곰팡이에서 분리한 Helicobacter pylori 항균물질의 분리 및 구조규명

Isolation and Structural Determination of Anti-Helicobacter pylori Compound from Fungus 60686.

본 실험에서는 만성위염, 위궤양, 십이지장궤양, 위암발생의 원인균으로 알려진 H. pylori를 저해하는 특이항균물질을 생성하는 균주를 토양에서 분리한 방선균액과 곰팡이 추출액을 대상으로 탐색하여 곰팡이 균주번호 60686을 선별하였다. Jar fermentor로 배양하여 얻은 균체를 acetone 및 EtOAc로 추출하였고, 얻어진 추출액을 silica column chromatography와 LH-20 gel chromatography를 수행하여 활성분획을 농축하였고 HPLC를 사용하여 항균 활성을 나타내는 단일물질 IDA를 분리 정제하였다. 항균 활성물질 IDA의 구조를 MS, NMR 분석등을 통해 추정한 결과 곰팡이의 2차 대사산물인 cytochalasan의 전형적 구조를 갖는 분자식 $C_{32}H_{36}N_2O_5$의 chaetoglobosin A라는 물질로 판명되었다. 항균물질 IDA의 항균력을 paper disk법으로 실험한 결과 그람양성 균주중에서는 S. aureus SG 511, 285와 503 3주에서만 항균력을 보였고, 그람음성 균주중에서는 H. pylori 4주에서만 항균력을 보였으나 동일농도 처리시 H. pylori에 대한 항균력이 S. aureus에 비해 우수한 항균효과를 가진다고 판단되었다.

Helicobacter pylori is a Gram-negative bacterium which causes chronic gastritis and is associated with gastric ulcer, duodenal ulcer and gastric carcinoma. In the process of screening of antibacterial activities against H. pylori from soil microorganisms, fungus No. 60686 was isolated. After fermentation of No.60686, the antibacterial compound was isolated, purified and followed by extraction of mycelium with organic solvents, acetone and ethyl acetate, through silica gel chromatography, LH-20 gel chromatography and HPLC. As a result of the structural analyses of the compound by IR, $^1$H- and $^{13}$C-NMR, FAB/Mass spectrophotometer, the compound having the antimicrobial activity was identified as chaetoglobosin A ($C_{32}H_{36}N_2O_5$), a cytochalasan derivative. The antimicrobial activity of chaetoglobosin A was tested against Gram-positive and negative bacteria by paper disk method. Among the test strains of 9 Gram-positive bacteria and 18 Gram-negative bacteria containing 4 H. pylori strains, the growth of 4 H. pylori strains and 3 S. aureus strains (SG 511, 285 and 503) was only inhibited by chaetoglobosin A. Also it was shown that its growth inhibition against H. pylori strains was stronger than that against S. aureus strains at the treatment of the same concentration. Therefore it was concluded that chaetoglobosin A has a specific growth inhibition against H. pylori of the tested bacteria.