Direct electrochemiluminescence (ECL) involving oxidized DNA was demonstrated in ultrathin films of cationic polymer [Os(bpy)2(PVP)10]2+ [PVP = poly(vinyl pyridine)] assembled layer-by-layer with DNA or oligonucleotides. Electrochemically oxidized Os(II) sites generated ECL from films containing oxo-guanines on DNA formed by chemical oxidation using Fenton reagent. Films combining DNA, [Ru(bpy)2(PVP)10]2+, and [Os(bpy)2(PVP)10]2+ had Os(II) sites that produced ECL specific for oxidized DNA, and Ru(II) sites gave ECL from reaction with oxo-adenines, chemically damaged DNA, and possibly from cleaved DNA strands.

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Oxidation of free guanine and guanine in salmon testes ds-DNA by hydroxyl radicals generated with Fenton reagent resulted in oscillating 8-oxoguanine concentrations. These oscillations were superimposed on a general trend of decreasing ratio of [8-oxoguanine]/{[8-oxoguanine] + [guanine]} with time, suggesting that a steady state 8-oxoguanine concentration would not be achieved. Mass spectrometry detected 8-oxoguanine and 5-guanidinohydantoin as products, suggesting that the latter was the product of oxidation of 8-oxoguanine. Guanidinohydantoin and other possible intermediates and products may be involved in a complex mechanism leading to the observed behavior. Oscillatory fluctuations in 8-oxoguanine may need to be considered in assessing its clinical significance as a biomarker for oxidative DNA damage.

With their unique supermacroporous architecture, polyHIPEs (high internal phase emulsions) and cryogels have huge potential as analytical separation stationary phases.

8-Oxo-7,8-dihydroguanine (8-oxoGua), an important biomarker of DNA damage in oxidatively generated stress, is highly reactive towards further oxidation. Much work has been carried out to investigate the oxidation products of 8-oxoGua by one-electron oxidants, singlet oxygen, and peroxynitrite. This report details for the first time, the iron-and copper-mediated Fenton oxidation of 8-oxoGua and 8-oxo-7,8-dihydro-29-deoxyguanosine (8-oxodGuo). Oxidised guanidinohydantoin (Gh ox ) was detected as the major product of oxidation of 8-oxoGua with iron or copper and hydrogen peroxide, both at pH 7 and pH 11. Oxaluric acid was identified as a final product of 8-oxoGua oxidation. 8-oxodGuo was subjected to oxidation under the same conditions as 8-oxoGua. However, dGh ox was not generated. Instead, spiroiminodihydantoin (Sp) was detected as the major product for both iron and copper mediated oxidation at pH 7. It was proposed that the oxidation of 8-oxoGua was initiated by its one-electron oxidation by the metal species, which leads to the reactive intermediate 8-oxoGua ? + , which readily undergoes further oxidation. The product of 8-oxoGua and 8-oxodGuo oxidation was determined by the 29-deoxyribose moiety of the 8-oxodGuo, not whether copper or iron was the metal involved in the oxidation.

In this article, we report the findings of a comprehensive structure-activity relationship study of N-(6-ferrocenyl-2-naphthoyl) dipeptide ethyl esters, in which novel analogues were designed, synthesized, and evaluated in vitro for antiproliferative effect. Two new compounds, 2 and 16, showed potent nanomolar activity in the H1299 NSCLC cell line, with exceptional IC(50) values of 0.13 and 0.14 μM, respectively. These compounds were also found to have significant activity in the Sk-Mel-28 malignant melanoma cell line (IC(50) values of 1.10 and 1.06 μM, respectively). Studies were also conducted to elucidate the mode of action of these novel organometallic anticancer compounds. Cell cycle analysis in the H1299 cell line suggests these compounds induce apoptosis, while guanine oxidation studies confirm that 2 is capable of generating oxidative damage via a ROS-mediated mechanism.