Avena Rhealba® inhibits a23187-stimulated arachidonic acid mobilization, eicosanoid release, and cPLA2 expression in human keratinocytes:: Potential in cutaneous inflammatory disorders

The aim of the present study was to examine the effects of Avena Rhealba (c) (AR) oatmeal extract on the metabolism of arachidonic acid (AA) and eicosanoids as well as on the expression of cytosolic phospholipase A(2) (cPLA(2)) in the human keratinocyte cell line HaCaT. For this purpose, we examined the effects of AR on basal and A23187-triggered release of [H-3]-AA from phospholipids and on the production of [H-3]-labeled metabolites of the cyclooxygenase (CO) and 5-lipoxygenase (LO) pathways. AR was found to inhibit A23187-triggered [H-3]-AA mobilization from phospholipids (p < 0.05) and production of [H-3]-labeled metabolites of CO (p < 0.05) and LO (p < 0.05) pathways. These results suggest AR decreases PLA(2)-dependent mobilization of AA from phospholipids. A closer examination of the effects of AR on prostaglandin 6KF1 alpha (6KPGF1 alpha), the stable metabolite of prostacyclin, revealed dose-dependent inhibition of this AA metabolite. AR also decreased A23187- and tumor necrosis factor alpha-induced cPLA(2) overexpression, as shown by cPLA(2) immunodetection and mRNA expression. These results demonstrate the high potential of AR in the treatment of inflammatory diseases of the skin.