Malondialdehyde (MDA) is considered a presumptive biomarker for lipid peroxidation in live organisms and cultured cells. The present study adapts an accurate and reproducible method to measure MDA by high-performance liquid chromatography (HPLC) as its 2,4-dinitrophenylhydrazone derivative in human hepatoma HepG2 cells in culture. Since MDA is assumed to increase in conditions of cellular oxidative stress, two compounds that induce pharmacological oxidative stress in cell cultures, hydrogen peroxide (H(2)O(2)) and tert-butyl hydroperoxide (t-BOOH), have been used in HepG2 cells. The results report a significant increase in the content of MDA derivative after treatment with 200 and 500microM t-BOOH for 3h, while H(2)O(2) in doses up to 500microM failed to evoke a similar response, indicating a stronger lipid peroxidation of t-BOOH to HepG2 cells than H(2)O(2). Thus, MDA can be used as a reliable biomarker for cellular oxidative stress in human hepatoma HepG2.