Nitroxyl radical catalysts oxidize alcohols under an applied electric potential. It is possible to quantify the alcohol concentration from the resulting oxidation current. In this work, we evaluated the catalytic activity of nitroxyl radicals (or their corresponding hydroxylamines), including 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) as representative nitroxyl radicals, acetoamido-TEMPO, which shows higher oxidation potential than TEMPO owing to the acetoamido group, AZADO, Nor-AZADO, and NNO as less-hindered bicyclic nitroxyl radicals, and NHPI as an N,N-diacyl-type hydroxylamine, in acetonitrile solution. TEMPO, AZADO and NNO were also evaluated for their ability to oxidize alcohols in organic solvents, and their reactivity was compared with the electrochemical response. The most active NNO was used for electrochemical detection of cyclosporin A, a drug with a hydroxyl group.

Chagas disease (CD), caused by Trypanosoma cruzi, is a neglected tropical disease prevalent in Latin America. The treatment of infected patients is aimed at eliminating the parasite, reducing the risk of cardiomyopathy, and interrupting the disease transmission cycle. At present, the World Health Organization only recognizes benznidazole (BZ) and nifurtimox as effective drugs for treating CD. However, both present low cure rates in the chronic phase and often have serious side effects. T. cruzi infection produces an intense inflammatory response in several tissues, critical for controlling parasite proliferation and CD evolution. Compounds that liberate nitric oxide (NO) (NO donors) have been used as therapeutic agents against T. cruzi. However, to date, there is no evidence about the related nitrogen oxide, nitroxyl (HNO) on the outcome of T. cruzi infection. In this study, we investigated the effect of the HNO donor Angeli's salt (AS) on C57BL/6 mice infected with T. cruzi (Y strain, 5 × 103 trypomastigotes, i.p.). The use of AS showed positive results, such as a decrease in the number of parasites present in the bloodstream and in nests within the heart, as well as improved the protective antioxidant capacity of erythrocytes in infected animals, leading to an overall decrease in the severity of the disease. Furthermore, in vitro experiments showed that AS treatment reduced parasite uptake and the release of trypomastigotes by macrophages. Taken together, these findings from both the mouse model and in vitro testing suggest that AS could be a promising therapy for CD.