Synthesis and radical-scavenging activity of C-methylated fisetin analogues

Kohei Imai, Ikuo Nakanishi, Kei Ohkubo, Akiko Ohno, Mirei Mizuno, Shunichi Fukuzumi, Ken ichiro Matsumoto, Kiyoshi Fukuhara

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


The radical-scavenging reaction of fisetin, a natural antioxidant found in strawberries, is known to proceed via hydrogen transfer to produce a fisetin radical intermediate. Thus, introduction of an electron-donating group into the fisetin molecule is expected to stabilize the radical, leading to enhanced radical-scavenging activity. In this study, fisetin derivatives in which methyl substituents were introduced at the ortho positions relative to the catechol hydroxyl groups were synthesized and their radical scavenging activities were evaluated and compared with that of the parent fisetin molecule. Among the methyl derivatives, 5′-methyl fisetin, in which the inherent planar structure of fisetin was retained, exhibited the strongest radical scavenging activity. Introduction of methyl substituents may be effective for the enhancement of various biological activities of antioxidants, particularly radical-scavenging activity.

Original languageEnglish
Pages (from-to)1720-1727
Number of pages8
JournalBioorganic and Medicinal Chemistry
Issue number8
StatePublished - 15 Apr 2019

Bibliographical note

Funding Information:
This work was partially supported by Grant-in-Aid ( 15K18901 to K.I., 26460056 to I.N. and 18K06588 to K.F.) from the Ministry of Education, Culture, Sports, Science and Technology , Japan.

Publisher Copyright:
© 2019


  • Antioxidant
  • Antioxidant activity
  • Fisetin
  • Methyl group
  • Radical-scavenging activity


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