The importance of pK a in an analysis of the interaction of compounds with DNA

Saha, Mouli; Nandy, Promita; Chakraborty, Mousumi; Das, Piyal; Das, Saurabh

doi:10.1016/j.bpc.2018.02.001

Cited by 8 publications

(8 citation statements)

References 33 publications

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“…Titrations were repeated thrice. The values obtained were in the range of 2.73 × 10 4 to 5.47 × 10 4 M –1 . ,− Figure B is a plot of Δ A /Δ A max versus concentration of calf thymus DNA. Nonlinear curve fitting was applied (eqs and ) on three separate titrations and an average apparent binding constant ( K app = 6.87 × 10 4 M –1 ) were evaluated. ,− The inset of Figure B provides a value for n b (=8.0), the number of nucleotides bound to the complex following its interaction with calf thymus DNA.…”

Section: Results and Discussionmentioning

confidence: 88%

“…The values obtained were in the range of 2.73 × 10 4 to 5.47 × 10 4 M –1 . 33 , 35 − 39 Figure 4 B is a plot of Δ A /Δ A max versus concentration of calf thymus DNA. Nonlinear curve fitting was applied ( eqs 3 and 4 ) on three separate titrations and an average apparent binding constant ( K app = 6.87 × 10 4 M –1 ) were evaluated.…”

Section: Results and Discussionmentioning

confidence: 99%

“…Nonlinear curve fitting was applied ( eqs 3 and 4 ) on three separate titrations and an average apparent binding constant ( K app = 6.87 × 10 4 M –1 ) were evaluated. 33 , 35 − 39 The inset of Figure 4 B provides a value for n b (=8.0), the number of nucleotides bound to the complex following its interaction with calf thymus DNA.…”

Section: Results and Discussionmentioning

confidence: 99%

“… L represents the complex and K d the dissociation constant whose reciprocal provides a value for the apparent binding constant ( K app ). 33 , 36 − 39 Equation 2 is generated from eq 1 where the reciprocal of the change in absorbance was plotted against the reciprocal of ( C D – C 0 ). C D refers to concentration of calf thymus DNA and C 0 to complex.…”

Section: Methodsmentioning

confidence: 99%

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Multitargeting Antibacterial Activity of a Synthesized Mn²⁺ Complex of Curcumin on Gram-Positive and Gram-Negative Bacterial Strains

et al. 2020

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Curcumin is an important molecule with a plethora of pharmacological activities and therapeutic potentials. Despite its efficacy, it remained a potential drug candidate owing to hydrolytic instability and poor aqueous solubility. To overcome the limitations related to low solubility, low bioavailability, and the fact that curcumin is never present in solution as a “single unit”, its complex was prepared with Mn II with the idea that binding to a metal ion might help to resolve these issues. The complex was characterized by elemental and spectral analysis. The structure of the complex was determined by density functional theory calculations. The complex was stable at physiological buffer conditions, unlike curcumin. It did not have any detrimental effect on mammalian cells. There was a significant enhancement in the antibacterial activity of the complex compared to curcumin against both Gram-positive ( Staphylococcus aureus ) and Gram-negative ( Escherichia coli ) bacteria. It showed a strong affinity for deoxyribonucleic acid (DNA) evident from a high binding constant value with calf thymus DNA and also from the retarded electrophoretic mobility of bacterial plasmid DNA. The complex showed “superoxide dismutase-like” activity leading to the generation of reactive oxygen species (ROS). The complex caused bacterial membrane perturbation evident from calcein leakage assay, which was further corroborated by scanning and transmission electron microscopic experiments. Overall, the present study shows improved stability and antibacterial potency of a nontoxic complex over curcumin. Its multitargeting mode of action such as ROS-production, effective binding with DNA, and permeabilization of bacterial membrane together allows it to be an effective antibacterial agent that could be taken further for therapeutic use against bacterial infections.

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Section: Results and Discussionmentioning

confidence: 88%

Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Multitargeting Antibacterial Activity of a Synthesized Mn²⁺ Complex of Curcumin on Gram-Positive and Gram-Negative Bacterial Strains

et al. 2020

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“…Há significância entre as amostras pelo teste ANOVA (p < 0,05 %). Os valores apresentados são os valores médios ( ̅ ) obtidos a partir da equação ̅ = A espectroscopia de UV-Vis limita-se a moléculas que apresentam sistemas conjugados [47], mas que pode ser aplicado a várias situações problema, desde o monitoramento de parâmetros ambientais [49], questões relacionadas à saúde [50,51] ou na alteração e estudo de novos materiais [52,53]. As moléculas que apresentam sistemas conjugados ou insaturados estão presentes em sistemas químicos, físicos e/ou biológicos em amostras sólidas, líquidas ou gasosas [54][55][56][57][58][59].…”

Section: Análise Por Espectroscopia De Uv-visunclassified

O uso de corantes alimentícios como tema gerador em aulas experimentais de Química

et al. 2018

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Este artigo apresenta uma estratégia didático-pedagógica que utiliza as propriedades dos corantes alimentícios como tema gerador em aulas experimentais de Química para a introdução dos conceitos de espectroscopia de UV-Vis e cromatografia, visto que estas técnicas são complementares e apresentam-se hifenadas na cromatografia líquida, por exemplo. A partir de análises espectroscópicas e cromatográficas, foram determinados e comparados os parâmetros físico-químicos energia de transição molar (ET), absortividade molar (ε) e os índices de retenção (Rf) dos corantes amaranto, amarelo de tartrazina e azul de indigotina. Observam-se pequenas alterações dos comprimentos de onda máximos dos corantes testados, com a variação da polaridade dos solventes utilizados, principalmente do corante azul de indigotina, o que reflete em diferentes valores de ET. Com essa proposta de atividade experimental é possível fortalecer o processo de ensino e aprendizagem, de forma significativa, a qual está baseada na observação, na análise dos dados experimentais, seguida de uma conclusão, pautada pela contextualização entre o tema gerador e com o cotidiano dos estudantes.

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Selective, pH‐Dependent Colorimetric and Fluorimetric Detection of Quadruplex DNA with 4‐Dimethylamino(phenyl)‐Substituted Berberine Derivatives

Wickhorst

Ihmels

2021

Chemistry A European J

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The 9‐ and 12‐dimethylaminophenyl‐substituted berberine derivatives 3 a and 3 b were readily synthesized by Suzuki‐Miyaura reactions and shown to be useful fluorescent probes for the optical detection of quadruplex DNA (G4‐DNA). Their association with the nucleic acids was investigated by spectrometric titrations, CD and LD spectroscopy, and with DNA‐melting analysis. Both ligands bind to duplex DNA by intercalation and to G4‐DNA by terminal π stacking. At neutral conditions, they bind with higher affinity (Kb=105−106 M−1) to representative quadruplex forming oligonucleotides 22AG, c‐myc, c‐kit, and a2, than to duplex calf thymus (ct) DNA (Kb=5‐7×104 M−1). At pH 5, however, the affinity of 3 a towards G4‐DNA 22AG is higher (Kb=1.2×106 M−1), whereas the binding constant towards ct DNA is lower (Kb=3.9×103 M−1) than under neutral conditions. Notably, the association of the ligand with DNA results in characteristic changes of the absorption and emission properties under specific conditions, which may be used for optical DNA detection. Other than the parent berberine, the ligands do not show a noticeable increase of their very low intrinsic emission intensity upon association with DNA at neutral conditions. In contrast, a fluorescence light‐up effect was observed upon association to duplex (Φfl=0.01) and quadruplex DNA (Φfl=0.04) at pH 5. This fluorimetric response to G4‐DNA association in combination with the distinct, red‐shifted absorption under these conditions provides a simple and conclusive optical detection of G4‐DNA at lower pH.

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The importance of pK a in an analysis of the interaction of compounds with DNA

Cited by 8 publications

References 33 publications

Multitargeting Antibacterial Activity of a Synthesized Mn²⁺ Complex of Curcumin on Gram-Positive and Gram-Negative Bacterial Strains

Multitargeting Antibacterial Activity of a Synthesized Mn²⁺ Complex of Curcumin on Gram-Positive and Gram-Negative Bacterial Strains

O uso de corantes alimentícios como tema gerador em aulas experimentais de Química

Selective, pH‐Dependent Colorimetric and Fluorimetric Detection of Quadruplex DNA with 4‐Dimethylamino(phenyl)‐Substituted Berberine Derivatives

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The importance of pK a in an analysis of the interaction of compounds with DNA

Cited by 8 publications

References 33 publications

Multitargeting Antibacterial Activity of a Synthesized Mn2+ Complex of Curcumin on Gram-Positive and Gram-Negative Bacterial Strains

Multitargeting Antibacterial Activity of a Synthesized Mn2+ Complex of Curcumin on Gram-Positive and Gram-Negative Bacterial Strains

O uso de corantes alimentícios como tema gerador em aulas experimentais de Química

Selective, pH‐Dependent Colorimetric and Fluorimetric Detection of Quadruplex DNA with 4‐Dimethylamino(phenyl)‐Substituted Berberine Derivatives

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Product

Resources

About

Multitargeting Antibacterial Activity of a Synthesized Mn²⁺ Complex of Curcumin on Gram-Positive and Gram-Negative Bacterial Strains

Multitargeting Antibacterial Activity of a Synthesized Mn²⁺ Complex of Curcumin on Gram-Positive and Gram-Negative Bacterial Strains