title: Antiviral effect of catechins in green tea on influenza virus.
abstract: Polyphenolic compound catechins ((-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG) and (-)-epigallocatechin (EGC)) from green tea were evaluated for their ability to inhibit influenza virus replication in cell culture and for potentially direct virucidal effect. Among the test compounds, the EGCG and ECG were found to be potent inhibitors of influenza virus replication in MDCK cell culture and this effect was observed in all influenza virus subtypes tested, including A/H1N1, A/H3N2 and B virus. The 50% effective inhibition concentration (EC50) of EGCG, ECG, and EGC for influenza A virus were 22-28, 22-40 and 309-318 microM, respectively. EGCG and ECG exhibited hemagglutination inhibition activity, EGCG being more effective. However, the sensitivity in hemagglutination inhibition was widely different among three different subtypes of influenza viruses tested. Quantitative RT-PCR analysis revealed that, at high concentration, EGCG and ECG also suppressed viral RNA synthesis in MDCK cells whereas EGC failed to show similar effect. Similarly, EGCG and ECG inhibited the neuraminidase activity more effectively than the EGC. The results show that the 3-galloyl group of catechin skeleton plays an important role on the observed antiviral activity, whereas the 5'-OH at the trihydroxy benzyl moiety at 2-position plays a minor role. The results, along with the HA type-specific effect, suggest that the antiviral effect of catechins on influenza virus is mediated not only by specific interaction with HA, but altering the physical properties of viral membrane.
authors.affiliation: Department of Biotechnology, College of Engineering, Yonsei University, 134, Shinchon-dong, Seodaemun-gu, Seoul 120-749, South Korea.
authors.forename: Jae-Min
authors.initials: JM
authors.lastname: Song
authors.forename: Kwang-Hee
authors.initials: KH
authors.lastname: Lee
authors.forename: Baik-Lin
authors.initials: BL
authors.lastname: Seong
mesh_terms: D000818:Animals; D000998:Antiviral Agents; D002392:Catechin / Q000031:analogs & derivatives / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002645:Chickens; D004285:Dogs; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004912:Erythrocytes / Q000187:drug effects / Q000821:virology; D006385:Hemagglutination Inhibition Tests; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects*; D053122:Influenza A Virus, H3N2 Subtype / Q000187:drug effects*; D009981:Influenza B virus / Q000187:drug effects*; D009439:Neuraminidase / Q000037:antagonists & inhibitors; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013662:Tea / Q000737:chemistry; D013778:Tetrazolium Salts; D013844:Thiazoles; D010948:Viral Plaque Assay; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D013662:Tea; D013778:Tetrazolium Salts; D013844:Thiazoles; D002392:Catechin; C062669:epicatechin gallate; C045651:epigallocatechin gallate; D009439:Neuraminidase; C022616:thiazolyl blue