DNA and BSA binding study of an optically pure rosin derivative and its two copper(II) complexes

Abstract

To explain the differences found in cytotoxicity, interactions of an optically pure rosin derivative 2-amino-5-dehydroabietyl-1,3,4-thiadiazole (L) and its two copper(II) complexes [CuL4Cl]Cl·2CH2Cl2·H2O (1) and [CuL4Br]Br·2CH2Cl2 (2) with CT DNA and bovine serum albumins (BSA) have been studied. Emission spectral (K SV = 1.80 × 103 L mol−1 (L), 2.43 × 105 L mol−1 (1) and 2.31 × 105 L mol−1 (2)), DNA thermal denaturation and viscosity measurements reveal that 1 and 2 bind DNA through intercalation with 1 exhibiting a slight higher DNA binding ability, while L bound with DNA through groove interaction. Fluorescence and CD spectral data indicate that 1 and 2 have higher BSA affinity than L. Molecular docking analysis was carried out to explore the interactions of L, 1 and 2 toward DNA and BSA. All the findings reveal that the DNA and BSA binding affinity followed the order of 1 > 2 > L. In addition, their antitumor abilities were in this order, too.