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.