STRUCTURE-ACTIVITY RELATIONSHIP OF FLAVONOIDS IN SUPPRESSING RAT-LIVER LIPID-PEROXIDATION

145 flavonoids were studied for their inhibitory effects on the iron-induced lipid peroxidation in mitochondria obtained from rat livers. Of these compounds tested, 30, 57, 59, 67, 70, 72, 77, 102 and 110 (ED50 less-than-or-equal-to 0.5 nmol/mg prot) showed distinctly more potent inhibitory activity than baicalein (ED50 less-than-or-equal-to 5 nmol/mg prot) and 59 and 72 (ED50 less-than-or-equal-to 0.05 nmol/mg prot) exhibited the most potent activity. In order to elucidate the relationships between substituents on the flavonoid skeleton and the biological activity, the quantitative structure-activity relationships (QSAR) were analyzed by the adaptive least-squares (ALS) method for 142 flavonoids. The analysis has shown that the presence of the 1,4- and 1,2-hydroquinon in A-ring and/or B-ring of flavonoids and hydrophobicity of the molecule are responsible for the in vitro inhibitory activity.