Hemiasterella minor

Talpir, R. Benayahu, Y. Kashman, Y. Panell, L. Schleyer, M. (1994) Hemiasterlin and geodiamolide TA two new cytotoxic peptides from the marine sponge Hemiasterella minor. Tetrahedron Lett. 35,4453-6. 

Talpir R, Benayahu Y, Kashman Y, Panned L, Schleyer M (1994) Hemiasterlin and Geodiamolide TA Two New Cytotoxic Peptides from the Marine Sponge Hemiasterella minor (Kirkpatrick). Tetrahedron Lett 35 4453... 

An intriguing cytotoxic and highly methylated tripeptide, milnamide A (57), was recently isolated by Crews and coworkers from the orange sponge Auletta cf. constricta, collected in Papua New Guinea (55). Cytotoxicity observed in the crude extract was partitioned into a dichloromethane layer which was further purified to yield milnamide A and an unrelated cyclic peptide. The structure is based on spectroscopic data, especially 2D NMR techniques the stereochemistry has not been established. A related tripeptide from the South African sponge Hemiasterella minor (also reported without stereochemistry) lacks only the C(l) methylene, and thus the p-carboline ring system (56). 

Hemiasterlin (147), originally isolated from the South African Hemiasterella minor followed by the isolation from the Papua New Guinean Cymhastela sp., is a potent cytotoxic compound that inhibits tublin assembly. HTI-286 (148) was the most promising synthetic analog and was submitted to the phase II clinical trial by Wyeth. Further development by Wyeth was discontinued in 2005, but Esai s phase I clinical trial is still... 

The species Hemiasterella minor contains hemiasterlin, a cytotoxic linear tripeptide containing only unconventional amino adds, and a depsipeptide, geodiamolide TA, which contains a molecule of N-methyl-monoiodotyrosine (Talpir et al, 1994 Bai et al, 1999). 

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