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1.
Regulation of lithospermic acid B and shikonin production in Lithospermum erythrorhizon cell suspension cultures 总被引:6,自引:0,他引:6
Cell suspension cultures of Lithospermum erythrorhizon produced a large amount of lithospermic acid B, a caffeic acid tetramer, as well as shikonin derivatives (each ca. 10% of dry wt.) when cultured in shikonin production medium M-9. Various culture factors for increasing the production of lithospermic acid B were investigated. Lithospermic acid B production was inhibited by 2, 4-D or NH4+, whereas it was stimulated by Cu2+. These regulatory patterns were similar to those for the production of shikonin derivatives in these cell cultures, suggestive of close relations and similar metabolic regulation between the production of these compounds. Cultivation under light illumination, however, showed that these metabolisms were independently regulated. In particular, blue light showed a stimulatory effect on lithospermic acid B production, while shikonin production was strongly inhibited, indicative of an effective condition for lithospermic acid B production. 相似文献
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Neutral ruthenium(II) complexes [RuLL'(CN)2] (L, L' = bpy, dmb, dbb; bpy = 2,2'-bipyridine, dmb = 4,4'-dimethyl-2,2'-bipyridine, dbb = 4,4'-tert-butyl-2,2'-bipyridine) were prepared, and the luminescence characteristics of the complexes in the solid state were measured. The luminescence was tuned by crystal waters included in the crystals; for example, [Ru(dbb)2(CN)2] x 2H2O, [Ru(dbb)2(CN)2] x H2O, and [Ru(dbb)2(CN)2] emit luminescence at 640, 685, and 740 nm, respectively. 相似文献
4.
Ueda J Takeshita K Matsumoto S Yazaki K Kawaguchi M Ozawa T 《Photochemistry and photobiology》2003,77(2):165-170
The reaction of singlet oxygen (1O2) generated by ultraviolet-A (UVA)-visible light (lambda > 330 nm) irradiation of air-saturated solutions of hematoporphyrin with phenolic compounds in the presence of a spin trap, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), gave an electron spin resonance (ESR) spectrum characteristic of the DMPO-hydroxyl radical spin adduct (DMPO-*OH). In contrast, the ESR signal of 5,5-dimethyl-2-pyrrolidone-N-oxyl, an oxidative product of DMPO, was observed in the absence of phenolic compounds. The ESR signal of DMPO-*OH decreased in the presence of either a *OH scavenger or a quencher of *O2 and under anaerobic conditions, whereas it increased depending on the concentration of DMPO. These results indicate both 1O2- and DMPO-mediated formation of free *OH during the reaction. When DMPO was replaced with 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide (DEPMPO), no DEPMPO adduct of oxygen radical species was obtained. This suggests that 1O2, as an oxidizing agent, reacts little with DEPMPO, in which a strong electron-withdrawing phosphoryl group increases the oxidation potential of DEPMPO compared with DMPO. A linear correlation between the amounts of DMPO-*OH generated and the oxidation potentials of phenolic compounds was observed, suggesting that the electron-donating properties of phenolic compounds contribute to the appearance of *OH. These observations indicate that 1O2 reacts first with DMPO, and the resulting DMPO-1O2 intermediate is immediately decomposed/reduced to give *OH. Phenolic compounds would participate in this reaction as electron donors but would not contribute to the direct conversion of 1O2 to *OH. Furthermore, DEPMPO did not cause the spin-trapping agent-mediated generation of *OH like DMPO did. 相似文献
5.
4-Fluorinated UDP-MurNAc pentapeptide, 2, has been synthesized. In our previous study, UDP-MurNAc pentapeptide analogue 1 was found to be incorporated into the bacterial cell wall through biosynthesis. Compound 2 showed growth-inhibition activity against Gram-positive bacteria when it was added to growth media at 0.01 mg/mL. [structure--see text] 相似文献
6.
Ikuta A Mizuta N Kitahata S Murata T Usui T Koizumi K Tanimoto T 《Chemical & pharmaceutical bulletin》2004,52(1):51-56
Six novel branched beta-cyclodextrins (betaCDs) having beta-D-galactose residues on the non-reducing terminal of the sugar side chains, namely 6(1),6(4)-di-O-(beta-D-galactosyl)-betaCD (10), 6-O-(beta-D-galactosyl)-betaCD (11), 6(1),6(4)-di-O-(beta-lactosyl)-betaCD (14), 6-O-(beta-lactosyl)-betaCD (15), 6(1),6(4)-di-O-(4'-O-beta-D-galactosyl-beta-lactosyl)-betaCD (18), and 6-O-(4'-O-beta-D-galactosyl-beta-lactosyl)-betaCD (19), were chemically synthesized using the trichloroacetimidate method. The reaction products were separated by HPLC on an amino column into dibranched and monobranched betaCDs. Their structures were confirmed by mass spectrometry (MS) and two-dimensional (2D) NMR spectroscopic analysis. To study the length of the sugar side chains attached to the CD ring, which leads to differences in the functions of the branched CDs, interactions of these compounds with peanut (Arachis hypogaea) agglutinin (PNA) were investigated using an optical biosensor and an inhibition assay based on hemagglutination. The results showed that all branched betaCDs interacted with PNA, and the binding affinity was 18>14>10 and 19>15>11 when the derivatives were compared on the basis of side chain length. 相似文献
7.
[reaction: see text] A concise and enantioselective synthesis of (S)-2-cyclohexyl-2-phenylglycolic acid as a key intermediate for (S)-oxybutynin is reported. The crucial asymmetric tetrasubstituted carbon center was constructed with excellent stereoselectivity through the proline-catalyzed direct asymmetric aldol reaction between cyclohexanone and ethyl phenylglyoxylate under mild conditions. 相似文献
8.
Taichi Sato Takato Nakamura Toru Takahashi 《Journal of Thermal Analysis and Calorimetry》1985,30(1):97-106
The complexes (R3NHVO(OH)Cl2)2 and (R3RNVO(OH)Cl2)2 prepared by drying in vacuo the organic solutions from the extraction into benzene of aqueous vanadyl chloride solution with trioctylamine (TOA, R3N) and trioctylmethylammonium chloride (TOMAC, R3RNCl), were studied by thermogravimetry and differential thermal analysis under an atmosphere of nitrogen, and the products of their thermal decomposition, such as volatile matter and residues, by gas chromatography. X-ray diffraction and infrared spectroscopy. It was found that the complexes with TOA and TOMAC thermally decompose to V2O3 at 200–300° by cracking of the compounds R3NHVO(OH)Cl2 and R3RNVO(OH)Cl2 formed via dissociation of the complexes at about 150°.
We wish to thank the Koei Chemical Co. Ltd. for samples of TOA and TOMAC. 相似文献
Zusammenfassung Die Komplexe (R3NHVO(OH)Cl2)2 und (R3RNVO(OH)Cl2)2 wurden hergestellt, indem benzolische und wässrige Vanadylchlorid-Lösungen mit Trioctylamin (TOA, R3N) und Trioctylmethylammoniumchlorid (TOMAC, R3RNCl) extrahiert und die erhaltenen Lösungen im Vakuum eingedampft wurden. Die Komplexen wurden in Stickstoffatmosphäre mittels TG und DTA untersucht und die thermischen Zersetzungsprodukte, und zwar sowohl die flüchtigen Verbindungen als auch die Rückstände, gaschromatographisch bzw. röntgendiffraktometrisch und IR-spektroskopisch bestimmt. Es wurde festgestellt, daß die Komplexe mit TOA und TOMAC bei 150° in die Verbindungen R3NHVO(OH)Cl2 und R3RNVO(OH)Cl2 dissoziieren, die bei 200–300° thermisch zu V2O3 zersetzt werden.
(R3NHVO(OH)Cl2)2 (R3RNVO(OH)Cl2)2 (R3,) ( , R3RNCl). , , . , 200–300° V23 R3NV()l2 R3RNVO(OH)Cl2, 150°.
We wish to thank the Koei Chemical Co. Ltd. for samples of TOA and TOMAC. 相似文献
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10.
Taichi Sato 《无机化学与普通化学杂志》1970,376(2):205-208
The absorption spectra of sodium aluminate solutions have been examined at different concentrations. As a result, it was found that the characteristic absorption band due to aluminate ion shows a λmax at 265–270 mm?. 相似文献