38 下甑島産Theonella属海綿に含まれる細胞毒性物質Koshikamide Bの単離と構造決定(口頭発表の部)

概要

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The EtOH extract of a marine sponge of the genus Theonella collected off Shimokoshiki-jima Island was subjected to solvent partitioning, ODS flash chromatography, and gel-filtration followed by ODS HPLC to afford koshikamide B (1). The planar structure of 1 was elucidated by interpretation of 2D NMR data to be composed of fifteen common and two novel amino acid residues. Assignment of the pyrrolidone moiety was accomplished by interpretation of the COSY, HMBC, and ^<15>N HMQC spectra, while the structure of N^ω-carbamoyl Asn was determined by NMR data together with comparing the NMR data with a model compound. The sequence of the amino acid residues was unambiguously determined by interpretation of HMBC data. The absolute stereochemistries of amino acid residues in 1 were determined by Marfey and GC methods. Ala and N-MeaIle were shown to be 1:1 mixture of D- and L-forms. Their positions in the peptide were determined by analysis of two fragments obtained by partial acid hydrolysis. The absolute stereochemistry of the pyrrolidone moiety was established by chemical degradation and NMR data. Koshikamide B (1) exhibited cytotoxicity against P388 murine leukemia cells with an IC_<50> value of 0.45μg/mL.
天然有機化合物討論会の論文
2002-09-01