Biol. Pharm. Bull., 28(4),601-606, April 2005

Regular Articles

Avena Rhealba^® Inhibits A23187-Stimulated Arachidonic Acid Mobilization, Eicosanoid Release, and cPLA₂ Expression in Human Keratinocytes: Potential in Cutaneous Inflammatory Disorders

Marie-Françoise ARIES,^*,a Clémence VAISSIERE,^a Eric PINELLI,^b Bernard PIPY,^c and Marie CHARVERON^a

^a CERPER, Institut de Recherche Pierre Fabre, Laboratoire de Biologie Cellulaire Cutanée; BP 3071, 2 rue Viguerie, 31025 Toulouse Cédex 3, France: ^b Ecole Nationale Supérieure Agronomique de Toulouse; 1 avenue de l'Agrobiopˆole, Auzeville Tolosane, BP 107 F, 31326 Castanet Tolosan Cedex, France: and ^c UPRES EA2405, INSERM IFR31, CHU Rangueil; 1 avenue Jean Poulhes, 31403 Toulouse Cedex 4, France. * To whom correspondence should be addressed. e-mail: marie.francoise.aries@pierre-fabre.com

The aim of the present study was to examine the effects of Avena Rhealba^® (AR) oatmeal extract on the metabolism of arachidonic acid (AA) and eicosanoids as well as on the expression of cytosolic phospholipase A₂ (cPLA₂) in the human keratinocyte cell line HaCaT. For this purpose, we examined the effects of AR on basal and A23187-triggered release of [³H]-AA from phospholipids and on the production of [³H]-labeled metabolites of the cyclooxygenase (CO) and 5-lipoxygenase (LO) pathways. AR was found to inhibit A23187-triggered [³H]-AA mobilization from phospholipids (p<0.05) and production of [³H]-labeled metabolites of CO (p<0.05) and LO (p<0.05) pathways. These results suggest AR decreases PLA₂-dependent mobilization of AA from phospholipids. A closer examination of the effects of AR on prostaglandin 6KF1α (6KPGF1α), the stable metabolite of prostacyclin, revealed dose-dependent inhibition of this AA metabolite. AR also decreased A23187- and tumor necrosis factor α-induced cPLA₂ overexpression, as shown by cPLA₂ immunodetection and mRNA expression. These results demonstrate the high potential of AR in the treatment of inflammatory diseases of the skin.

Key words Avena Rhealba^®; keratinocyte; arachidonic acid; eicosanoid; cytosolic phospholipase A₂