IN-VITRO ACTIVITY OF GLUCOSINOLATE-DERIVED ISOTHIOCYANATES AGAINST POSTHARVEST FRUIT PATHOGENS

The authors assayed the ability of some reaction products, essentially isothiocyanates, derived from the myrosinase-catalysed hydrolysis (ne utral pH) of six natural glucosinolates to inhibit germination and myc elial growth of Botrytis cinerea, Rhizopus stolonifer, Monilinia laxa, Mucor piriformis and Penicillium expansum, the leading postharvest fu ngal pathogens of fruit and vegetable crops. All of the tested product s showed antifungal activity, although they proved less effective agai nst mycelial growth than in germination control. The isothiocyanates p roduced by enzymatic hydrolysis of glucoraphenin, sinalbin and sinigri n were particularly effective because they completely inhibited conidi c germination of all five pathogens considered. The sinigrin-derived i sothiocyanate exhibited a wide pathogen-control spectrum, either inhib iting conidia germination altogether or delaying by 3-6 days the onset of mycelial growth compared to the control.