Hot Topics in Medicinal Chemistry (Track)




DEVELOPMENT OF ANTI-RADIATION DRUGS

Helmut Durchschlag

Institute of Biophysics and Physical Biochemistry, University of Regensburg, Universitaetsstrasse 31, D-93040 Regensburg, Germany

Abstract:

As a consequence of nuclear accidents like those in Chernobyl or Fukushima, a lot of radiation is released and the most deleterious radioactive isotopes exposed to the environment are I-131, Cs-134 and Cs-137. On the other hand, deleterious effects caused by the depletion of the ozone layer are due to enhanced levels of UV-A and B light on earth. After the impact of ionizing and nonionizing radiation, manifold health impairments take place including thyroid, blood, eye, and skin damages, leukaemia, cancer of different organs, and a great many of other diseases.

While pills of normal (nonradioactive) KI can protect the thyroid gland effectively against short-lived radioactive iodine (provided KI has been taken in high doses and shortly after an accident), till now no pills have been developed against other deleterious isotopes such as long-lived Cs-137 (a gamma-ray emitter). Though several attempts have been made, to discover anti-radiation medicines (e.g. by browsing herbs with anti-oxidative properties), only marginal effects have been observed in the past. Similarly, no effective drugs against the enhanced attack of UV light have been described. The majority of reported effects are rather complicated or ambiguous findings, frequently absolute nonsense or science fiction, by no means based on a solid scientific background.

Based on systematic investigations of radiation effects on many classes of biomolecules and a great variety of protection and repair experiments [1, 2], the interaction between radiation and biological matter on the molecular level is now well understood and provides the scientific basis for the development of anti-radiation medications. A fundamental breakthrough can now be achieved by interpreting and applying comprehensive scientific findings of radiation physics, radiation chemistry and radiation biology, together with pharmacy and medicine. Any anti-radiation drug (mixture, food supplement), minimizing the consequences of a radioactive fall-out such as Cs-137, should exhibit the following features: high protecting efficiency of appropriate additives (preferably bioprotectants) against reactive oxygen species (mainly ·OH radicals produced by water radiolysis), additives must reach the respective target organs, suppression of further radiation damage, at least a partial (bio)chemical repair of already damaged particles, initiation of some kind of biological restoration cycle (restoration of already consumed protective agents), drugs should be harmless (even when administered in high doses for a long time) and cheap. In doing so, we achieved in developing anti-radiation pills for people affected by nuclear disasters or for the prevention of imminent hazards, stopping noxious reactions already on the molecular level and enhancing the natural defense system in our body (provided by some antioxidants and antioxienzymes). On the other hand, compounds exhibiting significant absorption behavior in the UV range turn out to act as potent protectants against high levels of UV light, functioning as ‘chemical sunglasses’.
 
[1]        Durchschlag H. et al.: Radiat. Phys. Chem. 47 (1996) 501-505, 55 (1999) 691-697, 67 (2003) 479-486.

[2]        Durchschlag, H., Zipper, P.: Abstr. 4th ICDDT 2012 Dubai/UAE (ISSN 0929 8673) p. 27; Proc. SAS 2012 Sydney/Australia (ISBN 1 921268 15 8) B2.2