Bromophycolides C−I from the Fijian Red Alga Callophycus serratus

Abstract
Bromophycolides C−I (1−7) were isolated from extracts of the Fijian red alga Callophycus serratus and identified by NMR and mass spectral techniques. These novel natural products share a carbon skeleton and biosynthetic origin with previously identified bromophycolides A (8) and B (9), which form a rare group of diterpene−benzoate macrolides. Bromophycolides C−I (1−7) displayed modest antineoplastic activity against a range of human tumor cell lines.