Bioactive Bromophycolides R−U from the Fijian Red Alga <i>Callophycus serratus</i>

Four new bromophycolides, R−U (<b>1</b>−<b>4</b>), were isolated from the Fijian red alga <i>Callophycus serratus</i> and were identified by 1D and 2D NMR and mass spectroscopic analyses. These compounds expand the known structural variety of diterpene-benzoate macrolides and exhibited modest cytotoxicity toward selected human cancer cell lines. Bromophycolide S (<b>2</b>) also showed submicromolar activity against the human malaria parasite <i>Plasmodium falciparum</i>.