K H Repana

Publications (6)13.23 Total impact

• Article: Synthesis, structural characterization and biological studies of the triphenyltin(IV) complex with 2-thiobarbituric acid.

  V I Balas, I I Verginadis, G D Geromichalos, N Kourkoumelis, L Male, M B Hursthouse, K H Repana, E Yiannaki, K Charalabopoulos, T Bakas, S K Hadjikakou
  [show abstract] [hide abstract]
  ABSTRACT: The reaction between 2-thiobarbituric acid (H(2)TBA), which was treated with an equimolar amount of potassium hydroxide, in a water with triphenytin chloride in methanol, results in the formation of the {[Ph(3)Sn(O-HTBA)]}(n) (1) complex. Crystals of the hydrated 1 with formula {[Ph(3)Sn(O-HTBA)]·0.7(H(2)O)}(n) were growth from methanol/acetonitrile solution, of the white precipitation, filtered off, from the reaction. The crystal structure of complex 1 has been determined by X-ray diffraction at 120 K. Complex 1 is polymeric. The geometry around the tin(IV) ions is trigonal bi-pyramidal with coordination to three C atoms from phenyl groups and one O atom from a de-protonated HTBA ligand. Complex 1 and the already known [(n-Bu)(3)Sn(O-HTBA)·H(2)O] (2) were evaluated for their in vitro cytotoxic activity (cell viability) against human cancer cell lines: HeLa (cervical), OAW-42 (ovarian), MCF-7 (breast, ER positive), MDA-MB-231 (breast, ER negative), A549 (lung), Caki-1 (renal) and additionally, the normal human lung cell line MRC-5 (normal human fetal lung fibroblast cells) and normal immortalized human mammary gland epithelial cell line MTSV17 with a Trypan Blue assay. Moreover complex 1 was evaluated for its in vitro cell growth proliferation activity against leiomyosarcoma cells (LMS), MCF-7 and MRC-5 cells with a Thiazolyl Blue Tetrazolium Bromide (MTT) assay. The type of cell death caused by complexes 1 and 2 was also evaluated by use of flow cytometry assay. The results showed that these compounds mediate a strong cytotoxic response to normal and cancer cell lines tested through apoptosis and induce cell cycle arrest in S phase of the cell cycle, suggesting DNA intercalation (direct or indirect) with the complexes. Finally, the influence of these complexes 1 and 2 upon the catalytic peroxidation of linoleic acid to hydroperoxylinoleic acid by the enzyme lipoxygenase (LOX) was kinetically and theoretically studied.
  European journal of medicinal chemistry 07/2011; 46(7):2835-44. · 3.27 Impact Factor
• Article: Synthesis, structural characterization and biological studies of the triphenyltin(IV) complex with 2-thiobarbituric acid

  V.I. Balas, I.I. Verginadis, G.D. Geromichalos, N. Kourkoumelis, L. Male, M.B. Hursthouse, K.H. Repana, E. Yiannaki, K. Charalabopoulos, T. Bakas, S.K. Hadjikakou
  [show abstract] [hide abstract]
  ABSTRACT: The reaction between 2-thiobarbituric acid (H2TBA), which was treated with an equimolar amount of potassium hydroxide, in a water with triphenytin chloride in methanol, results in the formation of the {[Ph3Sn(O-HTBA)]}n (1) complex. Crystals of the hydrated 1 with formula {[Ph3Sn(O-HTBA)]·0.7(H2O)}n were growth from methanol/acetonitrile solution, of the white precipitation, filtered off, from the reaction. The crystal structure of complex 1 has been determined by X-ray diffraction at 120 K. Complex 1 is polymeric. The geometry around the tin(IV) ions is trigonal bi-pyramidal with coordination to three C atoms from phenyl groups and one O atom from a de-protonated HTBA ligand.Complex 1 and the already known [(n-Bu)3Sn(O-HTBA)·H2O] (2) were evaluated for their in vitro cytotoxic activity (cell viability) against human cancer cell lines: HeLa (cervical), OAW-42 (ovarian), MCF-7 (breast, ER positive), MDA-MB-231 (breast, ER negative), A549 (lung), Caki-1 (renal) and additionally, the normal human lung cell line MRC-5 (normal human fetal lung fibroblast cells) and normal immortalized human mammary gland epithelial cell line MTSV17 with a Trypan Blue assay. Moreover complex 1 was evaluated for its in vitro cell growth proliferation activity against leiomyosarcoma cells (LMS), MCF-7 and MRC-5 cells with a Thiazolyl Blue Tetrazolium Bromide (MTT) assay. The type of cell death caused by complexes 1 and 2 was also evaluated by use of flow cytometry assay. The results showed that these compounds mediate a strong cytotoxic response to normal and cancer cell lines tested through apoptosis and induce cell cycle arrest in S phase of the cell cycle, suggesting DNA intercalation (direct or indirect) with the complexes. Finally, the influence of these complexes 1 and 2 upon the catalytic peroxidation of linoleic acid to hydroperoxylinoleic acid by the enzyme lipoxygenase (LOX) was kinetically and theoretically studied.Graphical abstractThe new complex {[Ph3Sn(O-HTBA)]·0.7(H2O)}n (1) is prepared, characterized and screened among with complex [(n-Bu)3Sn(TBA)·H2O] (2) against human cancer cell lines: HeLa, OAW-42, MCF-7, MDA-MB-231, A549, Caki-1, MRC-5 and MTSV17.Highlights► Structural characterization of a polymeric triphenyltin(IV) complex with 2-thiobarbituric acid. ► High cytostatic activity of triphenyltin(IV) complex with 2-thiobarbituric acid complexes. ► Experimental and theoretical study of the peroxidation of linoleic acid by the enzyme lipoxygenase in the presence of the organotin(IV) complex with 2-thiobarbituric acid.
  European Journal of Medicinal Chemistry. 01/2011; 46(7):2835-2844.
• Article: The unexpected formation of biologically active Cu(II) Schiff mono-base complexes with 2-thiophene-carboxaldehyde and dipropylenetriamine: crystal and molecular structure of CudptaSCl2.

  A Th Chaviara, P J Cox, K H Repana, A A Pantazaki, K T Papazisis, A H Kortsaris, D A Kyriakidis, G St Nikolov, C A Bolos
  [show abstract] [hide abstract]
  ABSTRACT: Two novel mononuclear Cu(II) coordination compounds of the type [Cu(dptaS)Cl(2)] and [Cu(dptaS)Br(2)] (dptaS=1,3-propanediamine, N(1)-[3-aminopropyl]-N(3)-[2-thienylmethylidene] or Schiff mono-base of dipropylenetriamine with 2-thiophene-carboxaldehyde) were prepared by the hydrolysis of the di-bases, [Cu(dptaSS)Cl(2)] and [Cu(dptaSS)Br(2)] (dptaSS=1,3-propanediamine, N(1)-[2-thienylmethylidene]-N(3)-[[2-thienylmethylidene]aminopropyl] or Schiff di-base of dipropylenetriamine with 2-thiophenecarboxaldehyde) to mono-bases with the release of one aldehyde molecule and freeing of the -NH(2) group of the coordinated dpta ligand. The X-ray determined structure of the compound [Cu(dptaS)Cl(2)] was confirmed by spectroscopic methods, magnetic and molar conductivity measurements. The Cu(II) atom is a five-coordinated CuN(3)Cl(2) chromophore with three nitrogen atoms coming up from the (dptaS) ligand and two chlorine atoms completing the square pyramidal geometry. Antiproliferative activity of both novel compounds was examined against a panel of different normal and cancer cell lines (MRC5, HeLa, MCF7, HT-29 and T47D) and showed that the Cu(II) Schiff mono-bases exhibit increased activity as compared to the starting materials. In vitro studies of plasmid DNA (pDNA) and double stranded DNA (dsDNA) interaction with the compounds under study support this difference. Some of the important factors contributing to the antiproliferative activity of the compounds under study, such as ionic character and dipole moment were also discussed in terms of the density functional theory calculated electronic structures of the ligands and their Cu(II) compounds.
  Journal of Inorganic Biochemistry 03/2005; 99(2):467-476. · 3.35 Impact Factor
• Article: The unexpected formation of biologically active Cu(II) Schiff mono-base complexes with 2-thiophene-carboxaldehyde and dipropylenetriamine: crystal and molecular structure of CudptaSCl2

  A. Th. Chaviara, P.J. Cox, K.H. Repana, A.A. Pantazaki, K.T. Papazisis, A.H. Kortsaris, D.A. Kyriakidis, G.St. Nikolov, C.A. Bolos
  Journal of inorganic biochemistry 01/2005; 99:467-476. · 3.25 Impact Factor
• Article: Copper(II) Schiff base coordination compounds of dien with heterocyclic aldehydes and 2-amino-5-methyl-thiazole: synthesis, characterization, antiproliferative and antibacterial studies. Crystal structure of CudienOOCl2.

  A Th Chaviara, P J Cox, K H Repana, R M Papi, K T Papazisis, D Zambouli, A H Kortsaris, D A Kyriakidis, C A Bolos
  [show abstract] [hide abstract]
  ABSTRACT: A new series of coordination compounds of the starting materials [Cu(dienX(2)Y(2))] and their adducts [Cu(dienXXY(2))(2a-5mt)] (where dien=diethylenetriamine, dienXX=Schiff bases of diethylenetriamine with 2-furaldehyde or 2-thiophene-carboxaldehyde, X=O, S, Y=Cl, Br, NO(3) and 2a-5mt=2-amino-5-methylthiazole) were synthesized by stepwise reactions and their structures were established by C, H, N, Cu analysis, spectroscopic, magnetic and molar conductivity measurements. The isolated compounds are monomers, paramagnetic and electrolytic compounds of the type 1:1. In all cases, the pentadentate Schiff base (dienXX) is bonded in a tridentate fashion through the 3 N atoms. In the CudienXXY(2) compounds the coordination sphere is completed by two Cl or Br or NO(3) groups in a square pyramidal arrangement. The proposed structure for this type of compound was further supported by X-ray diffraction analysis of the compound [Cu(dienOO)Cl(2)]. Its basal plane consists of three Cu-N contacts [2.017(2), 2.025(2) and 2.012(2) A] from dienOO, and the Cl(1) atom, while the Cl(2) atom possesses the apical position, the relevant distances being 2.2732(7) A for Cu-Cl(1) and 2.6051(7) A Cu-Cl(2). In the CudienX(2)Y(2).2a-5mt adducts the coordination sphere of copper is further completed by the nitrogen ring atom of the 2a-5mt, forming an octahedral configuration. The study of the biological activity of the compounds synthesized against a panel of different normal and cancer cell lines (MRC5, HeLa, MCF7, HT-29, OAW42, T47D) and bacteria (E. coli, B. cereus, B. subtilis) showed that the adducts of the type [Cu(dienXXY(2))(2a-5mt)] exhibit increased activity both in cancer cells and in bacteria, compared to the starting material of type [Cu(dienXXY(2))].
  Journal of Inorganic Biochemistry 09/2004; 98(8):1271-83. · 3.35 Impact Factor
• Article: The unexpected formation of biologically active Cu(II) Schiff mono-base complexes with 2-thiophene-carboxaldehyde and dipropylenetriamine: crystal and molecular structure of CudptaSCl2

  A.Th. Chaviara, P.J. Cox, K.H. Repana, A.A. Pantazaki, K.T. Papazisis, A.H. Kortsaris, D.A. Kyriakidis, G.St. Nikolov, C.A. Bolos
  [show abstract] [hide abstract]
  ABSTRACT: Two novel mononuclear Cu(II) coordination compounds of the type [Cu(dptaS)Cl2] and [Cu(dptaS)Br2] (dptaS = 1,3-propanediamine, N1-[3-aminopropyl]-N3-[2-thienylmethylidene] or Schiff mono-base of dipropylenetriamine with 2-thiophene-carboxaldehyde) were prepared by the hydrolysis of the di-bases, [Cu(dptaSS)Cl2] and [Cu(dptaSS)Br2] (dptaSS = 1,3-propanediamine, N1-[2-thienylmethylidene]-N3-[[2-thienylmethylidene]aminopropyl] or Schiff di-base of dipropylenetriamine with 2-thiophenecarboxaldehyde) to mono-bases with the release of one aldehyde molecule and freeing of the –NH2 group of the coordinated dpta ligand. The X-ray determined structure of the compound [Cu(dptaS)Cl2] was confirmed by spectroscopic methods, magnetic and molar conductivity measurements. The Cu(II) atom is a five-coordinated CuN3Cl2 chromophore with three nitrogen atoms coming up from the (dptaS) ligand and two chlorine atoms completing the square pyramidal geometry. Antiproliferative activity of both novel compounds was examined against a panel of different normal and cancer cell lines (MRC5, HeLa, MCF7, HT-29 and T47D) and showed that the Cu(II) Schiff mono-bases exhibit increased activity as compared to the starting materials. In vitro studies of plasmid DNA (pDNA) and double stranded DNA (dsDNA) interaction with the compounds under study support this difference. Some of the important factors contributing to the antiproliferative activity of the compounds under study, such as ionic character and dipole moment were also discussed in terms of the density functional theory calculated electronic structures of the ligands and their Cu(II) compounds.
  Journal of Inorganic Biochemistry. 99(2):467-476.