Phytochemical Analysis and Antimicrobial Activity of Cardaria draba (L.) Desv . Volatiles

Two different volatile isolates from the aerial parts of Cardaria draba (L.) Desv., obtained either by hydrodistillation ( Extract I ) or by CH 2 Cl 2 extraction subsequent to hydrolysis by exogenous myrosinase ( Extract II ), were characterized by GC‐FID and GC/MS analyses. The main volatiles obtained by hydrodistillation, i.e. , 4‐(methylsulfanyl)butyl isothiocyanate ( 1 ; 28.0%) and 5‐(methylsulfanyl)pentanenitrile ( 2 ; 13.8%), originated from the degradation of glucoerucin. In Extract I , also volatiles without sulfur and/or nitrogen were identified. These were mostly hexadecanoic acid (10.8%), phytol (10.2%), dibutyl phthalate (4.5%), and some other compounds in smaller percentages. Extract II contained mostly glucosinolate degradation products. They originated from glucoraphanin, viz. , 4‐(methylsulfinyl)butyl isothiocyanate ( 3 ; 69.2%) and 5‐(methylsulfinyl)pentanenitrile ( 4 ; 4.5%), glucosinalbin, viz. , 2‐(4‐hydroxyphenyl)acetonitrile ( 5 ; 7.2%), and glucoerysolin, viz. , 4‐(methylsulfonyl)butyl isothiocyanate ( 6 ; 5.0%). Moreover, the volatile samples were evaluated for their antimicrobial activity using the disc‐diffusion method and determining minimum inhibitory concentrations ( MIC ). All volatile isolates expressed a wide range of growth inhibition activity against both Gram ‐positive and Gram ‐negative bacteria and fungi. The MIC values varied between 4 and 128 μg/ml.