title: Singlet oxygen quenching ability of naturally occurring carotenoids.
abstract: The singlet oxygen quenching ability of various naturally occurring carotenoids was examined by measuring toluidine blue-sensitized photooxidation of linoleic aci. To assess quenching, the oxidation of linoleic acid was followed by measuring oxygen consumption and ultraviolet absorbance at 235 nm. We found that oxygen quenching increased as the number of conjugated double bonds in the carotenoids increased, but quenching varied with chain structure and functional groups. Acyclic carotenoids enhanced quenching more than did cyclic carotenoids. Conjugated keto groups and the presence of a cyclopentane ring stimulated quenching, while hydroxy, epoxy and methoxy groups showed lesser effects. The photosynthetic bacterial carotenoids, spirilloxanthin and rhodopin, were found to be most effective as quenchers, followed by the cayenne carotenoid, capsorbin.
authors.affiliation: Department of Food Nutrition, Faculty of Agriculture, Kinki University, Nara, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Hirayama
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: S
authors.initials: S
authors.lastname: Hamada
authors.forename: Y
authors.initials: Y
authors.lastname: Kobayasi
mesh_terms: D000818:Animals; D001419:Bacteria; D002338:Carotenoids; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000737:chemistry*; D010100:Oxygen; D010777:Photochemistry; D010788:Photosynthesis; D010944:Plants; D012474:Salmon; D026082:Singlet Oxygen; D014675:Vegetables
chemical_list: D008041:Linoleic Acids; D026082:Singlet Oxygen; D002338:Carotenoids; D019787:Linoleic Acid; D010100:Oxygen