7-Substituted 4-Hydroxychinoline-3-carboxylic Acids as Inhibitors of Dehydrogenase Enzymes and of the Respiration of Ehrlich Ascites Tumor Cells: Multivariate Analysis and Quantitative Structure-Activity Relationships for Polar Substitutens

Abstract

The title compds. I (R = Cl, OH, CO2H, SO2NH2, etc.) were evaluated for inhibitory activity against malate dehydrogenase [9001-64-3] of the mitochondria and cytoplasm, against muscle lactate dehydrogenase [9001-60-9], and against Ehrlich ascites tumor cells by principal component anal. The results show that enzyme inhibition and inhibition of Ehrlich ascites respiration are not directly connected so that none of the enzymes can be the sole target for the latter. The enzyme systems are reflected by the 1st component that can be identified with polar and steric parameters whereas hydrophobic effects are absent. The 2nd component is entirely due to the inhibition of ascites cell respiration that depends entirely on hydrophobicity. QSAR are discussed.