The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Kiyoyuki Yamada - One of the best experts on this subject based on the ideXlab platform.
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aplyronines d h from the Sea Hare aplysia kurodai isolation structures and cytotoxicity
Tetrahedron, 2012Co-Authors: Makoto Ojika, Hideo Kigoshi, Kiyotake Suenaga, Tsuyoshi Mutou, Yoshifumi Imamura, Kohji Yoshikawa, Takeshi Ishigaki, Akira Sakakura, Kiyoyuki YamadaAbstract:Five cytotoxic macrolides, aplyronines D–H (4–8), were isolated from the Japanese Sea Hare Aplysia kurodai. They are new congeners of the antitumor compound aplyronine A (1), which was previously isolated from the same organism. Their structures were determined by spectroscopic analysis (NMR and MS). The cytotoxicity of these new compounds was evaluated in comparison with that of aplyronines A–C (1–3), suggesting the importance of the 7-O-seryl ester group for mediating the potent cytotoxicity of aplyronines.
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Auriculol, a cytotoxic oxygenated squalene from the Japanese Sea Hare Dolabella auricularia: isolation, stereostructure, and synthesis
Tetrahedron Letters, 2001Co-Authors: Hideo Kigoshi, Kiyotake Suenaga, Takashi Itoh, T. Ogawa, Kenya Ochi, Mayuko Okada, Kiyoyuki YamadaAbstract:Abstract Auriculol, a cytotoxic oxygenated squalene, was isolated from the Japanese Sea Hare Dolabella auricularia , and its stereostructure was elucidated by spectral analysis and organic synthesis.
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Aurilol, a Cytotoxic Bromotriterpene Isolated from the Sea Hare Dolabella auricularia
Journal of Natural Products, 1998Co-Authors: Kiyotake Suenaga, Hideo Kigoshi, Takunobu Shibata, Noboru Takada, Kiyoyuki YamadaAbstract:Aurilol (1), a novel cytotoxic bromotriterpene, was isolated from the Sea Hare Dolabella auricularia. The structure of 1, including the absolute stereochemistry of the five stereocenters, was determined by spectroscopic and chemical analyses. Aurilol (1) exhibited cytotoxicity against HeLa S3 cells with an IC50 of 4.3 μg/mL.
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aurisides a and b cytotoxic macrolide glycosides from the japanese Sea Hare dolabella auricularia
ChemInform, 1997Co-Authors: Hiroki Sone, Hideo Kigoshi, Kiyoyuki YamadaAbstract:Bioassay-guided fractionation of the cytotoxic constituents of the Japanese Sea Hare Dolabella auricularia led to the isolation of two novel cytotoxic compounds, aurisides A (1) and B (2). Their gross structures were established by spectroscopic analysis including the 2D NMR technique. On the basis of the NOESY spectral analysis and the degradation experiments, their absolute stereostructures were determined to be 14-membered macrolide glycosides that contain a bromine-substituted conjugated diene structure, a cyclic hemiacetal moiety, and a 2,4-di-O-methyl-l-rhamnopyranoside part. Aurisides A (1) and B (2) show cytotoxicity against HeLa S3 cells with IC50 values of 0.17 and 1.2 μg/mL, respectively.
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dolabelides c and d cytotoxic macrolides isolated from the Sea Hare dolabella auricularia
Journal of Natural Products, 1997Co-Authors: Kiyotake Suenaga, Hideo Kigoshi, Takunobu Shibata, Tomohiro Nagoya, Kiyoyuki YamadaAbstract:Two new cytotoxic 24-membered macrolides, dolabelides C and D, were isolated from the Japanese Sea Hare Dolabella auricularia. Their gross structures were deduced by spectroscopic analysis including the 2D NMR technique, and their absolute stereochemistry was determined by means of chemical correlation with the known dolabelide A. Dolabelides C and D exhibited cytotoxicities against HeLa S 3 cells with IC 50 values of 1.9 and 1.5 μg/mL, respectively.
Hideo Kigoshi - One of the best experts on this subject based on the ideXlab platform.
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Aplysiasecosterols B and C: two new 9,11-secosteroids with a cis-fused 1,4-quinone structure from the Sea Hare Aplysia kurodai
Tetrahedron Letters, 2016Co-Authors: Masaki Kita, Atsushi Kawamura, Hideo KigoshiAbstract:Abstract Two new 9,11-secosteroids with a cis -fused 3β,5β-dihydroxy-1,4-quinone structure, aplysiasecosterols B and C, were isolated from the Sea Hare Aplysia kurodai . Their structures were determined by 1D- and 2D-NMR spectroscopic analysis, molecular modeling studies, and a modified Mosher’s method. Aplysiasecosterol B might be the biosynthetic precursor of aplysiasecosterol A, another 9,11-secosteroid with a tricyclic γ-diketone structure from A. kurodai , via two α-ketol rearrangements and intramolecular acetalization.
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aplysiasecosterol a a 9 11 secosteroid with an unprecedented tricyclic γ diketone structure from the Sea Hare aplysia kurodai
Angewandte Chemie, 2015Co-Authors: Atsushi Kawamura, Masaki Kita, Hideo KigoshiAbstract:A new 9,11-secosteroid having an unprecedented tricyclic γ-diketone structure, aplysiasecosterol A (1), was isolated from the Sea Hare Aplysia kurodai. The structure was determined by one- and two-dimensional NMR spectroscopic analysis, molecular modeling studies, a comparison of experimental and calculated ECD spectra, and a modified Mosher′s method. Aplysiasecosterol A (1) exhibited cytotoxicity against human myelocytic leukemia HL-60 cells. A biosynthetic pathway for 1 from a known cholesterol was proposed and includes twice α-ketol rearrangements and an intramolecular acetalization.
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Aplysiasecosterol A: A 9,11‐Secosteroid with an Unprecedented Tricyclic γ‐Diketone Structure from the Sea Hare Aplysia kurodai
Angewandte Chemie, 2015Co-Authors: Atsushi Kawamura, Masaki Kita, Hideo KigoshiAbstract:A new 9,11-secosteroid having an unprecedented tricyclic γ-diketone structure, aplysiasecosterol A (1), was isolated from the Sea Hare Aplysia kurodai. The structure was determined by one- and two-dimensional NMR spectroscopic analysis, molecular modeling studies, a comparison of experimental and calculated ECD spectra, and a modified Mosher′s method. Aplysiasecosterol A (1) exhibited cytotoxicity against human myelocytic leukemia HL-60 cells. A biosynthetic pathway for 1 from a known cholesterol was proposed and includes twice α-ketol rearrangements and an intramolecular acetalization.
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aplyronines d h from the Sea Hare aplysia kurodai isolation structures and cytotoxicity
Tetrahedron, 2012Co-Authors: Makoto Ojika, Hideo Kigoshi, Kiyotake Suenaga, Tsuyoshi Mutou, Yoshifumi Imamura, Kohji Yoshikawa, Takeshi Ishigaki, Akira Sakakura, Kiyoyuki YamadaAbstract:Five cytotoxic macrolides, aplyronines D–H (4–8), were isolated from the Japanese Sea Hare Aplysia kurodai. They are new congeners of the antitumor compound aplyronine A (1), which was previously isolated from the same organism. Their structures were determined by spectroscopic analysis (NMR and MS). The cytotoxicity of these new compounds was evaluated in comparison with that of aplyronines A–C (1–3), suggesting the importance of the 7-O-seryl ester group for mediating the potent cytotoxicity of aplyronines.
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aplaminal a novel cytotoxic aminal isolated from the Sea Hare aplysia kurodai
Organic Letters, 2008Co-Authors: Takeshi Kuroda, Hideo KigoshiAbstract:Aplaminal (1), a novel triazabicyclo[3.2.1]octane framework metabolite, has been isolated from the Sea Hare Aplysia kurodai. The structure was determined by analysis of NMR data and confirmed by single-crystal X-ray diffraction analysis. Aplaminal (1) exhibits cytotoxicity against Hela S3 cells.
Makoto Ojika - One of the best experts on this subject based on the ideXlab platform.
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aplyronines d h from the Sea Hare aplysia kurodai isolation structures and cytotoxicity
Tetrahedron, 2012Co-Authors: Makoto Ojika, Hideo Kigoshi, Kiyotake Suenaga, Tsuyoshi Mutou, Yoshifumi Imamura, Kohji Yoshikawa, Takeshi Ishigaki, Akira Sakakura, Kiyoyuki YamadaAbstract:Five cytotoxic macrolides, aplyronines D–H (4–8), were isolated from the Japanese Sea Hare Aplysia kurodai. They are new congeners of the antitumor compound aplyronine A (1), which was previously isolated from the same organism. Their structures were determined by spectroscopic analysis (NMR and MS). The cytotoxicity of these new compounds was evaluated in comparison with that of aplyronines A–C (1–3), suggesting the importance of the 7-O-seryl ester group for mediating the potent cytotoxicity of aplyronines.
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Aplysiallene, a New Bromoallene as an Na, K-ATPase Inhibitor from the Sea Hare, Aplysia kurodai
Bioscience biotechnology and biochemistry, 2001Co-Authors: Yoshihiro Okamoto, Makoto Ojika, Naoko Nitanda, Youji SakagamiAbstract:A new bromoallene metabolite, named aplysiallene, was isolated from the Japanese Sea Hare, Aplysia kurodai, as an Na, K-ATPase inhibitor. Its structure was elucidated by spectroscopic methods. The known metabolites, laurinterol and debromolaurinterol, isolated from this animal were also evaluated for their Na, K-ATPase inhibitory activity.
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isolation and stereostructures of dolastatin g and nordolastatin g cytotoxic 35 membered cyclodepsipeptides from the japanese Sea Hare dolabella auricularia
Journal of Organic Chemistry, 1996Co-Authors: Tsuyoshi Mutou, Makoto Ojika, Tadao Kondo, Kiyoyuki YamadaAbstract:A bioassay-directed fractionation of the cytotoxic constituents of the Japanese Sea Hare Dolabella auricularia resulted in the isolation of two 35-membered depsipeptides dolastatin G (1) and nordolastatin G (2), which showed cytotoxicity against HeLa S(3) cells with IC(50) values of 1.0 and 5.3 mg/mL, respectively. The gross structures of these substances were established by spectroscopic analysis including 2D NMR techniques. The absolute stereostructure of 1 was determined by chiral HPLC analysis of amino acid components obtained from acid hydrolysis of 1 and by the enantioselective syntheses of two degradation products arising from polyketide portions. Nordolastatin G (2) is a congener that has the same absolute stereochemistry as that of 1.
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Dolastatin H and Isodolastatin H, Potent Cytotoxic Peptides from the Sea Hare Dolabella auricularia: Isolation, Stereostructures, and Synthesis
Journal of the American Chemical Society, 1996Co-Authors: Hiroki Sone, Makoto Ojika, Takunobu Shibata, Tatsuya Fujita, Kiyoyuki YamadaAbstract:A bioassay-directed investigation of the cytotoxic constituents of the Japanese Sea Hare Dolabella auricularia resulted in the isolation of two cytotoxic compounds designated dolastatin H (2) and i...
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dolabelides a and b cytotoxic 22 membered macrolides isolated from the Sea Hare dolabella auricularia
Tetrahedron Letters, 1995Co-Authors: Makoto Ojika, Tomohiro Nagoya, Kiyoyuki YamadaAbstract:Abstract A new 22-membered macrolides, dolabelide A ( 1 ), and its deacetyl derivative, dolabelide B ( 2 ), have been isolated as cytotoxins from the Japanese Sea Hare Dolabella auricularia . The gross structures of 1 and 2 were determined by spectroscopic analysis, and their absolute stereochemistry was elucidated by a combination of chemical means and the NMR spectroscopic method.
Atsushi Numata - One of the best experts on this subject based on the ideXlab platform.
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pericosines antitumour metabolites from the Sea Hare derived fungus periconia byssoides structures and biological activities
Organic and Biomolecular Chemistry, 2007Co-Authors: Takeshi Yamada, Masashi Iritani, Katsuhiko Minoura, Hirohumi Ohishi, Kayo Tanaka, Mitsunobu Doi, Atsushi NumataAbstract:Pericosines A–E 1–5 have been isolated from a strain of Periconia byssoides originally separated from the Sea Hare Aplysia kurodai. Among them, pericosines C 3 and E 5 were separated as enantiomeric mixtures. Their stereostructures, except for compound 1, have been elucidated or identified on the basis of spectroscopic analyses, including 1D and 2D NMR techniques, and X-ray analysis. In addition, conformation for all the compounds has been discussed. Compounds 1–3 exhibited significant growth inhibition against tumour cell lines. Pericosine A 1 also showed significant in vivo tumour inhibitory activity. In addition, compound 1 inhibited the protein kinaseEGFR and topoisomerase II.
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cell adhesion inhibitors produced by a Sea Hare derived periconia sp
The Journal of Antibiotics, 2007Co-Authors: Takeshi Yamada, Katsuhiko Minoura, Reiko Tanaka, Atsushi NumataAbstract:Peribysin J and macrosphelide M have been isolated from a strain of Periconia byssoides originally isolated from the Sea Hare Aplysia kurodai. Their absolute stereostructures have been elucidated on the basis of spectroscopic analyses using 1D and 2D NMR techniques and some chemical transformations including the modified Mosher's method. These fungal metabolites inhibited the adhesion of human-leukemia HL-60 cells to human-umbilical-vein endothelial cells (HUVEC).
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Cell-adhesion Inhibitors Produced by a Sea Hare-derived Periconia sp. II
The Journal of Antibiotics, 2006Co-Authors: Takeshi Yamada, Katsuhiko Minoura, Reiko Tanaka, Atsushi NumataAbstract:Peribysins H ( 1 ) and I ( 2 ) have been isolated from a strain of Periconia byssoides originally separated from the Sea Hare Aplysia kurodai . Their absolute stereostructures have been elucidated on the basis of spectroscopic analyses using 1D and 2D NMR techniques and some chemical transformations including the modified Mosher's method. These metabolites inhibited the adhesion of human-leukemia HL-60 cells to HUVEC.
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cell adhesion inhibitors produced by a Sea Hare derived periconia sp ii absolute stereostructures of peribysins h and i
The Journal of Antibiotics, 2006Co-Authors: Takeshi Yamada, Katsuhiko Minoura, Reiko Tanaka, Atsushi NumataAbstract:Peribysins H (1) and I (2) have been isolated from a strain of Periconia byssoides originally separated from the Sea Hare Aplysia kurodai. Their absolute stereostructures have been elucidated on the basis of spectroscopic analyses using ID and 2D NMR techniques and some chemical transformations including the modified Mosher's method. These metabolites inhibited the adhesion of human-leukemia HL-60 cells to HUVEC.
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absolute stereostructures of cell adhesion inhibitors peribysins a e f and g produced by a Sea Hare derived periconia sp
The Journal of Antibiotics, 2005Co-Authors: Takeshi Yamada, Katsuhiko Minoura, Reiko Tanaka, Mitsunobu Doi, Atsuko Miura, Waka Harada, Mika Hiramura, Atsushi NumataAbstract:Peribysins E∼G (1∼3) have been isolated from a strain of Periconia byssoides originally separated from the Sea Hare Aplysia kurodai. Their absolute stereostructures have been elucidated on the basis of spectroscopic analyses using 1D and 2D NMR techniques and some chemical transformations. In addition, the absolute configuration of peribysin A (4), previously undetermined, has been established by conversion to 2 and 3. All these metabolites inhibited the adhesion of human-leukemia HL-60 cells to HUVEC.
Suchada Suntornchashwej - One of the best experts on this subject based on the ideXlab platform.
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malyngamide x the first 7r lyngbic acid that connects to a new tripeptide backbone from the thai Sea Hare bursatella leachii
Chemistry-an Asian Journal, 2007Co-Authors: Suchada Suntornchashwej, Khanit Suwanborirux, Kazushi Koga, Minoru IsobeAbstract:Malyngamide X (1), the first (7R)-lyngbic acid connected to a new tripeptide backbone, was isolated from the Thai Sea Hare Bursatella leachii. The gross structure of 1 was established on the basis of 1D and 2D NMR and mass spectroscopic data. Combination of the NMR spectroscopic experiments with alpha-methoxy-alpha-(trifluoromethyl)phenylacetic acid esters, 2,2,2-trifluoro-1-(9-anthryl)ethanol chiral solvating agent, and molecular mechanics of 1 and the synthetic molecular fragments allowed us to determine the absolute stereochemistry of all six stereogenic centers without hydrolytic degradation of the compound. Compound 1 displayed moderate cytotoxic, antitubercular, and antimalarial properties.
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Hectochlorin and morpholine derivatives from the Thai Sea Hare, Bursatella leachii.
Journal of natural products, 2005Co-Authors: Suchada Suntornchashwej, Narongsak Chaichit, Minoru Isobe, Khanit SuwanboriruxAbstract:Investigation of the EtOAc extract from the Thai Sea Hare, Bursatella leachii, resulted in the isolation of a potent stimulator of actin assembly, hectochlorin (1), and its new derivative, deacetylhectochlorin (2). Compound 2 exhibited more potent cytotoxicity than 1 against different human carcinoma cell lines. In addition, a new morpholine-2,5-dione analogue, syn-3-isopropyl-6-(4-methoxybenzyl)-4-methylmorpholine-2,5-dione (3), was co-isolated.