Abstract
To develop natural antimicrobial substances from Theaceae, Schima wallichii subsp. liukiuensis was selected from 218 woody plants, and antimicrobial compounds against bacteria, fungi, and yeast were isolated. The antimicrobial activity of ethanol extracts proved higher than those of other organic solvents. The antimicrobial activity of S. liukiuensis extract showed no differences in sesonal variation, but, that of plant part was high in bark at autumn. An antimicrobial substance was isolated from the extract of Schima using column chromatography packed with silica gel and sephadex LH-20, and then a purified antimicrobial substance (Compound I) was obtained using HPLC analysis. The Compound I in the analysis of UV, IR, and GC-MS presumed a triterpene or steroidal saponin, ${\alpha}$-sitisterol as aglycon combined three sugars. The minimal inhibitory concentration (MIC) of the Compound I against a bacteria, fungi, and yeast were 1.25 g/L, 5.0 g/L, and 0.040 g/L, respectively. This is much lower than the MIC of hinokitiol, an natural antimicrobial compound used commercially, which suggests that Compound I could be developed as a natural preservative and pharmaceuticals.
218종의 목본식물 자원으포부터 높은 항율력올 보인 Schima wallichii subsp. liukiuellsis로부터 항균활성물질을 추출, 정제하였다. Schim$\alpha$의 향균물질 추출에 가장 적합한 용매는 70% 에탄올이었으며, 계젤에 따른 항균활성은 차이를 보이지 않았고, 부위별로는 가을에 채취한 수피가 가장 좋았다. 조추출물을 유가용매로 정제하여 최종적으혹 buthanol 분획올 얻었고, 이를 silica gel과 sephadex LH-20 및 HPLC분석을 통 하여 흰색결정의 항균물질 Compound I을 얻었다. 항균물질은 UV, IR, MS분석 결과 aglycone으로 ${\alpha}$-sitosterol에 rhamnose, galactose, glucose가 1:1:1로 결합된 물질로 추정되었다. Compound I의 미생물에 대한 MIC는 3종의 bacteria에 L 1.25 g/L, 2종의 fungi에 5.0 g/L로 나타났으며, 효모에 대한 MIC는 0.04 g/L로 매우 높게 나타났다. Compound I은 천연 보존제, 의약품 등으로의 향후 개발이 기대된다.
