Free radical inhibitory effect of some anticancer compounds.

Conventional tests for polymerization initiated by free radicals indicate that alkylating agents vary in free radical inhibitory activity from negligible to moderately strong; antimetabolites from negligible to weak; hormones, steroids, and phenolics from very weak to very strong; and antibiotics from moderate to very strong. Vitamins A and C and copper, which potentiate the biological activity of some anticancer compounds, are relatively strong free radical inhibitors.