Suppressive effects of PG201, an antiarthritic botanical formulation, on lipopolysaccharide-induced inflammatory mediators
in Raw264.7 cells

Abstract

PG201, an ethanol extract from a mixture of 12 herbs, has strong antiarthritic activity. To understand the molecular mechanisms
underlying its anti-inflammatory effects, PG201-mediated suppression of inflammatory mediators was studied in Raw264.7, a
mouse macrophage cell line. PG201 decreased the expression of interleukin (IL)-1β, IL-6 and CC chemokine ligand-2, but not tumor necrosis factor-α, at the protein and mRNA levels in lipopolysaccharide-stimulated Raw264.7 cells. Results from a gel retardation assay indicated
that PG201 substantially reduced the DNA-binding activity of the activator protein-1 and cyclic adenosine monophosphate-responsive
element-binding protein transcription factors, but not nuclear factor-κB. Western blot and Northern blot analyses showed that PG201 reduced inducible nitric oxide synthase and cytosolic phospholipase
A₂ (cPLA₂) protein expression, but did not affect mRNA expression, ultimately resulting in decreased nitric oxide and prostaglandin
E₂. The protein expression of cPLA₂ was decreased by PG201 in the presence of cycloheximide, an inhibitor of translation, suggesting that PG201 may facilitate
the degradation of cPLA₂. Taken together, these results suggest that PG201 selectively affects the expression of proteins that play key roles in the
inflammatory response at transcriptional and post-translational levels.