Antiproliferative sesterterpenes from the Caribbean sponge Cacospongia cf. linteiformis

Two new sesterterpenes, lintenolides F (6 a, b) and G (7 a, b), were isolated from the Caribbean sponge Cacospongia cf. linteiformis. Their stereostructures were determined using spectroscopic and chemical methods. The new compounds (6 a, b and 7 a, b) and the related compounds lintenolides A-E (1 a, b-5 a, b), previously isolated from the sponge, exhibited antiproliferative activity on four cell lines.