Theaflavin is an active ingredient of black tea, a fermented or oxidized form of green tea [22]. Theaflavin also showed antiviral activity against influenza virus, ...Evidence-BasedComplementaryandAlternativeMedicine+JournalMenuPDFJournaloverviewForauthorsForreviewersForeditorsTableofContentsSpecialIssuesSubmitEvidence-BasedComplementaryandAlternativeMedicine/2020/ArticleArticleSectionsOnthispageAbstractIntroductionMaterialsandMethodsResultsDiscussionAbbreviationsDataAvailabilityConflictsofInterestAuthors’ContributionsAcknowledgmentsReferencesCopyrightResearchArticle|OpenAccessVolume2020|ArticleID5630838|https://doi.org/10.1155/2020/5630838MinsuJang,Yea-InPark,Yeo-EunCha,RackhyunPark,SimNamkoong,JinI.Lee,JunsooPark,"TeaPolyphenolsEGCGandTheaflavinInhibittheActivityofSARS-CoV-23CL-ProteaseInVitro",Evidence-BasedComplementaryandAlternativeMedicine,vol.2020,ArticleID5630838,7pages,2020.https://doi.org/10.1155/2020/5630838ShowcitationTeaPolyphenolsEGCGandTheaflavinInhibittheActivityofSARS-CoV-23CL-ProteaseInVitroMinsuJang,1Yea-InPark,1Yeo-EunCha,1RackhyunPark,1SimNamkoong,2JinI.Lee,1andJunsooPark11DivisionofBiologicalScienceandTechnology,YonseiUniversity,Wonju,RepublicofKorea2DepartmentofBiochemistry,KangwonNationalUniversity,Chuncheon,RepublicofKoreaShowmoreAcademicEditor:MichelM.MachadoReceived28May2020Revised14Aug2020Accepted09Sep2020Published17Sep2020COVID-19,aglobalpandemic,hascausedover750,000deathsworldwideasofAugust2020.AvaccineorremedyforSARS-CoV-2,thevirusresponsibleforCOVID-19,isnecessarytoslowdownthespreadandlethalityofCOVID-19.However,thereiscurrentlynoeffectivetreatmentavailableagainstSARS-CoV-2.Inthisreport,wedemonstratedthatEGCGandtheaflavin,themainactiveingredientsofgreenteaandblacktea,respectively,arepotentiallyeffectivetoinhibitSARS-CoV-2activity.Coronavirusesrequirethe3CL-proteaseforthecleavageofitspolyproteintomakeindividualproteinsfunctional.EGCGandtheaflavinshowedinhibitoryactivityagainsttheSARS-CoV-23CL-proteaseinadose-dependentmanner,andthehalfi