IC 50 values of 13 flavonoids to lipid peroxidation induced by OH · in liver microsomer from rat were evaluated and the relationship between structure and activity was studied. The flavonoids with catechol group, which usually have a higher energy in the highest occupied molecular orbital and lower ΔHOF values, have higher inhibitory activities than those without catechol group. The flavonoids without catechol group in B ring not being suitable structure to chelate with Fe 2+ have little inhibitory activities. The results suggest the anti-lipid peroxidation activity of flavonoids is related with the structure of flavonoids.
