Superpendentic index: a novel topological descriptor for predicting biological activity.

A simple highly degenerating, pendenticity based, topological descriptor termed as superpendentic index has been conceptualized and its discriminating power investigated with regard to antiulcer activity. A data set consisting of 128 analogues of 4-substituted-2-guanidino thiazoles was selected for the present study. These analogues are reversible, competitive, and selective inhibitors of gastric H+,K(+)-ATPase enzyme. The value of superpendentic index of each analogue in the data set was computed and active range was identified. The biological activity assigned to each analogue using superpendentic index was subsequently compared with the reported in vitro and in vivo inhibitory activities. The accuracy of classification of analogues based on in vivo activity was found to be 82% in the active range using superpendentic index.