Abstract
MultiCASE (version 2.80), a structure-activity relationship expert system, was applied to a series of structurally diverse compounds evaluated for sensory irritant properties. The resulting biophores (molecular fragments responsible for the observed activity) were interpreted in terms of their physicochemical properties. Aromatic, charge-charge, and lipophilic interactions with a hypothetical receptor site are proposed. Fragment overlaps were observed with other databases of toxicological interest. The MultiCASE model is useful for predictive purposes and for providing information of a mechanistic nature. Furthermore, the identified biophores can serve as starting points for in-depth exploration of the correlation between physicochemical properties and biological activity.