Assessment of the effect of fermented papaya preparation on oxidative damage in spontaneously hypertensive rat brain using electron spin resonance (ESR) imaging and L-band ESR spectroscopy

Oxidative and nitrosative stress mechanisms are widely implicated in the biological and pathological processes involved in aging, cardiovascular and neurodegenerative diseases. Although this has continued to fuel suggestions of the benefits of antioxidant functional foods, in vivo methods for assessing the integrity of this remain limited. A novel electron spin resonance (ESR) technique for evaluating oxidative stress and location of its damage in the brain of spontaneously hypertensive rats (SHR) has been described [Lee, M.-C., et al. (2004). Assessment of oxidative stress in the SHR brain using electron spin resonance (ESR) imaging and in vivo L-Band ESR. Hypertension Research, 27, 485–492]. The reconstructed 2D ESR images of the distribution of a blood brain barrier-permeable nitroxyl spin probe, 3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (MC-PROXYL) was used to investigate the ability of fermented papaya preparation (FPP, a product of yeast fermentation of Carica papaya Linn.) to modulate oxidative stress of SHR brain. Supplementation (5–7 months) with FPP (50 mg/rat/day) significantly increased the decay of the ESR images of the MC-PROXYL, suggesting that FPP may have up-regulated the redox defense activity in the SHR brain. Herein is an in vivo noninvasive technique for the study of oxidative stress and its modulation by dietary factors (that may be intended for applications as neuroprotectants in chronic degenerative disease involving loss of brain function).