Biomedical subjects
Publications and source records attributed to S Kadota.
Four new glucosides, bungeiside-A, -B, -C, and -D, were isolated from the roots of Cynanchum bungei Decne. The structures of the new compounds were determined by chemical and spectroscopic methods, including two-dimensional nuclear magnetic resonance (2D NMR) techniques, especially 1H-detected heteronuclear multiple-bond multiple-quantum coherence.
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The effects of Senkyu (Cnidii Rhizoma and Ligustici chuanxiong Rhizoma) on the drug skin penetration were studied to clarify its effectivity as the baths. Ether and methanol extracts, and some essential oils of Senkyu (i.e. ligustilide, neocnidilide and butylidenephthalide) enhanced remarkably the skin penetration of benzoic acid. Furthermore, an appreciable correlation between the enhancing ratio and the skin/donor partition coefficient of benzoic acid was observed. These facts suggest that the constituents of Senkyu influence the skin penetration by enhancing the partition coefficient.
1. Enzyme systems responsible for formation of cyclopropane ring-cleavage metabolites (M1 and M2) of illudin S in rat liver were characterized. 2. The enzymes were localized in the cytosol fraction and utilized NADPH alone as electron donor; they were not affected by oxygen and had low pH optima. 3. Formation of metabolites M1 and M2 was inhibited completely by dicumarol (10(-4) M), an inhibitor of DT-diaphorase. 4. Menadione (10(-4) M) and quercetin (10(-4) M) both inhibited formation of M1 and M2 by 35% and 15%, respectively, but quinacrine, barbital, pyrazole and p-chloromercuribenzoic acid had no significant effect. 5. Results show that the enzyme systems may differ from DT-diaphorase, aldehyde oxidase, xanthine oxidase, ketone reductase, aldose reductase, aldehyde reductase and alcohol dehydrogenase, known cytosolic enzymes responsible for xenobiotic metabolism.
The ether extract from the seeds of Swietenia mahagoni Jacq. (Meliaceae) was found to inhibit platelet-activating factor (PAF)-induced platelet aggregation. Systematic separation of the extract afforded twenty eight tetranortriterpenoids related to swietenine and swietenolide. Among them, several new compounds, named swietemahonin A, D, E, and G and 3-O-acetylswietenolide and 6-O-acetylswietenolide, showed a strong inhibition against PAF-induced aggregation in vitro and in vivo assays.
Two known lignans, liriodendrin and syringaresinol mono-beta-D-glucoside, have been isolated from the methanol extract of the roots of Boerhaavia diffusa L. (Nyctaginaceae), and the former compound was found to exhibit a significant calcium (Ca2+) channel antagonistic effect in frog heart single cells using the whole-cell voltage clamp method. Reexamination of the carbon-13 nuclear magnetic resonance (13C-NMR) spectra of these compounds was also carried out by the use of two-dimensional NMR techniques including a 1H-detected heteronuclear multiple bond connectivity (HMBC) experiment, and it was found that the previous signal assignments for C-1' and C-4' have to be revised.
This report discusses a novel type of arylsulfotransferase (AST) which was derived from human intestinal bacterium sulfated polyphenolic compounds when p-nitrophenyl sulfate (PNS) was taken as a donor substrate. (+)-Catechin, (+/-)-catechin, (-)-epicatechin and (-)-epicatechin gallate were better substrates than tyramine. (-)-Epigallocatechin and (-)-epigallocatechin gallate were slightly worse substrates than tyramine. Although gallic acid was a bad substrate, alkyl gallate esters were better substrates than tyramine. The degree of acceptor specificity increased in proportion to the length of the alkyl group up to the carbon number of five. Pedunculagin, geraniin and corilagin were less effective than tyramine. Rosmarinic acid and penta-O-galloyl-beta-D-glucose were similarly well sulfated. Two products, 4'-monosulfate and 4',5-disulfate of (+)-catechin, were detected at a two-fold molar excess of PNS over (+)-catechin. When (+)-catechin-4'-monosulfate as an acceptor was enzymatically sulfated with PNS as a donor, only the 4',5-disulfate was produced. Thus, arylsulfotransferase was useful for the convenient preparation of sulfate esters of polyphenols at their specific hydroxyl groups.
New antibiotics designated as thiazocins A and B were isolated from the culture broth of Actinosynnema sp. C-304. Thiazocins A and B exhibited inhibitory activities against an aldose reductase from human placenta.
We studied the in vitro production of rheumatoid factor (RF) by spleen cells of normal adult mice. IgG RF cross-reactive with rabbit IgG was produced in response to immune complexes of TNP-lipopolysaccharide (LPS) with murine IgG anti-TNP antibody in an Fc-specific manner, but not to a mixture of IgG and LPS. Antibody-uncomplexed LPS induced little IgG RF production, but suppressed the subsequent IgG RF response to antibody-complexed LPS, whereas IgM RF was induced by either LPS or antibody-complexed LPS. The IgG RF production followed as rapid a time course as IgM RF production; the rate of IgG RF production reached its maximum soon after a lag period of 1 day and declined after 5 days. Treatment of splenic B cells from BALB/c mice with anti-Ly-1.2 antibody and rabbit complement resulted in a selective reduction of IgM RF production by 90%, with little effect of IgG RF production. These results suggest that IgG RF is derived primarily from CD5- memory B cells which have been developed in normal mice by an unknown mechanism. Unlike the CD5+ precursor cells for IgM RF, these memory cells are unresponsive to polyclonal stimulation by LPS but are activated by simultaneous stimulation by aggregated Fc epitopes and the mitogenic stimulus from LPS.
Immune complexes of lipopolysaccharide (LPS) with homologous IgG antibody induces rheumatoid factor (RF) predominantly of the IgG class in normal mice, while LPS alone induces mostly IgM RF directed to homologous IgG1. In this study, IgG monoclonal RFs (mRF) were prepared from hybridomas derived from spleen cells of BALB/c mice which were immunized with complexes of TNP-LPS with anti-TNP mouse IgG and their specificity to mouse IgG subclasses was assessed by analysing dissociation kinetics of the ligands due to RF-specific and non-specific interactions. Of the 19 IgG mRFs (11 IgG1, five IgG2a, one IgG2b and two IgG3 types) tested, 14 were directed to either IgG3 or IgG2b or both, while only one exhibited a significant binding capacity to IgG1. Other mRFs, although reactive to rabbit IgG, exhibited little homophilic activity. None of these mRFs reacted strongly with their own isotypes. The results suggest that the IgG RF producing cells are not direct progenies of the IgG1-directed IgM RF-producing cells but may have developed via a rigorous selection process to eliminate clones that produce self-reactive RF.
Woodfruticosin (woodfordin C), a new cyclic dimeric hydrolyzable tannin having an inhibitory activity toward deoxyribonucleic acid (DNA) topoisomerase II, has been isolated from the leaves of Woodfordia fruticosa Kurz (Lythraceae) along with three known flavonol glycosides and three known flavonol glycoside gallates. The structure of wood fruticosin (woodfordin C) was determined by the use of two-dimensional nuclear magnetic resonance (2-D NMR) spectroscopy including heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple bond connectivity (HMBC) techniques. Detailed analyses of the proton and carbon-13 NMR (1H- and 13C-NMR) spectra of six known flavonoids were performed.
1. Illudin S, a toxic principle of the basidiomycete Lampteromyces japonicus, was incubated with rat liver 9000 g supernatant and its metabolites studied. 2. Two metabolites, M1 and M2, were isolated and identified as cyclopropane ring-cleavage compounds by n.m.r., i.r. and mass spectral analyses. Moreover, M2 contained a chlorine atom. 3. On the basis of detailed analyses of the 2D n.m.r. spectra and differential nuclear Overhauser effect experiments, the previous assignments of the cyclopropane carbons of illudin S were revised.
Both vanadate and hydrogen peroxide (H2O2) are known to have insulin-mimetic effects. We previously reported that the mixture of vanadate plus H2O2 results in the generation of a peroxide(s) of vanadate, which strongly enhances IGF-II binding to rat adipocytes (Kadota et al., 1987b). We now report that pervanadate mimics insulin in isolated rat adipocytes to (1) stimulate lipogenesis, (2) inhibit epinephrine-stimulated lipolysis, and (3) stimulate protein synthesis. The efficacy of pervanadate is comparable to that of insulin. However, it is 10(2)-10(3) times more potent than vanadate alone. Exposure of intact rat adipocytes to pervanadate was found to activate the WGA-purified insulin receptor tyrosine kinase assayed with the exogenous substrate poly(Glu80/Tyr20) in a dose-dependent manner to a maximum of 1464% of control at 10(-3) M compared with a maximum insulin effect of 1046% at 10(-6) M. In contrast, in vitro assayed autophosphorylation of the WGA-purified extract was increased 3-fold after exposure of intact cells to insulin but not significantly increased after pervanadate. Furthermore, high concentrations of pervanadate (10(-5) M) inhibited subsequent in vitro added insulin-stimulated autophosphorylation. In vitro addition of pervanadate to WGA-purified receptors could not stimulate autophosphorylation or exogenous tyrosine kinase activity and did not inhibit insulin-stimulated autophosphorylation. Labeling of intact adipocytes with [32P]orthophosphate followed by exposure to 10(-4) M pervanadate increased insulin receptor beta-subunit phosphorylation (7.9 +/- 3.0)-fold, while 10(-7) M insulin and 10(-4) vanadate increased labeling (5.3 +/- 1.8)- and (1.1 +/- 0.2)-fold, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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Hatomamicin, a new alkaloid antibiotic, was isolated from the culture filtrate of a strain of Saccharopolyspora. The antibiotic was extracted with EtOAc and purified by silica gel column chromatography. The free alkaloid was obtained as pale yellowish prisms from CH3CN solution. It exhibits antimicrobial activity against Gram-positive organisms. The apparent molecular formula of hatomamicin was determined to be C22H31NO5. The structure has been established by a combination of spectroscopic and X-ray crystallographic studies.
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Phospholine was isolated as an antitumor antibiotic from the fermentation broth of Streptomyces hygroscopicus. Phospholine is an amphoteric compound which has an amino group and a phosphoric acid ester as functional groups. Phospholine shows strong activities against L1210, P388 and EL-4.
A new thiolactone containing antibiotic 834-B1 was isolated from the culture broth of Streptomyces sp. Y-0834H which has also produced thiolactomycin and thiotetromycin at the same time. The structure of 834-B1 was determined as I by the decoupling experiment in NMR.