Many sessile suspension-feeding marine organisms rely on chemical defense to keep their surfaces free from fouling organisms. The brominated cyclopeptides barettin (cyclo[(6-bromo-8-entryptophan)arginine]) ( 1) and 8,9-dihydrobarettin (cyclo[(6-bromotryptophan)arginine]) ( 2) from the cold-water sponge Geodia barretti have previously displayed settlement inhibition of barnacle larvae in a dose-dependent manner. In this paper, we describe a novel dibrominated cyclopeptide, bromobenzisoxazolone barettin (cyclo[(6-bromo-8-(6-bromobenzioxazol-3(1 H)-one)-8-hydroxy)tryptophan)]arginine) ( 3), which we have isolated from G. barretti and which displays settlement inhibition of barnacle larvae ( Balanus improvisus) with an EC 50 value of 15 nM. The chemical structure was determined using MS and 2D-NMR.
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Mar Drugs
February 2014
Medicinal Chemistry Department, PharmaMar S.A., Avda. de los Reyes 1, Pol. In. La Mina, Colmenar Viejo, Madrid 28770, Spain.
Tanjungides A (1) (Z isomer) and B (2) (E isomer), two novel dibrominated indole enamides, have been isolated from the tunicate Diazona cf formosa. Their structures were determined by spectroscopic methods including HRMS, and extensive 1D and 2D NMR. The stereochemistry of the cyclised cystine present in both compounds was determined by Marfey's analysis after chemical degradation and hydrolysis.
View Article and Find Full Text PDFJ Nat Prod
March 2008
Department of Medicinal Chemistry, Uppsala University, Sweden.
Many sessile suspension-feeding marine organisms rely on chemical defense to keep their surfaces free from fouling organisms. The brominated cyclopeptides barettin (cyclo[(6-bromo-8-entryptophan)arginine]) ( 1) and 8,9-dihydrobarettin (cyclo[(6-bromotryptophan)arginine]) ( 2) from the cold-water sponge Geodia barretti have previously displayed settlement inhibition of barnacle larvae in a dose-dependent manner. In this paper, we describe a novel dibrominated cyclopeptide, bromobenzisoxazolone barettin (cyclo[(6-bromo-8-(6-bromobenzioxazol-3(1 H)-one)-8-hydroxy)tryptophan)]arginine) ( 3), which we have isolated from G.
View Article and Find Full Text PDFLett Appl Microbiol
July 2005
Pacific Institute of Bioorganic Chemistry of the Far-Eastern Branch of the Russian Academy of Sciences, Vladivostok, Russian Federation.
Aims: This study aims at evaluating the impact of the nutrient medium components on the in vitro production of the cytotoxic alterochromides.
Methods And Results: The employment matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) facilitated the identification of a range of brominated cyclic depsipeptides with molecular masses of 843/845, 857/859 and 922/924/926 Da, and 936/938/940 Da produced by the marine bacterium Pseudoalteromonas maricaloris KMM 636T. The fractions of cytotoxic yellow pigments yielded after methanol extraction of P.
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