Secondary metabolome and its defensive role in the aeolidoidean , (Gastropoda, Heterobranchia, Nudibranchia).

is the largest aeolidoidean species known to date, and extremely rich in terpenoid chemistry. Herein we report the isolation of a total of 19 secondary metabolites from a single specimen of this species, i.e., steroids , cembranoid diterpenes , complex biscembranoids and , and the chatancin-type diterpenes . These compounds resemble those from soft corals of the genus , of which to date, however, only is described as a food source for . Fish feeding deterrent activity was determined using the tropical puffer fish , and showed activity for (2)-isosarcophytoxide (), cembranoid bisepoxide and 4-oxochatancin (). Determining the metabolome of and its bioactivity, makes it evident that this seemingly vulnerable soft bodied animal is well protected from fish by its chemical arsenal.