Accumulation of Nε-(hexanoyl)lysine, an oxidative stress biomarker, in rice seeds during storage

N-epsilon-(hexanoyl)lysine (HEL) is a potentially useful marker of oxidative stress in animals. We investigated whether HEL might be useful as a marker in rice seeds damaged by oxidative stress during storage, as well as in animals. The germination ability of rice decreased with lipid peroxidation during storage at 40 degrees C for three months. Moreover, we observed accumulation of HEL in the damaged rice. In addition, the activities of antioxidative enzymes, catalase and superoxide dismutase, significantly decreased in the rice seeds during storage at 40 degrees C. These results suggest that HEL might be a useful marker of oxidative stress in rice.