Antioxidant Activity of Isolated Compounds from the Heartwoods of Rhus verniciflua

The heartwoods of Rhus verniciflua was extracted with $H_2O$ and the concentrated extract was partitioned with $CHCl_3$, EtOAc, n-BuOH and $H_2O$, successively. From the EtOAc and n-BuOH fractions, four compounds were isolated through the repeated silica gel, ODS and Sephadex LH-20 column chromatographies. They were determined as sinapyl aldehyde (1), 2,4-dihydroxybenzaldehyde (2), 2,4-dihydroxybenzoic acid (3) and 2,4-dihydroxyphenylglyoxylic acid (4) on the basis of spectroscopic data, respectively. Among the isolated compounds, sinapyl aldehyde $(34.7{\pm}0.6%)$ and 2,4-dihydroxyphenylglyoxylic acid $(43.8{\pm}0.9%)$ showed the strong antioxidative activity than artificial antioxidant BHT $(14.4{\pm}0.3%)$ in DPPH radical scavenging activity.

옻나무(Rhus verniciflua) 목질부에서 분리한 화합물의 항산화활성

옻나무 목질부를 열수 추출하고, 얻어진 추출물을 $CHCl_3$, EtOAc, H-BuOH 및 $H_2O$로 용매 분획하였다. 이중 EtOAc와 n-BuOH분획으로부터 silica gel, ODS 및 Sephadex LH-20 column chromatography로 정제하여 4개의 화합물을 분리하였다. 각 화합물의 화학구조는 NMR 스펙트럼 데이터를 해석하여, sinapyl aldehyde (1), 2,4-dihydroxybenzaldehyde (2), 2,4-dihydroxybenzoic acid (3) 및 2,4-dihydroxyphenyl-glyoxylic acid (4)으로 동정하였다. 이 화합물들 중 2-4은 옻나무목질부에서 처음 분리된 화합물이다. 이들 화합물 중 sinapyl aldehyde (1)와 2,4-dihydroxyphenylglyoxylic acid (4)의 DPPH radical 소거작용이 $34.7{\pm}0.6%$와 $43.8{\pm}0.9%$로 나타나 합성항산화제인 $BHT(14.4{\pm}0.3%)$보다 높게 나타났다.