Protective Effects of Melanoidins Derived from Soy Sauce and Soy Paste on NO-Induced DNA Damage

Abstract

We determined the protective activity of melanoidins against DNA damage using the comet assay. We used nitric oxide (NO) as a DNA damaging agent and HL60 (human promyelocytic leukemic cell line). Melanoidins were prepared from soy sauce and soy paste (miso). When the cells were incubated with NO (1 mM) and melanoidin (0-0.25%) for 30 min, soy sauce melanoidin strongly inhibited NO-induced DNA damage in a dose dependent manner. Miso melanoidin and melanoidin prepared from a glycine/gjucose model system also inhibited the DNA damage. Melanoidins showed the protective effect even when cells were subsequently incubated with NO after the treatment and removal of melanoidins. As melanoidins did not trap NO under the condition used, they seemed to inhibit the DNA damage indirectly through a modification of some cellular function.