The n-butanol fraction of Naematoloma sublateritium suppresses the inflammatory response through downregulation of NF-κB in human endothelial cells

Naematoloma sublateritium (Fr.) P. Karst is a chestnut mushroom that is currently a popular edible fungus in the USA, Japan, China and Korea. Although its therapeutic potential in the treatment of diseases has been demonstrated, the pharmacological effect of N. sublateritium (NS) has been poorly studied. In the present study, we demonstrate for the first time that NS suppresses TNF-α-induced inflammatory response in human umbilical vein endothelial cells. The n-butanol fraction of NS (BFNS) inhibited TNF-α-induced monocyte adhesion to endothelial cells in a dose-dependent manner. The anti-adhesive activity of BFNS correlated with suppressed expression of vascular cell adhesion molecule-1, intercellular adhesion molecule-1, monocyte chemoattractant protein-1 and interleukin-8 at both the mRNA and protein levels. In addition, BFNS dose-dependently decreased the expression of inducible nitrogen oxygen synthase (iNOS) and cyclooxygenase-2 (COX-2). Notably, BFNS significantly regulated the nuclear factor (NF)-κB transcriptional activity that was activated by TNF-α stimulation. When considered together, these results suggest that BFNS inhibits the expression of TNF-α-induced adhesion molecules in addition to regulating the iNOS/COX-2 pathways through the modulation of NF-κB in endothelial cells. In conclusion, we propose that BFNS may be a potential therapeutic agent against vascular inflammation, such as atherosclerosis.