Effect of single and long-term administration of 4-methylthio-3-butenyl isothiocyanate on sugar tolerance test, blood glucose, and serum cholesterol levels in rats

摘要

We previously demonstrated that powdered daikon radish (Raphanus sativus) sprouts and their water-soluble extract reduced blood glucose levels; however, the active ingredient responsible for this action has not yet been identified. In this study, we focused on 4-methylthio-3-butenyl isothiocyanate (MTBI), a pungent component of daikon radish sprouts and examined the effect of MTBI on the blood glucose and serum cholesterol levels in rats. Wistar rats were administered a single intragastric dose of MTBI (0.2 or 0.4 mg/kg body weight), and subsequently underwent a sucrose tolerance test. Moreover, we fed MTBI-containing diets for a long period to streptozotocin (STZ)-induced diabetic rats to examine the effect of MTBI on the blood glucose and serum cholesterol levels. The sucrose tolerance test showed that the MTBI-treated groups had lower blood glucose changes than the control at 1 hr post-load and earlier, but presented elevated blood glucose levels at 2 hr post-load compared to the control. The long-term administration test showed that the blood glucose levels were not significantly different between the MTBI and control groups, whereas the serum cholesterol levels were reduced in the groups administered MTBI (0.4 mg/kg body weight). Taken together, it is unlikely that MTBI is attributed to the lowering effect of daikon radish sprouts on the blood glucose level, but MTBI has the possibility to improve the level of serum cholesterol.