title: Kinobeon A, purified from cultured safflower cells, is a novel and potent singlet oxygen quencher.
abstract: We recently reported that kinobeon A, produced from safflower cells, suppressed the free radical-induced damage of cell and microsomal membranes. In the present study, we investigated whether kinobeon A quenches singlet oxygen, another important active oxygen species. Kinobeon A inhibited the singlet oxygen-induced oxidation of squalene. The second-order rate constant between singlet oxygen and kinobeon A was 1.15 x 10(10) M(-1)s(-1) in methanol containing 10% dimethyl sulfoxide at 37 degrees C. Those of alpha-tocopherol and beta-carotene, which are known potent singlet oxygen quenchers, were 4.45 x 10(8) M(-1)s(-1) and 1.26 x 10(10) M(-1)s(-1), respectively. When kinobeon A was incubated with a thermolytic singlet oxygen generator, its concentration decreased. However, this change was extremely small compared to the amount of singlet oxygen formed and the inhibitory effect of kinobeon A on squalene oxidation by singlet oxygen. In conclusion, kinobeon A was a strong singlet oxygen quencher. It reacted chemically with singlet oxygen, but it was physical quenching that was mainly responsible for the elimination of singlet oxygen by kinobeon A. Kinobeon A is expected to have a preventive effect on singlet oxygen-related diseases of the skin or eyes.
authors.affiliation: Department of Environmental and Preventive Medicine, Graduate School of Medical Science, Kanazawa University, Ishikawa, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kambayashi
authors.forename: Susumu
authors.initials: S
authors.lastname: Takekoshi
authors.forename: Minoru
authors.initials: M
authors.lastname: Nakano
authors.forename: Masafumi
authors.initials: M
authors.lastname: Shibamori
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Hitomi
authors.forename: Keiki
authors.initials: K
authors.lastname: Ogino
mesh_terms: D000475:Alkenes / Q000302:isolation & purification / Q000494:pharmacology*; D031187:Carthamus tinctorius / Q000737:chemistry*; D002478:Cells, Cultured; D010084:Oxidation-Reduction; D026082:Singlet Oxygen; D024505:Tocopherols / Q000494:pharmacology; D019207:beta Carotene / Q000494:pharmacology
chemical_list: D000475:Alkenes; C477467:kinobeon A; D019207:beta Carotene; D026082:Singlet Oxygen; D024505:Tocopherols