LYCOPENE ENHANCES RADICAL REDUCING ABILITY IN VIVO

Lycopene is the most abounding carotenoid in tomato fruits and tomato-based products, and reported to be one of the most potent singlet oxygen quencher among various dietary antioxidants. However, there are no reports on the effect of orally administered lycopene on the radical reducing ability in vivo. The radiofrequency electron paramagnetic resonance (EPR) method is a unique technique by which the in vivo reducing ability of an experimental animal can be studied. In this study, the in vivo changes in the renal reducing ability of rats orally administered lycopene were investigated using a 700 MHz EPR spectrometer equipped with a surface-coil-type resonator. Rats were fed either a control diet or a diet containing lycopene (250 mg lycopene/100 g diet) for two weeks and in vivo EPR measurements were conducted. The renal reducing ability of lycopene treated rats was significantly greater than that of the control. Although lycopene was absolutely accumulated in the kidney by lycopene supplementation, there were no notable changes in renal antioxidant enzyme activities such as superoxide dismutase and glutathione peroxidase and renal α-tocopherol concentration between two groups. This is the first verification of in vivo antioxidant enhancement via dietary lycopene administration, although we need to clarify the mechanism of in vivo antioxidant enhancement by lycopene.