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Crystal Structure, Cytotoxicity and Interaction with DNA of Zinc (II) Complexes with o-Vanillin Schiff Base Ligands.

Niu MJ, Li Z, Chang GL, Kong XJ, Hong M, Zhang QF - PLoS ONE (2015)

Bottom Line: The results show that complex 1 exhibits higher interaction with CT-DNA than complex 2.In addition, in vitro cytotoxicity of the complexes towards four kinds of cancerous cell lines (A549, HeLa, HL-60 and K562) were assayed by the MTT method.Investigations on the structures indicated that the chirality and nuclearity of zinc complexes play an important role on cytotoxic activity.

View Article: PubMed Central - PubMed

Affiliation: School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, Shandong, 252059, China; Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, Liaocheng University, Liaocheng, Shandong, 252059, China.

ABSTRACT
Two new zinc complexes, Zn(HL1)2 (1) and [Zn2(H2L2)(OAc)2]2 (2) [H2L1 = Schiff base derived from o-vanillin and (R)-(+)-2-amino-3-phenyl-1-propanol, H3L2 = Schiff base derived from o-vanillin and 2-amino-2-ethyl-1,3-propanediol], have been synthesized and characterized by single crystal X-ray diffraction, elemental analyses, TG analyses, solid fluorescence, IR, UV-Vis and circular dichroism spectra. The structural analysis shows that complex 1 has a right-handed double helical chain along the crystallographic b axis. A homochiral 3D supramolecular architecture has been further constructed by intermolecular C-H··· π, O-H···O and C-H···O interactions. Complex 2 includes two crystallographically independent binuclear zinc molecules. The two binuclear zinc molecules are isostructural. The 2-D sheet supramolecular structure was formed by intermolecular hydrogen bonding interaction. The fluorescence of ligands and complexes in DMF at room temperature are studied. The interactions of two complexes with calf thymus DNA (CT-DNA) are investigated using UV-Vis, CD and fluorescence spectroscopy. The results show that complex 1 exhibits higher interaction with CT-DNA than complex 2. In addition, in vitro cytotoxicity of the complexes towards four kinds of cancerous cell lines (A549, HeLa, HL-60 and K562) were assayed by the MTT method. Investigations on the structures indicated that the chirality and nuclearity of zinc complexes play an important role on cytotoxic activity.

No MeSH data available.


Related in: MedlinePlus

UV-Vis absorption spectra of complexes 1 and 2 (10 μM) in the absence and presence of increasing amounts of DNA (0–10 μM).Arrow shows the absorbance changes upon increasing DNA concentration.
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pone.0130922.g009: UV-Vis absorption spectra of complexes 1 and 2 (10 μM) in the absence and presence of increasing amounts of DNA (0–10 μM).Arrow shows the absorbance changes upon increasing DNA concentration.

Mentions: To determine the binding ability of Zn (II) complexes with DNA helix, electronic absorption spectroscopy is employed [2]. When stacking interaction occurred between the aromatic chromophore of the test complexes and DNA base pairs, hypochromism and bathochromic shift in wavelength could be observed. The extent of hypochromism is commonly consistent with the strength of intercalative interaction [34]. The absorption spectrum of complexes 1 and 2 in the absence and presence of CT-DNA are shown in Fig 9. The strong absorption spectra at about 360 nm for tow complexes may be assigned to the ligand-to-metal charge transfer (LMCT). With the increase of the concentration of DNA, all the adsorption bands showed hypochromism accompanied with bathochromic shifts, similar to those previously reported metal intercalators. Generally, the complex could intercalate to the base pairs of DNA. And the π* orbital of the intercalators may couple with the π orbital of the base pairs, decrease the π-π* transition probabilities and consequently lead to hypochromism. The intrinsic binding constant Kb was calculated according to the equation: [DNA]/(εa−εf) = [DNA]/(εb−εf) + 1/Kb(εa−εf) [35]. The Kb values for complex 1−2 were calculated to be 5.21×104, 7.11×103 M-1, respectively. From the results of the binding constants, the intrinsic binding constant Kb values of chiral complex 1 are higher than achiral complex 2. This is consistent with the experimental results of fluorescence quenching.


Crystal Structure, Cytotoxicity and Interaction with DNA of Zinc (II) Complexes with o-Vanillin Schiff Base Ligands.

Niu MJ, Li Z, Chang GL, Kong XJ, Hong M, Zhang QF - PLoS ONE (2015)

UV-Vis absorption spectra of complexes 1 and 2 (10 μM) in the absence and presence of increasing amounts of DNA (0–10 μM).Arrow shows the absorbance changes upon increasing DNA concentration.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4482705&req=5

pone.0130922.g009: UV-Vis absorption spectra of complexes 1 and 2 (10 μM) in the absence and presence of increasing amounts of DNA (0–10 μM).Arrow shows the absorbance changes upon increasing DNA concentration.
Mentions: To determine the binding ability of Zn (II) complexes with DNA helix, electronic absorption spectroscopy is employed [2]. When stacking interaction occurred between the aromatic chromophore of the test complexes and DNA base pairs, hypochromism and bathochromic shift in wavelength could be observed. The extent of hypochromism is commonly consistent with the strength of intercalative interaction [34]. The absorption spectrum of complexes 1 and 2 in the absence and presence of CT-DNA are shown in Fig 9. The strong absorption spectra at about 360 nm for tow complexes may be assigned to the ligand-to-metal charge transfer (LMCT). With the increase of the concentration of DNA, all the adsorption bands showed hypochromism accompanied with bathochromic shifts, similar to those previously reported metal intercalators. Generally, the complex could intercalate to the base pairs of DNA. And the π* orbital of the intercalators may couple with the π orbital of the base pairs, decrease the π-π* transition probabilities and consequently lead to hypochromism. The intrinsic binding constant Kb was calculated according to the equation: [DNA]/(εa−εf) = [DNA]/(εb−εf) + 1/Kb(εa−εf) [35]. The Kb values for complex 1−2 were calculated to be 5.21×104, 7.11×103 M-1, respectively. From the results of the binding constants, the intrinsic binding constant Kb values of chiral complex 1 are higher than achiral complex 2. This is consistent with the experimental results of fluorescence quenching.

Bottom Line: The results show that complex 1 exhibits higher interaction with CT-DNA than complex 2.In addition, in vitro cytotoxicity of the complexes towards four kinds of cancerous cell lines (A549, HeLa, HL-60 and K562) were assayed by the MTT method.Investigations on the structures indicated that the chirality and nuclearity of zinc complexes play an important role on cytotoxic activity.

View Article: PubMed Central - PubMed

Affiliation: School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, Shandong, 252059, China; Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, Liaocheng University, Liaocheng, Shandong, 252059, China.

ABSTRACT
Two new zinc complexes, Zn(HL1)2 (1) and [Zn2(H2L2)(OAc)2]2 (2) [H2L1 = Schiff base derived from o-vanillin and (R)-(+)-2-amino-3-phenyl-1-propanol, H3L2 = Schiff base derived from o-vanillin and 2-amino-2-ethyl-1,3-propanediol], have been synthesized and characterized by single crystal X-ray diffraction, elemental analyses, TG analyses, solid fluorescence, IR, UV-Vis and circular dichroism spectra. The structural analysis shows that complex 1 has a right-handed double helical chain along the crystallographic b axis. A homochiral 3D supramolecular architecture has been further constructed by intermolecular C-H··· π, O-H···O and C-H···O interactions. Complex 2 includes two crystallographically independent binuclear zinc molecules. The two binuclear zinc molecules are isostructural. The 2-D sheet supramolecular structure was formed by intermolecular hydrogen bonding interaction. The fluorescence of ligands and complexes in DMF at room temperature are studied. The interactions of two complexes with calf thymus DNA (CT-DNA) are investigated using UV-Vis, CD and fluorescence spectroscopy. The results show that complex 1 exhibits higher interaction with CT-DNA than complex 2. In addition, in vitro cytotoxicity of the complexes towards four kinds of cancerous cell lines (A549, HeLa, HL-60 and K562) were assayed by the MTT method. Investigations on the structures indicated that the chirality and nuclearity of zinc complexes play an important role on cytotoxic activity.

No MeSH data available.


Related in: MedlinePlus