PubMed Health⌕ Search

Biomedical subjects

I Kitagawa

Publications and source records attributed to I Kitagawa.

At least 37 records · Page 2Linked to original sources
PubMed1997

Indonesian medicinal plants. XIX. 1) Chemical structures of four additional resin-glycosides, mammosides A, B, H1, and H2, from the tuber of Merremia mammosa (Convolvulaceae).

Four new resin-glycosides, named mammosides A (10), B (11), H1 (12), and H2 (13), were isolated from the tuber of Merremia mammosa (Convolvulaceae), a Jamu raw material. Their chemical structures have been elucidated on the bases of chemical and physicochemical evidence, including synthesis of a glycosidic acid designated as mammoside I.

Carbohydrate Sequence↗
PubMed1996

Triterpenoid glycosides from bark of Meliosma lanceolata.

From the bark of Meliosma lanceolate, nine triterpenoid glycosides including the 28-O-beta-D-glucopyranosyl ester of bayogenin-3-O-beta-D-glucuronopyranoside, its 4'-O-beta-D-galactopyranoside and 4'-O-alpha-L-arabinopyranoside were isolated and the structures characterized along with that of 28-O-beta-D-glucopyranosyl-bayogenin-3-O-beta-D-4'-anhydro-4', 5'-didehydroglucuronopyranoside. Bisdesmosidic triosides of hederagenin were obtained as minor components.

Carbohydrate Sequence↗
PubMed1996

Picomole scale stereochemical analysis of sphingosines and dihydrosphingosines.

We have developed a simple picomole (low nanogram) scale HPLC scheme which can separate all eight isomers of sphingosine and dihydrosphingosine thus leading to the identification of their relative and absolute configurations. The amino group of the sample is derivatized to its fluorescent N-naphthimide which is analyzed by normal and chiral phase HPLC, coupled with fluorescence peak detection. If necessary, the results of this HPLC method can be further corroborated by measurements of circular dichroic (CD) spectra of the N-naphthimido-derivatives and/or N,O-chromophoric derivatives.

Chromatography, High Pressure Liquid↗
PubMed1996

Inhibition of in vitro tumor cell invasion by ginsenoside Rg3.

The effect of plant glycosides on tumor cell invasion was examined. Among the glycosides tested, ginsenoside Rg3 was found to be a potent inhibitor of invasion by rat ascites hepatoma cells (MM1), B16FE7 melanoma cells, human small cell lung carcinoma (OC10), and human pancreatic adenocarcinoma (PSN-1) cells, when examined in a cell monolayer invasion model. Structurally analogous ginsenosides, Rb2, 20(R)-ginsenoside Rg2 and 20(S)-ginsenoside Rg3 (a stereoisomer of Rg3), showed little inhibitory activity. Neither Rh1, Rh2, 20(R)-ginsenosides Rh1, Rb1, Rc nor Re had any effect. The effective ginsenoside, Rg3, tended to inhibit experimental pulmonary metastasis by highly metastatic mouse melanoma B16FE7 cells as well. Taking account of our previous finding that 1-oleoyl-lysophosphatidic add (LPA) induced invasion by MM1 cells in the monolayer invasion model, the effect of Rg3 on molecular events associated with the invasion induced by LPA was analyzed in order to understand the mechanism of the inhibition. Rg3, which suppressed the invasion induced by LPA, dose-dependently inhibited the LPA-triggered rise of intracellular Ca2+. Protein tyrosine phosphorylation triggered by LPA was not inhibited by Rg3.

Adenocarcinoma↗
PubMed1996

Indonesian Medicinal Plants. XIV. Characterization of 3'-O-Caffeoylsweroside, a new secoiridoid glucoside, and kelampayosides A and B, two new phenolic apioglucosides, from the bark of Anthocephalus chinensis (Rubiaceae).

A new secoiridoid glucoside named 3'-O-caffeoylsweroside (1), and two new phenolic apioglucosides, named kelampayoside A (4) and kelampayoside B (6), together with eleven known compounds (five iridoids and six alkaloids), were isolated from the bark of Anthocephalus chinensis (Rubiaceae), an Indonesian medicinal plant from Sumatra Island, Indonesia. The chemical structures of 1, 4 and 6 have been elucidated respectively as 3'-O-caffeoylsweroside (1), antiarol 1-O-beta-D-apiofuranosyl (1 --> 6)-beta-D-glucopyranoside (4), and antiarol 1-O-beta-D-5"-O-caffeoylapiofuransoyl (1 --> 6)-beta-D-glucopyranoside (6) on the bases of their chemical and physiochemical properties. Among fourteen constituents characterized, cadambine (13), one of the major indole alkaloid constituents of A. chinensis, was shown to exhibit moderate growth-inhibitory activity against the malarial parasite Plasmodium falciparum (a chloroquine-resistant K1 strain) cultured in human erythrocytes.

Animals↗
PubMed1996

Bioactive saponins and glycosides. III. Horse chestnut. (1): The structures, inhibitory effects on ethanol absorption, and hypoglycemic activity of escins Ia, Ib, IIa, IIb, and IIIa from the seeds of Aesculus hippocastanum L.

Five bioactive triterpene oligoglycosides named escins, Ia, Ib, IIa, IIb, and IIIa were isolated from the seeds of horse chestnut tree, Aesculus hippocastanum L. (Hippocastanaceae). The chemical structures of escins Ia, Ib, IIa, IIb, and IIIa were determine on the basis of chemical and physicochemical evidence, which included selective cleavage of the glucuronide linkage using photochemical reaction and lead tetraacetate decarboxylation reaction. Escins Ia, Ib, IIa, and IIb were found to exhibit an ethanol absorption-inhibitory effect and hypoglycemic activity in the oral glucose tolerance test in rats. Some structure-activity relationships are reported.

Animals↗
PubMed1996

Indonesian medicinal plants. XV. Chemical structures of five new resin-glycosides, merremosides a, b, c, d, and e, from the tuber of Merremia mammosa (Convolvulaceae).

Five new resin-glycosides, named merremosides a (1), b (2), c (3), d (4), and e (5), were isolated from the tuber of Merremia mammosa (LOUR.) HALLIER f. (Convolvulaceae), an Indonesian medicinal plant. The structures of 1, 2, 3, 4, and 5 have been elucidated on the basis of chemical and physiochemical evidence, including syntheses of (11S)-(+)- and (11R)-(--)-jalapinolic acid (16b and 18b) and the glycosidic acid designated as merremoside i (6).

Carbohydrate Sequence↗
PubMed1996

Indonesian medicinal plants. XVI. Chemical structures of four new resin-glycosides, merremosides f, g, h1, and h2, from the tuber of Merremia mammosa (Convolvulaceae).

Four new resin-glycosides named merremosides f (6), g (7), h1 (8), and h2 (9) were isolated from the tuber of Merremia mammosa (Lour.) Hallier f. (Convolvulaceae), an Indonesian medicinal plant. Their chemical structures have been elucidated on the bases of their chemical and physicochemical properties.

Carbohydrate Sequence↗
PubMed1996

Indonesian medicinal plants. XVII. Characterization of quassinoids from the stems of Quassia indica.

Four new quassinoids named samaderines X (1), Y (2) and Z (3), and indaquassin X (5), and a new C19 quassinoid glycoside, 2-O-glucosylsamaderine C (10), together with five known quassinoids, samaderines B (7), C (8), and E (4), indaquassin C (6), and simarinolide (9), were isolated form the stems of Quassia indica (Simaroubaceae), an Indonesian medicinal plant. The chemical structures of these quassinoids have been elucidated on the bases of their chemical and physiochemical properties. Samaderines X (1), Z (3), E (4), and B (7) were shown to exhibit significant growth-inhibitory activity against the cultured malarial parasite Plasmodium falciparum (a chloroquine- resistant K1 strain), and 1--8 were shown to exhibit in vitro cytotoxicity (IC50: 0.04--100 micrograms/ml) against KB cells. Samaderines X (1), B (7) and C (8), as well s indaquassin X (5), exhibited inhibitory activity in the in vitro endothelial cell-neutrophil leukocyte adhesion assay, whereas samaderines X (1) and B (7) were found to exhibit significant anti-inflammatory activity.

Animals↗
PubMed1996

Marine natural products. XXXVI. Biologically active polyacetylenes, adociacetylenes A, B, C, and D, from an Okinawan Marine sponge of Adocia sp.

Adociacetylenes A (1), B (2), C (3), and D (4) were isolated as new polyacetylenes from an Okinawan marine sponge of Adocia sp. Their chemical structures have been elucidated on the bases of their chemical and physicochemical properties. Adociacetylenes A (1), C (3), and D (4) exhibited inhibitory activity in the in vitro endothelial cell-neutrophil leukocyte adhesion assay.

Acetylene↗
PubMed1996

[Chemical study of Indonesian medicinal plants].

A series of scientific expeditions in Indonesia for collecting informations and materials concerning locally used medicinal plants and Javanese traditional medicine "jamu" have been carried out by us since 1985. This article reviews pharmacochemical investigations of nine Indonesian medicinal plants: i.e. Pongamia pinnata (Papilionaceae), Fagara rhetza (Rutaceae), Calotropis gigantea (Asclepiadaceae), Beilschmiedia madang (Lauraceae), Caesalpinia major (Fabaceae), Peronema canescens (Verbenaceae), Taxus sumatrana (Taxaceae), Alyxia reinwardtii (Apocynaceae), and Merremia mammosa (Convolvulaceae), which were selected among plant materials collected in those surveys.

Animals↗
PubMed1995

Suppression of the formation of sister chromatid exchanges by low concentrations of ginsenoside Rh2 in human blood lymphocytes.

To assess the antimutagenic potentials of ginsenoside Rh2 (Rh2), its effects on the baseline and mitomycin C-induced sister chromatid exchange (SCE) were examined in human peripheral blood lymphocytes (PBLs). The SCE frequency in PBLs treated with various concentrations of Rh2 for 72 h was decreased in a dose-dependent manner and was significantly lower than the baseline levels at 1.0 x 10(-10) M and 1.0 x 10(-7) M. The SCE frequency in PBLs treated with both Rh2 and mitomycin C was significantly (P < 0.001) less than that in PBLs treated with only mitomycin C. Cell cycle kinetics, as indicated by the proliferation and mitotic indices, was not significantly affected by Rh2 of various concentrations in the PBLs throughout the present experiments. This is the first report which showed convincingly a reduction of SCE in normal human cells. The mechanism remains to be elucidated in future studies.

Adult↗
PubMed1995

Taxol and its related taxoids from the needles of Taxus sumatrana.

Through bioassay-guided separation of the chemical constituents of the needles of Taxus sumatrana, taxol (1), cephalomannine (2), and a new taxoid 19-hydroxy-13-oxobaccatin III (8) have been isolated together with 7-epi-10-deacetyltaxol (3), 7-epi-10-deacetylcephalomannine (4), baccatin III (5), 19-hydroxybaccatin III (6), and 10-deacetyl-13-oxobaccatin III (7). The chemical structure of 8 has been elucidated on the bases of its chemical and physicochemical properties.

Antineoplastic Agents↗
PubMed1995

[Chemical studies on crude drug processing. X. On the constituents of rehmanniae radix (4): comparison of the constituents of various rehmanniae radixes originating in China, Korea, and Japan].

In order to characterize the chemical change of their constituents during the processing of various Rehmanniae Radixes, we have investigated the constituents by comparing with those of Chinese Juku-jio (variously processed root of Chinese Rehmannia sp.), Korean Kan-jio (dried root of Korean Rehmannia sp.) and each two species of Japanese Sho-jio (fresh root), Japanese Kan-jio (dried root), and Japanese Juku-jio (steamed root), prepared from Rehmannia glutinosa Libosch. var. purpurea Makino (Akaya-jio in Japanese) and Rehmannia glutinosa Libosch. forma hueichingensis Hsiao (Kaikei-jio in Japanese). It was found that, during the processing for preparing Kan-jio and Juku-jio from Sho-jio, jio-serebroside (9) and acteoside (10) were provided, and that the iridoid glycosides were completely degradated or their contents decreased remarkably. Quantitative analysis by means of gas liquid chromatography (GLC) has confirmed that the contents of monosaccharides and oligosaccharides in Kan-jio and Juku-jio increased more than those in Sho-jio. During the course of these studies, a new iridoid glycoside named 6'-O-acetylcatalpol (2) was isolated from Japanese Sho-jio and the structure has been determined.

Chromatography, Gas↗
PubMed1994

Differential inhibition of eukaryotic DNA polymerases by halenaquinol sulfate, a p-hydroquinone sulfate obtained from a marine sponge.

Halenaquinol sulfate, a p-hydroquinone sulfate obtained from a marine sponge, inhibited the activity of eukaryotic DNA polymerases in varying degrees; the Ki values for DNA polymerases, alpha, beta, delta and epsilon were 1.3, 80, 17.5 and 2.0 microM, respectively, whereas it was less effective against E. coli DNA polymerase I. The inhibition occurred competitively with each of dATP and dTTP, but non-competitively with dCTP, dGTP and the template DNA. Thus, halenaquinol sulfate is demonstrated to be a potential inhibitor of DNA polymerases alpha and epsilon, and be a useful tool for analyzing the dNTP binding sites of DNA polymerases.

Animals↗
PubMed1994

Differential effects of ginsenoside Rb1 and malonylginsenoside Rb1 on long-term potentiation in the dentate gyrus of rats.

Ginseng saponins are known to have various pharmacological actions on the central nervous system. In the present study, we investigated the effects of ginsenoside Rb1 (GRb1) and malonylginsenoside Rb1 (GRb1-m) on the induction of long-term potentiation (LTP) in the dentate gyrus using anesthetized rats. Injection (i.c.v.) of GRb1 did not affect the basal synaptic responses evoked by low-frequency test stimulation, but significantly attenuated the magnitude of LTP induced by strong tetanus (100 pulses at 100 Hz). The inhibitory effect of GRb1 depended on its doses (0.5-50 nmol, i.c.v.). On the other hand, GRb1-m did not affect the LTP induced by the strong tetanus, but facilitated the generation of LTP by the weak tetanus (20 pulses at 60 Hz) that produced only short-lasting potentiation in normal condition. The LTP-facilitating effect of GRb1-m was seen maximally at a dose of 5 nmol (i.c.v.) and diminished at a higher dose (50 nmol, i.c.v.). Since another ginseng saponin ginsenoside Rg1 did not affect the induction of LTP at all, the inhibition and facilitation of LTP induction are probably specific actions of GRb1 and GRb1-m, respectively. This is the first report providing direct evidence that ginseng saponins affect the activity-dependent synaptic plasticity in the brain.

Anesthesia↗
PubMed1994

Malonylginsenoside Rb1 potentiates nerve growth factor (NGF)-induced neurite outgrowth of cultured chick embryonic dorsal root ganglia.

Effects of malonylginsenoside Rb1 (GRb1-m) isolated from dried root of Panax ginseng C. A. Meyer (Araliaceae) on neuronal survival and neurite outgrowth were compared with those of ginsenoside Rb1 (GRb1) using organ culture of chick embryonic dorsal root ganglia (DRG) and cell culture of DRG neurons. In the organ culture, nerve growth factor (NGF) showed neurite outgrowth promoting effect. GRb1-m (30 microM) significantly potentiated this NGF-induced neurite outgrowth with similar potency to that of GRb1 (30 microM). Low density cell culture of DRG neurons was employed to minimize the contribution of contaminating non-neuronal cells. NGF (10 ng/ml) prolonged duration of neuronal survival. Neither GRb1-m nor GRb1 (1-30 microM) changed the prolongation effect of NGF, nor did NGF show a significant effect on the neurite elongation and re-elongation after axotomy by laser beam irradiation. However, GRb1-m (10 microM) potentiated initial neurite elongation when co-treated with NGF. In the process of re-elongation of neurites, GRb1-m (1, 30 microM) also promoted it in the presence of NGF. These results suggest, first, that GRb1-m potentiates NGF-induced neurite outgrowth of chick embryonic DRGs and DRG neurons, but behaves in a slightly different manner from GRb1, and, second, that the effects of the two saponins may work primarily on neurons causing the potentiation of NGF-induced neurite outgrowth.

Animals↗