Prevention of radiation-induced chromosomal aberrations in bone marrow of mice by Indian medicinal plant, Alstonia scholaris

Full text: It is well established that ionizing radiation can damage biologically important macromolecules such as DNA via both direct and indirect mechanisms. Chromosomal aberrations are a measure of direct effects on the genetic material and serve as useful biological dosimeter. With the realization of deleterious effects of ionizing radiation, a need was felt to protect human beings against these harmful effects by using physical and/or chemical means. Numerous chemical compounds have been tested for their ability to protect against ionizing radiation. Despite extensive screening of several synthetic compounds for radio protective activity, no single compound has emerged as a good radio protector so far. The plants have been the companion of man since time immemorial, providing several useful drugs for the treatment of various ailments. Therefore, it is natural that the choices of alternative radio protectors would include plants and plants products. However, some plants have been tested for radio protective action but a detailed study, with all possible end points, is still lacking. Hence, screening of natural products presents a major avenue for the discovery of new radioprotective drugs. Alstonia scholaris, a non toxic herbal preparation, has been reported to be clinically effective in treating syphilis insanity and epilepsy. A. scholaris has also been reported to inhibit liver injuries. These results encourage us to conduct further experiments to prove its radioprotective potential. The present study was performed to verify the radioprotective capacity of Alstonia scholaris on radiation-induced clastogenic change in term of chromosomal aberrations. For this purpose, one group of male Swiss albino mice was exposed to 5 Gy gamma radiation to serve as the control while the other group received Alstonia scholaris bark extract (100 mg/kg b. wt.) orally for 5 consecutive days before irradiation to serve as experimental. Such animals were pretreated with colchicine for chromosomal study and were autopsied between 12 hrs to 30 days and chromosomal preparations were made from their bone marrow. Chromosomal aberrations including aberrant cells, chromatid breaks, centric rings, chromosomal exchanges, dicentrics and acentric fragments were scored higher at early intervals (12 hrs and 24 hrs) but later decreased gradually towards normalcy at the last autopsy interval. The pattern of change in chromosomal aberrations is almost similar as irradiated control but their frequency is found to be significantly lesser in Alstonia treated irradiated animals. From the results it is concluded that such plant extract has the potentiality to reduce radiation-induced cytogenetic lesions