DNA binding and cytotoxicity activity of a chiral iron(III) triangle complex based on a natural rosin product
•The first chiral iron(III) trinuclear complex of rosin product was synthesized.•The iron(III) complex shows stronger binding affinity to DNA compared with the ligand.•The binding mode between the complex and DNA is intercalation.•The in vitro cytotoxicity of the complex was weaker than the ligand.•Our work provides a rationale for designing new potential anticancer drugs from natural product.
The first chiral trinuclear iron(III) complex [Fe3(μ3-O)(L)6(CH3OH)2(CH3O)]⋅H2O (2) of a natural rosin product dehydroabietic acid (HL, 1) was synthesized and fully characterized. The interactions of 1 and 2 with salmon sperm DNA were investigated by viscosity measurements, UV, fluorescence and circular dichroism (CD) spectroscopic techniques. Absorption spectral (Kb = 1.30 × 105 M−1 (1), 1.40 × 105 M−1(2)), emission spectral (KSV = 1.19 × 104 M−1 (1), 1.79 × 104 M−1 (2)) and viscosity measurements reveal that 1 and 2 interacted with DNA through intercalation and 2 exhibited a slight higher DNA binding ability. The Stern–Volmer quenching constant (KSV) and corresponding thermodynamic parameters (ΔG, ΔH and ΔS) of the binding processes were determined. The negative ΔH and ΔG values indicate that the binding reactions were exothermic and spontaneous. 1 and 2 were also screened for their cytotoxic ability and 1 demonstrated higher growth inhibition of the selected cancer cells at concentrations of 25 μM and 50 μM, this result was not identical with their DNA binding ability order. Thus, the involvement of Fe(III) centers had positive effect on DNA binding ability and negative effect on cytotoxicity.
Graphical abstractThe first chiral trinuclear iron(III) complex [Fe3(μ3-O)(L)6(CH3OH)2(CH3O)]·H2O (2) based on dehydroabietic acid (HL, 1) has been synthesized. The involvement of Fe(III) centers has positive effect on DNA binding ability and negative effect on cytotoxicity of 1.Figure optionsDownload full-size imageDownload as PowerPoint slide
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 142, January 2015, Pages 77–85