해양유래 유해세균에 대한 감태추출물의 항균특성

Abstract

It is well known that seaweeds contain specific metabolites exhibiting several biologically activities including antimicrobial, antioxidative, and anti-inflammatory activity. Recently, many studies have been performed to discover novel metabolites showing specific biological activities from several edible seaweeds. However, less research has been done an antimicrobial activity of seaweeds. Moreover, less information is only available on antibacterial activity of seaweeds against marine bacterial pathogens. Therefore, the object of this study is to evaluate antibacterial activity of edible seaweeds against marine bacterial pathogens. In addition, it assessed the effectiveness of fungal fermentation on enhancing the antibacterial activity. Among of seaweed extracts used in this study, Ecklonia cava methanolic extract showed the strongest antibacterial activity against marine bacterial pathogens used in this study. E. cava is commonly used as foodstuff, and pharmaceutical and nutraceutical materials. It has been well known that the edible brown seaweed contains several bioactive activity such as antibacterial, antioxidant, and antimutagenic activity. For further study, the methanolic extracts was fractionated with n-hexane, dichloromethane, ethyl acetate (EtOAc), n-buthanol, and water (H2O) in the order. Among of them, the EtOAc soluble fraction showed the strongest antibacterial activity against marine bacterial pathogens tested in this study. The EtOAc soluble fraction showed the highest antibacterial activity against marine bacterial pathogens with MIC ranging 128 to 256 μg/mL. In order to elucidate the characteristic of the EtOAc soluble fraction against marine bacterial pathogenic, it was performed to HPLC analysis. The HPLC analysis revealed that the EtOAc soluble fraction contains abundant dieckol, a phlorotannins compound, compared to other solvent soluble fractions. It is several reports on the antibacterial activity of dieckol. Thus, the highest antibacterial activity of EtOAc soluble fraction will be related with the content of dieckol. It was previously reported that the microbial fermentation of seaweed extracts using mold, yeast and bacteria resulted in the enhancement of its antibacterial activity. In this study, it was also tried the microbial fermentation to evaluate the effectiveness on the antibacterial activity E. cava extracts against marine bacterial pathogens. The antibacterial activity was enhanced as the fermentation by Aspergillus oryzae was progressed. This result indicates that the microbial fermentation will result in the break-down of an active compound or the production of an active compound in E. cava extract. In order to address this issue in more detail, it was need further study such as HPLC analysis during the periods of fermentation.