Binding interaction of N-acetylated acridine conjugate with ct-DNA and β-cyclodextrin: Synthesis and photophysical studies

Abstract

In the present work we are reporting the synthesis and binding interaction of a saturated fatty acid containing 9-aminoacridine derivative (AC-PA) with ct-DNA and β-cyclodextrin (β-CD). From Steady-state fluorescence experiments this newly synthesized 9-aminoacridine derivative, AC-PA, shows more efficient binding interaction with ct-DNA as compared to the 9-aminoacridine (AC). The extent of interaction of AC-PA and AC with ct-DNA was found out by calculating the fluorescence quenching by using Stern–Volmer quenching equation. The calculated quenching constants of AC-PA and AC are (4.5 ± 0.5) × 103M−1 (3.7 ± 0.5) × 103M−1 respectively. The mechanism of fluorescence quenching of AC-PA and AC, were understand by using Stern–Volmer plots as well as time-resolved fluorescence experiments. The fluorescence quenching of AC-PA and AC by ct-DNA are static in nature and take place by formation of ground state complexes. The binding mode between AC-PA and AC were understood by DNA melting analysis experiment. The DNA melting analysis experiments were reveals that the binding interactions between fluorophores (AC-PA and AC) with ct-DNA are intercalative in nature. The melting temperature and mode of binding intercalative mode of binding between AC-PA and AC were further confirmed by DSC and CD experiments. The steady-state and time-resolved fluorescence parameters of AC-PA are quite sensitive towards the formation of inclusion complexes between AC-PA and β-CD. Long hydrophobic tail containing acridine conjugate (AC-PA) shows more efficient binding interactions with the β-CD and the calculated binding constants value of AC-PA is 0.51 × 102M−1. Whereas, the parent molecule, AC not showing any binding interactions with β-CD.