Minimizing Phototoxicity of Xenobiotics by In Vitro and In Vivo Research of their Structural Analogues

Abstract

Simultaneous exposure to (sun)light and a xenobiotic may provoke a phototoxic effect. Effects often concern the skin. However, normal photobiological processes in man, such as the light-induced Vitamin D₃ production or the conversion of bilirubin with visible light, as well as animal experiments with xenobiotics (Beijersbergen van Henegouwen et al., 1987), show that systemic effects may also occur. Xenobiotics involved are present in drugs, cosmetics, food products, in chemicals used in agriculture, in the household etc. The variety in molecular structure of phototoxic compounds is immense, which implies that they can be found in virtually all classes of xenobiotics. Important objective of the research is to find the part of the molecular structure of a given xenobiotic that causes the unwanted effects. This gives the opportunity to alter the structure in such a way that the phototoxicity diminishes, whereas the desired properties of the xenobiotic, e.g. a drug, are conserved. This aim may be reached by a combination of data from 3 different research lines: a photoreactivity in vitro of the phototoxic xenobiotic and structure analogues whether or not in the presence of essential bio(macro)molecules. b phototoxicity in microbiogical test systems (bacteries, yeast, mammalian cell cultures).