Spin trapping of hydroperoxyl radical by a cyclic nitrone conjugated to β-cyclodextrin: a computational study.

ABSTRACT: Spin trapping of hydroperoxyl radical (HOO.) by the amide-linked conjugate of 5-carbamoyl-5-methyl-1-pyrroline N-oxide (AMPO) to β-cyclodextrin (β-CD) was studied computationally using a two-layered ONIOM method. From a conformational perspective, the "internal" conformation of 5R-β-CD-AMPO is more favored than the "external" conformation in which the nitrone is located outside of the cavity of the β-CD. When the HOO. addition product is formed, the most stable isomer has the nitroxyl (N1-O1) moiety pointing inside the cavity of the β-CD. Thus, this "internal" conformation might protect the N1-O1 moiety of the resulting spin adduct from access by reducing agents, thereby improving the lifetime of the radical adduct. The computed energetic barrier for HOO. addition to the 5R-β-CD-AMPO is 8.

SUBMITTER: Bao X 

PROVIDER: S-EPMC3621576 | biostudies-literature | 2012 Jul

REPOSITORIES: biostudies-literature