Conjugates of natural compounds with nitroxyl radicals as a basis for creation of pharmacological agents of new generation.

Synthesis and research of pharmacological properties of polyfunctional "hybrid" compounds containing fragments of nitroxyl radicals (NR) in a molecule (spin-labeled conjugates) is a rapidly developing area of medicinal chemistry. Many examples of various classes of natural compounds have shown that the introduction of nitroxyl fragment into a molecule leads to either strengthening of biological activity or its modification, decrease of general toxicity, or increase of selective cytotoxicity. The review of the published data on spin-labeled biologically active natural compounds has revealed that various classes of natural compounds, such as anthracycline antibiotics, lignans, triterpene acids, chromanes, flavonoids, stilbenoids, alkaloids, amino acids, etc. are used for obtaining conjugates with nitroxyl radicals. Some spinlabeled derivatives of natural compounds are used for the treatment and prevention of the most dangerous diseases. Conjugates of nitroxyl radicals with "molecular compasses" (e.g. folic acid, fragments of gramicidin, heparin) may well serve as drug delivery systems to pathological areas of a body for diagnostics and treatment of diseases. We have summarized the results of the last decade on the synthesis and study of biological activity of conjugates with nitroxyl radicals.