USE OF QUANTITATIVE SHAPE-ACTIVITY RELATIONSHIPS TO MODEL THE PHOTOINDUCED TOXICITY OF POLYCYCLIC AROMATIC-HYDROCARBONS - ELECTRON-DENSITY SHAPE-FEATURES ACCURATELY PREDICT TOXICITY

The quantitative shape-activity relationship (QShAR) methodology, base d on accurate three-dimensional election densities and detailed shape analysis methods, has been applied to a Lemna gibba photoinduced toxic ity data set of 16 polycyclic aromatic hydrocarbon (PAH) molecules. In the first phase of our studies, a shape fragment QShAR database of PA Hs was developed. The results provide a very good match to toxicity ba sed on a combination of the local shape features of single rings in co mparison to the central ring of anthracene and a more global shape fea ture involving larger molecular fragments. The local shape feature app ears as a descriptor of the susceptibility of PAHs to photomodificatio n and the global shape feature is probably related to photosensitizati on activity.