Cyclotheonellazoles A-C, Potent Protease Inhibitors from the Marine Sponge Theonella aff. swinhoei

Michal Issac, Maurice Aknin, Anne Gauvin-Bialecki, Nicole De Voogd, Alisson Ledoux, Michel Frederich, Yoel Kashman, Shmuel Carmeli

Research output: Contribution to journalArticlepeer-review


The extract of a sample of the sponge Theonella aff. swinhoei collected in Madagascar exhibited promising in vitro antiplasmodial activity. The antiplasmodial activity was ascribed in part to the known metabolite swinholide A. Further investigation of the extract afforded three unusual cyclic peptides, cyclotheonellazoles A-C (1-3), which contain six nonproteinogenic amino acids out of the eight acid units that compose these natural products. Among these acids the most novel were 4-propenoyl-2-tyrosylthiazole and 3-amino-4-methyl-2-oxohexanoic acid. The structure of the compounds was elucidated by interpretation of the 1D and 2D NMR data, HRESIMS, and advanced Merfay’s techniques. The new compounds were found to be nanomolar inhibitors of chymotrypsin and sub-nanomolar inhibitors of elastase, but did not present antiplasmodial activity.

Original languageEnglish
Pages (from-to)1110-1116
Number of pages7
JournalJournal of Natural Products
Issue number4
StatePublished - 28 Apr 2017


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