New insight for fluoroquinophenoxazine derivatives as possibly new potent topoisomerase I inhibitor

Da Hye Kang, Jung Sook Kim, Mi Ja Jung, Eung Seok Lee, Yurngdong Jahng, Youngjoo Kwon, Younghwa Na

Research output: Contribution to journalArticlepeer-review

51 Scopus citations


Fluoroquinolones, represented by ciproxacin and norfloxacin, are well-known clinical antimicrobial agents, and their phenyl ring expanded quinophenoxazines are reported as possible antitumor active compounds. These quinophenoxazines are known to inhibit DNA topoisomerase II essential for cell replication cycle. But there were no reports for topoisomerase I inhibition study for these compounds. In this report, we have prepared a few quinophenoxazine analogues and tested their topoisomerases I and II inhibitory activities and cytotoxicity. From the result, we found that quinophenoxazine analogues possessed strong topoisomerase I inhibitory capacity as well as topoisomerase II inhibition. Among the compounds prepared, A-62176 analogues showed strong topoisomerases I and II inhibitory activities. Interestingly, compound 8 missing the 3-aminopyrrolidine moiety at C2 position has similar potent inhibitory capacity against topoisomerases I and II at higher concentrations (20 and 10 μM, respectively). But compound 8 inhibited topoisomerase I function more selectively at lower concentration, 2 μM. Our observation might strongly implicate that fluoroquinophenoxazines can be developed as efficient topoisomerase I inhibitor with the elaborate modification.

Original languageEnglish
Pages (from-to)1520-1524
Number of pages5
JournalBioorganic and Medicinal Chemistry Letters
Issue number4
StatePublished - 15 Feb 2008

Bibliographical note

Funding Information:
This work was financially supported by Catholic University of Daegu, Korea.


  • Anti-cancer agents
  • Fluoroquinophenoxazines
  • Topoisomerases I and II inhibition


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