DNA damage protecting and free radical scavenging properties of mycosporine-2-glycine from the Dead Sea cyanobacterium in A375 human melanoma cell lines

Mycosporine-like amino acids (MAAs) are a group of natural sunscreen compounds that possess highly photoprotective properties. The most commonly found MAAs in marine organisms is shinorine, porphyra-334, and mycosporine-glycine. However, the halophilic species accumulate mycosporine-2-glycine (M2G) as the major MAA. In this study, we have investigated the protective effect of M2G against oxidative stress. In vitro radical scavenging activity revealed that M2G exhibited a significant inhibition with scavenging concentration (SC) 50 value of 22±1.4μM. In vivo analysis using the human melanoma A375 and a control cell line (NHSF) showed that M2G at low concentration (i.e. micromolar range) protected the cells against the oxidative stress (H2O2)-induced cell death. Comet assay to assess total DNA strand breaks demonstrated that M2G was not genotoxic and protected against the DNA damage by H2O2 treatment at the same level as ascorbic acid. To our knowledge, this is the first evidence demonstrating potential protective role of the natural sunscreen compound M2G against oxidative stress-induced DNA damage in human cell lines. The potent antioxidant activity combined with DNA protection ability of M2G may support its endorsement as a potential natural sunscreen with antioxidant property. These findings provide important clues for possible use of M2G in pharmaceutical and biotechnological applications.