Inhibitory effect of phytoglycoprotein (115 kDa) on the expression of TNF-alpha and interleukin-1beta via inhibition of MAP kinase in primary cultured mouse thymocytes

Abstract

The present study was performed to investigate the anti-inflammatory potential of 115 kDa glycoprotein isolated from Zanthoxylum piperitum DC leaves (ZPDC glycoprotein) in primary cultured mouse thymocytes. To determine whether the ZPDC glycoprotein has inhibitory capacity against inflammation in vitro, we evaluated the activities of inflammation-related factors such as phosphorylations of p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) 1/2, and the activities of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) in 12-O-tetradecanoylphorbol 13-acetata (PMA, 50 nM)-treated mouse thymocytes. Our results showed that the ZPDC glycoprotein (200 mug/ml) has a suppressive effect on the expression of MAPK (ERK1/2 and p38 MAPK), on mRNA expression of pro-inflammatory cytokines (TNF-alpha and IL-1beta), and on protein expression of pro-inflammatory proteins (iNOS and COX-2). We speculate that the ZPDC glycoprotein is an example of a natural compound that blocks pro-inflammatory signal transduction pathways.