Evaluation of the colorimetric tetrazolium assay for the cytotoxicity testing a commercial vanilla flavouring

The tetrazolium colorimetric assay (MTT-assay) has been used to evaluate the cytotoxicity of a vanilla flavouring found on the market. It was characterised by the use of 1,2-propylene glycol and glycerol as diluents and by the presence of vanillin, heliotropine and the corresponding 1,2-propylene and glycerol acetals. The method developed by Mosmann (J. Immunol. Methods 65, 55–63-1983) was used with some modifications. The same assay was applied to the diluent 1,2-propylene glycol in order to verify its possible influence on the toxic effect. This technique proved useful for preliminary screening useful to evidence doubts relating to the safety of flavouring preparations.