AD 0261 displays strong inhibitory action on the generation of lipid peroxides (IC ₅₀ =0.022 μM) and superoxide anions (IC ₅₀ = 0.9-4.0 μM). AD 0261 inhibits cytokine release and/or production from PHA-P-stimulated lymphocytes in a dose-dependent manner. AD 0261 inhibits all parameters which are indicative of lymphocyte activation with 50% inhibition being achieved in a range of 1-10 μM. AD 0261 suppresses ornithine decarboxylase activity, the IC ₅₀ value being around 1.0 μM.