The physicochemical property of phenolic acids to generate hydrogen peroxide (H2O2) in cell culture media has been underreported when describing multiple biological effects in vitro. Our aim was to focus on examining the relative capacity of four common phenolic acids widely consumed in the Western diet for autoxidation potential to generate H2O2 during in vitro culture. Furthermore, quantifying H2O2 derived from different phenolic acids cultured in Dulbecco's modified Eagle's medium (DMEM) was associated with changes in cell proliferation in non-differentiated human intestinal carcinoma cells. Results showed that the different percentage losses of phenolic acids, namely, caffeic (84.78 ± 1.51), chlorogenic (37.3 ± 0.38), ferulic (1.26 ± 0.78), and gallic (100%), paralleled a relative capacity to generate H2O2 when present in DMEM media for 24 h. The rate and total H2O2 generated was dependent on both phenolic acid type and concentration (p < 0.05). Gallic acid had the greatest capacity to generate H2O2 in culture without the presence of cells (p < 0.05). When cultured with non-differentiated Caco-2 cells, gallic acid evoked the greatest bioactivity that included cytotoxicity, anti-proliferation, apoptosis, and nuclear condensation, respectively (p < 0.05). Corresponding treatments with cells with phenolic acids in the presence of catalase confirmed that H2O2 generated from phenolic acid autoxidation was involved in cell proliferation and apoptosis.
Keywords: H2O2; apoptosis; cell proliferation; non-differentiated Caco-2 cells; phenolic acids.