase viability of H2O2-stressed cells. Further, viability data suggest that 100 micromol/L epigallocatechin gallate (EGCG) increases basal viability, but has no rescue effect on cells stressed with CoCl2 or H2O2. Analysis of intracellular reactive oxygen species (ROS) shows that EGCG, methyl gallate, and gallic acid are effective in reducing CoCl2-derived ROS, and that methyl gallate is effective in attenuating H2O2-derived ROS. Examination of nitric oxide concentrations shows that methyl gallate significantly increases nitric oxide, both in nonstressed and H2O2-stressed cells, whereas EGCG results are consistent with the scavenging of nitric oxide under nonstressed and stressed conditions. Furthermore, analysis of total glutathione levels reveals that EGCG, methyl gallate, and gallic acid pretreatments with and without H2O2 stress have the ability to significantly alter glutathione metabolism. These findings suggest that EGCG, methyl gallate, and gallic acid may have potential therapeutic properties.

The functionality of polymorphonuclear leukocytes (PMNs) once they migrate into the digestive lumen is still ill defined. More specifically, phagocytic function and bactericidal action of PMNs after transepithelial migration have not received much attention. The aim of the present study is to compare PMN behavior before and after transepithelial migration, in particular (i) phagocytosis and bactericidal activity; (ii) expression of surface molecules, particularly those involved in phagocytosis; and (iii) apoptosis. Cultured human intestinal epithelial T84 cell monolayers were used. The effect of transepithelial migration on phagocytosis was evaluated by immunofluorescence and electron microscopy and by flow cytometric assessment of the engulfment of a strain of Escherichia coli transfected with the green fluorescent protein. Superoxide production by PMNs was investigated by luminol-mediated chemiluminescence. Expression of various surface molecules on PMNs was evaluated by flow cytometry, while PMN apoptosis was assayed by morphologic changes and DNA fragmentation. E. coli phagocytosis by the PMNs was markedly increased after transepithelial migration without modification of superoxide production. CD11b/CD18 and CD47 expression was increased upon PMN transmigration, whereas CD16 expression was decreased and CD29, CD46, CD49e, CD49f, CD55, CD59, CD61, CD95 levels remained unchanged. Apoptosis in transmigrated PMNs was slightly advanced and was observed after 12 h compared to 16 h for nontransmigrated PMNs. In conclusion, the phagocytic capacity of the PMNs is augmented after transepithelial migration, with a dramatic increase in the level of CD11b/CD18 and preservation of the superoxide production. These results suggest a higher bactericidal activity of the PMNs once they have translocated into the digestive lumen.