Isolation and biological evaluation of filiformin, plakortide F, and plakortone G from the Caribbean sponge Plakortis sp.

The bioassay- and spectroscopic-guided fractionation of the antimalarial ex tract from a Jamaican sponge, Plakortis sp., resulted in the isolation of t hree metabolites. The previously reported bromoaromatic filiformin (1) was obtained from our sample of Plakortis sp., and the potential origins of thi s compound are discussed, The peroxide-containing metabolite, plakortide F (2), is a more typical Plakortis metabolite and was shown to exhibit signif icant activity against Plasmodium falciparum in vitro. The isolation, struc ture, and bioactivity of a new lactone, plakortone G (3), are also reported .