Biological effects of dietary antioxidants from almonds and cocoa.

摘要

Over the last two decades, a large body of scientific evidence has amassed implicating the presence of reactive oxygen species (ROS) in the development and progression of various age-related disorders including atherosclerosis, cancer, diabetes, rheumatoid arthritis, and macular degeneration. To combat ROS and the damage that they can cause, oxidant defense systems exist, consisting of enzymes (superoxide dismutase, catalase, glutathione peroxidase) and cellular antioxidants (glutathione, uric acid, α-tocopherol, polyphenols, vitamin C), complementing each other functionally in order to maintain homeostasis.; Polyphenols, specifically flavonoids, are reported to be powerful antioxidants and may function by various mechanisms. Recent research has focused on the biological effects of cocoa flavonoids, including potent antioxidant effects, and reductions in platelet reactivity. More recently, research characterizing the polyphenols in almonds shows compounds similar in structure and function to those found in cocoa to be present in the skins.; The present research investigated the effects of dietary antioxidants, including polyphenols, from almonds and cocoa, on oxidant defense systems, markers of oxidative damage, and eicosanoid synthesis in a cell culture model, and in rats, and humans. The effects of cocoa flavonoids on eicosanoid profiles in human aortic endothelial cells and in vivo in humans were examined. In both in vitro and in vivo experiments, improvements in the leukotriene:prostacyclin ratios, (decreasing by 58% and 52% respectively), were noted.; The effects of almond consumption in two populations at risk for increased oxidative stress were examined. After six weeks of almond consumption in male runners, we observed a trend towards increased plasma α-tocopherol concentrations, however this did not result in any changes in markers of oxidative damage or oxidant defense. Similarly, there were no changes observed in eicosanoid synthesis with almond consumption. The results from the smokers study were confounded by complications with the batch of almonds used.; Finally, we examined the effects of almond meal, almond skin, and cocoa on erythrocyte hemolysis in rats. The inclusion of almond skin or cocoa in the diet resulted in improvements in antioxidant capacity (TRAP) and partially protected erythrocytes from AAPH-induced hemolysis. The effects at the level of the erythrocyte seem to be due to the flavonoids present in the almonds and the cocoa.