Noriyuki Hara

Tokyo Institute of Technology, Edo, Tōkyō, Japan

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Publications (69)121.16 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A chemical investigation of the fruit juice of Flacourtia inermis furnished five caffeoylquinic acid derivatives: methyl chlorogenate (1), methyl 5-O-caffeoylquinate (2), methyl 4-O-caffeoylquinate (3), n-butyl chlorogenate (4), n-butyl 5-O-caffeoylquinate (5) and a rare phenolic glucoside (rel)-6α-benzoyloxy-1α,2α-dihydroxy-5-oxocyclohex-3-enecarboxylic acid 2-(6-O-benzoyl-β-D-glucopyranosyloxy)-5-hydroxybenzyl ester (6), together with quinic acid (7) and malic acid (8). Compounds 1, 2, 4 and 5 showed strong radical scavenging properties towards the 2,2'-diphenyl-1-picrylhydrazyl radical.
    Natural product research 01/2012; 26(3):278-81. · 1.01 Impact Factor
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    ABSTRACT: The C-24 configurations of (22E)-24-ethyl-24-methylcholesta-5,22-dien-3β-ol (1) and 24-ethyl-24-methylcholest-5-en-3β-ol (2), isolated from the Colombian Caribbean sponge Topsentia ophiraphidites, were determined to be R and S, respectively, by comparing their NMR data with those of stereodefined (24R)- and (24S)-samples that were synthesized in routes involving the orthoester Claisen rearrangement of Δ23-22-allylic alcohols. This is the first synthetic study where the Claisen rearrangement is used to introduce a C-24 quaternary center in a stereospecific manner with acceptable yield. X-ray analysis of 1 confirmed these stereochemical assignments.
    Journal of the Brazilian Chemical Society 11/2011; 22(5):997. · 1.28 Impact Factor
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    ABSTRACT: The C-24 configurations of (22E)-24-ethyl-24-methylcholesta-5,22-dien-3β-ol (1) and 24-ethyl-24-methylcholest-5-en-3β-ol (2), isolated from the Colombian Caribbean sponge Topsentia ophiraphidites, were determined to be R and S, respectively, by comparing their NMR data with those of stereodefined (24R)- and (24S)-samples that were synthesized in routes involving the orthoester Claisen rearrangement of Δ23-22-allylic alcohols. This is the first synthetic study where the Claisen rearrangement is used to introduce a C-24 quaternary center in a stereospecific manner with acceptable yield. X-ray analysis of 1 confirmed these stereochemical assignments.
    Journal of the Brazilian Chemical Society 05/2011; 22(5):997-1004. · 1.28 Impact Factor
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    ABSTRACT: Six new lanostane triterpenes, artabotryols A, B, C1, C2, D, and E (1, 2, 3a, 3b, 4, and 5, resp.) have been isolated from the seeds of Artabotrys odoratissimus (Annonaceae). Their structures have been established as (3α,22S,25R)-3-hydroxy-22,26-epoxylanost-8-en-26-one (1), (3α,22S,25R)-22,26-epoxylanost-8-ene-3,26-diol (2), (3α,22S,25R,26R)-26-methoxy-22,26-epoxylanost-8-en-3-ol (3a), (3α,22S,25R, 26S)-26-methoxy-22,26-epoxylanost-8-en-3-ol (3b), (3α,22S,25R)-3,22-dihydroxylanost-8-en-26-oic acid (4) and (3α,7α,11α,22S,25R)-3,7,11-trihydroxy-22,26-epoxylanost-8-en-26-one (5) by spectroscopic studies and chemical correlations.
    Helvetica Chimica Acta 10/2010; 93(10):1925 - 1932. · 1.38 Impact Factor
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 07/2010; 28(30).
  • Teigo Asai, Noriyuki Hara, Yoshinori Fujimoto
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    ABSTRACT: Ibicellalutea and Proboscidea louisiana, both of the Martyniaceae family, are known for rich glandular trichomes on their leaves and stems. Chemical investigations of the glandular trichome exudates on leaves of the two plants furnished three types of secondary metabolites, glycosylated fatty acids, glycerides (2-O-(3,6-diacetyloxyfattyacyl)glycerols and 2-O-(3-acetyloxyfattyacyl)glycerols) and dammarane triterpenes. The glycosylated fatty acids from I. lutea were determined to be 6(S)-(6-O-acetyl-beta-D-glucopyranosyloxy)-octadecanoic acid (1A), -eicosanoic acid (1B) and -docosanoic acid (1C), as well as their respective deacetyl congeners (2A, 2B and 2C), whereas P. louisiana furnished 8(S)-(6-O-acetyl-beta-D-glucopyranosyloxy)-eicosanoic acid (3A) and -docosanoic acid (3B) and their respective deacetyl congeners (4A and 4B), together with 2B. Both plants contained 12 identical 2-O-[(3R,6S)-3,6-diacetyloxyfattyacyl]glycerols (5A-L), in which the fatty acyl moieties contained between 17 and 21 carbon atoms. The corresponding mono-acetyloxy compounds, 2-O-[(3R)-3-acetyloxyfattyacyl]glycerols (6A-L) were detected in both plants. Among these glycerides, ten compounds (5A, 5C, 5F, 5H, 5K, 6A, 6C, 6F, 6H and 6K) had iso-fattyacyl structures and four (5E, 5J, 6E and 6J) had anteiso-fattyacyl structures. A previously unknown dammarane triterpene, betulatriterpene C 3-acetate (7), was isolated together with three known dammarane triterpenes, 24-epi-polacandrin 1,3-diacetate (8), betulatriterpene C (9) and 24-epi-polacandrin 3-acetate (10) from I. lutea, whereas 12 dammarane triterpenes, named probosciderols A-L (12-23), and the known compound betulafolienetriol (11) were isolated from P. louisiana. The structures of these compounds were elucidated by spectroscopic analysis including 2D-NMR techniques and chemical transformations. The 6-O-acetylglucosyloxy-fatty acids 1A-C (42%) and the dammarane triterpenes 7-10 (31%) were the two most abundant constituents in the glandular trichome exudate of I. lutea, whereas the dammarane triterpenes 11-23 (47%) and the glucosyloxy-fatty acids (4A, 4B and 2B) (38%) were the most abundant constituents in the glandular trichome exudate of P. louisiana.
    Phytochemistry 04/2010; 71(8-9):877-94. · 3.35 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 02/2010; 28(7).
  • [Show abstract] [Hide abstract]
    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 01/2010; 26(5).
  • [Show abstract] [Hide abstract]
    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 01/2010; 28(30).
  • ChemInform 01/2010; 27(9).
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    ABSTRACT: Chemical investigations of the glandular trichome exudates on the leaves of Paulownia tomentosa (Scrophulariaceae) led to the identification of the thirty acylglycerols (=glycerides) 1–30, including five known ones (2, 3, 6, 9, and 15) (Fig. 1). Spectroscopic analysis combined with GC/MS studies of the glycerides and the liberated fatty acids, in the form of trimethylsilyl ether derivatives and trimethylsilylated methyl esters, respectively, established that the constituents belonged to 1,3-di-O-acetyl-2-O-(fatty acyl)glycerols, 1-O-acetyl-2-O-(fatty acyl)-sn-glycerols, and 2-O-(fatty acyl)glycerols, wherein the fatty acyl moiety was either an eicosanoyl or an octadecanoyl group bearing OH and/or AcO groups at the 3-, 3,6-, 3,7-, 3,8-, or 3,9-positions. The 1-O-acetyl-2-O-[(3R,6S)-3-(acetyloxy)-6-hydroxyeicosanoyl]-sn-glycerol (12; 20% of the total glycerides), 2-O-[(3R,8R)-3,8-bis(acetyloxy)eicosanoyl]glycerol (17; 14%), 2-O-[(3R,9R)-3,9-bis(acetyloxy)eicosanoyl]glycerol (18; 12%), and 2-O-[(3R)-3-(acetyloxy)eicosanoyl]glycerol (10; 12%) were relatively abundant constituents. The configurations of the stereogenic centers of the fatty acyl moieties were determined by 1H-NMR analysis of the monoesters obtained from (R)- and (S)-2-(naphthalen-2-yl)-2-methoxyacetic acid ((R)- and (S)-2NMAOH and the hydroxy-substituted fatty acid methyl esters (Fig. 2). The configuration at C(2) of the glycerol moiety of the 1-O-acetyl-2-O-(fatty acyl)glycerols was determined to be (2S) by chemical conversion of, e.g., G-2 (=2/3 1 : 10) to (+)-3-O-[tert-butyl)diphenylsilyl]-sn glycerol of known absolute configuration.
    Helvetica Chimica Acta 08/2009; 92(8):1473 - 1494. · 1.38 Impact Factor
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    ABSTRACT: 2, 22, 25-Trideoxyecdysone (5β-ketodiol) has been shown to be derived from cholesterol in eggs of the silkworm, Bombyx mori. In order to investigate the difference in ecdysteroid metabolism between diapause eggs and non-diapause eggs of the silkworm, 3H-5β-ketodiol was microinjected into eggs at several stages of early embryogenesis, and the metabolites were characterized using high-performance liquid chromatography. The injected 3H-5β-ketodiol was metabolized not only to free ecdysteroids, but also to conjugates (phosphoric esters of ecdysteroids), in both diapause eggs and non-diapause eggs. Among these metabolites, 20-hydroxyecdysone, which is considered as the active hormone in silkworm eggs, was detected in non-diapause eggs. However, in diapause eggs, various radioactive putative precursors of 20-hydroxyecdysone, such as 2, 22-dideoxyecdysone, 2-deoxyecdysone and ecdysone, were detectable, but 3H-20-hydroxyecdysone was not found. These results suggest that the 20-hydroxylation of ecdysone, which is catalyzed by ecdysone 20-monooxygenase, may be a rate-limiting step in the formation of 20-hydroxyecdysone from ketodiol in the silkworm eggs.
    ZOOLOGICAL SCIENCE 01/2009; · 1.08 Impact Factor
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    ABSTRACT: In various insects, 20-hydroxyecdysone (20E) is indispensable for embryonic development. In eggs of the silkworm Bombyx mori, 20E has been demonstrated to be produced by two metabolic pathways: de novo synthesis from cholesterol and dephosphorylation of ovary-derived physiologically inactive ecdysteroid phosphates. In the former, ecdysone 20-hydroxylase (E20OHase) has been suggested to be a key enzyme. In the latter, it has been demonstrated that the dephosphorylation of ecdysteroid phosphates is catalyzed by a specific enzyme, ecdysteroid-phosphate phosphatase (EPPase). In this study, a cDNA encoding E20OHase was cloned from 3-day-old nondiapause eggs of B. mori and sequenced using PCR techniques. The protein exhibited the signature sequences characteristic of P450 enzymes, and mediated the conversion of ecdysone to 20E using the baculovirus expression system. Semi-quantitative analysis revealed that the E20OHase mRNA is expressed predominantly during gastrulation and organogenesis in nondiapause eggs, but is scarcely detected in diapause eggs whose development is arrested at the late gastrula stage. The developmental changes in the expression patterns of E20OHase and EPPase suggest that both enzyme activities are regulated at the transcription level, and both enzymes contribute cooperatively to 20E formation during embryonic development.
    Comparative Biochemistry and Physiology Part B Biochemistry and Molecular Biology 04/2008; 149(3):507-16. · 2.07 Impact Factor
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    ABSTRACT: Chemical investigation of the methanol extract of the viscous secretion on the surface of immature fruits of Paulownia tomentosa furnished nine geranylated flavanones, 6-geranyl-5,7-dihydroxy-3',4'-dimethoxyflavanone (1), 6-geranyl-3',5,7-trihydroxy-4'-methoxyflavanone (2), 6-geranyl-4',5,7-trihydroxy-3',5'-dimethoxyflavanone (3), 6-geranyl-4',5,5',7-tetrahydroxy-3'-methoxyflavanone (4), 6-geranyl-3,3',5,7-tetrahydroxy-4'-methoxyflavanone (5), 4',5,5',7-tetrahydroxy-6-[6-hydroxy-3,7-dimethyl-2(E),7-octadienyl]-3'-methoxyflavanone (6), 3,3',4',5,7-pentahydroxy-6-[6-hydroxy-3,7-dimethyl-2(E),7-octadienyl]flavanone (7), 3,3',4',5,7-pentahydroxy-6-[7-hydroxy-3,7-dimethyl-2(E)-octenyl]flavanone (8), and 3,4',5,5',7-pentahydroxy-3'-methoxy-6-(3-methyl-2-butenyl)flavanone (9), along with six known geranylated flavanones. Among these, compounds 4, 6-9 and the known 6-geranyl-3',4',5,7-tetraahydroxyflavanone (diplacone), 6-geranyl-3,3',4',5,7-pentahydroxyflavanone (diplacol) and 3',4',5,7-pentahydroxy-6-[7-hydroxy-3,7-dimethyl-2(E)-octenyl]flavanone showed potent radical scavenging effects towards DPPH radicals.
    Phytochemistry 04/2008; 69(5):1234-41. · 3.35 Impact Factor
  • Biochemical Systematics and Ecology 04/2008; 36(4):323-325. · 1.15 Impact Factor
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    ABSTRACT: Chemical investigation of the n-butanol extract from the methanol extract of the root bark of Artocarpus nobilis furnished four new prenylated flavonoids together with artonin E 2'-methylether (4), isoartonin E 2'-methylether (5), dihydroisoartonin E 2'-methylether (6), artonin V 2'-methylether (7), artobiloxanthone (1), artonin E (2) and cycloartobiloxanthone (3). All these compounds showed strong radical scavenging properties towards DPPH radical.
    Fitoterapia 02/2008; 79(1):37-41. · 2.23 Impact Factor
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    ABSTRACT: Chemical investigation of polar fractions of the methanol extract of the fruits of Diploclisia glaucescens of the family Menispermaceae furnished two new phenyl glycosides, 4-(2-nitroethyl)phenyl-beta-D-xylopyranosyl-(l approximately 6)-beta-D-glucopyranoside, and 4-cyanophenyl-beta-D-xylopyranosyl-(l approximately 6)-beta-D-glucopyranoside.
    Natural Product Research 04/2007; 21(3):260-4. · 1.03 Impact Factor
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    ABSTRACT: A new glucoside ester, named flacourside, has been isolated together with known methyl 6-O-(E)-p-coumaroyl glucopyranoside and 6-O-(E)-p-coumaroyl glucopyranose from the n-butanol extract of fruit juice of the Flacourtia indica. The structure of flacourside has been determined to be 4-oxo-2-cyclopentenylmethyl 6-O-(E)-p-coumaroyl-β-d-glucopyranoside on the basis of spectroscopic studies.
    Food Chemistry. 01/2007; 102(1):95-97.
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    ABSTRACT: The C-24 configuration of (22E,24xi)-24-isopropenyl-22-dehydrocholesterol (1), which was recently isolated from the Colombian Caribbean sponge, Topsentia ophiraphidites, was investigated. Synthesis of the stereodefined (24R)- and (24S)-(22E)-24-isopropenyl-22-dehydrocholesterols (1a, 1b) followed by (1)H- and (13)C-NMR data comparison of these sterols established the (24R)-configuration of 1. In addition, (24R)- and (24S)-24-isopropenylcholesterols (2a and 2b) were also synthesized and their NMR data are provided. The C-24 configurations of the samples of 24-isopropenylcholesterol reported previously are discussed.
    CHEMICAL & PHARMACEUTICAL BULLETIN 11/2006; 54(10):1473-7. · 1.56 Impact Factor
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    ABSTRACT: Hyosmin (1) a new lignan has been isolated from the seeds of Hyoscyamus niger L. (Solanaceae), and its structure shown to be the 3-{[(2R)-2-carbomethoxy-2-hydroxy]ethyl}benzoate ester of {(2R,3S,4S)-2-(4-hydroxy-3-methoxyphenyl)-3-hydroxymethyl-4-[(4-hydroxy-3-methoxyphenyl)methyl]tetrahydrofuran
    Journal of Chemical Research 09/2006; 2006(10):675-677. · 0.70 Impact Factor

Publication Stats

334 Citations
121.16 Total Impact Points

Institutions

  • 1995–2011
    • Tokyo Institute of Technology
      • • Department of Chemistry and Materials Science
      • • Chemistry Department
      Edo, Tōkyō, Japan
  • 2010
    • Kanazawa University
      • Department of Laboratory Sciences
      Kanazawa, Ishikawa, Japan
  • 1993–2010
    • Banaras Hindu University
      • Department of Medicinal Chemistry
      Vārānasi, Uttar Pradesh, India
  • 2009
    • Konan University
      • Department of Biology
      Kōbe-shi, Hyogo-ken, Japan
  • 2001–2008
    • Institute of Fundamental Studies
      Mahanuvara, Central, Sri Lanka
  • 1994–2006
    • Kyoritsu College of Pharmacy
      Edo, Tōkyō, Japan
  • 2002–2005
    • National University of Colombia
      • Departamento de Química (Bogotá)
      Bogotá, Bogota D.C., Colombia
  • 2003
    • National Institute for Agro-Environmental Sciences in Japan
      Tsukuba, Ibaraki, Japan