Research Article Investigating Potential Inhibitory Effect of Uncaria tomentosa (Cat’s Claw) against the Main Protease 3CL pro of SARS-CoV-2 by Molecular Modeling Andres F. Yepes-P´ erez , 1 Oscar Herrera-Calderon , 2 Jos´ e-Emilio S´ anchez-Aparicio , 3 Laura Tiessler-Sala , 3 Jean-Didier Mar´ echal , 3 and Wilson Cardona-G 1 1 Chemistry of Colombian Plants, Institute of Chemistry, Faculty of Exact and Natural Sciences, University of Antioquia-UdeA, Calle 70 No. 52-21, A.A 1226, Medellin, Colombia 2 Academic Department of Pharmacology, Bromatology and Toxicology, Faculty of Pharmacy and Biochemistry, Universidad Nacional Mayor de San Marcos, Jr Puno 1002, Lima 15001, Peru 3 Insilichem, Departament de Qu´ ımica, Universitat Aut` onoma de Barcelona, Edifici C.n., 08193 Cerdanyola del Vall´ es, Barcelona, Spain CorrespondenceshouldbeaddressedtoAndresF.Yepes-P´ erez;andresf.yepes@udea.edu.co,OscarHerrera-Calderon; oherreracalderon@gmail.com,andJean-DidierMar´ echal;jeandidier.marechal@uab.cat Received 7 May 2020; Accepted 25 July 2020; Published 1 October 2020 GuestEditor:ZhengFeeiMa Copyright©2020AndresF.Yepes-P´ erezetal.isisanopenaccessarticledistributedundertheCreativeCommonsAttribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. COVID-19isadiseasecausedbysevereacuterespiratorysyndromecoronavirus2.Presently,thereisnoeffectivetreatmentfor COVID-19. As part of the worldwide efforts to find efficient therapies and preventions, it has been reported the crystalline structureoftheSARS-CoV-2mainproteaseM pro (alsocalled3CL pro )boundtoasyntheticinhibitor,whichrepresentsamajor druggabletarget.edruggabilityofM pro couldbeusedfordiscoveringdrugstotreatCOVID-19.Amultilevelcomputational studywascarriedouttoevaluatethepotentialantiviralpropertiesofthecomponentsofthemedicinalherb Uncaria tomentosa (Cat’sclaw),focusingontheinhibitionofM pro .e in silico approachstartswithprotein-liganddockingof26Cat’sclawkey components,followedbyligandpathwaycalculations,moleculardynamicssimulations,andMM-GBSAcalculationofthefree energyofbindingforthebestdockedcandidates.estructuralbioinformaticsapproachesledtoidentificationofthreebioactive compounds of Uncaria tomentosa (speciophylline, cadambine, and proanthocyanidin B2) with potential therapeutic effects by strong interaction with 3CL pro . Additionally, in silico drug-likeness indices for these components were calculated and showed good predicted therapeutic profiles of these phytochemicals. Our findings suggest the potential effectiveness of Cat’s claw as complementary and/or alternative medicine for COVID-19 treatment. 1. Introduction Severe acute respiratory syndrome coronavirus 2 (SARS- CoV-2) is a part of coronavirus (CoV) family and was initiallyidentifiedinWuhan,China,attheendofDecember 2019.COVID-19ishighlycontagiousandismostfrequently transmitted from human to human, spreading the virus easilytoothercountriesinaveryshorttime[1].According tothelastreportoftheWorldHealthOrganization(WHO), the severe acute respiratory syndrome (coronavirus disease (COVID-19)) caused by SARS-CoV-2 is considered a pandemic,affectingAsiaandEuropewiththehighestdeath ratefollowedbyAmericaandotherregions,causingserious public health problems and considerable economic losses worldwide [2]. Respiratory viral infections are the frequent causes of morbidity and millions of hospital admissions in developing countries every year [3]. For this reason, the pharmacotherapy based on natural products may be a proper alternative for treating viral diseases. On the other hand, traditional medicine is practiced by native South Hindawi Evidence-Based Complementary and Alternative Medicine Volume 2020, Article ID 4932572, 14 pages https://doi.org/10.1155/2020/4932572