Isolation and Structure Determination of Antioxidants from the Root of Paeonia lactiflora

작약(芍藥)(Paeonia lactiflora) 뿌리로부터 항산화활성 물질의 분리

On the purpose of development of novel antioxidative compounds from natural sources, 38 plants expected to show antioxidant activity have been examined concerning DPPH radical scavenging activity. Among them, thirteen plants, including Paeoniae radix, the root of Paeonia lactiflora, exhibited the activity. In order to isolate active component, the root was extracted in 80% aqueous MeOH and solvent fractionated with EtOAc, n-BuOH and water, successively. Silica gel column chromatographies of the EtOAc and n-BuOH fraction exhibiting antioxidant activity. were repeatedly carried out with monitoring by DPPH assay to afford three active compounds. On the basis of spectral data and the chemical characteristics, the structures of the compounds were determined as (+)-catechin, $1,2,3,4-tetragalloyl-6-digalloyl-{\beta}-D-glucose$ and $1,2,3,4,6-penta-galloyl-{\beta}-D-glucose$.

국내 식물자원으로부터 천연 항산화물질을 탐색하기 위하여 항산화활성이 기대되는 38종의 식물을 MeOH 수용액으로 추출한 후, EtOAc와 물로 분배, 추출하였다. 각 추출물에 대하여 DPPH radical 소거활성을 검정하였고, 이중에 작약을 포함한 13종의 식물에서 활성이 확인되었다. 작약뿌리로부터 항산화물질을 분리하기 위하여 80% MeOH 수용액으로 추출, 농축하였고, 이를 EtOAc, n-BuOH 및 물로 계통분획하였다. 활성이 확인된 n-BuOH과 EtOAc층에 대하여 활성을 추적해가며 column chromatography를 반복하여 3종의 활성물질을 분리하였다. 이들의 화학구조를 NMR 등의 spectral data를 해석하여 (+)-catechin, $1,2,3,4-tetragalloyl-6-digalloyl-{\beta}-D-glucose$ 및 $1,2,3,4,6-pentagalloyl-{\beta}-D-glucose$로 동정하였다.