A Comparative Study On The Mutagenicity Of Natural Borneol And Synthetic Borneol

Objective Borneol, which is divided into Natural Borneol and Synthetic Borneol, has been employed in the treatment of cardiovascular and surgical diseases long since. However, there are still not relevant reports in its genetic toxicology until now. Through combination of in vitro experiment and animal experiment, our research was focused on the comparison of new source Natural Borneol and Synthetic Borneol and provided the original materials for preclinical evaluation of its safety.MethodAt first, the inherited characteristics of four strains of Salmonella Typhimurium histidine auxotrophic mutant TA97,TA98,TA100,TA102 were examined. Next, in the presence of S9mix or not respectively, the Ames test was conducted for detecting genic mutation. Then, with or without the presence of S9 metabolic activation , the impairment of CHL cells whose karyotype is 25 was investigated by the chromosomal aberration test; meanwhile, the phenomenon of chromosomal aberration was observed by the MN test. Relying on the above methods, the mutagenicity of new source Natural Borneol and Synthetic Borneol was comprehensively compared and analyzed in the genic and chromosomal level respectively.Result1. From the examination results of inherited characteristics of bacterial strains: histidine demand, rfa mutation ,ΔuvrB mutation,ampicillin resistance,tetracycline resistance,the inherited characteristics of four chosen bacterial strains accorded with the experimental requirement of examining the mutagenicity of drugs.2. In Ames test, the number of backward mutant colony of four strains induced by Natural Borneol and Synthetic Borneol at the concentration within 0.4~250μg/plate was quantified. The results did not display a significant increase compared with that induced by dimethylsulfoxide, whether with S9 metabolic activation or not. Moreover, the backward mutant colony had normal background. The number of backward mutant colony of four bacterial strains induced by the direct mutagen and the indirect mutagen, in the activated state or not respectively, was over two times than the control agent dimethylsulfoxide.3. In the MTT assay, IC50 of Natural Borneol for CHL cells was 207.86 μg·ml－1; IC50 of Synthetic Borneol for CHL cells was 85.74 μg·ml－1 (relevant coefficient r＞0.9). CHL cellswere treated with Natural Borneol at the concentration of 200,100,50,25,12.5(μg·ml－1) and the dose of Synthetic Borneol is 80,40,20,10,5(μg·ml－1). After 24h(in the presence of S9MIX or not respectively) and 48h(－S9mix), the proportion of chromosomal aberration was always less than 5％ with the alteration of dose.4. As shown by the chromosomal aberration test, the proportion of chromosomal aberration of CHL cells treated with MMC(0.25μg·ml－1) in the presence of S9mix (24h/48h)was 38％,45％. 34％ of cells appeared chromosomal aberration after treated with CP(20μg·ml－1)24h in the activated state.5. The acute toxicity study showed that: LD50 of the Nature Borneol is 4.656 g/kg·bw in mice;LD50 of the Synthesize Borneol is 4.881 g/kg·bw . After treated with Natural Borneol at the dose of 2.328,1.164,0.582(g/kg·bw) respectively, the micronucleus rate(MNR)of PCE in the bone marrow of mice was 0.3±0.5‰,0.4±0.5‰,0.3±0.5‰. Contrastively, the MNR was 0.4±0.7‰,0.3±0.5‰,0.4±0.5‰ in the presence of Synthetic Borneol at the dose of 2.4405g,1.2203,0.6010(g/kg·bw). There was not significant difference between these results obtained from the Borneol assay and the negative control assay(P＞0.05 ), and however, the rates of MN in the Borneol assay was obviously less than the positive control assay(P＜0.01).Conclusions1. Whether with S9 metabolic activation or not, The negative result of Ames test revealed two kinds of Borneol did not possess evident mutagenicity.2. Both Natural Borneol and Synthetic Borneol were not display the potential to lead to the chromosomal aberration of CHL cells.3. In the MN test, the increase of the micronucleus rate of PCE induced by Natur...