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Nazumazoles D–F, Cyclic Pentapeptides That Inhibit Chymotrypsin, from the Marine Sponge Theonella swinhoei

Author:
Fukuhara, Kazuya, Takada, Kentaro, Okada, Shigeru, Matsunaga, Shigeki
Source:
Journal of natural products 2016 v.79 no.6 pp. 1694-1697
ISSN:
1520-6025
Subject:
Porifera, amino acids, chymotrypsin, cytotoxicity, gels, nuclear magnetic resonance spectroscopy, oxidation, reversed-phase high performance liquid chromatography
Abstract:
Nazumazoles D–F (1–3) were isolated from the marine sponge Theonella swinhoei. The compounds gave extremely broad peaks by reversed-phase HPLC using an ODS column. HPLC using a gel permeation column was instrumental for the separation of the three compounds. Their planar structures were determined by interpretation of NMR data to be cyclic pentapeptides. Nazumazoles D–F contained one residue each of α-keto-l-norvaline (l-Knv) {or α-keto-d-leucine (l-Kle)}, l-alanyloxazole (l-Aox), d-Abu (or d-Ser), N-α-CHO-β-l-Dpr, and cis-4-methyl-l-proline. The absolute configuration of each amino acid residue was determined by Marfey’s method in combination with conversion of the α-keto-β-amino acid to the α-amino acid by oxidation. Nazumazoles D–F are not cytotoxic against P388 cells at 50 μM, but inhibit chymotrypsin.
Agid:
5498557