Substituted xanthones as antimycobacterial agents. Part 3: QSAR investigations.

Quantitative Structure Activity-Relationships between the antituberculous activity of a series of 61 substituted xanthones and their 13C NMR chemical shifts, lipophilicity, and molar refractivities of the substituents were investigated. In addition to these structural parameters, the test concentrations of the compounds were considered because of the varying solubility. While the multiple linear regression-based Adaptive Least Squares analysis revealed only weak correlations between the antituberculous activity classes of the compounds and their physicochemical parameters, significantly better results were obtained by the Artificial Neural Network technique, which describes nonlinear relationships between the activity as dependent and the physicochemical parameters as independent variables.