Abstract: antioxidants Review The Coronavirus Disease 2019 (COVID-19): Key Emphasis on Melatonin Safety and Therapeutic Efficacy Eva Ramos 1 , Francisco López-Muñoz 2,3,4,5 , Emilio Gil-Martín 6 , Javier Egea 7,8 , Iris Álvarez-Merz 9,10 , Sakshi Painuli 11 , Prabhakar Semwal 11,12 , Natália Martins 13,14 , Jesús M. Hernández-Guijo 9,10 and Alejandro Romero 1, * 1 2 3 4 5 6



 Citation: Ramos, E.; López-Muñoz, F.; Gil-Martín, E.; Egea, J.; 7 8 9 Álvarez-Merz, I.; Painuli, S.; Semwal, P.; Martins, N.; Hernández-Guijo, 10 J.M.; Romero, A. The Coronavirus Disease 2019 (COVID-19): Key 11 Emphasis on Melatonin Safety and Therapeutic Efficacy. Antioxidants 12 2021, 10, 1152. https://doi.org/ 13 10.3390/antiox10071152 Academic Editors: Helen Galley and Juan Carlos Mayo Received: 19 June 2021 Accepted: 14 July 2021 Published: 20 July 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article 14 * Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Complutense University of Madrid, 28040 Madrid, Spain; eva.ramos@ucm.es Faculty of Health Sciences, University Camilo José Cela, C/Castillo de Alarcón 49, Villanueva de la Cañada, 28692 Madrid, Spain; flopez@ucjc.edu Neuropsychopharmacology Unit, Hospital 12 de Octubre Research Institute (i + 12), Avda. Córdoba, s/n, 28041 Madrid, Spain Portucalense Institute of Neuropsychology and Cognitive and Behavioural Neurosciences (INPP), Portucalense University, R. Dr. António Bernardino de Almeida 541, 4200-072 Porto, Portugal Thematic Network for Cooperative Health Research (RETICS), Addictive Disorders Network, Health Institute Carlos III, MICINN and FEDER, 28029 Madrid, Spain Nutrition, Food & Plant Science Group NF1, Department of Biochemistry, Genetics and Immunology, Faculty of Biology, University of Vigo, 36310 Vigo, Spain; egil@uvigo.es Health Research Institute, Hospital Universitario de la Princesa, 28006 Madrid, Spain; javier.egea@inv.uam.es Molecular Neuroinflammation and Neuronal Plasticity Research Laboratory, Hospital Universitario Santa Cristina, Instituto de Investigación Sanitaria-Hospital Universitario de la Princesa, 28006 Madrid, Spain Department of Pharmacology and Therapeutic, Teófilo Hernando Institute, Faculty of Medicine, Universidad Autónoma de Madrid, Av. Arzobispo Morcillo 4, 28029 Madrid, Spain; iris.alvarez@estudiante.uam.es (I.Á.-M.); jesusmiguel.hernandez@uam.es (J.M.H.-G.) Ramón y Cajal Institute for Health Research (IRYCIS), Hospital Ramón y Cajal, Carretera de Colmenar Viejo, Km. 9100, 28029 Madrid, Spain Department of Biotechnology, Graphic Era University, Dehradun, Uttarakhand 248002, India; sakshipainuli@geu.ac.in (S.P.); semwal.prabhakar@geu.ac.in (P.S.) Uttarakhand State Council for Science and Technology, Dehradun, Uttarakhand 248007, India Faculty of Medicine, Institute for Research and Innovation in Health (i3S), University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal; ncmartins@med.up.pt Institute for Research and Advanced Training in Health Sciences and Technologies, Cooperativa de Ensino Superior Politécnico e Universitário (CESPU), Rua Central de Gandra, 1317, 4585-116 Gandra, Portugal Correspondence: manarome@ucm.es; Tel.: +34-913-943970 Abstract: Viral infections constitute a tectonic convulsion in the..