6-(Methylsulfinyl)hexyl isothiocyanate protects acetaldehyde-caused cytotoxicity through the induction of aldehyde dehydrogenase in hepatocytes.

In the body, alcohol dehydrogenase rapidly converts ethanol to its toxic metabolite, acetaldehyde, which is further metabolized to non-toxic acetic acid by aldehyde dehydrogenase (ALDH). 6-(methylsulfinyl)hexyl isothiocyanate (6-MSITC), a major bioactive compound in Wasabi (Wasabia japonica) has various physiological effects such as anti-oxidative, anti-inflammatory and anti-cancer effects. However, the effect of 6-MSITC on alcohol metabolism has not been studied. In this study, we investigated the effects of 6-MSITC on hepatic ALDH activity and protein expression both in vitro and in vivo. 6-MSITC inhibited ethanol- and acetaldehyde-induced cytotoxicity. Treatment with 6-MSITC to HepG2 cells enhanced ALDH activity through the induction of mitochondrial ALDH2 expression, but not cytosolic ALDH1A1. Knockdown of Nrf2 canceled the 6-MSITC-induced ALDH2 expression, indicating that Nrf2 regulated ALDH2 expression. Moreover, 6-MSITC increased the nuclear translocation of Nrf2 and the expression levels of HO-1 and SOD2, Nrf2-regulated phase II drug-metabolizing enzymes. Oral administration of 6-MSITC increased the mitochondrial ALDH2 activity and its expression in the liver of C57BL/6J mice. These results suggested that 6-MSITC is possible to protect acetaldehyde toxicity in hepatocytes by induction of mitochondrial ALDH2 expression through Nrf2/ARE pathway.