Optimization of a rapid luminescence bioassay for the assessment of toxicity of contaminants in XTC's pills

Evaluation of biological effects of synthesized molecules are generally based on cell cultures and animals in-vitro and in-vivo assays. These tests are expensive and time-consuming. In case of toxicity screening, recent studies have emphasized the benefits of rapid, reproducible and cost effective bacterial assays [1]. In aim to evaluate the possible toxicity of contaminants found in illegally purchased XTC's pills, we have optimized a bioassay coupling directly luminescent bacteria, Vibrio fischeri, with thin-layer chromatography [2]. For the chemical characterization of investigated tablets, we have developed an extraction method of XTC's components and chromatographic conditions for GC/MS analysis. In all investigated pills, the major constituent, 3,4-methylenedioxymethamphetamine (MDMA or „Ecstasy“) was jointly present with a series of by-products, precursors (natural products like safrole) and adjuvants. Although the toxicity of MDMA has been thoroughly investigated, few authors have considered the possible importance of such contaminants. The CCM-bioluminescence assay allows the separation of these complex mixtures and points out biologically active compounds by spot inhibition of bioluminescence visualized with the use of Bioluminizer (Camag, Switzerland). In order to identify the active compounds, the inhibition zones were scrapped and eluted with methanol, concentrated and analyzed by GC/MS. No relevant molecules have yet been identified, but further studies by LC/MS/MS could help to identify molecules not-detectable in GC/MS.

The genotoxicity of samples was also investigated by a second bacterial bioassay, Vitotox® [3].

These optimized toxicity bioassays could be considered for the routine, toxicity screening, notably of medicinal plants.

Acknowledgements: We thank the CAMAG company for making this work possible by allowing access to a bioluminizer.

References:1. Parvez, S. et al. (2006) Environ Int. 32:265–268. 2. Eberz, G. et al. (1996) Chromatographia 43:5–9.

3. Verschaeve, L. et al. (1999) Environ Mol Mutagen. 33:240–248.