Inhibitory Effect of Chinese Propolis on Phosphatidylcholine‐Specific Phospholipase C Activity in Vascular Endothelial Cells

To understand the mechanisms underlying the anti-inflammatory action of Chinese propolis, we investigated its effect on the activity of phosphatidylcholine-specific phospholipase C (PC-PLC) that plays critical roles in control of vascular endothelial cell (VEC) function and inflammatory responses. Furthermore, p53 and reactive oxygen species (ROS) levels and mitochondrial membrane potential (Δ ψ m) were investigated. Our data indicated that treatment of Chinese propolis 6.25 and 12.5  μ g/ml for 12 hours increased VEC viability obviously. Exposure to Chinese propolis 6.25, 12.5, and 25  μ g/ml for 6 and 12 hours significantly decreased PC-PLC activity and p53 level, and ROS levels were depressed by Chinese propolis 12.5  μ g/ml and 25  μ g/ml dramatically. The Δ ψ m of VECs was not affected by Chinese propolis at low concentration but disrupted by the propolis at 25  μ g/ml significantly, which indicated that Chinese propolis depressed PC-PLC activity and the levels of p53 and ROS in VECs but disrupted Δ ψ m at a high concentration.