Disclosed herein are pseudopterosin compounds obtained from Symbiodinium spp. symbionts. Also disclosed are methods of obtaining, isolating, purifying or preparing at least one pseudopterosin compound comprising obtaining, isolating, purifying or preparing the pseudopterosin compound from at least one Symbiodinium spp. symbiont. In preferred embodiments, the host is Pseudopterogorgia, preferably, P. elisabethae. As disclosed, preferred pseudopterosin compounds and pseudopterosin compositions are of non-animal origin, substantially free of animal impurities, or both. Treatment methods using the pseudopterosin compounds and compositions are also disclosed.