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The consumption of a diet rich in certain flavonoids, including the flavanol sub-class, has been associated with a reduced risk for vascular disease. We evaluated the effects of the regular consumption (14 d) of a flavanol-containing milk chocolate (FCMC) or cocoa butter chocolate (CBC) on variables related to vascular disease risk, oxidative stress and physical activity. Twenty-eight free-living, young (18–20 years old) male soccer players consumed daily 105 g of FCMC (168mg of flavanols) or CBC (,5mg of flavanols), as part of their normal diet. The consumption of FCMC was significantly associated with a decrease in diastolic blood pressure (25mmHg), mean blood pressure (25mmHg), plasma cholesterol (211%), LDLcholesterol (215%), malondialdehyde (212%), urate (211%) and lactate dehydrogenase (LDH) activity (211%), and an increase in vitamin E/cholesterol (þ12%). No relevant changes in these variables were associated with CBC consumption. No changes in the plasma levels of (2)-epicatechin were observed following analysis of fasting blood samples. In conclusion, FCMC consumption was associated with changes in several variables often associated with cardiovascular health and oxidant stress. The presence of significant quantities of flavanols inFCMC is likely to have been one of the contributing factors to these
results.

The capacity of the flavan-3-ols [(-)-epicatechin (EC) and (+)-catechin (CT)] and a B dimeric procyanidin (DP-B) to modulate phorbol 12-myristate 13-acetate (PMA)-induced NF-kappaB activation in Jurkat T cells was investigated. The classic PMA-triggered increase in cell oxidants was prevented when cells were preincubated for 24 h with EC, CT, or DP-B (1.7-17.2 microM). PMA induced the phosphorylation of IKKbeta and the subsequent degradation of IkappaBalpha. These events were inhibited in cells pretreated with the flavonoids. PMA induced a 4.6-fold increase in NF-kappaB nuclear binding activity in control cells. Pretreatment with EC, CT, or DP-B decreased PMA-induced NF-kappaB binding activity and the transactivation of the NF-kappaB-driven gene IL-2. EC, CT, and DP-B inhibited, in vitro, NF-kappaB binding to its DNA consensus sequence, but they had no effect on the binding activity of CREB or OCT-1. Thus, EC, CT, or DP-B can influence the immune response by modulating NF-kappaB activation. This modulation can occur at early (regulation of oxidant levels, IKK activation) as well as late (binding of NF-kappaB to DNA) stages of the NF-kappaB activation cascade. A model is presented for possible interactions between DP-B and NF-kappaB proteins, which could lead to the inhibition of NF-kappaB binding to kappaB sites.

The flavan-3-ols (-)-epicatechin (epicatechin) and (+)-catechin (catechin) and their related oligomers (procyanidins) isolated from cocoa were assayed for their capacity to inhibit the UVC-mediated formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (oxo(8)dG) in calf thymus DNA. The above-mentioned compounds inhibited oxo(8)dG production in a concentration- and time-dependent manner. After 30 min of irradiation (30 kJ/m(2)), 0.1, 1.0, 10, and 100 microM epicatechin inhibited oxo(8)dG formation by 20, 36, 64, and 74%, respectively. For the same dose of UVC, 0.1, 1.0, 10, and 100 microM catechin inhibited oxo(8)dG formation by 1, 23, 50, and 70%, respectively. Epicatechin was more efficient than catechin with respect to inhibiting oxo(8)dG formation (IC(50) 1.7 +/- 0.7 vs 4.0 +/- 0.7 microM). Monomer, tetramer, and hexamer fractions were equally effective in inhibiting oxo(8)dG formation when assayed at 10 microM monomer equivalent concentration. At similar concentrations (1-50 microM), the inhibition of the UVC-mediated oxo(8)dG formation by flavan-3-ols and procyanidins was in the range of that of alpha-tocopherol, Trolox, ascorbate, and glutathione. These results support the concept that flavan-3-ols and their related procyanidins can protect DNA from oxidation at concentrations that can be physiologically relevant. Both epimerism and degree of oligomerization are important determinants of the antioxidant activity of flavan-3-ols and procyanidins.