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Biomedical subjects

H Itokawa

Publications and source records attributed to H Itokawa.

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

Cytotoxic flavonoids from Vitex agnus-castus.

Four new flavonoids, luteolin 6-C-(4"-methyl-6"-O-trans-caffeoylglucoside), luteolin 6-C-(6"-O-trans-caffeoylglucoside), luteolin 6-C-(2"-O-trans-caffeoylglucoside), and luteolin 7-O-(6"-p-benzoylglucoside), together with four known ones 5, 4'-dihydroxy-3,6,7,3'-tetramethoxyflavone, luteolin, artemetin and isorhamnetin, were isolated from the root bark of Vitex agnus-castus. The structures were elucidated by spectroscopic means.

Antineoplastic Agents, Phytogenic↗
PubMed1997

Thionation of segetalins A and B, cyclic peptides with estrogen-like activity from seeds of Vaccaria segetalis.

Thionation of estrogen-like active cyclic peptides, segetalins A (1) and B (2), with Lawesson's reagent provided each two thiosegetalins; thiosegetalin A1 [Gly-1-psi(CS-NH)-Val-2; Trp-5-psi (CS-NH)-Ala-6]segetalin A, thiosegetalin A2 [Gly-1-psi(CS-NH)-Val-2; Ala-6-psi(CS-NH)-Gly-1]segetalin A, thiosegetalin B1 [Gly-1-psi (CS-NH)-Val-2; Ala-3-psi(CS-NH)-Trp-4]segetalin B, and thiosegetalin B2 [Gly-1-psi(CS-NH)-Val-2; Trp-4-psi(CS-NH)-Ala-1]segetalin B. Thiosegetalin A2 only showed estrogen-like activity against ovariectomized rats. On the basis of their conformations analysed by NMR experiments, the backbone conformation was considered to play an important role in estrogen-like activity for segetalins.

Animals↗
PubMed1997

Conformational preference for segetalins G and H, cyclic peptides with estrogen-like activity from seeds of Vaccaria segetalis.

Three-dimensional structures in DMSO-d0 of segetalins G [cyclo(-Gly-Val-Lys-Tyr-Ala-)] and H [cyclo(-Gly-Tyr-Arg-Phe-Ser-)], cyclic pentapeptides from seeds of Vaccaria segetalis, showing estrogen-like activity, were determined by the distance geometry calculation and restrained energy minimization from NMR data. The backbone structure of segetalin G contains one beta-turn: a beta II-like turn at Tyr4-Ala5, and that of segetalin H one beta-turn: a beta II' turn at Gly1-Tyr2 and one gamma-turn at Arg3-Phe4-Ser5 sequence. The results of distance comparison analysis proposed a pharmacophore model of estrogen-like cyclic peptides, segetalins.

Binding Sites↗
PubMed1997

Taxuspinananes A and B, new taxoids from Taxus cuspidata var. nana.

New taxoids, taxuspinanane A (1), showing potent cytotoxic activity, and taxuspinanane B (2), have been isolated from the stems of Taxus cuspidata Sieb. et. Zucc. var. nana Rehder. Their structures were elucidated by extensive 2D NMR and MS spectroscopic analysis.

Animals↗
PubMed1996

A cyclic heptapeptide from Vaccaria segetalis.

A new cyclic heptapeptide, segetalin E, cyclo(-Gly-Tyr-Val-Pro-Leu-Trp-Pro-), has been isolated from the seeds of Vaccaria segetalis and the structure elucidated by extensive two-dimensional NMR methods and chemical degradation.

Amino Acid Sequence↗
PubMed1996

Cytotoxic azadirachtin-type limonoids from Melia azedarach.

Four new limonoids, 1-tigloyl-3,20-diacetyl-11-methoxymeliacarpinin, 3-tigloyl-1,20-diacetyl-11-methoxymeliacarpinin, 1-cinnamoyl-3-hydroxy-11-methoxymeliacarpinin, and 1-deoxy-3-methacrylyl-11-methoxymeliacarpinin, together with a known limonoid, 1-cinnamoyl-3-acetyl-11-methoxymeliacarpinin, were isolated from the extract of the root bark of Melia azedarach. The structures were elucidated by spectroscopy.

Animals↗
PubMed1996

Anthraquinones from the polar fractions of Galium sinaicum.

The new anthraquinones, 6,7-dimethoxy xanthopurpurin, 6-hydroxy-7-methoxy rubiadin, 5-hydroxy-6-hydroxymethyl anthragallol 1, 3-dimethyl ether, 7-carboxy anthragallol 1,3-dimethyl ether, anthragallol 1-methyl ether 3-O-beta-D-glucopyranoside, anthragallol 1-methyl ether 3-O-rutinoside, anthragallol 3-O-rutinoside and alizarin 1-methyl ether 2-O-primeveroside were isolated from the CH2Cl2 and n-BuOH extracts of Galium sinaicum roots and their structures were established by various spectroscopic techniques. In addition, two known anthraquinones were also isolated and fully characterized.

Anthraquinones↗
PubMed1996

Cytotoxic trichilin-type limonoids from Melia azedarach.

Five new trichilin-type limonoids, named 12-deacetyltrichilin I (1), 1-acetyltrichilin H (2), 3-deacetyltrichilin H (3), 1-acetyl-3-deacetyltrichilin H (4), 1-acetyl-2-deacetyltrichilin H (5), together with four known trichilins, meliatoxin B1 (6), trichilin H (7), trichilin D (8) and 1,12-diacetyltrichilin B (9) were isolated from the extract of the root bark of Melia azedarach. The structures were elucidated by spectroscopic means and their cytotoxic activities against P388 cells in vitro were tested by means of MTT assay.

Animals↗
PubMed1996

Macrocarpals H, I, and J from the Leaves of Eucalyptus globulus.

A 50% EtOH extract of Eucalyptus globulus leaves yielded eight phloroglucinol--sesquiterpene-coupled constituents, including three novel compounds named macrocarpals, H, I, and J. Some of these compounds possessed antibacterial activity against oral pathogenic microorganisms with MIC values ranging from 0.20 micrograms/mL to 6.25 micrograms/mL. Inhibition of glucosyltransferase activity by these compounds was also noted.

Anti-Bacterial Agents↗
PubMed1996

Cyclic peptides from higher plants. XXVIII. Antitumor activity and hepatic microsomal biotransformation of cyclic pentapeptides, astins, from Aster tataricus.

Antitumor activities on Sarcoma 180A of a series of cyclic pentapeptides, astins, isolated from the roots of Aster tataricus, were examined. The activities on various congeners of the dichlorinated proline residues prepared by chemical conversion and a hepatic microsomal biotransformation in rats suggested that 1,2-cis dichlorinated proline residues of astins A, B and C play an important role in the antitumor activity of astins.

Animals↗
PubMed1996

Conformational analysis of a cyclic heptapeptide, pseudostellarin D by molecular dynamics and Monte Carlo simulations.

Restrained molecular dynamics calculation in vacuo using AMBER force field implemented in MacroModel/Batchmin showed a major solution conformation in dimethyl sulfoxide-d6 of pseudostellarin D, cyclo(Gly-Tyr-Gly-Pro-Leu-Ile-Leu-). This is a cyclic heptapeptide isolated from Pseudostellaria heterophylla possessing characteristics of a beta-bulge motif with three intramolecular hydrogen bonds, two beta-turns (one type I at Pro4 and Leu5 residues, and one type II at Leu7 and Gly1 residues) and all trans amide bonds. The solution form of pseudostellarin D, which was homologous to that observed in the solid state, was also supported by Monte Carlo simulation study.

Carbohydrate Sequence↗
PubMed1996

Aneurysm formation and rupture at the site of anastomosis following bypass surgery. Case report.

Four years after undergoing a superficial temporal artery-middle cerebral artery bypass procedure, this patient presented with a ruptured aneurysm at the anastomosis site. The ruptured aneurysm caused subarachnoid and intracerebral hemorrhages and was treated by surgically clipping its neck. Characteristics of the aneurysm included: 1) a relatively large size (8 x 6 x 6 mm): 2) a thickened wall; 3) a location apart from the suture line; 4) a projection in a direction consistent with hemodynamic stress; and 5) a time interval from bypass surgery to rupture that lasted 4 years. These features, along with the well-known fact that hemodynamic stress can cause aneurysms, led the authors to believe that this aneurysm was a true one. The authors present a case of this unusual complication following bypass surgery and provide a brief review of the literature.

Anastomosis, Surgical↗
PubMed1995

Eucalyptone from Eucalyptus globulus.

A new cariostatic compound named eucalyptone was isolated from the leaves of Eucalyptus globulus. The structure of this compound was elucidated by spectroscopic methods.

Anti-Bacterial Agents↗
PubMed1995

Antitumor and antimicrobial activities of Fe(II)/Fe(III) complexes derived from some heterocyclic compounds.

The antitumor activities of some Fe(II)/Fe(III) complexes containing 1,3-diacetyl-2H-benzimidazole-2-thione along with a few derivatives of 1,2,4-triazol, 1,3,4-oxadiazole and 1,3,4-thiadiazole as co-ligands have been investigated. Antibacterial and antifungal activities of disulfido-/dichloro-bridged dinuclear Fe(III)/Fe(II) complexes containing similar heterocycles as terminal ligands have also been investigated.

Animals↗
PubMed1995

An improved source of bryostatin 10, Bugula neritina from the Gulf of Aomori, Japan.

Bryostatins have been isolated from diverse Japanese coastal specimens of Bugula neritina guided by inhibitory activity against fertilized sea urchin egg cell division. B. neritina from the Gulf of Aomori, Japan, has been found to contain bryostatin 10 [1b] in high yield (10(-3)%) for this class of compounds. The 1H- and 13C-nmr signals of bryostatin 10 [1b] were reassigned by 2D nmr techniques. The conformation of bryostatin 10 [1b] in solution was revealed by nmr studies. This compound also exhibited activity in a steroidogenesis assay by increasing the production of adrenocortical hormones nearly twofold.

Animals↗