**4. Conclusion**

The obtained results enable us to resume the following astaxanthin effects on irradiated cells that may be clearly observed depending on the phase of the cell cycle and the duration of cells cultivation after irradiation:


All of these effects are potentially radio- and genoprotective. However, we have previously shown that the protective action of astaxanthin concerning the radiation-induced cytogenetic effect similarly to its apoptotic effect was observed exclusively when irradiated cells were on the G<sup>0</sup> phase of the cell cycle. Moreover, analyzing the ChA spectra (**Figure 3**), we found that supplementation with astaxanthin reduces exactly the levels of classic unstable cytogenetic markers of radiation exposure (dicentric and centric ring chromosomes), and it is known that the cells bearing unstable chromosomal aberrations are eliminated by apoptosis in the first place [42]. So, the radioprotective effect of astaxanthin rather may be due to its ability to stimulate apoptosis in cells that carry a subcritical number of DNA breaks than its potential genoprotective properties (defenses DNA from damages or activates of DNA repair processes).
