Callophycoic Acids and Callophycols from the Fijian Red Alga Callophycus serratus

Abstract
Callophycoic acids A−H (1−8) and callophycols A and B (9 and 10) were isolated from extracts of the Fijian red alga Callophycus serratus, and identified by NMR, X-ray, and mass spectral analyses. These natural products represent four novel carbon skeletons, providing the first examples of diterpene−benzoic acids and diterpene−phenols in macroalgae. Compounds 1−10 exhibited antibacterial, antimalarial, and anticancer activity, although they are less bioactive than diterpene-benzoate macrolides previously isolated from this red alga.