title: Chemistry of carotenoid neutral radicals.
abstract: Proton loss from the carotenoid radical cations (Car(+)) to form neutral radicals (#Car) was investigated by numerous electrochemical, EPR, ENDOR and DFT studies described herein. The radical cation and neutral radicals were formed in solution electrochemically and stabilized on solid silica-alumina and MCM-41 matrices. Carotenoid neutral radicals were recently identified in Arabidopsis thaliana plant and photosystem II samples. Deprotonation at the terminal ends of a zeaxanthin radical cation could provide a secondary photoprotection pathway which involves quenching excited state chlorophyll by the long-lived zeaxanthin neutral radicals formed.
authors: Valdosta State University, Department of Chemistry, Valdosta, GA 31698, United States. Electronic address: alfocsan@valdosta.edu.
authors: A
authors: A
authors: Ligia Focsan
authors: The University of Alabama, Department of Chemistry, Box 870336, Tuscaloosa, AL 35487, United States.
authors: Adam
authors: A
authors: Magyar
authors: The University of Alabama, Department of Chemistry, Box 870336, Tuscaloosa, AL 35487, United States.
authors: Lowell D
authors: LD
authors: Kispert
mesh_terms: D002338:Carotenoids / Q000737:chemistry* / Q000378:metabolism; D004563:Electrochemistry; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry / Q000378:metabolism; D008027:Light; D011789:Quantum Theory
chemical_list: D005609:Free Radicals; D002338:Carotenoids
keywords: Carotenoid neutral radicals; Photoprotection; Quenching; Zeaxanthin radical cation