He, Universitdegli Studi di Milano La Statale, By means of Mangiagalli, 25, 20133 Milano, Italy
He, Universitdegli Studi di Milano La Statale, Through Mangiagalli, 25, 20133 Milano, Italy; [email protected] CREA, Food and Nutrition Study Centre, 00100 Rome, Italy; [email protected] CNR NANOTEC, Campus Ecotekne, University of Salento, By means of Monteroni, 73100 Lecce, Italy Correspondence: [email protected] (A.L.C.); [email protected] (C.L.); Tel.: +39-06-4991-3945 (A.L.C.); +39-02503-19372 (C.L.) These authors equally contributed to this function.Abstract: This function describes an untargeted analytical method for the screening, identification, and characterization in the trans-epithelial transport of green tea (Camellia sinensis) catechin extracts with in vitro inhibitory effect against the SARS-CoV-2 papain-like protease (PLpro) activity. Following specific catechin extraction, a chromatographic separation obtained six fractions were carried out. The fractions were assessed in vitro against the PLpro target. Fraction five showed the highest inhibitory activity against the SARS-CoV-2 PLpro (IC50 of 0.125 mL-1 ). The untargeted characterization revealed that (-)-epicatechin-3-gallate (ECG) was by far the most abundant compound inside the fraction as well as the key molecule absorbed by differentiated Caco-2 cells. Benefits indicated that fraction 5 was approximately 10 times far more active than ECG (IC50 worth equal to 11.62 0.47 mL-1 ) to inhibit the PLpro target. All round, our findings highlight the synergistic effects in the various components in the crude extract compared to isolated ECG. Keywords: Caco-2 cells; catechins; COVID-19; polyphenols; high-resolution mass spectrometry; in vitro protease assay; C. sinensis1. Introduction COVID-19 is actually a viral disease triggered by SARS-CoV-2, a new strain of single-stranded RNA viruses with the Coronavirus (CoV) loved ones, which is responsible for the existing pandemic outbreak [1,2]. The pandemic emergency prompted the scientific community to GLPG-3221 MedChemExpress pursue efforts for BSJ-01-175 Inhibitor building pharmacological therapies through the screening of some old drugs capable of operating against SARS-CoV-2 and vaccines for counteracting this new illness threat [3,4]. In this context, identifying organic compounds able to prevent infection represents an efficient and complementary strategy. Certainly, numerous bioactive substances, which are naturally present in foods, have extensively displayed potent biological activity [5,6]. As a result, organic substances, especially those within plant-derived phytocomplexes, may possibly represent sources of active compounds that may well synergistically impair the SARS-CoV-2 infection and COVID-19 progression [7,8]. Catechins, a class of phenolic compounds, primarily present in food merchandise, for example cocoa, red wine, fruits, vegetables, and tea leaves, are already well known for their exciting health-promoting activities, like anti-inflammatory and antioxidant antibacterial,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 short article is an open access post distributed under the terms and conditions from the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).Molecules 2021, 26, 6744. https://doi.org/10.3390/moleculeshttps://www.mdpi.com/journal/moleculesMolecules 2021, 26,2 ofanticancer, and neuroprotective ones [9]. Within this field, green tea (C. sinensis) is one of the wealthiest catechin sources that contains (-)-epicatechin (E.