Inhibition of endothelial cell adhesion by the new anti-inflammatory agent alpha-iso-cubebene

The current study explored if alpha-iso-cubebene, a novel cubebene sesquiterpene compound purified from Schisandra chinensis, could attenuate the activities of adhesion molecules in tumor necrosis factor-alpha (TNF-alpha)-stimulated human umbilical vein endothelial cells (HUVECs). The study was performed on HUVECs that were pretreated with 25 microg/ml of alpha-iso-cubebene before TNF-alpha treatment. Treatment of HUVECs with alpha-iso-cubebene for 6 h significantly inhibited TNF-alpha-induced reactive oxygen species (ROS) formation. HUVECs treated with alpha-iso-cubebene showed markedly suppressed TNF-alpha-induced mRNA expression of VCAM-1 and E-selectin, but little alteration in ICAM-1 mRNA expression. alpha-iso-Cubebene treatment also significantly decreased the TNF-alpha-induced cell surface and total protein expression of VCAM-1 and E-selectin without affecting ICAM-1 expression. In addition, treatment of HUVECs with alpha-iso-cubebene markedly reduced U937 monocyte adhesion to TNF-alpha-stimulated HUVECs. alpha-iso-Cubebene treatment did not affect translocation of NF-kappaB transcription factor from the cytosol into the nucleus. However, alpha-iso-cubebene significantly inhibited NF-kappaB transcription factor activation in TNF-alpha-stimulated HUVECs. The new anti-inflammatory agent alpha-iso-cubebene attenuates TNF-alpha-stimulated endothelial adhesion to monocytes by inhibiting intracellular ROS production, the activation of redox-sensitive NF-kappaB transcription factor and expression of VCAM-1 and E-selectin. Based on these findings, alpha-iso-cubebene is proposed as an effective new anti-inflammatory agent that may have a potential therapeutic use for the prevention and treatment of vascular diseases.