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61.
淫羊藿根与叶活性成分的分析和比较 总被引:8,自引:0,他引:8
采用细胞膜色谱法(CMC)筛选,并结合离体药理实验确定主要活性成分,利用高效液相色谱法分析比较了淫羊藿根与叶中的活性成分及其差异性.色谱条件为Kromasil ODS 柱(150 mm× 4.6 mm.I.D )流动相甲醇-水(70:30,V:V);检测波长270nm。筛选发现淫羊藿根中的两个有效成分YYH-214和YYH-216对血管有较强的舒张作用,表明活性成分在CMC模型体系中的保留特性与药理作用之间存在良好的相关性。在此色谱条件下淫羊藿叶未检测到这两种活性成分. 相似文献
62.
S-Alkylation of 2-acetamido-9-(2-acetoxyethoxymethyl)-6-oxo-8-thioxopurine was used to synthesize its novel S- and N(7)-substituted derivatives. We have established the effect of the structure of the alkylating agent on the reaction conditions and its regioselectivity. We have shown that the synthesized guanine derivatives can be modified further. 相似文献
63.
64.
Z. A. Starikova A. I. Yanovsky Yu. T. Struchkov S. V. Zubkov I. I. Seifullina 《Russian Chemical Bulletin》1996,45(9):2157-2162
The crystal structure of the product of the condensation of (salicylideneamino)nitroguanidine with salicylaldehyde on a Ni2+ ion template, K[Ni(C15H10N5O4)] · DMF, has been studied. It was established that a planar Ni complex, consisting of isolated [NiL]– anions and solvated [K+ · DMF] cations, is formed. The negative charge of the anion is localized mainly on the O atoms of the nitro group. The nitroguanidine fragment of the ligand occurs in the tautomeric form, which was not reported previously.Deceased in 1995Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2273–2277, September, 1996. 相似文献
65.
Junko Kuwahara Hideo Akisada Tamaki Kato Norikazu Nishino 《Colloid and polymer science》2005,283(7):747-752
A series of peptides containing various hydrophobic amino acids [methionine (Met), leucine (Leu), norleucine (Nle), phenylalanine (Phe), 2-aminooctanoic acid (Aoc), and 2-aminodecanoic acid (Ade)] were synthesized and their conformations were studied using circular dichroism (CD) spectroscopy in different solvents such as water, methanol, and aqueous solution of ammonium tetradecanesulfonate. Peptides containing hydrophobic amino acids with linear side chains formed -sheets in water and methanol. Electrostatic interaction between the charged side chain (lysine) and a micelle consisting of an anionic surfactant, ammonium tetradecanesulfonate, is necessary for the formation of -helices in micellar environments. The conformational transition from -helix to -sheet structure required moderate hydrophobicity and linear side chains. This conformational transition depended on the surfactant concentration. 相似文献
66.
Capillary electrophoresis with end-column amperometric detection of urinary 8-hydroxy-2'-deoxyguanosine 总被引:1,自引:0,他引:1
Urinary 8-hydroxy-2'-deoxyguanosine (8OHdG) is an excellent marker of oxidative DNA damage. Until now, urinary 8OHdG has been measured by high-performance liquid chromatography with electrochemical detection. A simple and sensitive method for the analysis of urinary 8OHdG by capillary electrophoresis with end-column amperometric detection has been developed in our laboratory. A single-step solid-phase extraction procedure was optimized and used for extracting 8OHdG from human urine. To improve the sensitivity of this method, a new focusing technique based on a dynamic pH junction was used. The limit of detection was 20 nM (signal-to-noise ratio S/N = 3), the linear range was 50 nM-10 microM, and the correlation coefficient was better than 0.999. The relative standard deviation (RSD) was found to be 0.57% for migration time, and 4.79% for peak current. To show the usefulness of the method, the urinary concentration of 8OHdG in nine healthy persons and ten cancer patients was determined. The urinary concentration of 8OHdG in cancer patients was significantly higher than that in healthy persons. 相似文献
67.
Complexation of AlIIIby 8-hydroxyquinoline and fluorescence behavior of the quinolinate(s) were studied in reverse micellar systems at low water content, and compared to aqueous media. Two surfactants were used: one was cationic (CTAC: cetyltrimethylammonium chloride) and the other was anionic (AOT: sodium bis(2-ethylhexyl)sulfosuccinate). The results obtained in the CTAC/dichloromethane system (W= [H2O]/[surfactant] = 0.9) showed that complexation occurred very likely in the oil phase and no micellar effect was observed. On the contrary, in the presence of AOT, specific micellar effects were observed due to the presence of the anionic polar heads: stabilization of the positively charged 1:1 and 1:2 chelates, at the expense of the neutral water-insoluble 1:3 chelate which is formed in aqueous solutions under similar conditions;drastic fluorescence enhancement factorsof 120 and 100 in AOT/heptane (W= 1.5) and AOT/dichloromethane (W= 1.6), respectively. Such factors have never been reported so far in either hydroorganic or direct micellar systems. In return, the length of time for the production of the complex(es) is increased because of the microheterogeneity of the medium and the small sizes of the water pools. 相似文献
68.
The kinetics of the reaction between organocobaloximes, RCo(DH)2H2O, and iodine have been investigated. They reveal the participation of an RCo(DH)2H2O · I2 intermediate which undergoes intramolecular transalkylation and acts as an electrophile towards a second organocobaloxime molecule. The trend in reactivity as the R group is varied is discussed. 相似文献
69.
Pentacoordinate complex cations of the general formula [(C6F5)2SbL3]3+ stabilized as solid salts in combination with tetraphenylborate (BPh4), tetrafluorobroate (BF4) anions, where L=DMSO, Ph3AsO, PyO, DMF, α-, β- and γ-picoline have been isolated. The newly formed complexes were characterized by elemental analysis, molar conductance measurements, solid-state IR and and NMR. From these results, a five-fold coordination around antimony was required. 相似文献
70.
Cheng-Hsien Lin 《中国化学会会志》1993,40(5):485-487
6,13-Dihydroxyimino-5,12-dimethyl-7,14-dioxo-1,4,8,11-tetraazacyclotetradeca-4,11-diene 2 was prepared by condensation of ethyl α-oximinoacetoacetate with ethylenediamine in tetrahydrofuran at room temperature. Reduction of 2 gave the corresponding 6,13-dihydroxyimino-5,12-dimethyl-7,14-dioxo-1,4,8,11-tetraazacyclotetradecane 3 . Acylation of 2 afforded 6,13-bis(O-acetoxyimino)-5,12-dimethyl-7,14-dioxo-1,4,8,1 l-tetraazacyclotetradeca-4,11-diene 4 . The structures of 2 , 3 and 4 were determined by IR, NMR and mass spectroscopy. 相似文献