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ABSTRACT: A manzamine related alkaloid, zamamiphidin A (1), consisting of a new heptacyclic ring system has been isolated from an Okinawan marine sponge Amphimedon sp. The structure of 1 including the relative stereochemistry was elucidated on the basis of the spectroscopic data. Compound 1 showed antibacterial activity against Staphylococcus aureus (MIC, 32 μg/mL).
Organic Letters 01/2013; · 5.86 Impact Factor
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The Journal of Antibiotics 01/2013; · 1.65 Impact Factor
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ABSTRACT: Metachromins are a series of sesquiterpenoid quinones isolated from Okinawan marine sponges. Inhibitory effects of metachromins L-Q (1-6), sesquiterpenoid quinones with an amino acid residue, and their related analogs (7-18) prepared from metachromins A (19) and C (20) against receptor tyrosine kinases EGFR and HER2 were investigated. Two analogs 11 and 12 showed relatively stronger inhibitory activity against EGFR, while metachromins L-Q (1-6) and seven analogs (8, 10, 11, and 15-18) showed inhibitory activities against HER2.
Bioorganic & medicinal chemistry letters 11/2012; · 2.65 Impact Factor
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ABSTRACT: Three new polyketides, manzamenones L-N (1-3), have been isolated from an Okinawan marine sponge of the genus Plakortis. The structures of 1-3 were elucidated on the basis of spectroscopic data. Manzamenones L-N (1-3) were new dimeric fatty-acid derivatives consisting of a tetrahydroindenone with three carboxy groups and two hexadecanyl chains. Manzamenones M (2) and N (3) showed antimicrobial activity against several bacteria and fungi.
Bioorganic & medicinal chemistry letters 11/2012; · 2.65 Impact Factor
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ABSTRACT: Two new structurally unique dimeric sesquiterpenoids, halichonadins K (1) and L (2), were isolated from an Okinawan marine sponge Halichondria sp. The structures of 1 and 2 were elucidated on the basis of spectroscopic analysis including a single crystal X-ray diffraction analysis and chemical conversion. Halichonadins K (1) and L (2) are homodimers of the eudesmane sesquiterpene linked with a piperidine ring through amide bonds. Halichonadin K (1) showed moderate cytotoxicity against KB cells.
Organic Letters 06/2012; 14(13):3498-501. · 5.86 Impact Factor
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ABSTRACT: Four new bromotyrosine alkaloids, tyrokeradines C-F (1-4), have been isolated from Okinawan marine sponges of the order Verongidae. The structures of 1-4 were elucidated on the basis of spectroscopic data. Tyrokeradines C (1) and D (2) are new bromotyrosine alkaloids possesing an imidazole ring, while tyrokeradines E (3) and F (4) are new bromotyrosine alkaloids possesing a cyano group.
Chemical & pharmaceutical bulletin 01/2012; 60(12):1599-601. · 1.70 Impact Factor
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ABSTRACT: Three new heteroaromatic alkaloids, nakijinamines C-E (1-3), which are a hybrid of the aaptamine-type and bromoindole alkaloids possessing a taurine- or histidine-derived residue, have been isolated from an Okinawan marine sponge Suberites species. The structures of 1-3 were elucidated on the basis of spectroscopic data and chemical conversions. Nakijinamines C (1) and E (3) are the first natural products possessing a 1H-oxazolo[4',5':4,5]benzo[1,2,3-de][1,6]naphthyridine ring system.
Organic Letters 06/2011; 13(12):3016-9. · 5.86 Impact Factor
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ABSTRACT: Four new β-carboline alkaloids, eudistomidins H-K (1-4), were isolated from an Okinawan marine tunicate Eudistoma glaucus and the structures of 1-4 were elucidated on the basis of spectroscopic data. Eudistomidins H (1) and I (2) were new β-carboline alkaloids possessing a unique fused-tetracyclic ring system consisting of a tetrahydro β-carboline ring and a hexahydropyrimidine ring. Eudistomidin J (3) showed relatively potent cytotoxicity against murine leukemia cells P388 and L1210, and human epidermoid carcinoma cells KB in vitro.
Bioorganic & medicinal chemistry letters 05/2011; 21(14):4220-3. · 2.65 Impact Factor
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ABSTRACT: Two novel alkaloids with a furo[2,3-b]pyrazin-2(1H)-one moiety and a guanidino group, hyrtioseragamines A (1) and B (2), have been isolated from an Okinawan marine sponge Hyrtios species. The structures of 1 and 2 were elucidated on the basis of spectroscopic data and chemical conversions. Compounds 1 and 2 are the first natural products possessing a furo[2,3-b]pyrazine-related moiety.
Organic Letters 02/2011; 13(4):628-31. · 5.86 Impact Factor
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ABSTRACT: Two new 3-alkylpyridine alkaloids, pyrinodemins E (1) and F (2), were isolated from an Okinawan marine sponge Amphimedon sp. and the structures of 1 and 2 were elucidated on the basis of spectroscopic data. Pyrinodemins E (1) and F (2) were novel 3-alkylpyridine alkaloids possessing a 4-(methoxyamino)piperidinone moiety and an indol-3-glyoxylamide moiety, respectively. Pyrinodemin E (1) showed cytotoxicity against P388 and L1210 murine leukemia cells.
Bioorganic & medicinal chemistry letters 01/2011; 21(1):267-70. · 2.65 Impact Factor
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ABSTRACT: Three new Lycopodium alkaloids, lyconadins D (1) and E (2), and complanadine E (3), were isolated from the club moss Lycopodium complanatum. Lyconadin D (1) was the first example of fastigiatine-type alkaloid isolated from Lycopodium complanatum. The structures and relative stereochemistry of 1-3 were elucidated on the basis of spectroscopic data. Complanadine E (3) enhanced mRNA expression for NGF.
Bioorganic & medicinal chemistry 01/2011; 19(2):749-53. · 2.82 Impact Factor
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ABSTRACT: Three new bromotyrosine alkaloids, ceratinadins A-C (1-3), were isolated from an Okinawan marine sponge Pseudoceratina sp. and the structures of 1-3 were elucidated on the basis of spectroscopic data. Ceratinadin A (1) was a novel bromotyrosine alkaloid possessing an N-imidazolyl-quinolinone moiety. Ceratinadins A (1) and B (2) showed antifungal activity.
Bioorganic & medicinal chemistry letters 08/2010; 20(15):4569-72. · 2.65 Impact Factor
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ABSTRACT: A new beta-carboline alkaloid, eudistomidin G (1), has been isolated from the Okinawan marine tunicate Eudistoma glaucus, and the structure was elucidated from spectroscopic data. Furthermore, the structure of eudistomidin B (2), which has been isolated from the same tunicate, was revised from 2a to 2b by detailed analyses of spectroscopic data. Asymmetric synthesis of the revised structure (2b) of eudistomidin B (2) and its (1S,10S)-diastereomer (2c) has been accomplished with the Noyori catalytic asymmetric hydrogen-transfer reaction. The absolute configuration of eudistomidin B (2) was confirmed to be 2b possessing (1R,10S)-configuration, from comparison of the (1)H NMR data, CD spectra, [alpha](D) values, and HPLC analysis of 2b, 2c, and natural eudistomidin B.
Bioorganic & medicinal chemistry letters 07/2010; 20(14):4100-3. · 2.65 Impact Factor
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ABSTRACT: Nine new sesquiterpenoid quinones, nakijiquinones J-R (1-9), have been isolated from three collections of Okinawan marine sponges of the family Spongiidae, and the structures and configurations were elucidated from the spectroscopic data and chemical correlations. Nakijiquinones J-L (1-3), M and N (4 and 5, respectively), O (6), P and Q (7 and 8, respectively), and R (9) are new sesquiterpenoid quinones possessing (S)-2-methylbutylamine, isopentylamine, isobutylamine, phenethylamine, and taurine residues, respectively, attached to each quinone ring.
Journal of Natural Products 12/2009; 73(3):467-71. · 3.13 Impact Factor
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ABSTRACT: Four new benzophenone-O-rhamnosides, petiolins F-I (1-4), were isolated from aerial parts of Hypericum pseudopetiolatum var. kiusianum, and the structures were elucidated by spectroscopic data and chemical means.
Chemical & pharmaceutical bulletin 10/2009; 57(10):1171-3. · 1.70 Impact Factor
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ABSTRACT: Three new Lycopodium alkaloids, lannotinidines H-J (1-3), were isolated from the club moss Lycopodium annotinum. The structures and relative stereochemistry of 1-3 were elucidated on the basis of spectroscopic data and the absolute stereochemistry of 2 was assigned by chemical correlation. Lannotinidine H (1) is the first Lycopodium alkaloid possessing a lycopodane skeleton with an additional C(3) unit.
CHEMICAL & PHARMACEUTICAL BULLETIN 09/2009; 57(8):877-81. · 1.59 Impact Factor
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ABSTRACT: About two hundred Daphniphyllum alkaloids have so far been isolated from thirteen species of the genus Daphniphyllum. This comprehensive review summarizes all the research into the isolation and structure elucidation of these alkaloids reported since investigations began in 1996. The structures of the Daphniphyllum alkaloids are classified based on six Daphniphyllum alkaloids (daphniphylline, secodaphniphylline, yuzurimine, daphnilactone A, daphnilactone B and yuzurine); these are also a number of newly found skeletons. The biosynthetic pathways, total syntheses, and bioactivities of the Daphniphyllum alkaloids are also described.
Natural Product Reports 08/2009; 26(7):936-62. · 9.79 Impact Factor
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ABSTRACT: Three new Daphniphyllum alkaloids, daphnezomines T-V (1-3), were isolated from the leaves and branches of Daphniphyllum humile (Daphniphyllaceae). The structures and relative stereochemistry of 1-3 were elucidated on the basis of spectroscopic data. Daphnezomine T (1) is the first alkaloid without a branched C(1) unit at C-5 among all Daphiniphyllum alkaloids reported so far.
CHEMICAL & PHARMACEUTICAL BULLETIN 06/2009; 57(5):504-7. · 1.59 Impact Factor
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ABSTRACT: Two new Lycopodium alkaloids, serratezomines D (1) and E (2), were isolated from the club moss Lycopodium serratum var. serratum. Serratezomine D (1) is a new lucidine-type alkaloid, while serratezomine E (2) is a new phlegmarane-type alkaloid. The structures and relative stereochemistry of 1 and 2 were elucidated on the basis of spectroscopic data. Serratezomine D (1) exhibited an inhibitory activity against acetylcholinesterase.
Bioorganic & medicinal chemistry letters 06/2009; 19(13):3577-80. · 2.65 Impact Factor
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ABSTRACT: Two new dimeric bromopyrrole alkaloids, nagelamides Q (1) and R (2), have been isolated from Okinawan marine sponges of the genus Agelas (SS-1134 and SS-956, respectively), and the structures and stereochemistry were elucidated from spectroscopic data. Nagelamide Q (1) is a rare dimeric bromopyrrole alkaloid possessing a pyrrolidine ring, while nagelamide R (2) is the first bromopyrrole alkaloid having an oxazoline ring. Nagelamides Q (1) and R (2) showed antimicrobial activity.
Organic Letters 05/2009; 11(8):1785-8. · 5.86 Impact Factor
