Stability and Antimicrobial Property of 4-Methylthio-3-butenyl Isothiocyanate, the Pungent Principle in Radish.

Stability of 4-methylthio-3-butenyl isothiocyanate (MTBI) was studied in an aqueous medium. Most of (E)-MTBI was degraded within 3h by shaking or sonicating and within 6h on an agar plate. (Z)MTBI was more stable. Antimicrobial activity of MTBI on 8 bacteria, 3 yeasts, and 5 fungi was estimated in a gaseous phase. The growth of fungi were strongly inhibited by MTBI in the dose range 2.5-7.5 μmol/ plate. The fact that the maximum amount of MTBI in head space was only 0.2% of the dose suggested that the antimicrobial activity of MTBI was very high.