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ABSTRACT: Five new diterpenoids belonging to labdane and isopimarane skeletons, mumic acids A-E (1-5), have been isolated from mumiyo. Their structures and absolute configurations were elucidated on the basis of spectroscopic data and chemical derivatization.
Journal of Natural Medicines 04/2013; · 1.39 Impact Factor
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ABSTRACT: Determination of the absolute configuration (AC) is often a challenging aspect in the structure elucidation of natural products. When chiral compounds possess appropriate chromophore(s), electronic circular dichroism (ECD) may provide a powerful approach to the determination of their absolute configuration. Recently, ECD calculations by time-dependent density functional theory (TDDFT) have come to be used more commonly. In the present review, we give several examples of recent studies using TDDFT-calculated ECD spectra for the AC determination of natural products.
Journal of Natural Medicines 04/2013; · 1.39 Impact Factor
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ABSTRACT: Three new terpenoids, opaciniols A-C (1-3), were isolated from the barks of Garcinia opaca, together with malabarica-17,21-dien-3β,14-diol (4) and 13βH-malabarica-14,17,21-trien-3β-ol (5). Their structures were determined on the basis of NMR spectroscopic data. 3 and 4 showed moderate cytotoxicity against HL-60 cells.
Journal of Natural Medicines 03/2013; · 1.39 Impact Factor
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ABSTRACT: In our search for lipid-droplets accumulation (LDA) inhibitors, some ceramicines, a series of limonoids isolated from the barks of Chisocheton ceramicus, were discovered to be active as anti-LDA. Preliminary structure-activity relationships (SAR) of ceramicines as LDA inhibitors based on ceramicines A-L (1-12) and ceramicine B derivatives were described.
Bioorganic & medicinal chemistry letters 01/2013; · 2.65 Impact Factor
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ABSTRACT: Two new limonoids, sanjecumins A (1) and B (2), have been isolated from the leaves of Sandoricum koetjape, together with sandoripins A (3) and B (4). Their structures and absolute configurations were elucidated on the basis of NMR and CD data. Sandoripins A (3) and B (4) moderately inhibited nitric oxide production in mouse macrophage-like cell line J774.1 stimulated by lipopolysaccharide.
Journal of Natural Medicines 06/2012; · 1.39 Impact Factor
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ABSTRACT: Two new isocoumarin glucosides, haworforbins A (1) and B (2), and a new chromone, haworforbin C (3), have been isolated from Haworthia cymbiformis. Their structures and absolute configurations were elucidated on the basis of NMR and CD data. Haworforbin C (3) exhibited moderate inhibition of nitric oxide production in lipopolysaccharide-stimulated RAW264.7 cell line.
Journal of Natural Medicines 03/2012; · 1.39 Impact Factor
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ABSTRACT: Six new diterpenoids, sabiperones A-F (1-6) have been isolated from the aerial part of Juniperus sabina. Their structures were elucidated by spectroscopic methods including 2D NMR techniques. Sabiperone F showed moderate cell growth inhibitory activities against five human cancer cell lines.
Chemical & pharmaceutical bulletin 01/2012; 60(1):154-9. · 1.70 Impact Factor
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ABSTRACT: Eight new guaipyridine sesquiterpene alkaloids, rupestines F-M (1-8) were isolated from the leaves of Artemisia rupestris and their structures were elucidated on the basis of 2D-NMR data. The absolute configurations of 1-8 have been assigned by comparison of their experimental and calculated circular dichroism (CD) spectra.
Chemical & pharmaceutical bulletin 01/2012; 60(2):213-8. · 1.70 Impact Factor
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ABSTRACT: Three new limonoids, ceramicines J (1), K (2), and L (3), were isolated from the hexane layer of Chisocheton ceramicus bark extract. Their structures were elucidated from 1D and 2D NMR data. Ceramicines J-L (1-3) exhibited dose-dependent moderate cytotoxicity against the HL-60 cell line.
Journal of Natural Medicines 12/2011; 66(3):566-70. · 1.39 Impact Factor
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Chin Piow Wong,
Misae Shimada,
Yuta Nagakura, Alfarius Eko Nugroho,
Yusuke Hirasawa,
Toshio Kaneda,
Khalijah Awang,
A Hamid A Hadi,
Khalit Mohamad,
Motoo Shiro,
Hiroshi Morita
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ABSTRACT: Five new limonoids, ceramicines E-I (1-5), have been isolated from the bark of Chisocheton ceramicus. The structures and relative stereochemistry of them were fully elucidated based on 1D- and 2D-NMR data. Ceramicines E-I (1-5) exhibited moderate cell growth inhibitory activities on a range of cell lines (HL-60, A549, MCF7, and HCT116). The absolute structure of previously isolated ceramicine B (6) was also elucidated by circular dichroism (CD) and X-ray analysis.
Chemical & pharmaceutical bulletin 01/2011; 59(3):407-11. · 1.70 Impact Factor
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Ahmad Kaleem Qureshi,
Mat Ropi Mukhtar,
Yusuke Hirasawa,
Takahiro Hosoya, Alfarius Eko Nugroho,
Hiroshi Morita,
Osamu Shirota,
Khalit Mohamad,
A Hamid A Hadi,
Marc Litaudon,
Khalijah Awang
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ABSTRACT: Two new indole alkaloids, neolamarckines A and B (1, 2) were isolated from the leaves of Neolamarckia cadamba (Rubiaceae). Structural elucidation of 1 and 2 was performed by combination of 2D-NMR and circular dichroism (CD) spectra, and chemical correlations. Neolamarckine A (1) showed inhibition of inducible nitric oxide synthase (iNOS) dose dependently.
Chemical & pharmaceutical bulletin 01/2011; 59(2):291-3. · 1.70 Impact Factor
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ABSTRACT: Two novel indole alkaloids, alsmaphorazines A and B, were isolated from the leaves of Alstonia pneumatophora (Apocynaceae), and their structures were determined on the basis of the 2D NMR and MS spectral analysis. These alkaloids possessed a new skeleton consisting of an 1,2-oxazinane and an isoxazolidine chromophore. The absolute configuration of alsmaphorazine B was determined by using CD spectral analysis. Alsmaphorazine A inhibited the NO production in the LPS-stimulated J774.1 cells dose-dependently without affecting the cell viability.
Organic Letters 09/2010; 12(18):4188-91. · 5.86 Impact Factor
