Vitamin E quinone Alpha-tocopherylquinone is formed during free radical attack on vitamin E and has been shown to undergo reduction by NQO1 (NAD(P)H dehydrogenase [quinone] 1) to generate vitamin E hydroquinone. Since it has been recognized that alpha-tocopherylquinone in living tissue for global assessment of antioxidative defense system. The ratio of alpha-tocopherol alpha-tocopherylquinone concentrations were increased under oxidative stress with the exception of plasma. Alpha-tocopherylquinone and a low fat diet have positive effect on a patient with chronic continuous ulcerative colitis. The patient's condition improved dramatically with both colonic and extraintestinal manifestations of the disease. Withdrawal of alpha-tocopherylquinone for periods of one to two days produced recurrence of inflammation, which was again reduced upon re-introduction of alpha-tocopherylquinone.