Clavelina lepadiformis

Kubanek, J., Williams, D. E., de Silva, E. D., Allen, T., and Andersen, R. J., Cytotoxic alkaloids from the flatworm Prostheceraeus villatus and its tunicate prey Clavelina lepadiformis, Tetrahedron Lett., 36, 6189, 1995. 

On the other hand, Steffan isolated lepadin B from the tunicate Clavelina lepadiformis, and, four years later, Andersen and co-workers isolated lepadin B, and C along with lepadin A from the same tunicate. Professor Andersen also reported lepadin A and B showed significant cytotoxic activity toward a variety of murine and human cancer cell lines. The absolute stereochemistry of these alkaloids was also unknown. 

Lepadins constitute a class of recently discovered antimalarial marine alkaloids. These molecules are decahydroquinoline derivatives bearing a linear eight-carbon chain isolated from two marine invertebrates of Australian origin, Clavelina lepadiformis [49] and Didemnum sp. [50]. 

Biard JF, Guyot S, Roussakis C, Verbist JE, Vercauteren J, Weber JF, Boukef K (1994) Lepadiformine, a New Marine Cytotoxic Alkaloid from Clavelina lepadiformis Miiller. Tetrahedron Lett 35 2691... 

A total synthesis of (it)-lepadiformine A, isolated from the tunicate Clavelina lepadiformis, was accomplished by... 

Curiously, the conformation of ds-decalin in lepadin A is the same as that of pumiliotoxin C, extracted from toads of the family Dendrobatidae, especially Den-drobates pumilio (Daly et al, 1969). Subsequently, lepadins B-H were isolated from the same species, Clavelina lepadiformis, harvested in Norway and from its predator, the platyhelminth Prostheceraeus villatus, from the species Aplidium tabascum and an undetermined species of the genus Didemnum, both collected in Australia on the Great Barrier Reef The ds-decalin nuclei of lepadins exist with two different conformations depending on whether the NH bond is located in an axial or equatorial position... 

These alkaloids belong to the group of cylindricdnes because most of them were isolated from the species Clavelina cylindrica harvested in Tasmania (Blackman et al., 1993 Li and Blackman, 1994, 1995). Three other alkaloids related to cylindridnes, lepadiformines A-C, " have been isolated from Clavelina lepadiformis and Clavelina moluccensis harvested in Tunisia and Djibouti (Biard et al., 1994c Juge et al., 2001 Sauviat et al, 2006). 

Biard, J.-F., Guyot, S., Roussakis, C., Verbist, J.-F., Vercauteren, J., Weber, J.F., and Boukef, K. (1994c) Lepadiformine, a new marine cytotoxic alkaloid from Clavelina lepadiformis Muller. Tetrahedron Lett., 35, 2691-2694. 

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