Kinobeon A, purified from cultured safflower cells, is a novel and potent singlet oxygen quencher

Yasuhiro Kambayashi, Susumu Takekoshi, Minoru Nakano, Masafumi Shibamori, Yoshiaki Hitomi, Keiki Ogino

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8 Citations (Scopus)


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 × 1010 M -1s-1 in methanol containing 10% dimethyl sulfoxide at 37°C. Those of α-tocopherol and β-carotene, which are known potent singlet oxygen quenchers, were 4.45 × 108 M-1s-1 and 1.26 × 1010 M -1s-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 e.ect on singlet oxygen-related diseases of the skin or eyes.

Original languageEnglish
Pages (from-to)903-907
Number of pages5
JournalActa Biochimica Polonica
Issue number4
Publication statusPublished - 2005


  • Antioxidant
  • Endoperoxide
  • Kinobeon A
  • Quencher
  • Safflower
  • Singlet oxygen

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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