A QSAR Study of Quinolones Based on Electrotopological State Index for Atoms

A series of 18 quinolone antibacterials were used in a quantitative structure-activity relationship (QSAR) study based on electrotopological state (E-state) index for atoms. The results were correlated with minimum inhibitory concentrations (MICs) against E. coli H560 and the DNA gyrase cleavage values. The QSAR equations indicated that the in vitro antibacterial activity was strongly dependent on the E-state indexes for the atom at position 6 and the O(sp2) of the carbonyl and carboxyl groups. This suggests the possibility of an electrostatic interaction between the atom at position 6 and the receptor; as well as the formation of hydrogen bonds between the carbonyl groups of the quinolone and the receptor.