title: Fisetin and rutin as 3C protease inhibitors of enterovirus A71.
abstract: Enterovirus A71 (EV-A71) causes severe complications: encephalitis, pulmonary edema, and death. No effective drug has been approved for clinical use. This study investigated the antiviral effects of flavonoids against EV-A71. An in vitro inhibitor screening assay using recombinant EV-A71 3C protease (3Cpro) demonstrated fisetin and rutin inhibiting 3Cpro enzymatic activity in a dose-dependent manner. Cell-based fluorescence resonance energy transfer (FRET) assay with an EV-A71 3Cpro cleavage motif probe also confirmed that fisetin and rutin inhibited the replication of EV-A71 in cells. A virus replication assay indicated that fisetin and rutin reduced significantly the EV-A71-induced cytopathic effect and viral plaque titers in RD cells culture. The IC(50) values of plaque reduction against EV-A71 were 85 μM for fisetin and 110 μM for rutin. Therapeutic indices (CC50/IC50 of plaque reduction assays) of fisetin and rutin exceeded 10. The study suggests that fisetin and rutin inhibit the replication of EV-A71.
authors.affiliation: Department of Medical Research, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Ying-Ju
authors.initials: YJ
authors.lastname: Lin
authors.forename: Yi-Chih
authors.initials: YC
authors.lastname: Chang
authors.forename: Nai-Wan
authors.initials: NW
authors.lastname: Hsiao
authors.forename: Jing-Ling
authors.initials: JL
authors.lastname: Hsieh
authors.forename: Ching-Ying
authors.initials: CY
authors.lastname: Wang
authors.forename: Szu-Hao
authors.initials: SH
authors.lastname: Kung
authors.forename: Fuu-Jen
authors.initials: FJ
authors.lastname: Tsai
authors.forename: Yu-Ching
authors.initials: YC
authors.lastname: Lan
authors.forename: Cheng-Wen
authors.initials: CW
authors.lastname: Lin
mesh_terms: D000086042:3C Viral Proteases; D000998:Antiviral Agents / Q000494:pharmacology*; D002460:Cell Line; D003546:Cysteine Endopeptidases; D003588:Cytopathogenic Effect, Viral / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D029821:Enterovirus A, Human / Q000187:drug effects* / Q000201:enzymology*; D005419:Flavonoids / Q000494:pharmacology*; D044948:Flavonols; D006801:Humans; D020128:Inhibitory Concentration 50; D008826:Microbial Sensitivity Tests; D011480:Protease Inhibitors / Q000494:pharmacology*; D012431:Rutin / Q000494:pharmacology*; D019562:Viral Load; D010948:Viral Plaque Assay; D014764:Viral Proteins / Q000037:antagonists & inhibitors*; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D005419:Flavonoids; D044948:Flavonols; D011480:Protease Inhibitors; D014764:Viral Proteins; D012431:Rutin; D003546:Cysteine Endopeptidases; D000086042:3C Viral Proteases; C017875:fisetin