Screening for drug photosensitization activity by measuring the variations in oxygen consumption of Bacillus subtilis

An original method is described for detecting the photosensitizing ability of a compound. The principle of this method is based on the analysis of variations in the consumption of oxygen by Bacillus subtilis (measured with Warburg's apparatus or an oxygenometric cell), induced by irradiation of the test compound added to the bacterial culture medium. This methodology was applied to 7 substances: 5 known photosensitizers (8-MOP, chlorpromazine, 5-fluorouracil, Vitamin A acid and benzoyl peroxide) and 2 products without any photoactive properties (aspirin and erythromycin). The comparison of results obtained with the method of photo-patch tests and the analysis of the photophysical properties of the compounds confirm the reliability, reproducibility and the quantitative nature of this method.