Anti-inflammatory effects of escin are correlated with the glucocorticoid receptor/NF-κB signaling pathway, but not the COX/PGF2α signaling pathway

Abstract

In China, escin has been widely used in the clinic as a potent anti-inflammatory drug. Previous studies have indicated that escin exerts its anti-inflammatory effect by enhancing the release of glucocorticoids (GCs) and prostaglandin-F2α (PGF2α), and this has been documented in the drug description. However, our previous studies demonstrated that escin did not increase the secretion of GCs, but instead elevated the protein expression of the GC receptor (GR), which may have repressed nuclear factor (NF)-κB-mediated gene expression. The aim of this study was to determine the functions of NF-κB and PGF2α with regard to the anti-inflammatory effect of escin. We investigated the anti-inflammatory effects of dexamethasone, diclofenac and escin against carrageenan-induced paw edema in rats, and observed that escin exerted a GC-like anti-inflammatory effect. In addition, we studied the role of PGF2α in the anti-inflammatory effect exerted by escin in an acetic acid-induced capillary permeability model in mice. The results revealed that the coadministration of escin and diclofenac, a potent prostaglandin-synthesis inhibitor, did not affect the anti-inflammatory effect of escin. Furthermore, we investigated the function of NF-κB with regard to the anti-inflammatory effect exerted by escin in lipopolysaccharide (LPS)-treated mice, and demonstrated that escin significantly inhibited the expression of NF-κB. These results suggest that escin has a GC-like anti-inflammatory effect, and that its mechanisms may be correlated with the GC receptor/NF-κB signaling pathway, but not the COX/PGF2α signaling pathway.