Chemical studies of porostome nudibranchs: comparative and ecological aspects

Abstract

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 no6o biosynthesis, rigorously demonstrated for some Dendrodoris molluscs, may occur.

Terpenoids in Marine Heterobranch Molluscs

“…D. arborescens possess the known sesquiterpene 7-deacetoxy-olepupuane (22) ( Figure 4) [111], while D. carbunculosa presents several cytotoxic drimane sesquiterpenes, the dendrocarbins A-N [112]. Moreover, D. krebsi from Mexico also possess drimane sesquiterpenes and esters [113], allocated in the body in a way similar to that previously described for other Dendrodoris species [114]. D. denisoni from New Zealand presents cinnamolide, olepupuane, and polygodial in its mantle [78].…”

“…Two more diastereomeric acetates of pelseneeriol-1 and -2 ( Figure 4) were further described in that study. Moreover, both D. albopunctata from the Pacific and D. areolata from the Atlantic also contain drimane sesquiterpenes and ent-pallescensin A [113], located in their bodies in a way similar to the Dendrodoris species [114]. Doriopsilla pharpa contains polygodial, and their extracts are deterrent to two fish, the blenny Chasmodes bosquianus, and the mummichog Fundulus heteroclitus, which learned to avoid food items that contained extracts from D. pharpa [120], while extracts of the slug were also rejected by the crabs Callinectes similus and Panopeus herbstii in the field.…”

Biosynthesis in opisthobranch molluscs: General outline in the light of recent use of stable isotopes

“…Almost 20 years ago, feeding experiments with Mediterranean Dendrodoris (1) proved, for the first time, the ability of opisthobranchs to construct de novo their own defensive allomones (Cimino et al, 1983). Successively, several studies (Cimino et al, 1980(Cimino et al, , 1981(Cimino et al, , 1982(Cimino et al, , 1985aOkuda et al, 1983;Fontana et al, 1999;Gavagnin et al, 2001a;Sakio et al, 2001) led to clarify that drimane sesquiterpenoids are a chemical marker present in all Dendrodoris species. Figure 17 summarizes the biosynthetic pathway based upon the results obtained injecting [2-14 C]-mevalonate into Mediterranean D. limbata and D. grandiflora and Pacific D. arborescens .…”

The chemistry and chemical ecology of nudibranchs

“…212 Other studies have reported drimane sesquiterpenes from Dendrodoris carbunculosa, 214 D. nigra, D. tuberculosa and D. krebsii. 215,216 The anatomical distribution and role that such terpenes may play has been investigated in Mediterranean Dendrodoris nudibranchs. 217 The presence of sequestered sponge metabolites might indicate a dual defence for Dendrodoris species but they were completely absent from the mantle, where one would expect to nd defence allomones.…”

“…61 Cinnamolide (58) has previously only been obtained from terrestrial plants. 220 Studies of species of the related Doriopsilla genus including D. albopunctata 215,216 D. janaina, 215 D. pelseneeri 221 and D. areolata 211,[222][223][224] indicated that they also contained drimane sesquiterpenoids, as well as enantiomerically related sesquiterpenoids of the ent-pallescensin A skeleton. [221][222][223][224] Biosynthetic investigations of D. areolata 222,223 and D. pelseneeri 225 indicated that they produce both drimane sesquiterpenoids and sesquiterpenoids with the ent-pallescensin A skeleton de novo and their presence in the mantle of D. areolata indicated that they too were involved in the chemical defence of the nudibranch.…”