Protective role of Carotenoides on the Resistance of Haloarcula IRU1 against Hydrogen Peroxide

Haloarcula IRU1 is an extreme halophilic archaeon isolated from Uromia salt lake. This isolate shows high resistance to DNA damaging agents such as H2O2. This radioresistant organism contains red-orange pigments. In the present study, DNA strand breaks were produced by hydrogen peroxide in a Fenton reaction in the presence and absence of haloarchaeon carotenoid and β-carotene as a standard antioxidant. Carotenoids of Haloarcula IRU1 diminished significantly production of DNA strand breaks in comparison with β-carotene. We propose that radio-resistance of Haloarcula IRU1 is partially due to carotenoids which act as effective in vitro antioxidant.