Sage extract rich in phenolic diterpenes inhibits ultraviolet-induced erythema in vivo

Abstract

The leaves of sage (Salvia officinalis L., Lamiaceae) contain high amounts of phenolic diterpenes such as carnosol and carnosic acid. These compounds display antioxidant and anti-inflammatory effects in vitro. Here, we have investigated the anti-inflammatory potency of a sage extract (SE) rich in phenolic diterpenes in vivo using the ultraviolet (UV) erythema test. In a prospective randomised double-blind placebo-controlled study, test areas on the backs of 40 healthy volunteers were irradiated with the 1.5-fold minimal erythema dose. Subsequently, the test areas were treated occlusively with 2% SE in a hydrophilic ointment, compared to 1% hydrocortisone and 0.1% betamethasone as positive controls, and the vehicle alone as placebo. Erythema values were measured photometrically prior to irradiation and after 48 hours. Compared to placebo, SE significantly reduced the ultraviolet-induced erythema, to a similar extent as hydrocortisone. These data suggest that SE might be useful in the topical treatment of inflammatory skin diseases.