Molecular Spectroscopic Studies of Farrerol Interaction with Calf Thymus DNA

Abstract

The interaction between farrerol and calf thymus DNA in a pH 7.4 Tris-HCl buffer was investigated with the use of neutral red (NR) dye as a spectral probe by UV-vis absorption, fluorescence, and circular dichroism (CD) spectroscopy, as well as viscosity measurements and DNA melting techniques. It was found that farrerol molecules could intercalate into the base pairs of DNA as evidenced by decreases in iodide quenching effect and single-stranded DNA (ssDNA) quenching effect, induced CD spectral changes, and significant increases in relative viscosity and denaturation temperature of DNA. Furthermore, the spectral data matrix of the competitive reaction between farrerol and NR with DNA was resolved with an alternative least-squares (ALS) algorithm, and the concentration profiles in the reaction and the corresponding pure spectra for three species (farrerol, NR, and DNA-NR complex) were obtained. This ALS analysis demonstrated the intercalation of farrerol to the DNA by substituting for NR in the DNA-NR complex. Moreover, the thermodynamic parameters enthalpy change (ΔH°) and entropy change (ΔS°) were calculated to be -16.49 ± 0.51 kJ mol(-1) and 32.47 ± 1.02 J mol(-1) K(-1) via the van't Hoff equation, which suggested that the binding of farrerol to DNA was driven mainly by hydrophobic interactions and hydrogen bonds.

Design, synthesis and biological evaluation of berberine-benzimidazole hybrids as new type of potentially DNA-targeting antimicrobial agents

“…These meant a weak hypochromic effect existed between DNA and compound 5d. Furthermore, the intercalation of the aromatic chromophore of compound 5d into the helix and the strong overlap of π-π* states in the large π-conjugated system with the electronic states of DNA bases were consistent with the observed spectral changes [32,33]. Based on variations in the absorption spectra of DNA upon binding to 5d, eq 1 can be utilized to calculate the binding constant (K).…”

Studying non-covalent drug–DNA interactions

“…The stability of DNA on interaction with small molecules is easily studied using UV-visible absorption measurement. In general, the interaction of small molecules with DNA and the formation of a new complex lead to changes in UVvisible spectra [8,9]. To elaborate, the band intensity and position of the spectra of the free small molecule as well as its complex with DNA are recorded (Fig.…”

Interaction of Two Flavonoids With Calf Thymus Dna: A Multi - Spectroscopic, Electrochemical and Molecular Modelling Approach

“…The solution of DNA was found to be free from protein as evident from its absorbance ratio value in the range of 1.7. 29 All measurements were carried out at the physiological pH of 7.4 by using the TrisHCl buffer.…”