Co-Authors:
Lapidot, T., Department of Food Science, ARO Volcani Center, Bet Dagan 50250, Israel
Walker, M.D., Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
Kanner, J., Department of Food Science, ARO Volcani Center, Bet Dagan 50250, Israel
Abstract:
It has recently been suggested that the ability of apple extracts to inhibit proliferation of tumor cells in vitro may be due to phenolic/flavonoid antioxidants. Our study demonstrates that this inhibition is caused indirectly by H2O2 generated through interaction of the phenolics with the cell culture media. The results indicate that many previously reported effects of flavonoids and phenolic compounds on cultured cells may result from similar artifactual generation of oxidative stress. We suggest that in order to prevent such artifacts, the use of catalase and/or metmyoglobin in the presence of reducing agents should be considered as a method to decompose H2O2 and prevent generation of other reactive oxygen species, which could affect cell proliferation. The use of tumor cells and "nontumor cells" in a bioassay to measure antioxidant activity, in this context, is potentially misleading and should be applied with caution.