Comparison of Colorimetric Methods to Detect Malondialdehyde, A Biomarker of Reactive Oxygen Species

Excessive production of reactive oxygen species (ROS) is implicated in the pathogenesis of aging-related disorders such as cardiovascular diseases. However, monitoring of ROS in vivo remains elusive due to the short half-lives. ROS level can be assessed by measuring the level of malondialdehyde (MDA), a biomarker of lipid oxidation induced by ROS. Although there are many techniques to measure MDA, colorimetric analysis has advantages such as lower costs and simple instruments required. Here, three colorimetric methods, p-anisidine, Schiff reagent and methyl-2-phenylindole (MPI), were compared in specificity and sensitivity of MDA. Both MPI and p-anisidine generated specific peaks for MDA, an aldehyde, which were different from peaks for acetone, a ketone. For the sensitivity, three chemicals were reacted with MDA at normal (0.2 mu M) and diseased (0.6 mu M and 1 mu M) saliva conditions, and healthy (1 mu M) and diseased (2 mu M) serum conditions. Only MPI was sensitive enough to identify MDA in diseased conditions. MPI method was also able to detect extracellular MDA produced by RAW264.7 macrophages treated with H2O2. Based on the results in this study, we anticipate numerous applications of MPI for the detection of ROS overproduced.

Automated summary

Excessive production of reactive oxygen species (ROS) is implicated in aging-related disorders. However, monitoring ROS in vivo remains challenging due to their short half-lives. In this study, three colorimetric methods were compared for their specificity and sensitivity in detecting malondialdehyde (MDA), a biomarker of lipid oxidation induced by ROS. The results showed that the MPI method was sensitive enough to detect MDA in diseased conditions.