Study On Potential Toxic Mechanism And Evaluation Of Potential Toxcity Of Naphthoquinone Pigments

In order to study the potential toxicity mechanism of Lawsone, Acetyl Shikonin and Naphthazarine, UV-Vis spectrometry, Fluorescence spectrometry using two kinds of fluorescence probe, viscometric method, electrochemistry method and resonance light scattering spectroscopy were applied in study of the interaction between the three kinds of Naphthazarine and DNA.The DNA saturation value was applied to evaluate the toxicity of the three Naphthazarines. The research achievements were mainly as followed:The results of UV-Vis spectrometry showed that the Lawsone, Acetyl Shikonin and Naphthazarine could bind with DNA. The binding constant were 2.6×103 L/mol, 2.4×103 L/mol and 1.28×103 L/mol, respectively. The results of measurement of DNA melting temperature showed that the three Naphthazarines could intercalate into DNA and the degree of binding with DNA of Lawsone and Naphthazarine might be greater than Acetyl Shikonin.The results of fluorescence spectrometry using two kinds of fluorescence probe showed that the Lawsone and Naphthazarine could not only intercalate into the DNA Base pairs, but could also bind into the minor groove of DNA, which was weaker than the former. The type of fluorescence quenching of ethidium bromide-DNA was Mixed quenching. The Acetyl Shikonin could not only bind into the minor groove of DNA, but could also intercalate into the DNA Base pairs, which was weaker than the former. The type of fluorescence quenching of ethidium bromide-DNA was Mixed quenching.The results of viscometric method showed that the three Naphthazarines could intercalate into DNA and the degree of binding with DNA of Lawsone and Naphthazarine might be greater than Acetyl Shikonin.The results of electrochemistry method showed that the three Naphthazarines could intercalate into DNA and could not interact with DNA by electrostatic interaction. The electrode processes were mainly controlled by adsorption.The results of resonance light scattering spectroscopy showed that the three Naphthazarines could bind with DNA. By comparing the resonance light scattering spectroscopies of the interactions among three kinds of Naphthazarine and DNA, which includes double-stranded DNA and single-stranded DNA, and we found that the interacting way of Lawsone and Naphthazarine with DNA was intercalation, and the interacting way of Acetyl Shikonin with DNA was minor groove binding.The DNA saturation value of Lawsone, Acetyl Shikonin and Naphthazarine were 0.33, 1.67 and 0.17, respectively, which were much smaller than the ones of ethidium bromide and adriamycin, but similar to the ones of alizarin and 1-hydroxyl anthraquinone. The conclusion was that the three Naphthazarines were toxic, we should pay attention to them.Effect of sodium chloride, calcium chloride, glucose, isoleucine and vitamin C as coexisting components on saturation value of Lawsone-DNA, Acetyl Shikonin-DNA and Naphthazarine-DNA were studied to search the way of reducing toxicity of the three Naphthazarines. The results showed that sodium chloride could increase the toxicity of Lawsone and Naphthazarine, but reduce the toxicity of Acetyl Shikonin; glucose and vitamin C could reduce the toxicity of Lawsone, Acetyl Shikonin and Naphthazarine; the isoleucine had no effect on the three Naphthazarines.