Effects of various flavonoids isolated from Scutellaria baicalensis roots on skin damage in acute UVB-irradiated hairless mice

Abstract

Objectives Solar ultraviolet (UV) radiation causes skin damage including increasing skin thickness, edema and flush. Scutellaria baicalensis roots have been traditionally used as a remedy for allergic inflammatory diseases in China and Japan. In this study, we examined the effects of four flavonoids isolated from these roots, namely 2′,5, 5′,7-tetrahydroxy-6′,8- dimethoxyflavone (1), skullcapflavone II (2), 2(S)-2′,5,6′,7- tetrahydroxyflavanone (3) and 2(R), 3(R)-2′,3,5,6′,7- pentahydroxyflavanone (4), on acute UVB irradiation-induced skin damage in hairless mice. Methods The four flavonoids were orally administered twice daily, at doses of 10 and 50 mg/kg, for 14 consecutive days. The UVB irradiation was performed at a dose of 200 mJ cm-2 on days 7 and 8 after beginning oral administration of the four flavonoids. Key findings Compounds 1 and 4 prevented increases in skin thickness, levels of matrix metalloproteinases (MMP)-2 and MMP-9, and vascular endothelial growth factor (VEGF) induced by UVB irradiation. The other two flavonoids 2 and 3 had no effect. Conclusions Compounds 1 and 4 isolated from Scutellaria baicalensis roots may be useful for preventing skin inflammation induced by acute UVB irradiation. © 2011 The Authors.