두충나무(Eucommia ulmoides Oliver) 잎과 껍질의 에탄올 추출물의 항산화 활성

두충나무(Du-zhong, Eucommia ulmoides Oliver)의 잎과 껍질로부터 얻어진 50% 에탄올 추출물의 항산화 활성을 확인하였다. 두충나무 잎과 껍질 추출물의 수율은 각각 8.1±0.31과 17.4±0.89%, 총 폴리페놀 함량은 각각 64.1±3.35와 42.4±2.38 μg GAE/mg, 총 플라보노이드 함량은 각각 24.0±3.15와 36.7±3.18 μg QE/mg으로 나타났다. 두충나무 잎과 껍질 추출물은 농도에 비례하여 양이온라디칼, 유리라디칼과 아질산염을 소거하였고, 환원력을 증가시켰으며 지질과산화를 억제하였다. 두충나무 잎과 껍질추출물의 ABTS 양이온라디칼 소거에 대한 EC 50 값은 각각 560.6±17.65와 1,357.4±8.45 μg/mL이었고, DPPH 유리라디칼 소거에 대한 EC 50 값은 각각 574.2±14.70과 2,103.1±108.59 μg/mL로 나타났다. 또한 두충나무 잎과 껍질 추출물의 환원력에 대한 EC 50 값은 각각 319.9±13.42와 705.9±26.08 μg/mL였고, 아질산염 소거에 대한 EC 50 값은 각각 2,329.2±35.11과 5,467.6±243.92 μg/mL로 나타났다. 두충나무 잎 추출물은 74.8 μg/mL의 농도에서, 껍질 추출물은 177.2 μg/mL의 농도에서 linoleic acid의 과산화를 각각 70.0 및 79.1% 억제하였다. 두충나무 잎 추출물은 껍질 추출물에 비해 높은 항산화 활성을 보유하고 있었다. Antioxidative activities of 50% ethanolic extracts from Du-zhong (Eucommia ulmoides Oliver) leaf and bark were investigated. Yields of the leaf and bark extract were 8.1±0.31 and 17.4±0.89%, respectively. Polyphenol contents of the leaf and bark extract were 64.1±3.35 and 42.4±2.38 μg gallic acid equivalents/ mg, respectively. Flavonoid contents of the leaf and bark extract were 24.0±3.15 and 36.7±3.18 μg quercetin equivalents/mg, respectively. As concentration of the leaf and bark extract increased, their antioxidative activities proportionally increased. EC 50 values of the leaf and bark extract for cation radical scavenging were 560.6±17.65 and 1,357.4±8.45 μg/mL, respectively. EC 50 values of the leaf and bark extract for free radical scavenging were 574.2±14.70 and 2,103.1±108.59 μg/mL, respectively. EC 50 values of the leaf and bark extract for ferric reducing antioxidant power were 319.9±13.42 and 705.9±26.08 μg/mL, respectively. EC 50 values of the leaf and bark extract for nitrite scavenging were 2,329.2±35.11 and 5,467.6±243.92 μg/mL, respectively. In the presence of 74.8 μg/mL of the leaf extract and 177.2 μg/mL of the bark extract, linoleic acid peroxidation was inhibited by 70.0 and 79.1%, respectively. The Du-zhong leaf extract possessed higher antioxidative activities than its bark extract.