Koshikamide B, a cytotoxic peptide lactone from a marine sponge Theonella sp

Takahiro Araki, Shigeki Matsunaga*, Yoichi Nakao, Kazuo Furihata, Lyndon West, D. John Faulkner, Nobuhiro Fusetani

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


(Chemical Equation Presented) Koshikamide B (1) has been isolated from two separate collections of the marine sponge Theonella sp. as the major cytotoxic constituent. Koshikamide B is a 17-residue peptide lactone composed of six proteinogenic amino acids, two D-isomers of proteinogenic amino acids, seven N-methylated amino acids, and two unusual amino acid residues. The unusual amino acids are Nδ-carbamoylasparagine and 2-(3-amino-2-hydroxy-5- oxopyrrolidin-2-yl)propionic acid (AHPP); the former is first found as the constituent of peptides, whereas the latter is a new amino acid residue. The N-terminus of koshikamide B is blocked by a methoxyacetyl group. The structure of koshikamide B (1) has been determined by interpretation of spectral data and analysis of chemical degradation products. Koshikamide B (1) exhibits cytotoxicity against P388 murine leukemia cells and the human colon tumor (HCT-116) cell line with an IC50 value of 0.45 and 7.5 μg/mL, respectively.

Original languageEnglish
Pages (from-to)7889-7894
Number of pages6
JournalJournal of Organic Chemistry
Issue number20
Publication statusPublished - 2008 Oct 17

ASJC Scopus subject areas

  • Organic Chemistry


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