银杏叶提取物对大鼠抗氧化能力的影响

探讨了银杏叶提取物对大鼠抗氧化能力的影响.结果表明:银杏叶提取物可以增加运动机体抗氧化酶的活性,提高机体的抗氧化功能,减轻大强度耐力训练对大鼠组织造成的脂质过氧化损伤,改善运动造成的自由基代谢紊乱,加快自由基的清除.     

电化学发光淬灭法测定SOD

在硼酸缓冲溶液（pH6．7）中性介质中,O2和H2O2均对鲁米诺的电化学发光（ECL）有敏化作用,而超氧化物歧化酶（SOD）对此敏化的电化学发光具有淬灭作用,SOD的浓度与两种发光体系的ECL光强成线性关系,可用于SOD的测定,为SOD的测定提供了一种灵敏、可靠的测定方法。     

Metal Complexes or Chelators with ROS Regulation Capacity: Promising Candidates for Cancer Treatment

Reactive oxygen species (ROS) are rapidly eliminated and reproduced in organisms, and they always play important roles in various biological functions and abnormal pathological processes. Evaluated ROS have frequently been observed in various cancers to activate multiple pro-tumorigenic signaling pathways and induce the survival and proliferation of cancer cells. Hydrogen peroxide (H₂O₂) and superoxide anion (O₂^•−) are the most important redox signaling agents in cancer cells, the homeostasis of which is maintained by dozens of growth factors, cytokines, and antioxidant enzymes. Therefore, antioxidant enzymes tend to have higher activity levels to maintain the homeostasis of ROS in cancer cells. Effective intervention in the ROS homeostasis of cancer cells by chelating agents or metal complexes has already developed into an important anti-cancer strategy. We can inhibit the activity of antioxidant enzymes using chelators or metal complexes; on the other hand, we can also use metal complexes to directly regulate the level of ROS in cancer cells via mitochondria. In this review, metal complexes or chelators with ROS regulation capacity and with anti-cancer applications are collectively and comprehensively analyzed, which is beneficial for the development of the next generation of inorganic anti-cancer drugs based on ROS regulation. We expect that this review will provide a new perspective to develop novel inorganic reagents for killing cancer cells and, further, as candidates or clinical drugs.     

Metal-Based Molecular Design Tuning Biochemical Behavior: Synthesis,Characterization, and Biochemical Studies of Mixed Ligand Complexes Derived From 4-Aminoantipyrine Derivatives

Biosensitive mixed ligand complexes of metals (Fe(III), Co(II), Ni(II), Cu(II), and Zn(II)) with the Schiff bases of L¹ and HL² (L¹: obtained through the condensation of 4-aminoantipyrine with furfuraldehyde; HL²: derived from 2-aminophenol and 3-nitrobenzaldehyde) were synthesized. They were characterized using elemental analysis, magnetic susceptibility, molar conductance, proton nuclear magnetic resonance spectroscopy, ultraviolet–visible spectroscopy, infrared, and electron spin resonance techniques. Cyclic voltammogram of the complexes in dimethylsulfoxide solution at 300 K was recorded and their salient features were summarized. The X-band electron spin resonance spectrum of the copper complex in dimethylsulfoxide solution at 300 and 77 K was recorded. The in vitro biological screening effects of the investigated compounds were tested against the bacterial species Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, and Pseudomonas aeruginosa and the fungal species Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola, and Candida albicans by disc diffusion method. Comparative study of inhibition values of the Schiff bases and their complexes indicates that the complexes exhibit higher antimicrobial activity than the free ligands. DNA binding studies of metal complexes using ultra-violet-visible spectroscopy and cyclic voltammetry paved the way to probe their DNA binding abilities. The solvatochromism and superoxide dismutase activity of these complexes have also been examined.     

Circle measurements in ancient China

This paper discusses the method of Liu Hui (3rd century) for evaluating the ratio of the circumference of a circle to its diameter, now known as π. A translation of Liu's method is given in the Appendix. Also examined are the values for π given by Zu Chongzhi (429–500) and unsurpassed for a millenium. Although the method used by Zu is not extant, it is almost certain that the applied Liu's method. With the help of an electronic computer, a table of computations adhering to Liu's method is given to show the derivation of Zu's results. The paper concludes with a survey of circle measurements in China.     

Cu,Zn-SOD在银电极上的原位表面增强Raman光谱

本文应用原位共焦拉曼光谱技术观察了Cu ,Zn -SOD分子在经表面增强处理后的银电极上 ,吸附状态随电位跃迁变化的过程。结果表明在 -0 2V～ 0 1V的电位区间内 ,Cu,Zn -SOD分子经由羧酸根离子吸附于银电极表面 ,而在 0 2～ 0 4V电位区间内发生脱附 ,表面吸附的物种改变为缓冲溶液中的磷酸根离子。上述结果为SOD分子在固体电极表面电子传递机制的探索提供了依据。     

Antimycobacterial and anticancer activity of newly designed cinnamic acid hydrazides with favorable toxicity profile

A series of twelve novel hybrids of cinnamic acid and thiocarbohydrazones were designed, synthesized in high yield using a simple coupling strategy via acid chlorides, and evaluated for their impact against Mycobacterium tuberculosis (Mtb) and cancer cells survival. Among them, compound 3 demonstrated strong anti-Mtb activity by reducing bacilli survival for>90 % in all three treated Mtb isolates, whereas isoniazid and rifampicin did not. Moreover, compound 3 didn’t affect vitality of HepG-2 cells, implying on advantageous hepatotoxicity profile compared to current therapeutic options for tuberculosis. Compounds 2a and 3b displayed as strong inducers of apoptosis in A549 cells, both activating intrinsic caspase pathway and cell cycle arrest at the G0/G1 phase. Subsequent analyses disclosed differences in their activities, where 3b has ability to induce production of mitochondrial superoxide anions, while 2a significantly inhibited cellular mobility. More importantly, 3b considerably affected viability of HepG-2 and HaCaT cells, whereas 2a had moderate impact only on the later. Molecular modeling studies indicated high permeability and good absorption through the human intestine, and moderate aqueous solubility with poor blood–brain barrier permeability. In summary, our results reveal that novel compounds 3 and 2a represent promising agents for tuberculosis and cancer treatment, respectively, indicating that further investigation needs to be performed to clarify the mechanisms of their anti-Mtb and anticancer activity.     

Synthesis,Characterization and SOD Activities of IP-copper（Ⅱ）-L-amino Acid Complexes

Four new ternary complexes： [Cu（IP）（L-Val）（H2O）]ClO4·1.5H2O（1）, [Cu（IP）（L-Leu）（H2O）]ClO4（2）, [Cu（IP）（L-Tyr）（H2O）]ClO4·H2O（3） and [Cu（IP）（L-Trp）（H2O）]ClO4·1.5H2O（4） have been synthesized and character/zed by elementa/analysis, molar conductivity, infrared absorption spectroscopy, electronic absorption spectroscopy and cyclic voltammetry, where IP=imidazo[4,5-f][1,10] phenanthroline, L-Val=L-valinate, L-Leu=L-leucinate, L-Tyr=L-tyrosinate and L-Trp=L-tryptophanate. Complex 3 was structurally characterized by X-ray diffraction method, which crystallizes in orthorhornbic space group P21212 in a unit cell of dimensions a=3.0567（4） nm, b=0.74079（9） nm, c= 1.06198（13） nm, V=2.4047（5） nm^3, Z=4,μ=0.1084 cm^-1. The SOD-like activities of catalytic disrnutation of superoxide anions （O2^-· ） by the complexes were determined by means of modified nitroblue tetrazolium （NBT） photoreduction. The IC50 values of complexes 1, 2, 3 and 4 are 0.072, 0.147, 0.429 and 0.264 μmol·L^-1, respectively     

The Direct Electron Transfer of Iron‐Containing Superoxide Dismutase (Fe‐SOD) and its Catalysis for the Oxygen Reduction Reaction (ORR) in Room Temperature Ionic Liquids (RTILs) on a Gold Electrode

In this work, for the first time, the direct electron transfer of iron‐containing superoxide dismutase (Fe‐SOD) was observed by cyclic voltammetry on a gold (Au) electrode in three RTILs, i.e., 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (EMIBF₄), 1‐n‐propyl‐3‐methylimidazolium tetrafluoroborate (PMIBF₄) and 1‐n‐butyl‐3‐methylimidazolium tetrafluoroborate (BMIBF₄). And the results demonstrate that when the scan rate was as low as 1 mV/s, a pair of well‐defined quasi‐reversible peaks of Fe‐SOD was presented, while as the potential scan rate was above 10 mV/s, the reduction peak of Fe‐SOD disappeared though its oxidation peak could be clearly observed even as the potential scan rate was up to 400 mV/s, strongly indicating that these CVs we observed were attributable to Fe‐SOD rather than the impurities in RTILs. Its catalysis for oxygen reduction reaction (ORR) was directly verified by the shifting of formal potential, E⁰′, of ORR, to the positive direction though the value of standard rate constant, κ⁰, corresponding to ORR, was not much enhanced. In PMIBF₄, for the multi‐walled carbon nanotubes (MWCNTs)‐modified gold electrode, both the reduction peak current and oxidation peak current for oxygen redox reaction were all dramatically enhanced compared to the case of a bare gold electrode, and the value of κ⁰ was also increased from 3.1 × 10^?3 cm s^?1 for the bare gold electrode, to 17.5 × 10^?3 cm s^?1. Hence, in the presence of Fe‐SOD in RTILs, MWCNTs, showing catalysis for the electron transfer process of ORR, coupled with Fe‐SOD, leading to the shifting of formal potential corresponding to ORR to the positive direction, presented us a satisfactory catalysis for ORR in RTILs. Some reasons available for this catalysis behavior stemming from Fe‐SOD, and MWCNTs as well, for ORR are discussed based on the previously developed proposition.     

Synthesis, Structure and Biological Activity of Zn（Ⅱ） Complex with Tris（benzimidazol-2-yl-methyl）amine Ligand

A new Zn(II) mononuclear complex with tris(benzimidazol‐2‐yl‐methyl)amine (NTB) was synthesized with stoichiometry of [Zn(NTB)NO₃]NO₃ · DIPY · DMF (DIPY : 4,4′‐dipyridyl). The complex was characterized by elemental analysis, UV and IR spectra. The crystal structure was determined by using X‐ray diffraction analysis. The crystal structure indicates that four N atoms and one O atom coordinate to zinc ion to construct a distorted trigonal‐dipyramid configuration. Three nonprotonated N atoms from imidazole groups are in the equatorial plane, one alkylamino N atom and one O atom from NO₃^?_‐ in the axial directions. The biological activity assay shows that this complex presents certain biological activity by means of pyrogallol autoxidation and it can be called a model compound of superoxide dismutase (SOD).