Nakijiquinone S and Nakijinol C, New Meroterpenoids from a Marine Sponge of the Family Spongiidae

New meroterpenoids, nakijiquinone S (1) and nakijinol C (2), have been isolated from an Okinawan marine sponge of the family Spongiidae. The gross structures and relative stereochemistries of 1 and 2 were elucidated on the basis of their spectral data. Nakijiquinone S (1) and nakijinol C (2) were new meroterpenoids consisting of a clerodane-type decalin ring connected to a 2-butoxy-5-hydroxy-benzoquinone unit or methyl 2,3,4-trihydroxybenzoate unit through a methylene, respectively. Nakijiquinone S (1) and nakijinol C (2) showed antimicrobial activities against several bacteria and fungi.