Abstract

The objective of this study was to investigate the antioxidative capacity of Rhododendron brachycarpum 95% ethanol extracts. Total antioxidant status was examined by total antioxidant capacity against ABTS radical reactions. Total antioxidant capacities of R. brachycarpum extract at the concentrations of 0.2 and 1 mg/mL were 0.33 and 2.26 mM Trolox equivalents, respectively. Superoxide scavenging activities of R. brachycarpum extract at the concentrations of 0.2 and 1 mg/mL were 45.0 and 77.0%, respectively. Oxygen radical absorbance capacities of R. brachycarpum extract at the concentrations of 5 and 100 ${\mu}g/mL$ were 40.88 and 131.00 ${\mu}M$ Trolox equivalents, respectively. Total phenolic contents of R. brachycarpum extract at the concentrations of 0.2 and 1 mg/mL were 0.37 and 1.25 mM gallic acid equivalents, respectively. R. brachycarpum extract at the concentration of 0.1 mg/mL inhibited 0.2 mM and 0.5 mM tert-butyl hydroperoxide induced cyototoxicity by 52.1 and 30.3%, respectively, in HepG2 cell culture system. Thus, strong antioxidant and cytotoxicity-inhibiting effects of R. brachycarpum extract seem to be due to, at least in part, the prevention from free radicals-induced oxidation as well as high levels in total phenolic contents.

본 연구에서는 만병초 95% 에탄올추출물의 항산화 효과를 조사하였다. 총항산화 활성은 ABTS 라디칼에 대한 항산화능으로 측정하였다. 만병초 추출물 0.2 및 1 mg/mL의 총 항산화능은 각각 0.33 및 2.26 mM Trolox와 동등한 수준이었다. 만병초 추출물 0.2 및 1 mg/mL의 superoxide 소거능은 각각 45.0 및 77.0%이었다. 만병초 추출물 5 및 100 ${\mu}g/mL$의 산소라디칼 소거능은 각각 40.88 및 131.00 ${\mu}M$ Trolox와 동등한 수준이었다. 만병초 추출물 0.2 및 1 mg/mL의 총페놀 함량은 각각 0.37 및 1.25 mM gallic acid와 동등한 수준이었다. 또한, HepG2 세포주를 이용한 세포배양에서 만병초 추출물 0.1 mg/mL 농도의 첨가는 0.2 및 0.5 mM tert-butyl hydroperoxide로 유도된 세포독성을 각각 52.1 및 30.3% 감소시켰다. 따라서, 본 연구 결과들은 만병초 추출물의 강력한 항산화 효과와 세포독성 억제 효과를 나타내며, 이러한 효능은 적어도 자유라디칼의 산화 억제와 높은 총페놀 함량에 기인하는 것으로 사료된다.

Keywords

• Rhododendron brachycarpum;
• ABTS radical;
• Superoxide;
• ORAC;
• Cytotoxicity