Diarylheptanoids from Bark of Alnus hirsuta Turcz

물오리나무 수피의 Diarylheptanoid

This study was carried out to investigate the valuable antioxidative compound from extracts of Alnus hirsuta Turcz. which has a nationwide distribution. The bark (2 kg) was extracted with 70% aqueous acetone and fractionated, and the ethyl acetate and $H_2O$ fractions, separately, were chromatographed on a Sephadex LH-20 column to purify the mixture and to give two diarylheptanoid compounds. The isolated compounds were analyzed by NMR spectroscopy, including $^1H$, $^{13}C$ and two-dimensional NMR, and identified as oregonin (1) and 1,7-bis-(3,4-dihydroxyphenyl)-heptane-5-O-${\beta}$-D-xylopyranoside (2). The antioxidative activity was evaluated by DPPH method using two diarylheptanoids and acid-hydrolyzed oregonin derivative which indicated higher activity potential. Of those the acid-hydrolyzed oregonin derivative showed highly active potential with the value of 2.6 of $IC_{50}$.

본 연구는 우리나라 전역에 분포하고 있는 물오리나무의 추출성분으로부터 유용한 항산화 물질을 탐색하기 위해 수행되었다. 물오리나무 수피를 70% acetone 수용액으로 추출하여 분획한 후 ethyl acetate 분획과 수용성 분획을 Sephadex LH-20으로 충진된 column으로 chromatography를 수행하여 혼합물을 정제하고 두 개의 diarylheptanoid 화합물을 얻었다. 단리된 화합물은 $^1H$, $^{13}C$-NMR 및 2D-NMR 분석을 통하여 1,7-bis-(3,4-dihydroxyphenyl)-heptane-3-one-5-O-${\beta}$-D-xylopyranoside (1, oregonin)와 1,7-bis-(3,4-dihydroxyphenyl)-heptane-5-O-${\beta}$-D-xylopyranoside (2)로 구조를 규명하였다. 두 개의 diarylheptanoid 화합물과 oregonin 가수분해물에 대한 항산화 활성(DPPH)을 측정한 결과 세 화합물 모두 높은 활성을 보였으며, 특히 oregonin 가수분해물의 항산화 활성은 $IC_{50}$이 2.6으로 높은 활성을 보였다.