Abstract: The disease caused by human being exposed to high dose radiation in a short period of time is called acute radiation syndrome (ARS). It mostly occurs in nuclear radiation accidents and radiotherapy by high dose radiation, which can cause damage to the nerve and vascular system, gastrointestinal system, and hematopoietic system. In this paper, a new type of titronyl nitroxide radicals was designed and synthesized by introducing o-diphenol hydroxyl group. Through the cell radiation damage protection experiment, the effect of different doses of radiation damage and radiation damage protection in human embryonic liver cells (L-02) and human liver cancer cells (HepG-2) was studied. The experimental results show that the compound has a better radiation damage protection effect on the two types of cells with different doses of radiation, and has a better effect on 4 and 2 Gy medium and low dose cell radiation damage. The cell survival rate of the irradiated group is better than that of the single shot(increased by 10%~18%). Moreover, administration of the designed titronyl nitroxide radicals before irradiation (the cell survival rate is increased by 9%~20%) is better than post-radiation administration (the cell survival rate is increased by 1% to 6%), which provides experimental support for the research of new radiation protection drugs.

Key words: Titronyl nitroxide radicals, Radiation damage protection, Radiation protection drugs