Isolation and Structural Analysis of Acetyl Soyasaponin $A_1$ from Hypocotyl of Soybean

콩 Hypocotyl에서 Acetyl Soyasaponin $A_1$의 분리 및 구조 분석

Soyasaponins are phytochemicals of major interest fur their health benefits. Chemical investigation of a soybean phytochemical concentrate resulted in the isolation and identification of triterpenoid saponins. The MeOH extraction of defatted hypocotyl separated from soybeans was peformed by the automated solvent extractor (ASE). Fractionation was performed on a flash column ($150mm{\times}40mm$ i.d.) packed with a preparative $C_{18}$ reverse phase bulk packing material $(125\AA,\;55-105{\mu}m)$ and monitored at 210 nm, and collected 14 fractions. Consequent Fsat preparative column liquid chromatography (Fast PCLC) was performed for the purification of Fraction-I (Fr-I) collected from the fraction 8 and 9 of flash chromatography. Fsat PCLC was performed on a Luna $C_{18}\;10{\mu}m,\;100{\AA}$, semipreparative reverse phase column ($250cm{\times}50mm$ i.d.) for the purification of isolated unknown compound (Fr-I-2). Chemical structure of acetyl soyasaponin $A_1\;(MW:1436.6,\;C_{67}H_{104}O_{33})$ was identified and determined by a combination of extensive NMR ($^1H-NMR$, 400 MHz; $^{13}C-NMR$, 100 MHz; DEPT), IR, UV, and ESI-MS analysis.

본 연구는 국내육성 콩 품종 및 전통식품의 우수성을 입증하고, 생리활성이 우수한 고품질의 신품종 육성을 위한 기초기반기술 확립의 일환으로 group A soyasaponin의 분리 및 정제에 관한 연구를 수행한 결과를 요약하면 다음과 같다. 1. 콩 종실로부터 hypocotyl을 분리하고 탈지한 후 automated solvent extractor(ASE)를 이용하여 MeOH 추출 후 flash column($150mm{\times}40mm$ i.d.)을 이용하여 총 14개의 fraction을 분리하였다. 2. Flash column으로 얻어진 8 및 9번 fraction(Fraction-I) 을 Luna $C_{18}$ semipreparative reverse phase column($250cm{\times}50mm$ i.d.)을 이용하여 Fast PCLC로 정제하여 미지화합물(unknown compound : UKC)(Fr-I-2)을 분리하였다. 3. Compound 1을 NMR($^1H-NMR$, 600 MHz; $^{13}C-NMR$, 100 MHz; DEPT), IR, UV 및 ESI-MS 분석을 통하여 구조를 동정한 결과 분자량(MW)이 1436.6이며, 분자식이 $C_{67}H_{104}O_{33}$인 group A 계열의 acetyl soyasaponin $A_1$으로 확인되었다.