Inhibitory Effect of Orientin on Secretory Group IIA Phospholipase A2

It is well known that the expression level of secretory group IIA phospholipase A(2) (sPLA(2)-IIA) is elevated in inflammatory diseases and lipopolysaccharide (LPS) upregulates the expression of sPLA(2)-IIA in human umbilical vein endothelial cells (HUVECs). Orientin, a C-glycosyl flavonoid, is known to have anxiolytic, anti-oxidative, and anti-inflammatory activity. Here, orientin was examined for its effects on the expression and activity of sPLA(2)-IIA in HUVECs and mouse. Prior treatment of cells or mouse with orientin inhibited LPS-induced expression and activity of sPLA(2)-IIA. And orientin suppressed the activation of cytosolic phospholipase A(2) (cPLA(2)) and extracellular signal-regulated kinase (ERK) 1/2 by LPS. Therefore, these results suggest that orientin may inhibit LPS-mediated expression of sPLA(2)-IIA by suppression of cPLA(2) and ERK 1/2.