Inhibition of prostaglandin E2 release by salicylates, benzoates and phenols: a quantitative structure-activity study.

Concentrations inhibiting 50% of the prostaglandin E2 release from phorbol ester-stimulated mouse peritoneal macrophages in-vitro were determined for 59 monosubstituted congeners of salicylic acid, benzoic acid and phenol. Twenty-seven further compounds, mainly benzoic acids, were found to be inactive. An attempt was made to establish a quantitative structure-activity relationship (QSAR) form our experimental data using literature or calculated values for the logarithmic n-octanol/water partition coefficients of the compounds, molar refractivity and sigma values of substituents as well as structural indicator variables. The equations found have moderate predictive power and must be considered as a first step in the investigation of factors determining the biological activity of salicylates, benzoates and phenols.