Preparation and biological activity of four epiprogoitrin myrosinase-derived products

(SR)-5-Vinyl-1,3-oxazolidine-2-thione, (2S)-1-cyano-2-hydroxy-3-butene, and two diastereoisomeric erythro-(2S)- and threo-(2S)-1-cyano-2-hydroxy-3,4-e pithiobutanes were prepared in pure form starting from (2S)-2-hydroxybut-3- enyl glucosinolate(epiprogoitrin). This glucosinolate was isolated in almos t pure form using ripe seeds of Crambe abyssinica and then hydrolyzed under , different conditions. The hydrolysis was carried out using either myrosin ase immobilized on nylon, to produce (5R)-5-vinyl-1,3-oxazolidine-2-thione, or the endogenous myrosinase contained in defatted crambe meals, to produc e the other epiprogoitrin-derived products. After purification and physicoc hemical characterization, all four myrosinase degradation products were tes ted for their biological activity. A bioassay on Lactuca sativa-was chosen as a simple test to determine their apparent action on living tissues. (SR) -5-Vinyl-1,5-oxazolidine-2-thione: negatively affected mainly root growth, whereas (2S)-l-cyano-2-hydroxy-3-butene affected the early phase of germina tion, and both (BS)-1-cyano-2-hydroxy-3,4-epithiobutane diastereoisomers ap peared to negatively affect both germination and root growth at doses 5-10 times lower than those of (2S)-l-cyano-2-hydroxy-3-butene or (5R)-5-vinyl-1 ,3-oxazolidine-2-thione.