Synthesis, Structure, DNA interaction and Cytotoxicity of Pyridine-Based Mononuclear Cobalt(Ⅱ) Complex

Chun-Yan GAO Pei-Pei QIAO Huang-Ze YANG Peng-Fei ZHANG Yun-Bo LEI Yong-Po ZHANG Min WANG Ai-Qin YUE Jin-Zhong ZHAO Wei-Jun DU

Citation:  GAO Chun-Yan, QIAO Pei-Pei, YANG Huang-Ze, ZHANG Peng-Fei, LEI Yun-Bo, ZHANG Yong-Po, WANG Min, YUE Ai-Qin, ZHAO Jin-Zhong, DU Wei-Jun. Synthesis, Structure, DNA interaction and Cytotoxicity of Pyridine-Based Mononuclear Cobalt(Ⅱ) Complex[J]. Chinese Journal of Inorganic Chemistry, 2020, 36(9): 1783-1790. doi: 10.11862/CJIC.2020.208 shu

吡啶类单核钴(Ⅱ)配合物的合成、结构、与DNA的相互作用及细胞毒性

    通讯作者: 高春艳, gaocynk@163.com
    杜维俊, duweijun68@126.com
  • 基金项目:

    山西省高等学校大学生创新创业训练项目 2019137

    山西省高等学校大学生创新创业训练项目 2019136

    山西农业大学引进人才科研启动金 2013YJ40

    山西省自然科学基金 201701D221157

    山西省重点研发计划项目 201703D221008-4

    山西省重点研发计划项目 201703D211001

    山西省重点研发计划项目 201903D221036

    山西省重点研发计划项目 201703D221004-5

    山西省重点研发计划项目(No.201703D211001, 201903D221036, 201703D221008-4, 201703D221004-5)、山西省自然科学基金(No.201701D221157, 201701D221158)、山西农业大学引进人才科研启动金(No.2013YJ40)和山西省高等学校大学生创新创业训练项目(No.2019136, 2019137)资助项目

    山西省自然科学基金 201701D221158

摘要: 合成了一个新的单核钴配合物[Co(L)Cl2],配体L为吡啶类多齿配体4-甲基-N,N-二(吡啶-2-亚甲基)苯胺。对化合物进行了红外光谱、元素分析、X射线单晶衍射的表征。结果表明配合物的Co(Ⅱ)中心为五配位畸变的三角双锥构型。利用电子吸收、发射光谱和凝胶电泳等方法研究了配合物与DNA的相互作用。结果表明不加诱导剂时该配合物与DNA能表现出一定程度的切割活性,而加入诱导剂过氧化氢后,化学核酸酶活性显著提高。其切割机理为氧化切割机理,其中活性氧可能为·OH和1O2,且配合物与DNA的结合部位可能在大沟槽处。另外,用MTT实验测定了该配合物对体外HeLa、BGC-823、NCI-H460肿瘤细胞生长的抑制能力。

English

  • DNA, the deoxyribonucleotide, is a major compo-nent of chromosomes and plays an important role in the translation, transcription and replication of the genetic code of life. Also, DNA is an important target molecule for many antitumor drugs in vivo[1]. In recent years, the interaction of small molecule transition metal complex-es with DNA and its chemical nuclease activity has become a hot spot in bioinorganic chemistry research. Transition metal complexes have been widely used as DNA structure probes, DNA molecular light switches, DNA breaking agent and anticancer drugs[2-5]. In order to further explore the reaction mechanism of metal com-plexes and DNA interaction, people used copper, iron, zinc, ruthenium and other metals to synthesize a large number of metal complexes for research[6-9]. Spectro-scopic studies suggest that there exists an interaction between acyclic copper complex of Cu(L) (H2 O) and DNA[10]. The dipyridine copper complexes with guani-dine/amine side chains discovered by Ji Liang-Nian et al. can hydrolyze superhelix DNA and obtain linear products at the same time[11]. The ruthenium(Ⅱ) polypyr-idine complexes can intercalate into DNA base pairs, and it is found that single oxygen (1O2) is likely to be the ROS (reactive oxygen species) for catalytic cleav-age[12]. The zinc(Ⅱ) complex containing guanidine thios-emicarbazide shows that it has certain anti - tumor cell proliferation in vitro for lung cancer cells (A549) and breast cancer cells (MCF7) through cytotoxicity experi-ments and its action may be combined into cell DNA by partial insertion[13].

    Cobalt is an essential trace element found in all animals. Cobalt plays a crucial role in several biologi-cally important processes, and is predominately found in the form of vitamin B12 (cobalamin). Many biologi-cal enzymes rely on the reaction of cobalt to stimulate their activity, so as to complete the catalytic effect on the metabolic process in the organism. The different forms of cobalamin are necessary for proper formation of red blood cells, DNA synthesis and regulation, and the maintenance of normal brain and nerve function. There is also evidence implicating cobalamin in fatty acid and amino acid metabolism. Given the prominent role of cobalt in biological processes, humans have evolved mechanisms to overcome cobalt overload. Cobalt is thus less toxic to humans than non - essential metals like platinum[14-16]. Therefore, the study of cobalt complexes is of great significance in pharmacology, coordination chemistry and bioinorganic chemistry

    Herein, we synthesized a new cobalt complex and confirmed the crystal structure by X - ray single crystal diffractometer; further characterized the complex by infrared spectroscopy and elemental analysis; and interaction between the complex and CT - DNA were studied by electron absorption spectroscopy and fluo-rescence spectroscopy. The cleavage effect of the com-plex on the plasmid pBR322 DNA and its mechanism were studied by agarose gel electrophoresis. It provides preliminary work basis for the synthesis of chemical nucleases with DNA site-specific recognition and local-ization cleavage. Moreover, MTT method was used to determine the inhibitory effect of the complex on the growth of tumor cells in vitro.

    Elemental analysis (C, H, N) was conducted with a PerkinElmer 240Q elemental analyzer. IR spectra were obtained on a Bruker TENOR 27 Fourier trans-form infrared spectrometer. Electronic spectra were measured on a JASCO V-570 spectrophotometer. Fluo-rescence spectrum was measured with a Cary Eclipse fluorescence spectrometer. The electrophoresis experi-ment was performed with constant pressure DYY - Ⅲ electrometer, and the gel imaging experiment was per-formed with UVITEC gel automatic imaging analysis system.

    All reagents and solvents were purchased from commercial sources. The complex was soluble in H2O-DMF mixed solvent, 0.01 mol·L-1 in 10%(V/V) DMF/ H2O of the stock solution was stored at 4 ℃ and prepared to required concentrations for the chemical nuclease and bioactivity experiments. Tris, EDTA, DMSO, NaCl and H3BO3 used in biological activity experiments are guarantee reagents. Calf thymus DNA (CT-DNA) (BR) was produced by Fluka company. PBR322 DNA (BR) was purchased from Fermentas; ethidium bromide (EB) (AR) and agarose were Sigma- Aldrich products. Fetal bovine serum, RPMI1640, DMEM, and MTT were purchased from Solarbio.

    The synthesis and characterization of ligand L (4- methyl- N, N - bis(pyridin - 2 - ylmethyl) aniline) refer to published literature[17-18]. The ligand (0.2 mmol) was dissolved in 10 mL methanol and stirred. At the same time, 0.2 mmol N, N-diethyl-ethylamine was added dropwise. After stirring at room temperature for 30 min, 10 mL CoCl2·6H2O (0.2 mmol, 26 mg) ethanol solution was slowly added, and the stirring was contin- ued at room temperature for 5h. Then the mixture was filtered. The filtrate was allowed to stand at room tem- perature for one week until blue crystals suitable for X- ray collection was obtained. The excess solution was filtered, washed with ether, and dried in air. Yield: 38%. Element analysis Calcd. for C19H19Cl2CoN3(%): C, 54.44; H, 4.57; N, 10.02. Found(%): C, 54.49; H, 4.61;N, 9.99. FT-IR (KBr, cm-1): 3 428, 3 068, 2 918, 1 608, 1 516, 1 482, 1 446, 1 310, 1 266, 1 191, 1 056, 1 025, 858, 816, 776, 650.

    The crystal with suitable size (0.4 mm×0.25 mm× 0.2 mm) was selected for X-ray single crystal diffrac- tion. X - ray diffraction data were collected on Bruker Smart 1000 CCD diffractometer using Mo radiation (λ=0.071 073 nm) with ω-2θ scan mode at 293(2) K[19]. The intensity data was corrected by the SADABS pro- gram. The crystal structure was obtained by direct method, and the full matrix least squares correction was performed on all non-hydrogen atoms by anisotro- pic thermal parameter method. Hydrogen atoms were added by geometric theoretical hydrogenation proce- dures. All calculations were done using the SHELXS- 97 and SHELXL-97 programs[20-21]. Crystallographic data details and structure refinement parameters are presented in Table 1. Selected bond lengths and angles are listed in Table S1 (Supporting information).

    Table 1

    Table 1.  Crystallographic data for complex 1
    下载: 导出CSV
    Molecular formula C19H19Cl2CoN3
    Formula weight 419.2
    Crystal system Monoclinic
    Space group P21/n
    a/ nm 0.913 70(18)
    b/ nm 1.160 9(2)
    c/ nm 1.806 5(4)
    β/(°) 104.54(3)
    V/ nm3 1.854 8(6)
    Z 4
    D/ (g·cm-3) 1.501
    F(000) 860
    θrange for data collection / (°) 3.33~25.01
    Index range (h, k, l) -10 ≤ h ≤ 10, -13 ≤ k ≤ 13, -21 ≤ l ≤ 20
    Total diffraction point 10 381
    Independent diffraction point (Rint) 3 268 (0.043 0)
    Goodness-of-fit on F2 1.173
    R1, wR2[I > 2σ(I)] R1=0.050 9, wR2=0.098 5
    R1, wR2(all data) R1=0.066 4, wR2=0.103 9
    Largest diff. peak and hole / (e·nm-3) 303 and -394

    CCDC: 1966237.

    The chemical nuclease activity (absorption spec-troscopic assay, fluorescence spectrum assay and pBR322 DNA cleavage activity) and cytotoxicity exper-iments were conducted using the similar methods described previously[17-18, 23]. For complete experimental methods see the Supporting information.

    The crystal structure of complex belongs to the monoclinic system, P21/n space group. The crystal anal-ysis results show that the basic unit of the mononuclear cobalt complex is composed of a neutral [Co(L)Cl2] molecule. As shown in Fig. 1, the Co center of the complex shows a penta- coordinated geometry with N 3 Cl2 donor sets (a tertiary amine N atom, two pyridine N atoms, and two Cl atoms). τ =0.80[22], therefore the coordination center can be described as a trigonal-bipyramidal configuration. Two pyridine N atoms (N2 and N3) and one Cl1 atom occupy the triangular plane position, while the other Cl2 atom and N1 occupy the axial position.

    Figure 1

    Figure 1.  X-ray crystal structure of complex 1

    Hydrogen atoms are omitted for clarity

    The electronic absorption spectrum of the com-plex interacted with DNA and its corresponding fitting data are shown in Fig. 2a. The observed intense UV absorption peak at 210 nm for the complex are as-signed to the π - π* transition of intraligand. With the gradual addition of CT - DNA, the absorption peak can cause hypochromic effect and a little red shift (7 nm). It can be considered that the complex had an insertion effect with CT-DNA. In order to quantify the insertion capacity of the complex and CT-DNA, the binding con-stant Kb of interaction of the complex with DNA has been calculated according to the formula cDNA/(εa- εf)= cDNA/(εb-εf) +1/[Kb(εb-εf)] [23]. The relative calculatingresults are shown in Table S2, and the value of Kb was 9.03×104 L·moL-1, which suggests that the binding strength of the complex to DNA is moderate.

    Figure 2

    Figure 2.  (a) Absorption spectra of complex 1 (2.44 μmol·L-1) in the absence (dashed line) and presence (solid line) of increasing amounts of CT-DNA (22, 44, 66, 88, 109, 131, 152, 174, 195 and 216 μmol·L-1) in 5 mmol·L-1 Tris-HCl/50 mmol·L-1 NaCl buffer (pH=7.2); (b) Fluorescence emission spectra of EB (2.4 μmol·L-1) bound to CT-DNA (48 μmol·L-1) system in the absence (dashed line) and presence (solid lines) of complex 1 (0.99, 1.96, 2.91, 3.84, 4.76, 5.66, 6.54, 7.41, 8.26 and 9.09 μmol·L-1)

    Arrow shows the absorbance changes on increasing DNA concentration; Inset: plot of (εa-εf)/(εb-εf) versus cDNA for the titration of DNA to complex (a) and plot of I0/I versus the complex concentration (b)

    As a means for further explore the interaction of the complex with DNA, fluorescence spectra measure-ments were performed on CT-DNA by varying the con-centration of the complex. We used ethidium bromide (EB) as a fluorescent probe and evaluated the binding tendency of the complex to CT-DNA. Fig. 2b shows the fluorescence intensity of EB - DNA gradually decreases with the gradual addition of complex, which indicates that the complex can compete with EB to bind DNA. In order to quantitatively calculate the binding capacity to DNA, a straight line should be obtained by plotting the concentration of the quencher with I0/I according to the classical fluorescence quenching theory (I0 and I repre-sent the fluorescence intensities in the absence and presence of quencher, respectively). According to the Stern - Volmer equation[24], I0/ I (the ratio of the fluores-cence intensity of EB - DNA before and after the addi-tion of the complex) was plotted on the ordinate and the concentration of the complex was taken as the horizon-tal coordinate. According to the equation KEBcEB= Kappccomplex, KEB=1.0×107 L·mol-1(cEB=2.4 μmol·L-1), theKappof the complex was calculated to be 7.12×105L·moL-1, which was smaller than the classical bonding constant 107 L·moL-1 [25]. The results showed that the in-teraction between the complex and DNA is a medium intercalative mode. It is consistent with the results of electron spectroscopy.

    2.3.1   Concentration-dependent DNA cleavage activity without any inducer

    The covalent closed-loop supercoiled plasmid DNA (SC DNA) is commonly referred to as Form Ⅰ, the open-loop nicked DNA (NC DNA) produced by sin-gle - strand cleavage is called Form Ⅱ, and the linear DNA (LC DNA) produced by double -strand cleavage is called Form Ⅲ[26]. In the absence of external agent, the concentration - dependent DNA cleavage activity was performed under the nearly physiological conditions (pH=7.2, 37 ℃, 3 h). The extent of DNA cleavage was estimated by the histogram distribution according to the corresponding gel electrophoresis diagram, which is shown in Fig. 3. The distribution of Form Ⅰ (SC DNA) gradually reduced and that of Form Ⅱ (NC DNA) increased with the increasing concentration of the complex. The complex 1 concentration of 0.65 mmol·L-1 (Lane 5) could make DNA produce about 55% of Form Ⅱ. It is demonstrated that the Co(Ⅱ)com-plex shows certain concentration-dependent DNA cleavage activity without any external agent.

    Figure 3

    Figure 3.  Histogram for cleavage of pBR322 DNA (0.1 μg·μL-1) with complex 1 in the absence of inducer

    Inset: gel electrophoresis diagrams of pBR322 DNA cleavage activities in Tris-HCl/NaCl buffer (pH=7.2) and 37 ℃ (3 h); Lane 0: DNA control; Lane 1~5: DNA+complex 1 (0.05, 0.2, 0.35, 0.5, 0.65 mmol·L-1)

    2.3.2   Concentration-dependent DNA cleavage activity with H2O2 as inducer

    To further assess the chemical nuclease activity of complex, the concentration -dependent DNA cleavage experiment by complex was also performed in the pres-ence of H2O2 under the same physiological conditions (pH=7.2, 37 ℃, 3 h). As shown in Fig. 4, the distribu-tion of Form Ⅰ gradually reduced and Form Ⅱ increased as the concentration changed (0.005~0.05 mmol·L-1). It is worth to mention that the complex could generate about 70% Form Ⅱ from supercoiled plasmid DNA in the presence of H2 O2 at 0.05 mmol·L-1 concentration (Lane 5), while the complex could not induce obvious DNA cleavage without any external agent at the same concentration (Fig. 3, Lane 1). The re-sult shows that the DNA cleavage efficiency of complex exhibits remarkable increase due to the addition of H2O2.

    Figure 4

    Figure 4.  Histogram for cleavage of pBR322 DNA (0.1 μg·μL-1) with complex 1 in the presence of inducer(H2O2)

    Inset: gel electrophoresis diagrams of pBR322 DNA cleavage activities in Tris-HCl/NaCl buffer (pH=7.2) and 37 ℃ (3 h); Lane 0: DNA control; Lane 1: DNA+0.25 mmol·L-1 H2O2; Lane 2~5: DNA+H2O2+complex 1 (0.005, 0.02, 0.035, 0.05 mmol·L-1)

    2.3.3   Mechanism of DNA cleavage

    In order to further explore the active oxygen spe-cies (ROS) which was responsible for the DNA cleav-age, we have studied several possible inhibitors under aerobic conditions: NaN3 as singlet oxygen (1O2) quencher, KI as hydroxyl radical scavenger (·OH), superoxide dismutase (SOD) as O2- radical scavenger, catalase as hydrogen peroxide scavenger and EDTA as the chelator of complex. In order to study the binding sites of complex and DNA interactions, we added small groove and large groove binding reagents such as SYBR green and methyl green[27-28].

    As shown in Fig. 5, the cleavage activity of DNA was significantly inhibited by the addition of the inhibi-tors NaN3 (Lane 3) and KI (Lane 4), which indicates that singlet oxygen and hydroxyl radical active species may be produced in the reaction process, and the addi-tion of D2O (Lane 5) enhanced the cleavage activity of DNA, producing linear DNA, further demonstrating the existence of singlet oxygen active species[29]. In addi-tion, the metal chelating agent EDTA can efficiently inhibit DNA cleavage (Lane 8), indicating metal ion plays the key role in the process of DNA cleavage. Moreover, the addition of methyl green (Lane 9), which is known to interact to DNA at major groove, partly inhibited DNA cleavage by the complex. The result suggests that the complex mainly has interaction with DNA through major groove.

    Figure 5

    Figure 5.  Histogram for cleavage of pBR322 DNA (0.1 μg·μL-1) in presence of 35 μmol·L-1 complex 1 and different inhibitors

    Inset: gel electrophoresis diagrams of pBR322 DNA cleavage activities in Tris-HCl/NaCl buffer (pH=7.2) and 37 ℃ (3 h); Lane 0: DNA control; Lane 1: DNA+0.25 mmol·L-1 H2O2; Lane 2: DNA+0.25 mmol·L-1 H2O2+35 μmol·L-1 complex 1 (0.07% DMF); Lane 3~10: DNA+0.25 mmol·L-1 H2O2+complex+inhibitors (1 mmol·L-1 NaN3, 1 mmol·L-1 KI, 10% D2O, 2 U·mL-1 SOD, 0.2 U·mL-1 Catalase, 0.5 mmol·L-1 EDTA, 0.1 mmol·L-1 methyl green, 0.15 μL·mL-1 SYBR green)

    The principle of MTT is that succinate dehydroge-nase in mitochondria of living cells can reduce exoge-nous MTT to water -insoluble blue-purple crystal forma-zan and deposit in cells, while dead cells have no such function. DMSO can dissolve formazan and measure the absorbance at 490 nm by a microplate reader, which can indirectly reflect the number of living cells. MTT method is often used for screening anti-tumor drugs, cytotoxicity test and radiosensitivity test. Cyto-toxicity is usually measured by the IC50 value. We used the MTT method to determine the inhibitory ability of the complex on the growth of HeLa, BGC-823 and NCI-H460 cells in vitro (Table 2), and the IC50 values were (243.27±7.82), (148.54±5.76) and (234.24±7.07) μmol·L-1, respectively. In addition, the cell viability of three cell lines after drug treatment for 48 h by com-plex have been shown in Fig. 6, and the result indicates that the complex is cytotoxic and inhibit the growth of cells in a dose - dependent manner. We found that the ligand itself showed very weak inhibitory effects on three cell lines. The results show that the complex has a certain degree of inhibition on cancer cells, and espe-cially has a significant inhibition on BGC-823 cells.

    Table 2

    Table 2.  IC50 values of complex 1 obtained with different cell lines for 48 h
    下载: 导出CSV
    Compound IC50 /(μmol·L-1)
    HeLa BGC-823 NCI-H460
    Cisplatin 23.07±1.64 2.23±0.14 16.31±0.05
    [Co(L)Cl2] 243.27±7.82 148.54±5.76 234.24±7.07
    L > 500 > 300 > 400

    Figure 6

    Figure 6.  Cell viability of three cell lines (BGC-823, HeLa and NCI-H460) after drug treatment for 48 h by complex 1

    A new polypyridyl mononuclear Co complex was synthesized and characterized using elemental analysis, IR, and X-ray crystallography techniques. The crystal structure analysis reveals that Co center of the complex is a distorted trigonal-bipyramidal con-figuration. Electronic spectra and fluorescence quench-ing experiments show a moderate insertion between the complex and CT - DNA. The DNA cleavage ability of the complex exhibits evident improvement after the ad-dition of the inducer H2O2. The oxidative mechanism is demonstrated preliminarily via a pathway involving formation of both singlet oxygen (1O2) and hydroxyl radicals (·OH) as active oxygen species. In addition, in vitrocytotoxicity of the drug has been tested by MTTagainst HeLa, BGC- 823 and NCI -H460 cell lines, and the result shows that the complex has certain inhibitory effects on the three cancer cells.

    Acknowledgements: This work was supported by Shanxi Key Research and Development Program (Grants No.201703D211001-02-03, 201903D221036, 201703D221008-4, 201703D221004 - 5), Natural Science Foundation of Shanxi (Grants No. 201701D221157, 201701D221158), the PhD Research Startup Foundation of Shanxi Agricultural University (Grant No. 2013YJ40) and College Students Innovation and Entrepreneurship Training Project of Shanxi (Grants No.2019136, 2019137).

    Supporting information is available at http://www.wjhxxb.cn


    1. [1]

      Komor A C, Barton J K. Chem. Commun., 2013, 49(35):3617-3630 doi: 10.1039/c3cc00177f

    2. [2]

      Barton J K. Comments Inorg. Chem., 1985, 3(6):321-348 doi: 10.1080/02603598508079690

    3. [3]

      Liu Y, Chouai A, Degtyareva N N, et al. Chem. Rev., 1998, 98(3):1109-1152 doi: 10.1021/cr960421s

    4. [4]

      Galal S A, Hegab K H, Kassab A S, et al. Eur. J. Med. Chem., 2009, 44(4):1500-1508 doi: 10.1016/j.ejmech.2008.07.013

    5. [5]

      Kumar P, Baidya B, Chaturvedi S K, et al. Inorg. Chim. Acta, 2011, 376(1):264-270

    6. [6]

      Ghosh K, Tyagi N, Kumar H, et al. Spectrochim. Acta A, 2015, 146:292-296 doi: 10.1016/j.saa.2015.03.003

    7. [7]

      Smolková R, Zeleňák V, Gyepes R, et al. Polyhedron, 2018, 141:230-238 doi: 10.1016/j.poly.2017.11.052

    8. [8]

      Srishailam A, Gabra N M, Kumar Y P, et al. J. Photochem. Photobiol. B, 2014, 141:47-58 doi: 10.1016/j.jphotobiol.2014.09.003

    9. [9]

      Xu X M, Yao J H, Mao Z W, et al. Inorg. Chem. Commun., 2004, 7(6):803-805 doi: 10.1016/j.inoche.2004.04.014

    10. [10]

      He J, Hu P, Wang Y J, et al. Dalton Trans., 2008(24):3207-3214 doi: 10.1039/b801549j

    11. [11]

      Du K J, Wang J Q, Kou J F, et al. Eur. J. Med. Chem., 2011, 46(4):1056-1065 doi: 10.1016/j.ejmech.2011.01.019

    12. [12]

      Balakrishnan N, Haribabu J, Anantha Krishnan D, et al. Polyhedron, 2019, 170:188-201 doi: 10.1016/j.poly.2019.05.039

    13. [13]

      Munteanu C R, Suntharalingam K. Dalton Trans., 2015, 44(31):13796-13808 doi: 10.1039/C5DT02101D

    14. [14]

      Yamada K. Interrelations between Essential Metal Ions and Human Diseases. Sigel A, Sigel H, Sigel R K O. Ed., Dordrecht:Springer, 2013:295-317

    15. [15]

      Randaccio L, Geremia S, Nardin G, et al. Coord. Chem. Rev., 2006, 250(11/12):1332-1350

    16. [16]

      Gao C Y, Ma Z Y, Zhang Y P, et al. RSC Adv., 2015, 5(39):30768-30779 doi: 10.1039/C4RA16755D

    17. [17]

      Zhang Y P, Ma Z Y, Gao C Y, et al. New J. Chem., 2016, 40(9):7513-7521 doi: 10.1039/C6NJ00346J

    18. [18]

      Sheldrick G M. Correction Software, University of Göttingen, Germany, 1996.

    19. [19]

      Sheldrick G M. SHELXS-97, Program for Crystal Structure Resolution, University of Göttingen, Germany, 1997.

    20. [20]

      Sheldrick G M. SHELXL-97, Program for Crystal Structures Analysis, University of Göttingen, Germany, 1997.

    21. [21]

      Addison A W, Rao T N, Reedijk J, et al. Dalton Trans., 1984, 7:1349-1356

    22. [22]

      Gao C Y, Qiao X, Ma Z Y, et al. Dalton Trans., 2012, 41(39):12220-12232 doi: 10.1039/c2dt31306e

    23. [23]

      Sung J, Shin K J, Lee S. Chem. Phys., 1992, 167(1/2):17-36

    24. [24]

      Patra A K, Dhar S, Nethaji M, et al. Dalton Trans., 2005(5):896-902 doi: 10.1039/b416711b

    25. [25]

      Kellett A, Molphy Z, Slator C, et al. Chem. Soc. Rev., 2019, 48:971-988 doi: 10.1039/C8CS00157J

    26. [26]

      Gibellini D, Vitone F, Schiavone P, et al. J. Clin. Virol., 2004, 29:282-289 doi: 10.1016/S1386-6532(03)00169-0

    27. [27]

      ElAmrani F B, Perelló L, Real J A, et al. J. Inorg. Biochem., 2006, 100:1208-1218 doi: 10.1016/j.jinorgbio.2006.01.036

    28. [28]

      Merkel P B, Kearns D R. J. Am. Chem. Soc., 1972, 94(3):1029-1030 doi: 10.1021/ja00758a071

  • Figure 1  X-ray crystal structure of complex 1

    Hydrogen atoms are omitted for clarity

    Figure 2  (a) Absorption spectra of complex 1 (2.44 μmol·L-1) in the absence (dashed line) and presence (solid line) of increasing amounts of CT-DNA (22, 44, 66, 88, 109, 131, 152, 174, 195 and 216 μmol·L-1) in 5 mmol·L-1 Tris-HCl/50 mmol·L-1 NaCl buffer (pH=7.2); (b) Fluorescence emission spectra of EB (2.4 μmol·L-1) bound to CT-DNA (48 μmol·L-1) system in the absence (dashed line) and presence (solid lines) of complex 1 (0.99, 1.96, 2.91, 3.84, 4.76, 5.66, 6.54, 7.41, 8.26 and 9.09 μmol·L-1)

    Arrow shows the absorbance changes on increasing DNA concentration; Inset: plot of (εa-εf)/(εb-εf) versus cDNA for the titration of DNA to complex (a) and plot of I0/I versus the complex concentration (b)

    Figure 3  Histogram for cleavage of pBR322 DNA (0.1 μg·μL-1) with complex 1 in the absence of inducer

    Inset: gel electrophoresis diagrams of pBR322 DNA cleavage activities in Tris-HCl/NaCl buffer (pH=7.2) and 37 ℃ (3 h); Lane 0: DNA control; Lane 1~5: DNA+complex 1 (0.05, 0.2, 0.35, 0.5, 0.65 mmol·L-1)

    Figure 4  Histogram for cleavage of pBR322 DNA (0.1 μg·μL-1) with complex 1 in the presence of inducer(H2O2)

    Inset: gel electrophoresis diagrams of pBR322 DNA cleavage activities in Tris-HCl/NaCl buffer (pH=7.2) and 37 ℃ (3 h); Lane 0: DNA control; Lane 1: DNA+0.25 mmol·L-1 H2O2; Lane 2~5: DNA+H2O2+complex 1 (0.005, 0.02, 0.035, 0.05 mmol·L-1)

    Figure 5  Histogram for cleavage of pBR322 DNA (0.1 μg·μL-1) in presence of 35 μmol·L-1 complex 1 and different inhibitors

    Inset: gel electrophoresis diagrams of pBR322 DNA cleavage activities in Tris-HCl/NaCl buffer (pH=7.2) and 37 ℃ (3 h); Lane 0: DNA control; Lane 1: DNA+0.25 mmol·L-1 H2O2; Lane 2: DNA+0.25 mmol·L-1 H2O2+35 μmol·L-1 complex 1 (0.07% DMF); Lane 3~10: DNA+0.25 mmol·L-1 H2O2+complex+inhibitors (1 mmol·L-1 NaN3, 1 mmol·L-1 KI, 10% D2O, 2 U·mL-1 SOD, 0.2 U·mL-1 Catalase, 0.5 mmol·L-1 EDTA, 0.1 mmol·L-1 methyl green, 0.15 μL·mL-1 SYBR green)

    Figure 6  Cell viability of three cell lines (BGC-823, HeLa and NCI-H460) after drug treatment for 48 h by complex 1

    Table 1.  Crystallographic data for complex 1

    Molecular formula C19H19Cl2CoN3
    Formula weight 419.2
    Crystal system Monoclinic
    Space group P21/n
    a/ nm 0.913 70(18)
    b/ nm 1.160 9(2)
    c/ nm 1.806 5(4)
    β/(°) 104.54(3)
    V/ nm3 1.854 8(6)
    Z 4
    D/ (g·cm-3) 1.501
    F(000) 860
    θrange for data collection / (°) 3.33~25.01
    Index range (h, k, l) -10 ≤ h ≤ 10, -13 ≤ k ≤ 13, -21 ≤ l ≤ 20
    Total diffraction point 10 381
    Independent diffraction point (Rint) 3 268 (0.043 0)
    Goodness-of-fit on F2 1.173
    R1, wR2[I > 2σ(I)] R1=0.050 9, wR2=0.098 5
    R1, wR2(all data) R1=0.066 4, wR2=0.103 9
    Largest diff. peak and hole / (e·nm-3) 303 and -394
    下载: 导出CSV

    Table 2.  IC50 values of complex 1 obtained with different cell lines for 48 h

    Compound IC50 /(μmol·L-1)
    HeLa BGC-823 NCI-H460
    Cisplatin 23.07±1.64 2.23±0.14 16.31±0.05
    [Co(L)Cl2] 243.27±7.82 148.54±5.76 234.24±7.07
    L > 500 > 300 > 400
    下载: 导出CSV
  • 加载中
计量
  • PDF下载量:  0
  • 文章访问数:  93
  • HTML全文浏览量:  11
文章相关
  • 发布日期:  2020-09-10
  • 收稿日期:  2020-03-07
  • 修回日期:  2020-05-27
通讯作者: 陈斌, bchen63@163.com
  • 1. 

    沈阳化工大学材料科学与工程学院 沈阳 110142

  1. 本站搜索
  2. 百度学术搜索
  3. 万方数据库搜索
  4. CNKI搜索

/

返回文章