In this study, the bactericidal activity of each extract from Sawa-wasabi (Wasabia japonica) root, stem and leaf against the fish pathogenic bacteria were examined. The main component related to bactericidal activity in Sawa-wasabi was well known to AlT. The Sawa-wasabi roots showed the highest AIT amount with 1.18 mg/g. Stems was 0.41 and leaves was 0.38 mg/g. All of them showed bactericidal activity against 2 strains of Vibrio hollisae, V. anguillarum, and 2 strains of Edwardsiella tarda, but weak effect against Staphylococcus capitis. The Sawawasabi leaves showed the strongest bactericidal activity with minimal bactericidal concentrations (MBCs) of 156.3mg of dry weight/mL against 2 strains of V. hollisae, V. anguillarum and 2 strains of E. tarda. The roots and stems showed a little weak bactericidal activities with 312-1,250mg of dry weight/mL against them. These results suggest that certain components besides AIT in Sawa-wasabi are affective in killing fish pathogenic bacteria.
