Evaluation of Antibacterial Activity of 3-Butenyl, 4-Pentenyl, 2-Phenylethyl, and Benzyl Isothiocyanate in Brassica Vegetables

This study investigated antibacterial activities of 4 isothiocyanates (3-butenyl, 4-phentenyl, 2-phenylethyl, and benzyl isothiocyanate) against 4 Gram-positive bacteria (Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, and Staphylococcus aureus) and 7 Gram-negative bacteria (Aeromonas hydrophila, Pseudomonas aeruginosa, Salmonella choleaesuis, Salmonella enterica, Serratia marcescens, Shigella sonnei, and Vibrio parahaemolyticus) by an agar disc diffusion assay. Benzyl isothiocyanate (> 90.00 mm inhibition zone diameter at 0.1 mu L/mL) and 2-phenylethyl isothiocyanate (58.33 mm at 0.2 mu L/mL) showed large inhibition zones especially against B. cereus. Also, 3-butenyl isothiocyanate (21.67 mm at 1.0 mu L/mL) and 4-pentenyl isothiocyanate (19.67 mm at 1.0 mu L/mL) displayed potent antibacterial activity against A. hydrophila. Benzyl and 2-phenylethyl isothiocyanate indicated higher activity against most of the pathogenic bacteria than 3-butenyl and 4-pentenyl isothiocyanate, and were more effective against Gram-positive bacteria than Gram-negative bacteria.