The present invention is directed in part to methods of preventing or reducing colon carcinogenesis comprising administering to a patient at risk of colorectal cancer, a pharmaceutical preparation comprising disclosed chemopreventive. In another aspect, the invention is directed to methods attenuation of oxygen free radicals comprising administrating to a patient in need thereof an antioxidant effective amount of a compound represented by formula (I), (IIa) or (IIb) as disclosed herein.
