2. Academic Validation
  3. Unraveling the anti-influenza effect of flavonoids: Experimental validation of luteolin and its congeners as potent influenza endonuclease inhibitors

Unraveling the anti-influenza effect of flavonoids: Experimental validation of luteolin and its congeners as potent influenza endonuclease inhibitors

  • Eur J Med Chem. 2020 Dec 15;208:112754. doi: 10.1016/j.ejmech.2020.112754.
Václav Zima 1,  Kateřina Radilová 2,  Milan Kožíšek 3,  Carlos Berenguer Albiñana 1,  Elena Karlukova 4,  Jiří Brynda 5,  Jindřich Fanfrlík 4,  Miroslav Flieger 6,  Jan Hodek 4,  Jan Weber 4,  Pavel Majer 4,  Jan Konvalinka 7,  Aleš Machara 8
Affiliations

Affiliations

  • 1 Department of Organic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 00, Prague 2, Czech Republic; Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Gilead Sciences and IOCB Research Center, Flemingovo n. 2, 166 10, Prague 6, Czech Republic.
  • 2 Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Gilead Sciences and IOCB Research Center, Flemingovo n. 2, 166 10, Prague 6, Czech Republic; First Faculty of Medicine, Charles University, Kateřinská 1660, 121 08, Prague 2, Czech Republic.
  • 3 Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Gilead Sciences and IOCB Research Center, Flemingovo n. 2, 166 10, Prague 6, Czech Republic. Electronic address: [email protected].
  • 4 Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Gilead Sciences and IOCB Research Center, Flemingovo n. 2, 166 10, Prague 6, Czech Republic.
  • 5 Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Gilead Sciences and IOCB Research Center, Flemingovo n. 2, 166 10, Prague 6, Czech Republic; Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, 140 00, Prague 4, Czech Republic.
  • 6 Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 140 00, Prague 4, Czech Republic.
  • 7 Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Gilead Sciences and IOCB Research Center, Flemingovo n. 2, 166 10, Prague 6, Czech Republic; Department of Biochemistry, Faculty of Science, Charles University, Hlavova 8, 128 00, Prague 2, Czech Republic.
  • 8 Department of Organic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 00, Prague 2, Czech Republic; Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Gilead Sciences and IOCB Research Center, Flemingovo n. 2, 166 10, Prague 6, Czech Republic. Electronic address: [email protected].
PMID: 32883638 DOI: 10.1016/j.ejmech.2020.112754
Abstract

The biological effects of Flavonoids on mammal cells are diverse, ranging from scavenging free radicals and anti-cancer activity to anti-influenza activity. Despite appreciable effort to understand the anti-influenza activity of Flavonoids, there is no clear consensus about their precise mode-of-action at a cellular level. Here, we report the development and validation of a screening assay based on AlphaScreen technology and illustrate its application for determination of the inhibitory potency of a large set of polyols against PA N-terminal domain (PA-Nter) of influenza RNA-dependent RNA polymerase featuring endonuclease activity. The most potent inhibitors we identified were luteolin with an IC50 of 72 ± 2 nM and its 8-C-glucoside orientin with an IC50 of 43 ± 2 nM. Submicromolar inhibitors were also evaluated by an in vitro endonuclease activity assay using single-stranded DNA, and the results were in full agreement with data from the competitive AlphaScreen assay. Using X-ray crystallography, we analyzed structures of the PA-Nter in complex with luteolin at 2.0 Å resolution and quambalarine B at 2.5 Å resolution, which clearly revealed the binding pose of these polyols coordinated to two manganese ions in the endonuclease active site. Using two distinct assays along with the structural work, we have presumably identified and characterized the molecular mode-of-action of Flavonoids in influenza-infected cells.

Keywords

Influenza; Neuraminidase; PA(N) endonuclease Inhibitors; Polyphenols; RNA polymerase.

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