Luminescence and binding properties of two isoquinoline alkaloids chelerythrine and sanguinarine with ctDNA

Junfen Li, Baohong Li, Yanbo Wu, Shaomin Shuang, Chuan Dong*, Martin M F CHOI

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)

Abstract

The binding mode and mechanism of the interactions between two planar cationic alkaloids chelerythrine (Che) and sanguinarine (San) with calf thymus DNA (ctDNA) were systematically investigated at pH 5.40 using UV-vis absorption spectroscopy, fluorescence spectroscopy and cyclic voltammetry. Che and San show strong fluorescence at 570 and 589 nm, respectively. Che displays fluorescence enhancement with ctDNA whereas the fluorescence of San is quenched on interaction with ctDNA. In addition, UV-vis spectra of both alkaloids show apparent hypochromicity and are bathochromic shifted, indicating that they could intercalate into ctDNA bases. The fluorescence polarization of Che and San increases in the presence of ctDNA, again implying the intercalation of two alkaloids with ctDNA. This conclusion was also supported by the results obtained from anion quenching and cyclic voltammetry. The binding constants of both alkaloids with ctDNA were calculated in the order of 10 5 L/mol. San binds with ctDNA 3-fold stronger than Che. The stoichiometric bindings are five nucleotides per Che or San. Electrostatic binding also exists between the alkaloids and DNA helix. Finally, theoretical calculations show that only certain parts of Che and San molecules intercalate into the DNA helix.

Original languageEnglish
Pages (from-to)80-85
Number of pages6
JournalSpectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
Volume95
DOIs
Publication statusPublished - Sep 2012

Scopus Subject Areas

  • Analytical Chemistry
  • Atomic and Molecular Physics, and Optics
  • Instrumentation
  • Spectroscopy

User-Defined Keywords

  • Binding
  • Calf thymus DNA
  • Chelerythrine
  • Sanguinarine
  • Spectroscopic methods

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