Improved spin trapping properties by β-cyclodextrin-cyclic nitrone conjugate

Spin trapping using a nitrone and electron paramagnetic resonance (EPR) spectroscopy is commonly employed in the identification of transient radicals in chemical and biological systems. There has also been a growing interest in the pharmacological activity of nitrones, and there is, therefore, a pressing need to develop nitrones with improved spin trapping properties and controlled delivery in cellular systems. The beta-cyclodextrin (beta-CD)-cyclic nitrone conjugate, 5-N-beta-cyclodextrin-carboxamide-5methyl-1-pyrroline N-oxide (CDNMPO) ws synthesized and characterized. 1-D and 2-D NMR show two stereoisomeric forms (i.e.,5S- and 5R-) for CDNMPO. Spin trapping using CDNMPO shows distinctive EPR spectra for superoxide radical anion O-2(<-), and how beta-CD can improve adduct stability via intramolecular interaction with O-2(<-) adduct.