Karatungiols A and B, two novel antimicrobial polyol compounds, from the symbiotic marine dinoflagellate Amphidinium sp.

Karatungiols A (1) and B (2), two novel antimicrobial polyol compounds, were isolated from the cultivated symbiotic marine dinoflagellate Amphidinium sp. Their structures were elucidated based on spectroscopic analysis and degradation reactions. Karatungiols A (1) and B (2) consisted of a C69-linear chain with a ketone moiety, 24 or 25 hydroxyl groups, and two tetrahydropyran rings. Karatungiol A (1) exhibited antifungal activity against Aspergillus niger at 12 μg/disc and antiprotozoan activity against Trichomonas foetus at 1 μg/ml.     

Amphirionin-5, a novel linear polyketide from a cultured marine dinoflagellate Amphidinium species with a potent cell proliferation-promoting activity

A novel linear polyketide, amphirionin-5 (1), has been isolated from the cultivated algal cells of the benthic dinoflagellate Amphidinium sp. (strain KCA09053), and the structure was elucidated on the basis of detailed analyses of 1D and 2D NMR data. Amphirionin-5 (1) resulted in a 282% increase in the proliferation of murine bone-marrow derived stromal ST-2 cells and 320% increase in the proliferation of murine osteoblastic MC3T3-E1 cells.     

Iriomoteolide-13a,a cytotoxic 22-membered macrolide from a marine dinoflagellate Amphidinium species

Iriomoteolide-13a (1) has been isolated from a benthic dinoflagellate Amphidinium sp. (strain KCA09053) as a new 22-membered macrolide containing one hexahydrofuro[3,2-b]furan ring, one tetrahydropyran ring, two tetrahydrofuran rings, three one-carbon branches, and three hydroxyl groups including two hemiketals. The structure of 1 was assigned on the basis of a detailed 2D NMR analysis. Compound 1 exhibited cytotoxic activity against human cervix adenocarcinoma HeLa cells (IC₅₀: 0.5 μg/mL).     

Zooxanthellamide A, a novel polyhydroxy metabolite from a marine dinoflagellate of Symbiodinium sp.

A novel polyhydroxy metabolite named Zooxanthellamide A, C₁₂₈H₂₂₂N₂O₅₄S₂, was isolated from a cultured marine dinoflagellate, Symbiodinium sp., and the chemical structure was determined by spectroscopic methods.     

Prorocentin-4, a novel linear polyketide from a marine dinoflagellate Prorocentrum sp.

Prorocentin-4, isolated from a cultured marine dinoflagellate Prorocentrum sp. was possessed of two tetrahydrofuran rings, conjugated dienes, four branched methyl groups, and a ketone moiety. The gross structure was elucidated by spectroscopic studies and the relative stereostructure was determined on the basis of spectral data.     

Lyngbyacyclamides A and B, novel cytotoxic peptides from marine cyanobacteria Lyngbya sp.

Lyngbyacyclamides A (1) and B (2), novel cyclic peptides, were isolated from marine cyanobacteria Lyngbya sp. collected in Okinawa, Japan. Their structures were determined by spectroscopic analyses and degradation studies. They moderately inhibited the growth of B16 mouse melanoma cells.     

Untenolide A, a new polyketide from an Okinawan marine sponge Plakortis sp.

A new polyketide, untenolide A (1), has been isolated from an Okinawan marine sponge Plakortis species, and the structure was elucidated from spectroscopic data and X-ray analysis. Untenolide A (1) is a new polyketide possessing a fused-pentacyclic skeleton with two hexadecanyl chains.     

Total synthesis of trunkamide A, a novel thiazoline-based prenylated cyclopeptide metabolite from Lissoclinum sp.

Full details of a total synthesis of the doubly prenylated cyclic peptide trunkamide A of marine origin, and also its C45 epimer, are described.     

Symbiodinolactone A,a new 12-membered macrolide from symbiotic marine dinoflagellate Symbiodinium sp.

A new 12-membered macrolide, symbiodinolactone A, was isolated from the culture broth of symbiotic marine dinoflagellate Symbiodinium sp. The gross structure of symbiodinolactone A was elucidated by spectroscopic analyses, and the relative configuration was elucidated by the J-based configuration analysis and density-functional theory calculations. Symbiodinolactone A is the new 12-membered macrolide possessing an E double bond between C-4 and C-5, a branched methyl group at C-7, and a 1,2,3-trihydroxybutyl group at C-11. Symbiodinolactone A is the first usual size macrolide and the first non-nitrogen-containing macrolide from dinoflagellate Symbiodinium sp. Symbiodinolactone A might be generated by the unexplained dinoflagellate polyketide biosynthetic machinery.     

Trisorbicillinone A, a novel sorbicillin trimer, from a deep sea fungus, Phialocephala sp. FL30r

A novel sorbicillin trimer, trisorbicillinone A (1), was isolated from a deep sea fungus, Phialocephala sp. FL30r. The structure and relative stereochemistry of 1 were determined based on spectroscopic methods. Trisorbicillinone A (1) showed cytotoxicity against P388 and HL60 cells with the IC₅₀ value of 9.10 and 3.14 μM, respectively.     

Plakoridine C, a novel piperidine alkaloid from an Okinawan marine sponge Plakortis sp.

A new piperidine alkaloid plakoridine C (1) has been isolated from an Okinawan marine sponge Plakortis species, and the structure was elucidated from spectroscopic data. Plakoridine C (1) is a new alkaloid possessing a piperidine ring connected to a β-keto-γ-lactone through a double bond.     

Kendarimide A, a novel peptide reversing P-glycoprotein-mediated multidrug resistance in tumor cells, from a marine sponge of Haliclona sp.

A novel modulator of multidrug resistance (MDR) in tumor cells, kendarimide A (1), was isolated from an Indonesian marine sponge of Haliclona sp. Compound 1 reversed MDR in KB-C2 cells mediated by P-glycoprotein (P-gp) at a 6 μM concentration, and the chemical structure of 1 was characterized to be a linear peptide composed of N-methylpyroglutamic acid (pyroMeGlu), N-methylated eight-membered cysteinyl-cysteine (ox-[MeCys-MeCys]) together with many N-methyl amino acid residues. The amino acid sequence of 1 was determined by 2D NMR and FAB MS analysis. The absolute configuration of the amino acid residues in 1 except for the MeCys part was determined to be l-form respectively, based on interpretation of the HPLC analysis of Marfey's derivatives of the hydrolysates of 1 and the synthetic method for the pyroMeGlu residue.     

Sinularianins A and B, novel sesquiterpenoids from the Formosan soft coral Sinularia sp.

Two novel sesquiterpenoids, sinularianins A and B (1 and 2), have been isolated from the Formosan coral Sinularia sp. The skeleton of sinularianins A (1), namely sinulariolane, was found to be unprecedented. Sinularianin B (2), with a novel spiro-butenolide moiety, possesses a valerenane skeleton, which had been reported mostly from the plant. The structures of both metabolites were established by extensive analysis of spectroscopic data.     

Bacillamide, a novel algicide from the marine bacterium, Bacillus sp. SY-1, against the harmful dinoflagellate, Cochlodinium polykrikoides

Bacillamide (1) was isolated as a new algicide against the harmful dinoflagellate, Cochlodinium polykrikoides, from the marine bacterium, Bacillus sp. SY-1, and its structure was elucidated by extensive two-dimensional NMR techniques including ¹H-¹⁵N HMBC analysis and mass analysis. Bacillamide showed algicidal activity against C. polykrikoides with LC₅₀ of 3.2 μg/ml.     

Bromine-containing alkaloids from the marine sponge Penares sp.

Two new unusual alkaloids were isolated from the sponge Penares sp., collected from Viet Nam waters (the South China Sea). The structures of these compounds were established by analysis of 1D, 2D NMR (¹H-¹H COSY, DEPT, HSQC, HMBC, H2BC, and NOE), and MS data. Compound 1 shows moderate cytotoxicity against the human tumor cells HL-60 and HeLa.     

Acremoxanthones A and B, novel antibiotic polyketides from the fungus Acremonium sp. BCC 31806

Acremoxanthones A and B, novel anthraquinone-xanthone heterodimers with a unique linkage pattern, together with two known compounds, acremonidins A and C, were isolated from the fungus Acremonium sp. BCC 31806. The structures of the acremoxanthones were determined by analysis of 2D NMR and mass spectrometric data. Acremoxanthones and acremonidins exhibited antibacterial, antifungal, antiplasmodial, and cytotoxic activities.     

Mycoediketopiperazine, a novel fungal metabolite from a Papularia sp.

A novel metabolite, mycoediketopiperazine, was isolated from a fungi culture (M-204036). Its structure and absolute stereochemistry was established by spectroscopic studies, including single-crystal X-ray diffraction analysis.     

Jaspolides G and H, unique bisisomalabaricanes from the Chinese marine sponge Jaspis sp.

Two unique bisisomalabaricanes jaspolides G (1) and H (2) were isolated from the marine sponge Jaspis sp. Their structures were elucidated on the basis of extensive spectroscopic data (IR, MS, and 1D and 2D NMR) analyses. A possible biogenetic pathway via Diels-Alder dimerization for jaspolides G and H was also proposed.     

Halichonadins A-D, new sesquiterpenoids from a sponge Halichondria sp.

A new dimeric sesquiterpenoid with two eudesmane skeletons through a urea linkage, halichonadin A (1), as well as three new eudesmane sesquiterpenoids having a carbamate, an isonitrile, or an amino functionality, halichonadins B (2), C (3), and D (4), respectively, have been isolated from a marine sponge Halichondria sp., and the gross structures and relative stereochemistry of 1-4 were elucidated on the basis of spectral data and chemical means.     

Chaetominedione, a new tyrosine kinase inhibitor isolated from the algicolous marine fungus Chaetomium sp.

A marine fungal isolate, identified as Chaetomium sp., was cultivated and found to produce a novel benzonaphthyridinedione derivative, chaetominedione (1). In addition to the known fungal metabolites, 2-furancarboxylic acid (2) and 5-(hydroxymethyl)-2-furancarboxylic acid (3) were obtained. The structures of all the compounds were determined based on extensive spectroscopic measurements (1D and 2D NMR, MS, UV, and IR). The total extract and compound 1 had significant inhibitory activity toward p56^lck tyrosine kinase (18.7% and 93.6% enzyme inhibition at 200 μg/mL, respectively).