Abstract: The contents of total isothiocyanate contents and 4-methylthio-3-butenyl isothiocyanate (MTBITC) in n-hexane extracts of radish seedlings from 6 cultivars at different development stages were measured. Along with this, their antioxidant properties in vitro were evaluated using commercial FRAP, ABTS, superoxide anion free radical and hydroxyl free radical assay kits. The present study found that over 80% of total isothiocyanates in radish seedlings was MTBITC during 15 days of development. Radish seedlings aged 5－10 days revealed higher MTBITC content. At the same development stage, the seedlings of Changchun white radish, Shengfeng white radish, ivory white radish and German Giant radish contained more MTBITC than those of Fushun red radish and Mantanghong red radish. Moreover, the seedlings of Changchun white radish, Shengfeng white radish, ivory white radish and German Giant radish indicated a positive antioxidant effect-MTBITC content correlation. Despite having lower MTBITC content, Fushun red radish and Mantanghong red radish presented strong antioxidant effect.

Key words: radish seedlings, isothiocyanates, 4-methylthio-3-butenyl isothiocyanate(MTBITC), dynamic change, antioxidant