Abstract
Two new resorcinols, 1-(5-acetyl-2,4-dihydroxyphenyl)-3-methylbutan-1-one (1) and 1-(5-acetyl-2-hydroxy-4-methoxyphenyl)-3-methylbutan-1-one (2), have been isolated from the brown algae Sargassum thunbergii (Mert.) O'Kuntze. Their structures were elucidated on the basis of spectroscopic methods.