A novel observation: melatonin's interaction with malondiadehyde.

OBJECTIVES A purpose of this study is to determine whether melatonin, a novel antioxidant, can interact with malondialdehyde in an in vitro condition. METHODS The reaction kinetics and thermodynamics of this reaction have been performed and a new product has been identified using liquid chromatography onlining with mass spectrometry. RESULTS A new product generated with an interaction of melatonin and malondialdehyde has been identified to be a three-ring structure with a molecular weight 286, which has the specific wavelength absorption with the maximum at 345 nm. The reaction was completed within a few minutes and the product was proportional to the concentrations of the reactants. Based on its molecular weight and the deduced structure of the new product, we speculate that this reaction occurs between one melatonin molecule and one malondialdehyde and to form a 3 ring conjugated adduct. CONCLUSION This is the first report to show that melatonin directly interacts with malondialdehyde to form a new product. The findings suggest that melatonin may detoxify unsaturated carbonyls and protect against cellular damage induced by oxidative stress.