Chemical studies of porostome nudibranchs: comparative and ecological aspects

Three porostome nudibranchs, Dendrodoris krebsii from Mexico, Doriopsilla albopunctata from California and Doriopsilla areolata from Portugal, have been chemically investigated. The presence of sesquiterpenes of the drimane class in these molluscs has been confirmed. In addition, these species have shown to contain sesquiterpenes of ent-pallescensin-A (or pallescensin-A) series, co-occurring with drimane metabolites. Most of these sesquiterpenes are typical sponge metabolites, suggesting a dietary origin in the molluscs, even though de novo biosynthesis, rigorously demonstrated for some Dendrodoris molluscs, may occur.