Li Sun,Xueliang Wang,Na Zou,Hongying Li,Zhangyu Yu
The interaction of formononetin (FN) with herring sperm DNA has been studied by electrochemical methods, UV-Vis spectroscopy and fluorescence. On a poly L-cysteine film modified electrode (PLC/GCE), FN showed a couple of well-defined voltammetric peaks in 0.1 M acetate buffer of pH 5.3. As adding the herring sperm DNA into above solution, the peak current of FN decreased and no new peaks appeared. Based on the electrochemical results, the binding constant and binding ratio between FN and herring sperm DNA were determined to be 1.98×10 4 M -3 and 1:3, respectively. The UV-Vis spectroscopy indicated that the maximum absorption of FN had obviously hyperchromic effect and red shift after the interaction of DNA and FN. The interaction of DNA and FN can also make the fluorescence intensity of FN enhancement. The electrochemical and spectroscopic results indicated that the interaction of FN to DNA was an intercalative mode.
The characteristics of binding of 2-tert-butyl-4-methylphenol (TBMP), a synthetic phenolic antioxidant with hydroxypropyl-β-cyclodextrin (Hp-βCD) and calf thymus DNA (ctDNA) were investigated by multi-spectroscopic techniques and molecular simulation. The results indicated that TBMP preferred to form a 1:1 inclusion complex with Hp-βCD, with an inclusion constant of determined to be 7.15 × 10 3 L mol −1 . The intercalative mode of TBMP to ctDNA was supported by ctDNA melting temperature and relative viscosity studies, salt quenching effect, competitive binding with methylene blue and molecular modeling. The changes in Fourier transformed infrared (FT-IR) and circular dichroism (CD) spectra suggested that TBMP mainly bound to the G–C rich region with inducing a significant perturbation in B-like DNA structure. It was also found that Hp-βCD decreased the binding ability of TBMP with ctDNA, but did not affect the interactive mode between TBMP and ctDNA, and the formed inclusion complex of TBMP–Hp-βCD decomposed in the presence of ctDNA. This study may provide insights into the mechanism of binding of TBMP with ctDNA and the role of Hp-βCD in the TBMP–ctDNA interaction.
In this work, we rationally designed and synthesized two novel triazene-amonafide derivatives 2-(2-(diisopropylamino)ethyl)-5-(3,3-dimethyltriaz-1-en-1-yl)-1H-benzo[ de ]isoquinoline-1,3(2H)-dione ( D-11 ) and 5-(3,3-diethyltriaz-1-en-1-yl)-2-(2-(diisopropylamino)ethyl)-1H-benzo[ de ]isoquinoline-1,3(2H)-dione ( D-12 ) as potential antitumor agents. The DNA damage induced by the intercalation mode of D-11 ( D-12 ) towards DNA was electrochemically detected through the construction of efficient biosensors. The consecutive processes of reversible redox of naphthylimide ring and irreversible oxidation of triazene moiety were elucidated on the surface of glassy carbon electrode (GCE) by CV, SWV, and DPV methods. Electrochemical biosensors were obtained through the immobilization of ct DNA, G-quadruplexes, poly(dG), and poly(dA), respectively, on the clean surface of GCE. After the incubation of biosensors with D-11 or D-12 , the peaks of dGuo and dAdo decreased prominently, and the peak of 8-oxoGua appeared at +0.50 V, suggesting that the interaction between D-11 ( D-12 ) and DNA could result in the oxidative damage of guanine. Unexpected, the as-prepared DNA biosensor possessed satisfactory anti-interference property and good practicability in real samples. UV–vis and fluorescence spectra, and gel electrophoresis assays were employed to further confirm the intercalation mode of D-11 ( D-12 ) towards DNA base pairs. Moreover, D-11 was proved to exhibit stronger anti-proliferation activity than mitionafide and amonafide against both A549 and HeLa cell lines.
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