earticle

영어

This study investigates the anti-inflammatory effects of several components isolated from Rheum tanguticum Maxim. (Polygonaceae). Previously, we found that 70 % ethanol extracts of Rheum Rhizoma (Rheum tanguticum, R. undulatum, R. palmatum, R. officinale, Rumex crispus) had anti-inflammatory properties on LPS-stimulated RAW 264.7 macrophages and carrageenan-induced paw edema model. Thus, we studied five anthraquinone derivatives isolated from Rheum tanguticum, including chrysophanol, chrysophanol-8-O-Glc, 2-methoxy-4-hydroxyanthraquinone-5-O-Glc, emodin, and physcion. Chrysophanol, chrysophanol-8-O-Glc, physcion and emodin inhibited nitric oxide (NO) production at micromolar concentrations in LPS-induced RAW 264.7 macrophages. Among these anthraquinones, emodin was found to be a potent inhibitor with its IC50 (the half maximal inhibitory concentration) value of 57.23 μM. In addition, these four compounds dose-dependently reduced inducible nitricoxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression conducted by Western blotting analysis. Taken together, our data suggest that chrysophanol, chrysophanol-8-O-Glc, physcion and emodin from R. tanguticum showed anti-inflammatory activities through their inhibition of iNOS and COX-2 expression. Emodin was already reported to exhibit anti-inflammatory effects especially on acute pacreatitis animal model (1-3). Therefore, the further study is required to clarify anti-inflammatory mechanism of emodin in detail.