Antioxidant and antiproliferative activities of methanolic extracts of beer

The beneficial effects of beer on human health, such as reduced risk of heart diseases and certain types of cancer, has been associated to its polyphenolic content and resulting antioxidant activity. The aim of this study was to verify the relationship between the antioxidant and antiproliferative activity of the compounds contained in beer. In order to evaluate different antioxidant profiles, methanolic extracts of various commercial beers and of samples collected during the brewing process were analyzed. Their antioxidant power was evaluated by measuring: i) the ferric reducing activity, ii) their ability in suppressing the release of thiobarbituric acid reactive substances and iii) the content of antioxidant compounds. The antiproliferative activity was detected by determining the inhibition of HeLa cancer cell growth following incubation with the extracts. The results of this study showed that most beer extracts have significant antiproliferative effects, but these effects were not due to the antioxidant power of the extracts. By contrast, they were found to be related to the extract-induced increase of the intracellular levels of reactive oxygen species. The antiproliferative action of the extracts could result from a pro-oxidant mechanism due to non–phenolic compounds