Ephedorae herba decreases lipopolysaccharide-induced cyclooxgenase-2 protein expression and NF-κB-dependent transcription in C6 rat glioma cells

We studied the effects of Mao (Ephedrae herba) on lipopolysaccharide (LPS)-induced expression of inducible cyclooxygenase (COX-2) in C6 rat glioma cells. Western blot analysis showed that Mao inhibited LPS-induced expression of COX-2 protein, but not that of constitutive cyclooxygenase. Reporter gene assays showed that Mao reduced LPS-inducible NF-κB-dependent transcription that plays a crucial role in induction of COX-2 gene expression. This crude drug decreased LPS-induced IκBα degradation in a concentration-dependent manner without affecting LPS-induced IκB phosphorylation. These results suggest that Mao prevents LPS-induced NF-κB-dependent transcription by inhibiting IκB degradation and suppresses an increase in COX-2 protein expression in C6 cells.