6-Methylsulfinylhexyl Isothiocyanate, an Antioxidant Derived from Wasabia japonica MATUM, Ameliorates Diabetic Nephropathy in Type 2 Diabetic Mice

Many studies have examined the protective effects of antioxidative agents against diabetic nephropathy, using various models. 6-Methylsulfinylhexyl isothiocyanate (6-MSITC) isolated from wasabi (Wasabia japonica MATUM) induces glutathione S-transferase in vitro, thus 6-MSITC may act as an antioxidant in vivo. The aim of this study was to examine whether wasabi powder (WP) and 6-MSITC suppress oxidative stress in vivo and inhibit the impairment of renal function and diabetic nephropathy, using type 2 diabetic mice. KK-Ay type 2 diabetic mice were assigned to three groups (n = 10 each); control mice were fed normal chow (CRF-1) and two experimental groups were fed CRF-1 containing 0.5% WP or 0.03% 6-MSITC for 4 wk. Urine volume, urinary albumin excretion, and creatinine clearance were significantly lower in the 6-MSITC group than in the control group. There was statistically no difference in TBARS or other biomarkers of oxidative stress among the three groups. However, urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG), one of the markers of oxidative stress tended to be lower in the 6-MSITC group than in the control group. In conclusion, the present results show that a sufficient supply of dietary 6-MSITC may prevent or delay renal dysfunction in diabetes by protecting against oxidative stress, and that dietary 6-MSITC may have beneficial effects on diabetic complications in type 2 diabetic mice.