Modulation of Activated Murine Peritoneal Macrophages Functions by Emodin, Aloe-emodin and Barbaloin Isolated from Aloe barbadensis
MULABAGAL VANISREE1, SHIH-HUA FANG2, CHAN ZU1 AND HSIN-SHENG TSAY1*
1. Institute of Biotechnology, Chaoyang University of Technology, 168 Gifong E. Rd., Wufong Township, Taichung City 413, Taiwan, R.O.C.
2. Department of Microbiology, School of Medicine, China Medical University, Taichung City 400, Taiwan, R.O.C.
(Received: January 25, 2005; Accepted: September 5, 2005)
ABSTRACT
Activated murine macrophages produce high level of nitric oxide by inducible nitric oxide synthase (iNOS), which is an important mechanism in macrophage-induced inflammation. In the present study, we isolated emodin, aloe-emodin and barbaloin compounds from Aloe barbadensis and investigated their inhibitory effects on the production of nitric oxide (NO), tumor necrosis factor-α (TNF-α) and interleukin (IL-12) from murine macrophages activated by lipopolysaccharide (LPS) and interferon-gamma (IFN-γ).
Our results showed that the 50% inhibition concentration (IC50) of emodin, aloe-emodin and barbaloin on NO, TNF-α and IL-12 from activated peritoneal macrophages were 120, 30 and 200 µM respectively. Our experimental results showed that reduction of NO level by emodin might inhibit both at the pretreated LPS/IFN-γ activation and post-LPS/IFN-γ activation pathway. Activities of aloe-emodin and barbaloin could be caused by inhibition at the pretreated LPS/IFN-γ activation event. Chemical structures of all the isolated components were identified by comparison of NMR, mass spectral data and melting points with those reported in literature.
Key words: Aloe barbadensis, liliaceae, emodin, aloe-emodin, tumor necrosis factor, nitric oxide, anti-inflammatory activity, lipopolysaccharide