Like many other powerful antioxidants, they show a biphasic action, depending on the dose. At the same, we badly need more research to investigate some unanswered questions about the dose range that produces optimum results. And of course, as usual, there are questions about in-vivo effects and complex interactions. We must remember that flavonoid research is still in infancy, and our knowledge is partial at best. A lot of the benefits of phenolic compounds stem from their antioxidant properties.
Flavonoids are powerful scavengers of free radicals.
They also enter the body's antioxidant network, boosting the levels of vitamin C and of our chief endogenous antioxidant, glutathione. Higher levels of ascorbate and glutathione mean better protection of DNA and cell proteins against free radical damage. Estrogens are excellent at protecting neural membranes from peroxidation and preventing neural death-but only if there is sufficient glutathione to keep recycling these powerful hormones to their antioxidant form. Thus, the ability of phenolic compounds such as anthocyanins to raise glutathione levels is extremely important. This, together with the inhibition of the enzymes needed for cell proliferation, such as tyrosine kinase and ornithine decarboxylase, leads to a longer cell cycle and a lower cellular turnover, since fewer damaged cells need to be replaced.