Repair of UVB-Damaged Skin by the Antioxidant Sulphated Flavone Glycoside Thalassiolin B Isolated from the Marine Plant Thalassia testudinum Banks ex König

Daily topical application of the aqueous ethanolic extract of the marine sea grass, Thalassia testudinum, on mice skin exposed to UVB radiation resulted in a dose-dependent recovery of the skin macroscopic alterations over a 6-day period. Maximal effect (90%) occurred at a dose of 240 μg/cm2, with no additional effects at higher doses. Bioassay-guided fractionation of the plant extract resulted in the isolation of thalassiolin B (1). Topical application of 1 (240 μg/cm2) markedly reduces skin UVB-induced damage. In addition, thalassiolin B scavenged 2,2-diphenyl-2-picrylhydrazyl radical with an EC50 = 100 μg/ml. These results suggest that thalassiolin B is responsible for the skin-regenerating effects of the crude extract of T. testudinum.