Anti-oxidant and Anti-inflammatory Properties of Clerodendrum trichotomum Leaf Extracts

누리장나무 잎 추출물의 항산화 및 항염증 활성

Clerodendrum trichotomum (CT) leaves and stems have been used in folk medicine for their anti-hypertension, arthritis, rheumatism, and anti-inflammatory properties. This study was performed to evaluate the potential of CT as an anti-oxidant and anti-inflammatory agent. CT leaves were extracted using 70% ethanol (EtOH). Then, using this extract, a hexane, chloroform ($CHCl_3$), ethyl acetate (EtOAc), and n-butanol (BuOH) fraction was prepared. The polyphenol contents were higher in the EtOAc fraction ($78.08{\mu}g/mg$) and BuOH fraction ($77.54{\mu}g/mg$) compared to the other fractions. Also, these two fractions exhibited strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities. Xanthine oxidase inhibitory activities were higher in the $CHCl_3$ fraction ($IC_{50}=4.43{\mu}g/ml$) and EtOAc fraction ($IC_{50}=5.69{\mu}g/ml$). Moreover, the EtOAc fraction effectively inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells ($IC_{50}=18.87{\mu}g/ml$). Thus, we investigated the effects of the EtOAc fraction on the expression of pro-inflammatory cytokines, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) in LPS-stimulated RAW 264.7 cells. The treatment of the EtOAc fraction ($100{\mu}g/ml$) effectively decreased the levels of the tumor necrosis factor ${\alpha}$ ($TNF-{\alpha}$) and interleukin-6 (IL-6), and the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). These results suggest the potential for CT extract and fractions as promising anti-oxidant and anti-inflammatory agents.

누리장나무의 잎과 줄기는 예로부터 항고혈압, 관절염, 류마티스 관절염, 항염증 등을 치료하는 민간약재로 사용되어 왔다. 본 연구에서는 누리장나무의 잎 추출물과 그 분획물의 항산화 및 항염증 소재로서의 활성가능성을 확인하기 위하여 수행되었다. 누리장나무 잎의 ethanol (EtOH)로 추출물과 이 추출물을 분획하여 얻은 hexane, chloroform ($CHCl_3$), ethyl acetate (EtOAc), n-butanol (BuOH) 분획물들의 총 폴리페놀 함량을 비교한 결과, 총 폴리페놀 함량은 EtOAc 분획물($78.08{\mu}g/mg$)과 BuOH 분획물($77.54{\mu}g/mg$)에서 높게 측정되었다. 각 분획물의 항산화 활성을 비교한 결과, 폴리페놀 함량이 높은 EtOAc 분획물과 BuOH 분획물에서 높은 DPPH (1,1-diphenyl-2-picrylhydrazyl) 및 ABTS (2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)) radical 소거활성을 나타내었다. 그리고 xanthine oxidase 저해활성은 $CHCl_3$ 분획물($IC_{50}=4.43{\mu}g/ml$)과 EtOAc 분획물($IC_{50}=5.69{\mu}g/ml$)에서 높게 나타났다. EtOAc 분획물은 RAW 264.7 세포에서 lipopolysaccharide (LPS)로 유도된 nitric oxide (NO)의 생성을 효과적으로 억제하였다($IC_{50}=18.87{\mu}g/ml$). 또한, EtOAc 분획물($100{\mu}g/ml$)은 LPS로 지극한 RAW 264.7 세포에서 tumor necrosis factor ${\alpha}$ ($TNF-{\alpha}$)와 interleukin-6 (IL-6)의 생성과 inducible nitric oxide synthase (iNOS)와 cyclooxygenase-2 (COX-2) 단백질의 발현을 효과적으로 억제하였다. 본 연구결과는 누리장나무 잎 추출물과 분획물이 항산화 및 항염증 소재로서의 활용가능성이 있음을 제시해 준다.