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The Effects of Extending of Co-planarity in a Series of Structurally Relative Polypyridyl Palladium(II) Complexes on DNA-binding and Cytotoxicity Properties.

Shahraki S, Mansouri-Torshizi H, Sori Nezami Z, Ghahghaei A, Yaghoubi F, Divsalar A, Saboury AA, H Shirazi F - Iran J Pharm Res (2014)

Bottom Line: EBr and Scatchard experiments for a-d complexes suggest efficient intercalative binding affinity to CT-DNA giving the order: d > c > b > a.Several binding and thermodynamic parameters are also described.The biological activity of these cationic and water soluble palladium complexes were tested against chronic myelogenous leukemia cell line, K562. b, c and d complexes show cytotoxic concentration (Cc50) values much lower than cisplatin.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Sistan & Baluchestan, Zahedan, Iran.

ABSTRACT
In depth interaction studies between calf thymus deoxyribonucleic acid (CT-DNA) and a series of four structurally relative palladium(II) complexes [Pd(en)(HB)](NO3)2 (a-d), where en is ethylenediamine and heterocyclic base (HB) is 2,2'-bipyridine (bpy, a); 1,10-phenanthroline (phen, b); dipyridoquinoxaline (dpq, c) and dipyridophenazine (dppz, d) (Figure 1), were performed. These studies have been investigated by utilizing the electronic absorption spectroscopy, fluorescence spectra and ethidium bromide (EBr) displacement and gel filtration techniques. a-d complexes cooperatively bind and denature the DNA at low concentrations. Their concentration at midpoint of transition, L1/2, follows the order a > b > c > d. Also the g, the number of binding sites per 1000 nucleotides, follows the order a > b ~ c > d. EBr and Scatchard experiments for a-d complexes suggest efficient intercalative binding affinity to CT-DNA giving the order: d > c > b > a. Several binding and thermodynamic parameters are also described. The biological activity of these cationic and water soluble palladium complexes were tested against chronic myelogenous leukemia cell line, K562. b, c and d complexes show cytotoxic concentration (Cc50) values much lower than cisplatin.

No MeSH data available.


Related in: MedlinePlus

Plots of the molar enthalpies of DNA denaturation in the interaction with [Pd(en)(bpy)](NO3)2 a, [Pd(en)(phen)](NO3)2 b, [Pd(en)(dpq)](NO3)2 c and [Pd(en)(dppz)](NO3)2 d complexes, in the range of 300 to 310 K
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Figure 5: Plots of the molar enthalpies of DNA denaturation in the interaction with [Pd(en)(bpy)](NO3)2 a, [Pd(en)(phen)](NO3)2 b, [Pd(en)(dpq)](NO3)2 c and [Pd(en)(dppz)](NO3)2 d complexes, in the range of 300 to 310 K

Mentions: Another important thermodynamic parameter found is the molar enthalpy of DNA denaturation in absence of metal complexes i.e. . For this, we calculated the molar enthalpy of DNA denaturation in presence of each metal complex, ΔH˚conformation or ΔH˚denaturation, (ΔH˚con), in the range of the two temperatures using Gibbs-Helmholtz equation (37). In addition, the molar enthalpies of DNA denaturation in the absence of metal complexes, (), were determined by interpolation of a plot of ΔH˚ against the concentration of each metal complex. Straight lines will be obtained which are shown in Figure 5. Interpolation of these lines (intercept on ordinate i.e. absence of metal complex) give the values of (Table 2). These plots show that in the range of 300 to 310 K the changes in the enthalpies in the presence of Pd(II) complexes are ascending. These observations indicate that, on increasing the concentration of Pd(II) complexes, the stability of CT-DNA is increased. Also, the molar entropies of DNA denaturation, (), in the absence of each metal complex have been calculated using equation ΔG = ΔH–TΔS for each temperature (300 and 310 K) (Table 2). These data show that increasing temperature does not show concrete change in values of the entropies. This might be due to proximity of the temperature range. Also, the metal-DNA complexes are more disordered than the native DNA, because the entropy changes are positive (Table 2). These thermodynamic parameters compare favorably well with those of palladium (II) complexes as reported earlier (33-35).


The Effects of Extending of Co-planarity in a Series of Structurally Relative Polypyridyl Palladium(II) Complexes on DNA-binding and Cytotoxicity Properties.

Shahraki S, Mansouri-Torshizi H, Sori Nezami Z, Ghahghaei A, Yaghoubi F, Divsalar A, Saboury AA, H Shirazi F - Iran J Pharm Res (2014)

Plots of the molar enthalpies of DNA denaturation in the interaction with [Pd(en)(bpy)](NO3)2 a, [Pd(en)(phen)](NO3)2 b, [Pd(en)(dpq)](NO3)2 c and [Pd(en)(dppz)](NO3)2 d complexes, in the range of 300 to 310 K
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4232794&req=5

Figure 5: Plots of the molar enthalpies of DNA denaturation in the interaction with [Pd(en)(bpy)](NO3)2 a, [Pd(en)(phen)](NO3)2 b, [Pd(en)(dpq)](NO3)2 c and [Pd(en)(dppz)](NO3)2 d complexes, in the range of 300 to 310 K
Mentions: Another important thermodynamic parameter found is the molar enthalpy of DNA denaturation in absence of metal complexes i.e. . For this, we calculated the molar enthalpy of DNA denaturation in presence of each metal complex, ΔH˚conformation or ΔH˚denaturation, (ΔH˚con), in the range of the two temperatures using Gibbs-Helmholtz equation (37). In addition, the molar enthalpies of DNA denaturation in the absence of metal complexes, (), were determined by interpolation of a plot of ΔH˚ against the concentration of each metal complex. Straight lines will be obtained which are shown in Figure 5. Interpolation of these lines (intercept on ordinate i.e. absence of metal complex) give the values of (Table 2). These plots show that in the range of 300 to 310 K the changes in the enthalpies in the presence of Pd(II) complexes are ascending. These observations indicate that, on increasing the concentration of Pd(II) complexes, the stability of CT-DNA is increased. Also, the molar entropies of DNA denaturation, (), in the absence of each metal complex have been calculated using equation ΔG = ΔH–TΔS for each temperature (300 and 310 K) (Table 2). These data show that increasing temperature does not show concrete change in values of the entropies. This might be due to proximity of the temperature range. Also, the metal-DNA complexes are more disordered than the native DNA, because the entropy changes are positive (Table 2). These thermodynamic parameters compare favorably well with those of palladium (II) complexes as reported earlier (33-35).

Bottom Line: EBr and Scatchard experiments for a-d complexes suggest efficient intercalative binding affinity to CT-DNA giving the order: d > c > b > a.Several binding and thermodynamic parameters are also described.The biological activity of these cationic and water soluble palladium complexes were tested against chronic myelogenous leukemia cell line, K562. b, c and d complexes show cytotoxic concentration (Cc50) values much lower than cisplatin.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Sistan & Baluchestan, Zahedan, Iran.

ABSTRACT
In depth interaction studies between calf thymus deoxyribonucleic acid (CT-DNA) and a series of four structurally relative palladium(II) complexes [Pd(en)(HB)](NO3)2 (a-d), where en is ethylenediamine and heterocyclic base (HB) is 2,2'-bipyridine (bpy, a); 1,10-phenanthroline (phen, b); dipyridoquinoxaline (dpq, c) and dipyridophenazine (dppz, d) (Figure 1), were performed. These studies have been investigated by utilizing the electronic absorption spectroscopy, fluorescence spectra and ethidium bromide (EBr) displacement and gel filtration techniques. a-d complexes cooperatively bind and denature the DNA at low concentrations. Their concentration at midpoint of transition, L1/2, follows the order a > b > c > d. Also the g, the number of binding sites per 1000 nucleotides, follows the order a > b ~ c > d. EBr and Scatchard experiments for a-d complexes suggest efficient intercalative binding affinity to CT-DNA giving the order: d > c > b > a. Several binding and thermodynamic parameters are also described. The biological activity of these cationic and water soluble palladium complexes were tested against chronic myelogenous leukemia cell line, K562. b, c and d complexes show cytotoxic concentration (Cc50) values much lower than cisplatin.

No MeSH data available.


Related in: MedlinePlus