Design and synthesis of a sulphur containing Schiff base drug: DNA binding studies and theoretical calculations

Abstract

The Schiff base compound MTA ((E)-5-methyl-N'-((5-methylthiophen-2-yl)methylene)-1H-pyrazole-3-carbohydrazide) derived from 2-thiophenecarboxaldehyde and 5-methylpyrazole-3-carbohydrazide has been designed to develop new sulphur containing DNA targeted molecule. The MTA has been characterized by elemental analyses, ¹H-NMR, single crystal X-ray diffraction studies as well as by geometry optimization of using DFT/B3LYP. The interaction of MTA with Calf thymus DNA (CT-DNA) was studied by spectroscopic and calorimetric techniques. The synthesized compound was found to bind with CT-DNA through groove binding mode, and the binding constant was estimated to be (4.15 ± 0.08) × 10⁴ M⁻¹. The negative ΔG⁰ and positive ΔS⁰ values obtained from the calorimetric technique confirmed the spontaneity of the binding of MTA with DNA.

Communicated by Ramaswamy H. Sarma

Keywords:

• Sulphur containing Schiff base
• Single crystal XRD
• CT DNA
• Photophysical studies
• Thermodynamic study

Acknowledgements

US and MD thank Science & Engineering Research Board (SERB), Govt. of India for the award of National Post-doctoral fellowships (Ref. No.PDF/2016/000080 and Ref No.PDF/2016/000334). SK thanks The Bhawanipur Education Society College for providing the research grant.

Disclosure statement

No potential conflict of interest was reported by the authors.