Journal of Fluorescence

, Volume 27, Issue 2, pp 701–714 | Cite as

Two New Mononuclear Copper(II)-Dipeptide Complexes of 2-(2′-Pyridyl)Benzoxazole: DNA Interaction, Antioxidation and in Vitro Cytotoxicity Studies

  • Qian Gan
  • Yongyu Qi
  • Yahong Xiong
  • Yinlian Fu
  • Xueyi Le


Two new mononuclear mixed ligand copper(II) complexes [Cu(PBO)(Gly-gly)(H2O)]·ClO4·1.5H2O (1) and [Cu(PBO)(Gly-L-leu)(H2O)]·ClO4 (2) (PBO is 2-(2′-pyridyl)benzoxazole, Gly-gly and Gly-L-leu are Glycyl-glycine anion and Glycyl-L-leucine anion, respectively), have been prepared and characterized by various analytical and spectral techniques. The interactions of the complexes with DNA were investigated using multi-spectroscopic methods (absorption, emission, circular dichroism), viscometry and electrochemical titration as well as molecular docking technique. The results indicated that 1 and 2 are bound to calf thymus DNA (CT-DNA) through an intercalative mode. The thermodynamic analyses revealed that the reactions between the Cu(II) complexes with DNA are spontaneous with negative Gibbs free energy (ΔG). The positive changes of enthalpy (ΔH) and entropy (ΔS) suggested that the binding processes are dominated by hydrophobic interaction accompanying with endothermic. Also, the complexes exhibited efficient oxidative cleavage of pBR322 plasmid DNA in the presence of ascorbic acid, probably induced by •OH as reactive oxygen species. In addition, 1 and 2 displayed excellent antioxidant activities with the IC50 values of 0.112 and 0.191 μM, respectively, using the mean of nitroblue tetrazolium (NBT) photochemical reduction under a nonenzymatic condition. Moreover, the complexes were screened for their in vitro cytotoxicity against three human carcinoma cell lines (HeLa, PC-3 and A549), in which 2 owns higher cytotoxicity, which was consistent with DNA binding and cleavage ability order of the complexes. This results showed the in vitro biochemical potentials of the Cu(II)-dipeptide complexes with aromatic heterocyclic, viz. effective metallopeptide-nucleases, SOD mimics and non-platinum chemotherapeutic metallopharmaceuticals and their structure-activity relationship, which may contribute to the rational molecular design of new metallopeptide based chemotherapeutic agents.


Cu(II)-dipeptide complexes DNA interaction Fluorescence quenching Molecular docking Antioxidation Cytotoxicity 



The authors gratefully acknowledge the financial support from the Program of Natural Science Foundation of Guangdong Province (2015A030313423) and Guangdong Province College Students’ Innovation and Entrepreneurship Training Program (No. 1056413042).

Supplementary material

10895_2016_1999_MOESM1_ESM.docx (5.7 mb)
ESM 1 (DOCX 5791 kb)


  1. 1.
    Siegel R, Ma J, Zou Z, Jemal A (2014) Cancer statistics, 2014. CA-Cancer J Clin 64:9–29CrossRefPubMedGoogle Scholar
  2. 2.
    Tabassum S, Al-Asbahy WM, Afzal M, Shamsi M, Arjmand F (2012) DNA binding and cleavage studies of new sulfasalazine-derived dipeptide Zn(II) complex: validation for specific recognition with 5′-TMP. J Lumin 132:3058–3065CrossRefGoogle Scholar
  3. 3.
    Arun T, Subramanian R, Raman N (2016) Novel bio-essential metal based complexes linked by heterocyclic ligand: synthesis, structural elucidation, biological investigation and docking analysis. J Photoch Photobio B 154:67–76CrossRefGoogle Scholar
  4. 4.
    Huang HY, Zhang PY, BL Y, Chen Y, Wang JQ, Ji LN, Chao H (2014) Targeting nucleus DNA with a cyclometalated dipyridophenazineruthenium(II) complex. J Med Chem 57:8971–8983CrossRefPubMedGoogle Scholar
  5. 5.
    Kumar RS, Arunachalam S (2009) DNA binding and antimicrobial studies of polymer–copper(II) complexes containing 1,10-phenanthroline and l-phenylalanine ligands. Eur J Med Chem 44:1878–1883CrossRefPubMedGoogle Scholar
  6. 6.
    Singh R, Afzal M, Zaki M, Ahmad M, Tabassum S, Bharadwaj PK (2014) Synthesis, structure elucidation and DFT studies of a new coumarin-derived Zn(II) complex: in vitro DNA/HSA binding profile and pBR322 cleavage pathway. RSC Adv 4:43504–43515CrossRefGoogle Scholar
  7. 7.
    Metcalfe C, Thomas JA (2003) Kinetically inert transition metal complexes that reversibly bind to DNA. Chem Soc Rev 32:215–224CrossRefPubMedGoogle Scholar
  8. 8.
    Rad FV, Housaindokht MR, Jalal R, Hosseini HE, Doghaei AV, Goghari SS (2014) Spectroscopic and molecular modeling based approaches to study on the binding behavior of DNA with a copper(II) complex. J Fluoresc 24:1225–1234CrossRefGoogle Scholar
  9. 9.
    Sarkar S, Mukherjee T, Sen S, Zangrando E, Chattopadhyay P (2010) Copper(II) complex of in situ formed 5-(2-pyridyl)-1,3,4-triazole through C-S bond cleavage in 1,2-bis(2-pyridylmethylthio)-bis-ethylsulphide: synthesis, structural characterization and DNA binding study. J Mol Struct 980:117–123CrossRefGoogle Scholar
  10. 10.
    Pravin N, Devaraji V, Raman N (2015) Targeting protein kinase and DNA molecules by diimine-phthalate complexes in antiproliferative activity. Int J Biol Macromol 79:837–855CrossRefPubMedGoogle Scholar
  11. 11.
    Nagaraj K, Sakthinathan S, Arunachalam S (2014) Synthesis, CMC determination, antimicrobial activity and nucleic acid binding of a surfactant copper(II) complex containing phenanthroline and alanine schiff-base. J Fluoresc 24:589–598CrossRefPubMedGoogle Scholar
  12. 12.
    Pulimamidi RR, Ravula C, Battu S (2016) New bio-based Cu(II) complexes and study of their anti-cancer activities. J Fluoresc 26:1183–1197CrossRefPubMedGoogle Scholar
  13. 13.
    He FH, Tao L, Li XW, Li YT, Wu ZY, Yan CW (2012) Syntheses and structures of new dicopper(II) complexes bridged by N-(2-hydroxyphenyl)-N′-(3-aminopropyl)oxamide: DNA-binding properties and cytotoxic activities. New J Chem 36:2078–2087CrossRefGoogle Scholar
  14. 14.
    Mendu P, Gyana Kumari C, Ragi C (2015) Synthesis, characterization, DNA binding, DNA cleavage and antimicrobial studies of schiff base ligand and its metal complexes. J Fluoresc 25:369–378CrossRefPubMedGoogle Scholar
  15. 15.
    Sun A, Prussia A, Zhan W, Murray EE, Doyle J, Cheng L, Yoon J, Radchenko EV, Palyulin VA, Compans RW, Liotta DC, Plemper RK, Snyder JP (2006) Nonpeptide inhibitors of measles virus entry. J Med Chem 49:5080–5092CrossRefPubMedGoogle Scholar
  16. 16.
    Seenaiah D, Reddy PR, Reddy GM, Padmaja A, Padmavathi V, Krishna NS (2014) Synthesis, antimicrobial and cytotoxic activities of pyrimidinyl benzoxazole, benzothiazole and benzimidazole. Eur J Med Chem 77:1–7CrossRefPubMedGoogle Scholar
  17. 17.
    Alper-Hayta S, Arisoy M, Temiz-Arpaci Ö, Yildiz I, Aki E, Özkan S, Kaynak F (2008) Synthesis, antimicrobial activity, pharmacophore analysis of some new 2-(substitutedphenyl/benzyl)-5-[(2-benzofuryl) carboxamido]benzoxazoles. Eur J Med Chem 43:2568–2578CrossRefPubMedGoogle Scholar
  18. 18.
    Czerwieniec R, Kapturkiewicz A, Lipkowski J, Nowacki J (2005) Re(I)(tricarbonyl)+ complexes with the 2-(2-pyridyl)-N-methyl-benzimidazole, 2-(2-pyridyl)benzoxazole and 2-(2-pyridyl)benzothiazole ligands- syntheses, structures, electrochemical and spectroscopic studies. Inorg Chim Acta 358:2701–2710CrossRefGoogle Scholar
  19. 19.
    Marmur JA (1961) Procedure for the isolation of deoxyribonucleic acid from micro-organisms. J Mol Biol 3:201–208Google Scholar
  20. 20.
    Vamsikrishna N, Kumar MP, Tejaswi S, Rambabu A, Shivaraj (2016) DNA binding, cleavage and antibacterial activity of mononuclear Cu(II), Ni(II) and Co(II) complexes derived from novel benzothiazole schiff bases. J Fluoresc 26:1317–1329CrossRefPubMedGoogle Scholar
  21. 21.
    Wolfe A, Shimer GHJ, Meehan T (1987) Polycyclic aromatic hydrocarbons physically intercalate into duplex regions of denatured DNA. Biochemistry 26:6392–6396CrossRefPubMedGoogle Scholar
  22. 22.
    Lang PT, Brozell SR, Mukherjee S, Pettersen EF, Meng EC, Thomas V, Rizzo RC, Case DA, James TL, Kuntz ID (2009) DOCK 6: combining techniques to model RNA-small molecule complexes. RNA 15:1219–1230CrossRefPubMedPubMedCentralGoogle Scholar
  23. 23.
    Hu W, Deng SW, Huang JY, Lu YM, Le XY, Zheng WX (2013) Intercalative interaction of asymmetric copper(II) complex with DNA: experimental, molecular docking, molecular dynamics and TDDFT studies. J Inorg Biochem 127:90–98CrossRefPubMedGoogle Scholar
  24. 24.
    Kielkopf CL, Erkkila KE, Hudson BP, Barton JK, Rees DC (2000) Structure of a photoactive rhodium complex intercalated into DNA. Nat Struct Mol Biol 7:117–121CrossRefGoogle Scholar
  25. 25.
    Le XY, Liao SR, Liu XP, Feng XL (2006) Synthesis, structure and SOD-like activity of a ternary Cu(II) complex with 1,10-phenanthroline and L-valinate. J Coord Chem 59:985–995CrossRefGoogle Scholar
  26. 26.
    Mosmann T (1983) Rapid colorimetric assay for cellular growth and survival: application to proliferation and cytotoxicity assays. J Immunol Methods 65:55–63CrossRefPubMedGoogle Scholar
  27. 27.
    Geary WJ (1971) The use of conductivity measurements in organic solvents for the characterisation of coordination compound. Coordin Chem Rev 7:81–122CrossRefGoogle Scholar
  28. 28.
    Nakamoto K (2009) Infrared and raman spectra of inorganic and coordination compounds (part B), 6th edn. John Wiley and Sons, New York, p. 65Google Scholar
  29. 29.
    Reddy PR, Raju N, Satyanarayana B (2011) Synthesis, characterization, and DNA binding and cleavage properties of copper(II)-tryptophanphenylalanine-1,10-phenanthroline/2,2′-bipyridine complexes. Chem Biodivers 8:131–144CrossRefPubMedGoogle Scholar
  30. 30.
    Hathaway BJ (1972) The correlation of the electronic properties and stereochemistry of mononuclear {CuN4-6} chromophores. J Chem Soc Dalton Trans:1196–1199. doi: 10.1039/DT9720001196
  31. 31.
    Lakowicz JR, Weber G (1973) Quenching of fluorescence by oxygen. A probe for structural fluctuations in macromolecules. Biochemistry 12:4161–4170CrossRefPubMedGoogle Scholar
  32. 32.
    Fei BL, Xu WS, Tao HW, Li W, Zhang Y, Long JY, Liu QB, Xia B, Sun WY (2014) Effects of copper ions on DNA binding and cytotoxic activity of a chiral salicylidene Schiff base. J Photoch Photobio B 132:36–44CrossRefGoogle Scholar
  33. 33.
    Gan XJ, Liu SP, Liu ZF, Hu XL (2012) Determination of tetracaine hydrochloride by fluorescence quenching method with some aromatic amino acids as probes. J Fluoresc 22:129–135CrossRefPubMedGoogle Scholar
  34. 34.
    Azab HA, Mogahed EM, Awad FK, El Aal RMA, Kamel RM (2012) Fluorescence and electrochemical recognition of nucleosides and DNA by a novel luminescent bioprobe Eu(III)-TNB. J Fluoresc 22:971–992CrossRefPubMedGoogle Scholar
  35. 35.
    Satyanarayana S, Dabrowiak JC, Chaires JB (1993) Tris(phenanthroline)ruthenium(II) enantiomer interactions with DNA: mode and specificity of binding. Biochemistry 32:2573–2584CrossRefPubMedGoogle Scholar
  36. 36.
    Ivanov VI, Minchenkova LE, Schyolkina AK, Poletayev AI (1973) Different conformations of double- stranded nucleic acid in solution as revealed by circular dichroism. Biopolymers 12:89–110CrossRefPubMedGoogle Scholar
  37. 37.
    Mahadevan S, Palaniandavar M (1998) Spectroscopic and voltammetric studies on copper complexes of 2,9-dimethyl-1,10-phenanthrolines bound to calf thymus DNA. Inorg Chem 37:693–700CrossRefGoogle Scholar
  38. 38.
    Xu XY, Wang DD, Sun XJ, Zeng SY, Li LW, Sun DZ (2009) Thermodynamic and spectrographic studies on the interactions of ct-DNA with 5-fluorouracil and tegafur. Thermochim Acta 493:30–36CrossRefGoogle Scholar
  39. 39.
    Li GY, Du KJ, Wang JQ, Liang JW, Kou JF, Hou XJ, Ji LN, Chao H (2013) Synthesis, crystal structure, DNA interaction and anticancer activity of tridentate copper(II) complexes. J Inorg Biochem 119:43–53CrossRefPubMedGoogle Scholar
  40. 40.
    Carter MT, Rodriguez M, Bard AJ (1989) Voltammetric studies of the interaction of metal chelates with DNA. 2. Tris-chelated complexes of cobalt(III) and iron(II) with 1,10-phenanthroline and 2,2′-bipyridine. J Am Chem Soc 111:8901–8911CrossRefGoogle Scholar
  41. 41.
    Li X, Li Y, Wu Z, Zheng Y, Yan C (2012) Synthesis, structure, DNA-binding properties and cytotoxic activities of a new one-dimensional polymeric copper(II) complex with N-benzoate-N′-[3-(2-hydroxyl- ethylammino)propyl]oxamide as ligand. Inorg Chim Acta 385:150–157CrossRefGoogle Scholar
  42. 42.
    Nagaraj K, Murugan KS, Thangamuniyandi P, Sakthinathan S (2014) Nucleic acid binding study of surfactant copper(II) complex containing dipyrido[3,2-a:2′-3′-c]phenazine ligand as an intercalator: in vitro antitumor activity of complex in human liver carcinoma (HepG2) cancer cells. RSC Adv 4:56084–56094CrossRefGoogle Scholar
  43. 43.
    Kelly JM, Lyons EG, Putten JMV, SmythM RE (1986) Analytical chemistry, symposium series, electrochemistry, sensors and analysis. Elsevier, Amsterdam, p. 205Google Scholar
  44. 44.
    Barton JK, Raphael AL (1984) Photoactivated stereospecific cleavage of double-helical DNA by cobalt(III) complexes. J Am Chem Soc 106:2466–2468CrossRefGoogle Scholar
  45. 45.
    Gulumian M, Van Wyk JA (1987) Hydroxyl radical production in the presence of fibres by a Fenton-type reaction. Chem Biol Interact 62:89–97CrossRefPubMedGoogle Scholar
  46. 46.
    Rohs R (2005) Molecular flexibility in ab initio drug docking to DNA: binding-site and binding-mode transitions in all-atom Monte Carlo simulations. Nucleic Acids Res 33:7048–7057CrossRefPubMedPubMedCentralGoogle Scholar
  47. 47.
    Potapov AS, Nudnova EA, Domina GA, Kirpotina LN, Quinn MT, Khlebnikov AI, Schepetkin IA (2009) Synthesis, characterization and potent superoxide dismutase-like activity of novel bis(pyrazole)-2,2 ‘-bipyridyl mixed ligand copper(II) complexes. Dalton Trans 23:4488–4498CrossRefGoogle Scholar
  48. 48.
    Kiningham KK, Clair DKS (1997) Overexpression of manganese superoxide dismutase selectively modulates the activity of Jun-associated transcription factors in fibrosarcoma cells. Cancer Res 57:5265–5271PubMedGoogle Scholar
  49. 49.
    Fu H, Zhou YH, Chen WL, Deqing ZG, Tong ML, Ji LN, Mao ZW (2006) Complexation, structure, and superoxide dismutase activity of the imidazolate-bridged dinuclear copper moiety with beta-cyclodextrin and its guanidinium-containing derivative. J Am Chem Soc 128:4924–4925CrossRefPubMedGoogle Scholar
  50. 50.
    Wu HL, Wang H, Wang XL, Pan GL, Shi FR, Zhang YH, Bai YC, Kong J (2014) V-shaped ligand bis(2-benzimidazolylmethyl)amine containing three copper(II) ternary complexes: synthesis, structure, DNA-binding properties and antioxidant activity. New J Chem 38:1052–1061CrossRefGoogle Scholar
  51. 51.
    Zhou YH, Fu H, Zhao WX, Chen WL, Su CY, Sun HZ, Ji LN, Mao ZW (2007) Synthesis, structure, and activity of supramolecular mimics for the active site and Arg141 residue of copper, zinc-superoxide dismutase. Inorg Chem 46:734–739CrossRefPubMedGoogle Scholar
  52. 52.
    Agotegaray MA, Dennehy M, Boeris MA, Grela MA, Burrow RA, Quinzani OV (2012) Therapeutic properties, SOD and catecholase mimetic activities of novel ternary copper(II) complexes of the anti-inflammatory drug Fenoprofen with imidazole and caffeine. Polyhedron 34:74–83CrossRefGoogle Scholar
  53. 53.
    Ramadan AM, El-Naggar MM (1996) Synthesis, characterization and demonstration of superoxide dismutase-like activity of copper(II) chloride, bromide, nitrate, thiocyanate, sulphate, and perchlorate complexes with 2-methyl-amino pyridine. J Inorg Biochem 63:143–153CrossRefGoogle Scholar
  54. 54.
    Wang XZ, Jiang GB, Xie YY, Liu YJ (2014) Synthesis, molecular structure, DNA interaction and antioxidant activity of novel naphthoxazole compound. Spectrochim Acta A 118:448–453CrossRefGoogle Scholar
  55. 55.
    Fu XB, Liu DD, Lin Y, Hu W, Mao ZW, Le XY (2014) Water-soluble DNA minor groove binders as potential chemotherapeutic agents: synthesis, characterization, DNA binding and cleavage, antioxidation, cytotoxicity and HSA interactions. Dalton Trans 43:8721–8737CrossRefPubMedGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2016

Authors and Affiliations

  • Qian Gan
    • 1
  • Yongyu Qi
    • 1
  • Yahong Xiong
    • 1
  • Yinlian Fu
    • 2
  • Xueyi Le
    • 1
  1. 1.Department of Applied ChemistrySouth China Agricultural UniversityGuangzhouPeople’s Republic of China
  2. 2.Department of Applied MathematicsSouth China Agricultural UniversityGuangzhouPeople’s Republic of China

Personalised recommendations