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Y Tezuka

Publications and source records attributed to Y Tezuka.

At least 91 records · Page 5Linked to original sources
PubMed1998

Synthesis of a biologically active fluorescent derivative of GM1, a main Ginseng saponin metabolite formed by intestinal bacteria.

A fluorescent derivative of GM1 [20-O-beta-D-glucopyranosyl-20(S)-protopanaxadiol], a main Ginseng saponin metabolite formed by intestinal bacteria, was obtained from the condensation of its trisnor-aldehyde derivative with dansyl hydrazine. The dansylated GM1 fluoresced strongly and showed almost the same properties as its parent compound in lipophilicity and biological activities, so this fluorescent compound might provide an insight into the mechanism of pharmacological activities of GM1.

Antineoplastic Agents↗
PubMed1998

Antiosteoporotic activity of the stems of Sambucus sieboldiana.

We previously found that a methanolic extract of the stems of Sambucus sieboldiana inhibited bone resorption in organ culture. In this study, we further fractionated the methanol extract guided by the activity towards bone resorption stimulated by parathyroid hormone (PTH) in vitro. The ethyl acetate fraction (EtOAc Fr.) of the methanolic extract inhibited PTH-stimulated bone resorption of neonatal mouse bones, and the inhibitory activity was more potent than those of other fractions. Oral administration of the EtOAc Fr. (50 and 100 mg/kg/d) to ovariectomized (OVX) rat prevented the decrease in bone mineral density (BMD) of the lumbar (L2-4) vertebra, indicating that the EtOAc Fr. is effective in vivo. Furthermore, the EtOAc Fr. (50, 100 and 150 mg/kg/d) decreased the serum calcium level elevated in low calcium dietary rats. The phenolic constituents of the EtOAc fraction were examined for their inhibitory effect on bone resorption stimulated by PTH in neonatal mouse bone. Among them, vanillic acid, vanillin and coniferyl alcohol showed significant inhibitory effects on bone resorption. Of the compounds examined, vanillic acid was found to have a significant inhibitory effect on the decrease of BMD in OVX mice. Therefore, the EtOAc Fr. of S. sieboldiana showed a suppressive effect on bone resorption in vitro and in vivo. In addition, the inhibitory effects of the EtOAc Fr. on bone resorption may be at least partly due to the inhibitory action of vanillic acid.

Acetates↗
PubMed1998

Comparative study of seventeen Salvia plants: aldose reductase inhibitory activity of water and MeOH extracts and liquid chromatography-mass spectrometry (LC-MS) analysis of water extracts.

The dry root and rhizome of Salvia miltiorhiza (Lamiaceae) are used as a crude drug Danshen, while those of S. deserta (Xinjiang-Danshen) are mixed in Danshen at Xinjiang province when the former is in short supply. The water and MeOH extracts of S. deserta showed strong aldose reductase (AR) inhibitory activity, and their active constituents were determined to be polar compounds different from "tanshinones" of S. miltiorhiza, i.e., lithospermic acid B (1), salvianolic acid K (2), salviaflaside (3), and rosmarinic acid (4) (IC50, 2.63-3.91 microM). We also examined the AR inhibitory activity of water and MeOH extracts of seventeen Salvia plants, including ten species of Danshen resources (S. bowleyana, S. deserta, S. miltiorhiza, S. miltiorhiza var. miltiorhiza f. alba, S. paramiltiorhiza, S. paramiltiorhiza f. purpureo-rubra, S. przewalskii, S. przewalskii var. mandarinorum, S. sinica f. purpurea, S. trijuga), and their water extracts were also analyzed by liquid chromatography-mass spectrometry (LC-MS). The results indicated that there were four types with regard to the AR inhibitory activity and three types with regard to the amount of 1. Ten species used as Danshen resources showed good correlation between the AR inhibitory activity and the morphological classification. However, the intensities of their AR inhibitory activity varied, and they contained 1 in varying amounts. These facts suggested that the ten species were not the same, and thus their use as a Danshen resource should be based on their activity and/or active constituents.

Aldehyde Reductase↗
PubMed1998

[Studies on flavonoids from Fenugreek (Trigonella foenumgraecum L.)].

OBJECTIVE: To study the flavonoids in fenugreek (Trigonella foenumgraecum) produced in China. METHOD: The flavonoids were isolated with silica gel, polyamide and Sephadex LH-20 chromatography, and their structures were identified by physical, chemical properties and spectral analysis. RESULT: Five flavonoid compounds were isolated from fenugreek seeds and identified as vitexin, tricin, naringenin, quercetin and tricin-7-O-beta-D-glucopyranoside. CONCLUSION: Three flavonoids, tricin, naringenin and tricin-7-O-beta-D-glucopyranoside, were isolated from fenugreek as well as from the plants of Trigonella for the first time.

Apigenin↗
PubMed1998

[Chemical research on stilbenes from Veratrum macckii Reg].

OBJECTIVE: To study the components in rhizome of Veratrum macckii. METHODS: Column chromatography and preparative thin layer chromatography with silica gel were employed for the isolation and purification of constituents. The structures were elucidated by IR, MS and 1H-NMR analysis. RESULTS: Two compounds were obtained and elucidated as resveratrol and 2,3',4,5'-tetrahydroxystilbene. CONCLUSION: The two compounds were separated from V. macckii for the first time.

Drugs, Chinese Herbal↗
PubMed1997

Carbohydrate analysis of porcine thyroglobulin isoforms with different iodine contents.

To further validate the relationship between thyroid hormone formation and the carbohydrate structure of thyroglobulin (Tg), we reinvestigated the relationship between the iodine content and the asparagine-linked oligosaccharide structures of porcine Tg. Purified porcine Tg was further separated into isoforms (Tg-F1, -F2 and -F3) with a DEAE-cellulose ion-exchange chromatography column. The iodine residues, neutral sugar and sialic acid were analyzed for the separated Tg isoforms and their asparagine-linked oligosaccharide structures were analyzed. The asparagine-linked oligosaccharides were released from Tg-F1, -F2 and -F3 by hydrazinolysis and each oligosaccharide was labeled with p-aminobenzoic acid octyl ester (ABOE). The ABOE-labeled oligosaccharides from Tg-F1, -F2 and -F3 were analyzed for their relative content in oligosaccharides of each structure type by chemical methods and DEAE- and ConA high-performance liquid chromatography (HPLC) columns. As a result, it was revealed that the Tg fraction eluted at higher ionic strength from a DEAE-cellulose column is apt to contain more of each iodoamino acid, as well as total content of iodine, larger negative zeta-potential, conforming to sialic acid content in the Tg molecule and to a higher content of di-sialo-bi-antennary complex and to high mannose type oligosaccharides. These results support the conclusion that iodine organification of the Tg molecule is correlated with asparagine-linked oligosaccharide completion.

Animals↗
PubMed1997

Aldose reductase inhibitory constituents of the root of Salvia miltiorhiza Bunge.

The constituents of the MeOH extract of Salvia miltiorhiza BUNGE, which showed strong aldose reductase (AR) inhibitory activity, were examined, and two new abietane-type diterpenoids, danshenol A (1) and danshenol B (2), were isolated together with six known ones: dihydrotanshimme I (3), cryptotanshinone (4), tanshinone I (5), tanshinone IIA (6), (-)-danshexinkun A (7), and sugiol (8). Among them, 4, 5, and 8 were weak AR inhibitors with IC50 from 4.80 to > 10.0 microM, while 1, 2, 3, 6, and 7 were strong inhibitors (IC50 from 0.10 to 1.75 microM). Danshenol A (1), the strongest inhibitor, had IC50 of 0.10 microM which is comparable to that of epalrestat in clinical use. Moreover, from a consideration of IC50, and yield of each compound, it was concluded that tanshinone IIA (6) is the major active constituent of the MeOH extract and danshenol A (I) and (-)danshexinkun A(7) are the minor ones.

Aldehyde Reductase↗
PubMed1997

Effect of Japanese angelica root extract on pentobarbital-induced sleep in group-housed and socially isolated mice: evidence for the central action.

We investigated the effect of the aqueous extract of Japanese angelica root (JAR) on pentobarbital (PB) sleep in group-housed and socially isolated mice. The JAR extract (1.25-2.5 g/kg, p.o.) dose-dependently reversed the decrease in PB sleep caused by isolation stress without affecting PB sleep in group-housed mice. The JAR extract (2.5 g/kg, p.o.) also antagonized the decrease in PB sleep caused by the alpha 2-adrenoceptor antagonists yohimbine and idazoxan (1 mg/kg, i.p.) and the alpha 1-adrenoceptor agonist methoxamine (200 nmol, i.c.v.) in group-housed mice. These results suggest that the JAR extract reverses changes in the arousal level caused by isolation stress and the activation of central noradrenergic systems.

Administration, Oral↗
PubMed1996

Furostanol glycosides from bulbs of Allium chinense.

Two new furostanol saponins, named chinenosides II and III, were isolated along with seven known compounds, from the bulbs of Allium chinese G. Don by a combination of silica gel, Diaion HP-20, and octadecylsilanized (ODS) silica gel column chromatographies and preparative HPLC. On the basis of chemical and spectroscopic evidence, the structures of chinenosides II and III were determined to be 26-O-beta-glucopyranosyl 3 beta,26-dihydroxy-(25R)-5 alpha-furost-20(22)-en-6-one 3-O-beta-xylopyranosyl-(1 --> 4)-[alpha-arbinopyranosyl(1 --> 6) ]-beta-glucopyranoside and 26-O-beta-glucopyranosyl 3 beta,26-dihydroxy-(25R)-5 alpha-furost-20 (22)-en-6-one 3-O-alpha-arabinopyranosyl (1 --> 6)-beta-glucopyranoside, respectively.

Allium↗
PubMed1996

New furostanol glycosides, chinenoside IV and V, from Allium chinense.

Further studies on water-soluble components in the bulbs of Allium chinense G. Don have led to the isolation of two new furostanol saponins, chinenoside IV (1) and V (2). On the basis of chemical evidence and spectral analyses [1H-, 13C-NMR (DEPT), 1H-1H COSY (COSY45 and p-type), 1H-1H relay-COSY, 1H-13C COSY, HMBC, and FAB-MS], the structure of 1 was established as 26-O-beta-glucopyranosyl-3 beta,26-dihydroxy-23-hydroxymethyl-25(R)- 5 alpha-furost-20(22)-en-6-one 3-O-beta-xylopyranosyl(1-->4)-[alpha- arabinopyranosyl(1-->6)]-beta-glucopyranoside and that of 2 to be 26-O-beta-glucopyranosyl-3 beta, 26-dihydroxy-23-hydroxymethyl-25-(R)-5 alpha-furost-20(22)-en-6-one 3-O-alpha-arabinopyranosyl (1-->6)-beta- glucopyranoside, respectively.

Allium↗
PubMed1996

Synthesis and characterization of a carbene-generating biotinylated lactosylceramide analog as a novel chromogenic photoprobe for GM3 synthase.

A new biotinylated lactose derivative bearing a nitro-substituted chromogenic diazirine was synthesized. The biotinyl group within the structure enabled the performance of a convenient assay of GM3 synthase based on avidin-biotin technology, and the Km values of this biotinylated photoprobe were determined as 40 and 47 microM using bovine brain and rat liver Golgi as enzyme sources, respectively. Furthermore, the sialylation of lactosylceramide, a natural acceptor substrate for GM3 synthase, was competitively inhibited by this synthetic analog. The reagent could be a useful chromogenic photoprobe for GM3 synthase.

Animals↗
PubMed1996

Michael-type addition of illudin S, a toxic substance from Lampteromyces japonicus, with cysteine and cysteine-containing peptides in vitro.

Reactions of illudin S with cysteine derivatives (cysteine methyl ester, glutathione and a peptide, Cys-Asp-Pro-Gly-Tyr-Ile-Gly-Ser-Arg) were investigated. In the reaction with cysteine methyl ester, four products (P1, P2, P3, P4) were obtained and their structures were determined, on the basis of MS and NMR data, to be adducts of the mercapto group of cysteine methyl ester with the alpha,beta-unsaturated carbonyl group of illudin S. In the reactions with glutathione and the peptide, two addition products in each case were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and NMR analyses. The structures of these adducts also indicated that the alpha,beta-unsaturated carbonyl group in illudin S behaves as a Michael acceptor for the mercapto group in cysteine.

Amino Acid Sequence↗
PubMed1996

Studies on metabolites of mycoparasitic fungi. V. Ion-spray ionization mass spectrometric analysis of trichokonin-II, a peptaibol mixture obtained from the culture broth of Trichoderma koningii.

The sequence of a peptide, trichokonin-II (TK-II), obtained from the culture broth of Trichoderma koningii OUDEMANS, was examined by ion-spray ionization mass spectrometry (ISI-MS), including the collision-induced dissociation (CID) technique. TK-II was concluded to be a mixture of three peptaibols, TK-IIa, TK-IIb, and TK-IIc.

Alamethicin↗
PubMed1996

Metabolism of illudin S, a toxic substance of Lampteromyces japonicus: urinary excretion of mercapturic acids in rat.

1. The urinary excretion of the mercapturic acids of illudin S after oral administration to rat has been studied. 2. From lc-ms/ms analysis of methanolic extracts of lyophilized rat urine, stereo-isomeric mercapturic acids were detected. 3. The mercapturic acids excreted 3 days following administration amounted to approximately 0.39-0.73% of the administered dose. 4. In vitro glutathione conjugation of illudin S by subcellular fractions was also examined. 5. No significant increases in the formation of glutathione adducts were observed in any subcellular fractions examined.

Acetylcysteine↗