Glucosinolates, glycosidically bound volatiles and antimicrobial activity of Aurinia sinuata (Brassicaceae)

Volatiles of Aurinia sinuata (L.) Griseb. were isolated from aerial parts and analysed by gas chromatography/gas chromatography–mass spectrometry (GC/GC–MS). The main compounds were glucosinolate degradation products originating from glucoberteroin, glucobrassicanapin and glucoalyssin. They were: 6-(methylthio)hexanenitrile (1.8–51.5%), 6-(methylsulfinyl)hexanenitrile (0–11.5%), 5-(methylsulfinyl)pentyl isothiocyanate (0–10.2%), 5-(methylthio)pentyl isothiocyanate (0.4–9.5%), 4-pentenyl isothiocyanate (0.7–8.9%), 5-hexenenitrile (2.6–14.6%) and 5,6-epithiohexanenitrile (0–3.4%). Also other volatiles were identified, such as fatty acids and esters (0.3–19.2%), phenols, phenylpropane derivatives and related compounds (0.4–15.8%), aliphatic alcohols and carbonyl compounds (4.2–11.6%) and some other compounds in smaller percentages.The O-glycosidically bound volatiles were isolated from aerial parts of A. sinuata. After the enzymatic hydrolysis and GC and GC–MS analyses, among 20 volatile aglycones identified, eugenol (73.0%) was the main one.The volatile samples containing glucosinolate degradation products were evaluated for antimicrobial activity using the disc diffusion method with calculated minimum inhibitory concentrations (MIC). All volatile samples expressed a wide range of growth inhibition activity against both Gram-positive and Gram-negative bacteria and fungi. The minimum inhibitory concentrations varied between 0.008 and 0.115 mg/ml.