• Title/Summary/Keyword: Marfey analysis

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Cytotoxic Polyketides from the Marine Sponge Discodermia calyx

  • Shinde, Pramod B.;Mansoor, Tayyab A.;Luo, Xuan;Hong, Jong-Ki;Lee, Chong-O.;Jung, Jee-H.
    • Bulletin of the Korean Chemical Society
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    • v.28 no.6
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    • pp.990-994
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    • 2007
  • Bioassay-guided fractionation of the MeOH extract from the sponge Discodermia calyx collected off the coast of Jeju Island, South Korea, led to the isolation of a polyketide, icadamide C (1), along with previously reported theopederin K (3). Structure elucidation was performed by a combination of high resolution mass and 2D-NMR (principally COSY, HMBC, HSQC, and NOESY) spectroscopy. Stereochemistry of compound 1 was determined as 2R*, 3R*, 6R*, 10S*, 11S*, 12R*, 13S*, 15R* and 2'S by NMR data and Marfey analysis. Isolated metabolites displayed potent cytotoxic activity against a small panel of five human solid tumor cell lines with ED50 values of less than 0.1 μg/mL.

Gamakamide-E, a Strongly Bitter Tasting Cyclic Peptide with a Hydantoin Structure from Cultured Oysters Crassostrea gigas

  • Lee, Jong-Soo;Satake, Masayuki;Horigome, Yoichi;Oshima, Yasukatsu;Yasumoto, Takeshi
    • Fisheries and Aquatic Sciences
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    • v.15 no.1
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    • pp.15-19
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    • 2012
  • A new cyclic peptide (six-membered amino acid), gamakamide-E (L-Leu-L-Met (SO)-L-Me-Phe-L-Leu-D-Lys-L-Phe), was isolated as a strongly bitter tasting compound from cultured oysters, Crassostrea gigas. The molecular formula of $C_{43}H_{61}N_7O_8S$ was deduced from high resolution fast atom bombardment mass spectrometry (HR FAB-MS) ($[M+H]^+$ m/z 836.4356 ${\Delta}$= -2.4 mmu). Its unique structure including a hydantoin structure was firstly elucidated by nuclear magnetic resonance (NMR) analysis. Stereochemistries of constituent amino acids were determined by chiral high performanced liquid chromatography analysis of natural and synthesized peptides.