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. 2015 Feb 11;5:8398. doi: 10.1038/srep08398

Figure 6. Circular dichroism spectra of pure DNA and a DNA-pyocyanin mixture in the presence and absence of glutathione, and UV-Vis spectra of pyocyanin in the presence and absence of ascorbic acid or glutathione.

Figure 6

CD spectra of pyocyanin-DNA demonstrate that as the concentration of glutathione (GSH) increases the intercalation property of pyocyanin (Pyo) decreases. The DNA-pyocyanin intercalation is not affected in presence of 100 μM glutathione, however, as the concentration of glutathione increased to 250 and 500 μM, the pyocyanin intercalation decreased gradually and was inhibited completely at 500 μM. CD spectra of DNA-GSH also confirm a direct interaction between the antioxidant and DNA (a). The UV-Vis spectra of pure pyocyanin, ascorbic acid (AA) and a pyocyanin-ascorbic acid mixture (b) and the pure glutathione and pyocyanin-glutathione mixture (c). The absorbance peak of pyocyanin at 379 nm shifted to 386 nm in the presence of ascorbic acid or glutathione and other pyocyanin absorbance peaks (238 and 311 nm) display altered intensity (b and c). Proton NMR spectra of pyocyanin (i), ascorbic acid (ii) and the pyocyanin-ascorbic acid reaction at ratios of 1:20 (iii), 1:5 (iv), 1:1 (v) and 1:0.5 (vi) at 22°C. The NMR spectra of pyocyanin-ascorbic acid mixtures indicated the disappearance of the pyocyanin aromatic peaks even at low concentration ratios of pyocyanin:ascorbic acid (1:1 and 1:0.5) (d).