New cytotoxic isomalabaricane triterpenes have been isolated from a sponge Stelletta sp. (1-7); anti-HIV pterocarpans (8 and 9) and isoflavanoids (12-16 and 18) were elucidated from two tropical plants in the genus Erythrina; and anti-HIV enniatins (20 and 22-23) were characterized from fungi in the genera Fusarium and Alternaria. The enniatins were evaluated for in vivo anti-HIV activity in the hollow fiber assay.