Mamoru Koketsu

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The cellular effects of eleven compounds including chalcone glycosides isolated from Brassica rapa L. ‘hidabeni’ and their synthetic derivatives were studied in rat pheochromocytoma PC12 cells. Of the compounds tested, 4′-O-β-d-glucopyranosyl-3′,4-dimethoxychalcone (A2) significantly increased the levels of the phosphorylated forms of extracellular(More)
Components from Dendranthema × grandiflorum cv. "Mottenohoka" that promote neurite outgrowth of PC12 cells were identified and the mechanism of neurite outgrowth stimulated by isolated components was studied. Components that promoted the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK 1/2) of PC12 cells were isolated. From various(More)
We found that ebselen [2-phenyl-1,2-benzisoselenazol-3(2H)-one] caused phosphorylation of mitogen-activated protein kinase (MAPK), followed by expression of neurofilament-M, a neuron-specific protein, in cultured PC12 rat pheochromocytoma cells. The ebselen-induced MAPK activation was suppressed by U0126, an inhibitor of MAPK kinase (MEK1/2), but not by(More)
Flavonoids are widely occurring polyphenols that are found in plants. The aim of this study was to investigate the structure–activity relationships of 5,7-dihydroxyflavones, with a focus on the effect of B ring structure substitution on the antiproliferative effects of the compounds in human leukemia HL-60 cells. We prepared a series of(More)
Helicobacter pylori is associated with various diseases of the upper gastrointestinal tract, such as gastric inflammation and duodenal and gastric ulcers. The aim of the study was to assess anti-H. pylori effects of the sesquiterpene lactone dehydrocostus lactone (DCL) from Magnolia sieboldii leaves, compared to commercial pure DCL, two previously known(More)
Hyaluronidase is one of the most important enzymes in the development of many diseases. In this study, a series of xyloside analogues bearing a triazole and tetrazole at the anomeric position were prepared from xylosylthioureas and evaluated their inhibitory effects on the hyaluronidase. Triazole and tetrazole skeletons were formed via the Hg(OAc)2-mediated(More)
Furonaphthoquinones are promising skeletons for anticancer drug molecules. In particular, methoxylated furonaphthoquinones are characteristic constituents of Tabebuia plants. In this research, we synthesized the furonaphthoquinones by effective one-pot cascade reactions of 3-phenyliodonio-1,2,4-trioxo-1,2,3,4-tetrahydronaphthalenides with 3-butyn-2-ol in(More)
The Staudinger ketene-imine [2 + 2] cycloaddition reaction for conversion of α-heteroatom-substituted exocyclic imines to C4 heterocyclic spiro-β-lactams has rarely been investigated due to their instability. Herein, we describe the Staudinger reaction between ketenes and α-selenium-substituted exocyclic imines to synthesize C4 spiro-β-lactams.
C-5-bromo-2-hydroxyphenylcalix[4]-2-methylresorcinarene (I) was synthesized by cyclocondensation of 5-bromo-2-hydroxybenzaldehyde and 2-methylresorcinol in the presence of concentrated HCl. Compound I was characterized by infrared and nuclear magnetic resonance spectroscopic data. X-ray analysis showed that this compound crystallized in a triclinic system(More)
Coumarin and its derivatives are well known for their anti-inflammatory and anti-oxidative effects. In this study, we synthesized 32 coumarin derivatives from commercially available 6-hydroxycoumarin (6HC) and 7-hydroxycoumarin (7HC) and examined their effects on lipopolysaccharide/interferon γ (LPS/IFNγ)-stimulated nitric oxide (NO) production in murine(More)