Lycopene-Induced hydroxyl radical causes oxidative DNA damage in Escherichia coli

Lycopene, which is a well-known red carotenoid pigment, has been drawing scientific interest because of its potential biological functions. The current study reports that lycopene acts as a bactericidal agent by inducing reactive oxygen species (ROS)-mediated DNA damage in Escherichia coli. Lycopene treatment elevated the level of ROS—in particular, hydroxyl radicals (•OH) —which can damage DNA in E. coli. Lycopene-induced DNA damage in bacteria was confirmed and we also observed cell filamentation caused by cell division arrest, an indirect marker of the DNA damage repair system, in lycopene-treated E. coli. Increased RecA expression was observed, indicating activation of the DNA repair system (SOS response). To summarize, lycopene exerts its antibacterial effects by inducing •OH-mediated DNA damage that cannot be ameliorated by the SOS response. Lycopene may be a clinically useful adjuvant for current antimicrobial therapies.