Eudistomins W and X, two new beta-carbolines from the micronesian tunicate Eudistoma sp (original) (raw)
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Eudistomins W and X, Two New β-Carbolines from the Micronesian Tunicate Eudistoma sp
Journal of Natural Products, 2003
Chemical investigation of the Micronesian ascidian Eudistoma sp. afforded two new eudistomin congeners, which were designated eudistomins W (1) and X (2). The structures of the new compounds were unambiguously established on the basis of NMR spectroscopic ( 1 H, 13 C, COSY, 1 H detected direct, and long-range 13 C-1 H correlations) and mass spectrometric (EI and ESIMS) data. Compound 2 exhibited antibiotic activity toward Bacillus subtilis, Staphyloccocus aureus, and Escherichia coli and was also found to be fungicidal against Candida albicans in an agar diffusion assay. Compound 1 was selectively active against C. albicans but showed no antibacterial activity.
BROMINATED ß-CARBOLINES FROM THE MARINE TUNICATE EUDISTOMA ALBUM
chemical investigation of the cytotoxic EtOH extract of the marine tunicate EzrdiJtoma album led to the isolation of three brominated ß-carbolines which were characterized by their spectral data. Two of them, eudistomin E, which is already known for its potent antiviral activity, and the novel compound eudista1bin.A [l], were shown to possess cytotoxic activity (ED,,<5.0 ng and 3.2 pg/ml respectively) in vitro against the growth of KB human buccal carinoma cells. The third compound, eudistalbin B [2}, is a new inactive natural product.
Bioprospection of cytotoxic compounds in the Brazilian endemic tunicate Eudistoma vannamei
Planta Medica, 2008
Previous studies demonstrated that the crude extract of the ascidian Eudistoma vannamei, endemic from northeasttern Brazil, strongly hinders growth of tumor cells in vitro by inducing apoptosis due to tryptophan derivatives, which are commonly found in bacteria. This study presents a bioactivity-guided screening among actinomycetes, associated with E. vannamei, aiming at recognizing active principles with biological relevance. Twenty strains of actinomycetes, designated as EVA 0101 through 0120, were isolated from colonies of E. vannamei among which 11 were selected for cytotoxicity evaluation. The extracts from EVA 0102, 0103, 0106, 0109 and 0113 were the most active, and were further studied for IC 50 determination and chemical analysis by 1 H NMR. IC 50 values obtained ranged from 3.62 µg mL-1 (for EVA 0109 in leukemia cells) to 84.65 µg/mL (for EVA 0106 in melanoma cells). All active extracts exhibited the same TLC and spectroscopic profiles, suggesting the presence of quinones and other related secondary metabolites. Furthermore, these strains were identified and compared based on their respective 16S rRNA sequences. The results herein identified the five strains as Micromonospora spp. while phylogenetic analysis suggests that they are possibly two different Micromonospora species producing the cytotoxic compounds.
Antimicrobial Agents and Chemotherapy, 2004
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In our search for bioactive metabolites from marine organisms, we have investigated the polar fraction of the organic extract of the Red Sea sponge Theonella swinhoei. Successive chromatographic separations and final HPLC purification of the potent antifungal fraction afforded a new bicyclic glycopeptide, theonellamide G (1). The structure of the peptide was determined using extensive 1D and 2D NMR and high-resolution mass spectral determinations. The absolute configuration of theonellamide G was determined by chemical degradation and 2D NMR spectroscopy. Theonellamide G showed potent antifungal activity towards wild and amphotericin B-resistant strains of