Radical scavenging and chemical repair of rutin observed by pulse radiolysis: as a basis for radiation protection

• Published in: Free radical research 2019-10, Vol.53 (9-10), p.1005-1013
• Main Authors: Yu, Hao, Yamashita, Shinichi
• Format: Article
• Language: English
• Subjects: Chemical repair; flavonoid; Flavonoids; pulse radiolysis; Pulse Radiolysis - methods; radiation protection; Radiation Protection - methods; radical scavenging; rutin; Rutin - chemistry
• ISSN: 1071-5762; 1029-2470
• DOI: 10.1080/10715762.2019.1667991

Pulse radiolysis was conducted to investigate: several fundamental reactions of a natural flavonoid, rutin, and its glycosylated form (αG-rutin) as a basis for their radiation protection properties; the reactions with * OH (radical scavenging) and dGMP radical, dGMP * (chemical repair), which was used as a model of initial and not yet stabilised damage on DNA. Three absorption peaks were commonly seen in the reactions of the flavonoids with * OH, showing that their reactive site is the common structure, i.e. aglycone. One among the three peaks was attributed to the flavonoid radical produced as a result of the removal of a hydrogen atom. The same peak was found in their reactions with dGMP * , showing that dGMP * is chemically repaired by obtaining a hydrogen atom supplied from the flavonoids. Such a spectral change due to the chemical repair was as clear as never reported. The rate constants of the chemical repair reaction were estimated as (9 ± 2)×10 8  M −1  s −1 and (6 ± 1)×10 8  M −1  s −1 for rutin and αG-rutin, respectively. The rate constants of the radical scavenging reactions towards * OH were estimated as (1.3 ± 0.3)×10 10  M −1  s −1 and (1.0 ± 0.1)×10 10  M −1  s −1 for rutin and αG-rutin, respectively. In addition, there was no obvious difference between rutin and αG-rutin, indicating that the glycosylation does not change early chemical reactions of rutin.