연구논문 : 홍조류 모로우붉은실(Polysiphonia morrowii)의 추출물과 이로부터 분리된 브로모페놀계 화합물의 in vitro 항균,항스쿠티카충 활성 및 구조-활성 상관성

Scuticociliates are regarded as serious pathogens in marine aquaculture worldwide. In Korea, they cause mass-mor-talities in fish such as the commercially important olive flounder Paralichthys olivaceus . In particular, mixed infec-tions of scuticociliates with pathogenic bacteria have been commonly reported. During efforts to identify natural marine-algae derived products that possess anti-bacterial and anti-scuticociliate properties, we found that an 80% methanolic extract of the red alga Polysiphonia morrowii Harvey exhibits both anti-scuticociliate activity against Miamiensis avidus , which is a major causative agent of scuticociliatosis, and anti-bacterial activities against fish pathogenic bacteria. Activity-guided fractionation and isolation of the 80% methanolic extract of P. morrowii yielded three bromophenols, which were identified as 3-bromo-4,5-dihydroxybenzyl methyl ether (1), 3-bromo-4,5-dihy-droxybenzaldehyde (2) and urceolatol (3) based on spectroscopic analyses. 3-bromo-4,5-dihydroxybenzyl methyl ether (1) showed the highest anti-bacterial and anti-scuticociliate activities, with a minimal inhibitory concentration (MIC) of 62.5 μg/mL (against Vibrio anguillarum ) and minimal lethal concentration (MLC) of 62.5 ppm (in seawa- ter). Investigations of the anti-bacterial and anti-scuticociliate activities of seventeen bromophenol derivatives, in-cluding the three isolated natural bromophenols, showed that the existence of an electron donating group or atom with a non-covalent electron pair at C4 of the 2-bromophenol structure may be important in anti-scuticociliate activity. These findings suggest that the extract and bromophenol derivatives of P. morrowii may provide useful alternatives in aquaculture anti-scuticociliate therapies.