Superoxide anion is generated from cellular metabolites by solar radiation and its components

J Free Radic Biol Med. 1985;1(5-6):381-5. doi: 10.1016/0748-5514(85)90150-3.


Several endogenous cellular constituents were tested for their ability to produce superoxide anion (O2-) from ground-state molecular oxygen upon irradiation by solar radiation. The pyridine cofactors NADPH and NADH, riboflavin, and the nucleosides 2-thiouracil and 4-thiouridine were found to sensitize the transmission of photon energy from solar radiation and monochromatic radiation (290, 334, 365, and 405 nm) to oxygen, resulting in O2- formation, as detected by superoxide dismutase-inhibitable cytochrome c reduction. Quantum yields for the production of O2- indicate that NADPH is the most efficient and riboflavin the least efficient of the compounds tested. These data indicate that endogenous compounds may participate in the production of O2- by solar radiation and imply that O2- may play a role in sunlight-induced erythema and dermal carcinogenesis.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Anions
  • Carcinogens
  • Cytochrome c Group / radiation effects
  • Dose-Response Relationship, Radiation
  • NAD / radiation effects
  • NADP / radiation effects
  • Riboflavin / pharmacology
  • Riboflavin / radiation effects
  • Sunlight*
  • Superoxide Dismutase / radiation effects
  • Superoxides / biosynthesis*
  • Superoxides / radiation effects
  • Ultraviolet Rays


  • Anions
  • Carcinogens
  • Cytochrome c Group
  • NAD
  • Superoxides
  • NADP
  • Superoxide Dismutase
  • Riboflavin