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↗
Biomedical subjects
K Takeya
Publications and source records attributed to K Takeya.
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↗
Cyclic peptides from higher plants, Part 15. Pseudostellarin H, a new cyclic octapeptide from Pseudostellaria heterophylla.
A new cyclic octapeptide, pseudostellarin H [1], was isolated from the roots of Pseudostellaria heterophylla. Based on spectral evidence and chemical degradation, the primary structure of 1 was established as cyclo(Gly-Thr-Pro-Thr-Pro-Leu-Phe-Phe).
Amino Acid Sequence↗
Estrogen-like activity of cyclic peptides from Vaccaria segetalis extracts.
Methanol and ethyl acetate extracts of Wang Bu Liu Xing (seeds of Vaccaria segetalis, Caryophyllaceae) and cyclic peptides (named segetalins A and B) obtained from the extracts were shown to have an estrogen-like activity.
Amino Acid Sequence↗
Cytotoxic limonoids and tetranortriterpenoids from Melia azedarach.
The ethanolic extract of the root bark of Melia azedarach exhibited cytotoxic activity against lymphocytic leukemia P388 cell lines in vitro. Systematic fractionation of the extract monitored by cytotoxic bioassay led to the isolation of two new azadirachtin-type limonoids, 1-tigloyl-3-acetyl-11-methoxymeliacarpinin (1) and 1-acetyl-3-tigloyl-11-methoxymeliacarpinin (2), together with three highly cytotoxic sendanin-type limonoids, 29-isobutylsendanin (3), 12-hydroxyamoorastin (4) and 29-deacetylsendanin (5). The acetylated derivatives of 4 also underwent cytotoxic bioassay.
Animals↗
Solution forms of antitumor cyclic pentapeptides with 3,4-dichlorinated proline residues, astins A and C, from Aster tataricus.
Conformational analysis of antitumor cyclic pentapeptides, astins A (1) and C (3), was made by a combination of NMR and computational techniques. These results indicated that the backbone conformations of 1 and 3, with lower activity than astin B (2), were different from that of 2. The backbone conformation together with a cis 3,4-dichlorinated proline residue was considered to play an important role in the antitumor activities of astins.
Antineoplastic Agents, Phytogenic↗
Structure of a new peptide, astin J, from Aster tataricus.
A new peptide called astin J (1) was isolated from the roots of Aster tataricus. The structure was elucidated by spectroscopic methods and chemical transformation from a cyclic pentapeptide, astin C, isolated from A. tataricus to the analogous acyclic peptide, 2. Antileukemic activities of the series of acyclic peptides are also described.
Amino Acid Sequence↗
Direct measurement of increased myocardial cellular 23Na NMR signals in perfused guinea-pig heart induced by dihydroouabain and grayanotoxin-I.
The effects of the cardiac glycoside dihydroouabain (DHO), and the ericaceous toxin grayanotoxin-I (GTX-I) on myocardial cellular sodium (Nai) concentrations were investigated using sodium-23 nuclear magnetic resonance (23Na NMR) spectroscopy at 30 degrees C in isolated perfused guinea-pig hearts. The Nai NMR signals from perfused Langendorff heart preparations were obtained by the modified inversion recovery (IR) method based on the previous observation that the spin-lattice relaxation time (T1) of the Nai (25 or 34 msec at 8.46 Tesla (T)) is much faster than that of extracellular sodium (64 msec at 9.4 T). Nai was estimated from the calibration curve of the frequency area of the 23Na NMR FT spectra plotted against the standard Na concentration. The Nai concentration of the heart increased concomitantly with the positive inotropic effects (PIE) of DHO, GTX-I and monensin (MON). The cumulative sequential addition of DHO (5 x 10(-6) M), GTX-I (7 x 10(-8) M) and MON (5 x 10(-6) M), each of which alone induced no appreciable PIE, produced a 22% elevation in Nai concentration relative to that of the control (100%) accompanying a PIE of 44%. The mechanism of this Nai elevation induced by combinational addition of DHO, GTX-I and MON may be mediated as follows: GTX-I increases the net Na-influx via Na+ channels; DHO inhibits the pumping out of Na+ from the cell; and MON transports external Na+ into the cell, acting as a sodium ionophore. Consequently, these drugs act synergistically to increase the Nai, thereby increasing the intracellular Ca2+ concentration via Na(+)-Ca2+. exchange.
Animals↗
Antibacterial trichorabdal diterpenes from Rabdosia trichocarpa.
Four antibacterial diterpenes, trichorabdals A, B, C and H were isolated from the leaves of Rabdosia trichocarpa and the relationship between their conformations analysed by spectroscopic and computational methods. Their antibacterial activity is discussed.
Anti-Bacterial Agents↗
Cytotoxic aromatic triterpenes from Maytenus ilicifolia and Maytenus chuchuhuasca.
The isolation and structure elucidation of four cytotoxic aromatic triterpenes [1-4] along with three known quinoid triterpenes [5-7] from the South American medicinal plants Maytenus ilicifolia and M. chuchuhuasca are described. The structures of these aromatic triterpenes contained aromatized A rings and C-6 oxygenated B rings, and were elucidated by 1H- and 13C-nmr spectroscopic studies and by X-ray crystallographic analysis of 3.
Antineoplastic Agents, Phytogenic↗
Cardiotonic flavonoids from Citrus plants (Rutaceae).
Two flavonoids, 3,5,6,7,8,3',4'-heptamethoxyflavone (HEPTA) and natsudaidain isolated from Citrus plants (Rutaceae), produced a positive inotropic effect (PIE) on guinea-pig papillary muscle. Natsudaidain (pD2 4.98 +/- 0.07) was more potent than HEPTA (pD2 4.33 +/- 0.08), but the maximum PIE of HEPTA was greater than that of natsudaidain. The PIE of HEPTA was completely inhibited by reserpinization of the guinea pig, and partially inhibited by metoprolol and carbachol. The carbachol inhibition was omitted by atropine. The mechanism of PIE of HEPTA is accounted for catecholamine release from cardiac tissue.
Animals↗
Structural and conformational studies of [Ile7] and [Leu7]surfactins from Bacillus subtilis natto.
A novel [Ile7]surfactin (1), which showed anti-human immunodeficiency virus activity, has been isolated from Bacillus subtilis natto. Structural and conformational analysis of the peptide backbone of [Ile7]surfactin was conducted by a combination of various two-dimensional (2D) nuclear magnetic resonance (NMR), circular dichroism (CD) spectroscopy and simulated annealing calculations, compared with a known [Leu7]surfactin (2). Both surfactins were shown to exist in different conformational states in both polar and apolar solvents.
Amino Acid Sequence↗
An investigation of diterpenes from the leaves of Rabdosia trichocarpa and their antibacterial activity against oral microorganisms.
The ethanolic extract of Rabdosia trichocarpa leaves showed antibacterial activity against cariogenic mutans streptococci and periodontopathic Porphyromonas gingivalis. Chromatographic separation and purification of the extract afforded ten diterpenes, including one novel ent-kauren type compound named trichoranin. Some of these compounds possess potent antibacterial activity against these oral micro-organisms, indicating that these diterpenes may be useful natural substances for the maintenance of oral health.
Anti-Bacterial Agents↗
[Anti-hypoxia and anti-glucose deficiency effects of PQS on guinea pig papillary muscle in low frequency electrical stimulation].
Panax quinquefolium saponin (PQS) increases the contractibility of papillary muscle of guinea pigs during electrical stimulation with frequency of 1/8-1/64Hz (P < 0.05). In Krebs-Henseleit solution purged with gas containing 95% N2 and 5% CO2 regardless of containing glucose or not, PQS (0.3mg/kg) has the effect of anti-hypoxia and anti-glucose deficiency (P < 0.05, P < 0.01) in the electrical stimulation with frequency of 1/8-1/64Hz.
Animals↗
Two antitumour bicyclic hexapeptides from Rubia cordifolia.
Two novel antitumour bicyclic hexapeptides, named RA-XV and -XVI, were isolated from Rubia cordifolia and their structures were characterized by spectroscopic and chemical means.
Amino Acid Sequence↗
Satisfactory separation and MS-MS spectrometry of six surfactins isolated from Bacillus subtilis natto.
We optimized HPLC conditions for the first time to achieve satisfactory separation of six surfactins, two of which were novel, isolated from Bacillus subtilis natto. Peptide sequences were analyzed by sophisticated MS-MS analysis, performed with a pair of two surfactins with different fatty acid substitutions. Fragment peaks were divided into two series; one was a series of the ions which carried fatty acid, and thus were characterized by the fatty acid mass difference, and the other was a series of the ions which consisted of pure peptide and thus showed a superimposable pattern between a pair of surfactins.
Amino Acid Sequence↗
Cytotoxic sesquiterpenes from Nardostachys chinensis.
Five cytostatic sesquiterpenes, desoxo-narchinol-A (1), nardosinone (2), debilon (3), nardosinonediol (4) and kanshone A (5), were isolated from the roots and rhizomes of Nardostachys chinensis (Valerianaceae). The steric structure of 1 was determined by nuclear Overhauser effects (NOEs) and the exciton chirality method. All five showed cytotoxic activity against P-388 cells and the structure-activity relationship of 1 was also discussed.
Animals↗
Preparation and cytotoxicity of cyclic hexapeptides, RA derivatives.
Several aromatic ring substituent modified RA derivatives were prepared from RA-VII (1), RA-V (8) and RA-II (11), and evaluated for cytotoxicity against P388 leukemia and KB cells. In terms of IC50 values, the C zeta methoxyl group of Tyr-3 greatly influenced the activities, while the substituents at the C zeta position of Tyr-6 were less important. One of the derivatives, Tyr-6-C zeta-deoxyRA-V (9, P388, IC50, 0.0025 micrograms/ml) was nearly as active as RA-VII (1, 0.0013 micrograms/ml), and also expressed promising anti-P388 in vivo activity (test/control = 171%, at 25 mg/kg).
Animals↗