Antimalarial, Antiviral, and Antitoxoplasmosis Norsesterterpene Peroxide Acids from the Red Sea Sponge <i>Diacarnus erythraeanus</i>

Abstract

A new norsesterterpene acid, named muqubilone (1), along with the known sigmosceptrellin-B and muqubilin were isolated from the Red Sea sponge Diacarnus erythraeanus. The structure determination of 1 was based primarily on 1D and 2D NMR analyses. Sigmosceptrellin-B exhibits significant in vitro antimalarial activity against Plasmodium falciparum (D6 and W2 clones) with IC(50) values of 1200 and 3400 ng/mL, respectively. Muqubilin and 1 show in vitro antiviral activity against herpes simplex type 1 (HSV-1) with ED(50) values of 7.5 and 30 microg/mL, respectively. Muqubilin and sigmosceptrellin-B display potent in vitro activity against Toxoplasma gondii at a concentration of 0.1 microM without significant toxicity.