Ursolic acid enhances cyclooxygenases and tumor necrosis factor-alpha expression in mouse skin.

An anti-inflammatory triterpenoid, ursolic acid (UA), has recently been found unexpectedly to induce the release of a pro-inflammatory mediator in resting macrophages. In this study, we found that topical applications of UA to mouse skin twice a week for 2 weeks significantly enhanced mRNA expression of cyclooxygenase (COX)-1, COX-2, and tumor necrosis factor-alpha, whereas its effect on tumor promotion was unclear.