녹차로부터 β-Glucogallin, Coumaroyl Quinic Acid Derivative, 그리고 Flavonol Triglycoside의 분리·동정 및 항산화 활성

Isolation and Identification of β-Glucogallin, Coumaroyl Quinic Acid Derivative, and Flavonol Triglycosides as Antioxidants from Green Tea

본 연구에서는 Amberlite？？ XAD-7 및 ODS open column chromatography을 이용하여 녹차에 함유된caffeine, 8종의 catechin류, 5종의 flavon-3-ol류 외 5종의 화합물을 분리하였다. 분리된 5종의 화합물은 MS 및NMR 분석을 통해 1-galloyl-β-D-glucopyranose (1), 5-O-cis-p-coumaroyl quinic acid methyl ester (2), quercetin 3-O-[β-D-glucopyranosyl(1→3)-O-α-L-rhamnopyranosyl(1→6)-O-β-D-galactopyranoside] (3), quercetin 3-O-[β -D-glucopyranosyl(1→3)-O-α-L-rhamnopyranosyl(1→6)-O-β-D-glucopyranoside] (4) 그리고 kaempferol 3-O-[β -D-glucopyranosyl(1→3)-O-α-L-rhamnopyranosyl(1→6)-O-β-D-glucopyranoside] (5)로 동정되었다. 화합물 1, 3, 4, 및 5는 우롱차나 홍차 등의 차에서 그 존재가 확인되었으나, 화합물 2는 차나무로부터는 처음 동정되었다. 화합물 1, 3, 4, 및 5를 대상으로 항산화 활성을 평가한 결과, free radical-scavenging 활성 및 철 환원력은 화합물 1 > 화합물 3 > 화합물 4 > 화합물 5 순으로 높았다. 동정된 화합물들의 항산화 활성은 catechol 및 gallol 골격에서 기인한 것으로 판단된다.

Five antioxidative compounds were purified and isolated from green tea by Amberlite？？ XAD-7 and ODS column chromatography. These compounds were identified as 1-galloyl-β-D-glucopyranose (1), 5-O-cis-p-coumaroyl quinic acid methyl ester (2), quercetin 3-O-[β-D-glucopyranosyl(1→3)-O-α-L-rhamnopyranosyl(1→6)-O-β-Dalactopyranoside] (3), quercetin 3-O-[β-D-glucopyranosyl(1→3)-O-α-L-rhamnopyranosyl(1→6)-O-β-D-glucopyranoside] (4), and kaempferol 3-O-[β-D-glucopyranosyl(1→3)-O-α-L-rhamnopyranosyl(1→6)-O-β-D-glucopyranoside] (5). These compounds were established by mass spectrometry and nuclear magnetic resonance analysis. Of them, the antioxidative activities of the four compounds (1, 3, 4, and 5) were evaluated using a 1,1-diphenyl-2-picrylhydrazyl and 2,2´-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)+ radical-scavenging and ferric ion reducing power assays. Compound 1 showed higher antioxidant activities than the other compounds. Overall, these compounds may contribute to the antioxidative effects of tea leaf and its processed foods.