Protective effect of Alstonia scholaris Linn. R. Br. against Bleomycin induced chromosomal damage in cultured human lymphocytes, in vitro.

It is both interesting and necessary to identify and develop nontoxic radioprotective compounds. Bleomycin (BLM), a known radiomimetic drug was used as a clastogen in the present study. The possible protective effects against BLM (15 μg/ml) induced clastogenicity by aqueous and methanolic extracts from Alstonia scholaris bark, stem and leaves were compared. The treatment of bark extracts significantly (p < 0.01) reduced total chromosomal aberrations. Such a reduction was not seen in case of stem and leaf treatments. The dose of 50 μg/ml was fixed for all extracts throughout the study. To understand the mechanism involved with the protective property of bark extracts, sensitive G2 assay was performed. Lymphocyte cultures from 12 healthy volunteers were exposed to aqueous (50 μg/ml) and methanolic (50 μg/ml) extracts of A. scholaris bark alone as well as in combination with Bleomycin under two different growth phases, G0 and G2 . There was a statistically significant reduction (p < 0.05) in the total chromatid breaks in all cultures which were exposed at G2 phase as compared to respective cultures exposed at G0 phase. The highest level (p < 0.0001) of reduction in total chromatid breaks was observed in cultures treated with aqueous bark extracts at G2 phase than those at G0 phase. This indicated that there could be certain compound(s) present in aqueous bark extracts which enhance DNA repair capacity. Therefore, the bark of A. scholaris could be further utilized to identify and bring out front line radio protective agents in the market with effective formulations.