Anti-inflammatory effects of Cynanchum taiwanianum rhizome aqueous extract in IL-1β-induced NRK-52E cells

Abstract

Context: Cynanchum taiwanianum T. Yamaza (Asclepiadaceae) is a medicinal herb used in folk medicine for the treatment of several inflammation-related diseases such as hepatitis and dermatitis in Taiwan. Objective: In the present study, we investigated the anti-inflammatory effect of C. taiwanianum T. Yamaza rhizome aqueous extract (CTAE). Materials and methods: The present study investigated the anti-inflammatory effect of CTAE using IL-1β-induced NRK-52E cells. Production of NO and PGE2 by ELISA, the mRNA and protein expression of iNOS and COX-2, phosphorylation of IκBα, and activation of NF-κB by RT-PCR and western blotting were determined. Results: The CTAE significantly (P < 0.05) inhibited NO and PGE2 production (decreased by 46.1% and 51%, respectively), and also significantly (P < 0.05) attenuated protein and mRNA expression of iNOS and COX-2 (decreased by 90% and 55% for iNOS and by 72% and 74%% for COX-2, respectively) in IL-1β-induced NRK-52E cells, in a dose-dependent manner, without obvious cytotoxic effects. Furthermore, the CTAE suppressed the NF-κB nuclear translocation, in terms of inhibition of IκBα phosphorylation. Discussion and conclusion: Our results provided evidence for its folkloric uses and suggest that the anti-inflammatory activities of CTAE may result from the inhibition of inflammatory mediators, such as NO and PGE2, and an upstream suppression of a NF-κB-dependent mechanism, might be involved. © 2011 Informa Healthcare USA, Inc.