New cyclic peptides with cytotoxic activity from the ascidian Lissoclinum patella

Abstract

The isolation and structures of a new patellamide (patellamide D) and two new lissoclinamides (lissoclinamides 4 and 5) from the aplousobranch ascidian Lissoclinum patella are described. Structures were determined largely by using two-dimensional NMR techniques and mass spectrometry. These peptides and other members of the patellamide and lissoclinamide families that have been reported previously are found within the obligate algal symbiont of the genus Prochloron. The cytotoxicities of the compounds toward fibroblast and tumor cell lines are reported. One of these compounds, lissoclinamide 4, is markedly more toxic than other members of the family. Structure-activity relationships are discussed.

Cyclic peptide marine metabolites and CuII

“…[22][23][24] Oxazoline-, thiazole-, and thiazoline-based cyclic pseudo-hepta-and pseudo-octapeptides, e.g. lissoclinamides, [25][26][27][28][29] patellamides, [30][31][32] and ascidiacyclamide 33,34 can be extracted from L. patella; L. bistratum on the other hand provides oxazoline-based cyclic pseudo-hexapeptides such as westiellamide 35,36 and bistratamide A-H (Scheme 1). 17,[37][38][39][40] In the cyclic peptides, heterocyclic moieties alternate with D-and L-amino acid residues in the peptide sequence.…”

Mass spectrometry of cyclic peptides

“…and patellamide D on the basis of two-dimensional NMR and molecular weights assessed by FABMS and EIMS combined with accurate mass measurements (174). They also characterized bistratamide A and B using the same method described in the further paper …”

Microbial diversity of biofilm communities in microniches associated with the didemnid ascidian Lissoclinum patella

“…The role and importance of ascidian-associated microbes versus the host as a source of such secondary metabolites remains largely unexplored. For example, Schmidt et al (2005) reported the production of bioactive cyclic peptides, patellamides, in the symbiotic prochlorophytic cyanobacterium Prochloron spp., which is found in large quantities within the cloacal cavity of the didemnid ascidian Lissoclinum patella (Schmidt et al, 2005), whereas others have reported patellamide production in L. patella itself (Degnan et al, 1989;Sings and Rinehart, 1996;Salomon and Faulkner, 2002). Another unique cyanobacterium, Acaryochloris marina, grows in biofilms on the underside of didemnid ascidians, where it uses chlorophyll (Chl) d to sustain its photosynthesis using near-infrared radiation (NIR; Kü hl et al, 2005).…”