Inhibitory Effect of Green Tea Extract on Collagenase Activity and Growth of Fish Pathogenic Bacteria

Abstract

Green tea extract has been suggested to possess properties of collagenase inhibition and antimicrobial effect to fish pathogenic bacteria. Most fish pathogenic bacteria showed collagenase activities of 0.08-0.7 unit/ml. Among them, Edwardsiella tarda produced large amount of collagenase in the ST medium at after 16 hrs. Biosynthesis of the enzyme from E. tarda was decreased to 1/3 by addition of 0.08-0.8 mg/ml of tea extract in the culture medium. The collagenase activity was inhibited almost 100% in the reaction mixture by 0.2 mg/ml of the extract. Then, the minimal inhibition concentration against E. tarda growth appeared as 8 mg/ml of the tea extract in the culture medium.