Radiation radioprotective agent

Many free-radical scavengers (including dithiols and dithiocarbamates) have potential therapeutic usefulness as radioprotective agents. Copper complexes are known to be scavenging agents for the superoxide radical, which is believed to play a role in the induction of radiation damage. The toxic effects of superoxide are believed to lie in its ability to reduce metal ions, for example Cu(II) to Cu(I),... 

The higher radiation protectiveness of polymeric compounds over low molecular weight compounds could be utilized in the design of radioprotective agents. A report dealing with the various polymeric antiradiation aibstances has been published ... 

A number of phosphorothioates show anti-radiation activity and are excellent radioprotective agents. Some of these compounds are (12.127) [14]. 

Chinese Herbal Medicines. Many traditional Chinese medicines have been screened for radioprotective activity in experimental animals. In one study of more than a thousand Chinese herbs, a number of agents increased the survival rate of dogs exposed to a lethal dose of y-rays by 30—40%, and some symptoms of radiation injury were ameHorated. These effects are potentially related to stimulation of the hemopoietic and immune systems (130). Extracts of five Chinese dmg plants, as weU as aspirin, effectively protected mice exposed to 7.5—8.0 Gy (750—800 rad) of y-radiation, and increased survival rates by 8—50% (131). Several Chinese traditional medicines, adininistered ip before or after irradiation, protected against Hpid peroxidation in a variety of mouse tissues, including BM, Hver, and spleen, as weU as in mouse Hver microsomal suspensions irradiated in vitro (132). 

Glutamine has been widely examined as a potential agent for enhancing intestinal repair foUowing radiation injury, although its value in this regard remains to be clearly estabHshed (144). Glutamine does exert radioprotective effects in cultured CHO ceUs. 

The 1,3-dioxolane ring is found in a major antifungal drug, ketoconazole (123). Ketoconazole is a broad spectrum, orally active antifungal agent and is used to treat a wide variety of superficial or deep fungal infections. Various workers, especially in Russia, have explored the use of simple oxathiolanes as radioprotectants. For example, the survival rate of mice irradiated with lethal doses of X- or -y-rays was 40% when they were pretreated with 2,2-dimethyl-l,3-oxathiolane. Other oxathiolanes were less active. 1,3-Oxathiolane, administered intravenously to dogs 2 or 3 times daily for 2-4 days before chronic irradiation with polonium-210, increased their life expectancy from 9 months to 3-7 years and alleviated radiation sickness. Some blood indicators were also restored to normal. 

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