Zinc Ionophore Activity of Quercetin and Epigallocatechin-gallate: From Hepa 1-6 Cells to a Liposome Model
In terms of public health, the 21st century has been characterized by coronavirus pandemics: in 2002-03 the virus SARS-CoV caused SARS; in 2012 MERS-CoV emerged and in 2019 a new human betacoronavirus strain, called SARS-CoV-2, caused the unprecedented COVID-19 outbreak. During the course of the current epidemic, medical challenges to save lives and scientific research aimed to reveal the genetic evolution and the biochemistry of the vital cycle of the new pathogen could lead to new preventive and therapeutic strategies against SARS-CoV-2. Up to now, there is no cure for COVID-19 and waiting for an efficacious vaccine, the development of “savage” protocols, based on “old” anti-inflammatory and anti-viral drugs represents a valid and alternative therapeutic approach. As an alternative or additional therapeutic/preventive option, different in silico and in vitro studies demonstrated that small natural molecules, belonging to polyphenol family, can interfere with various stages of coronavirus entry and replication cycle. Here, we reviewed the capacity of well-known (e.g. quercetin, baicalin, luteolin, hesperetin, gallocatechin gallate, epigallocatechin gallate) and uncommon (e.g. scutellarein, amentoflavone, papyriflavonol A) flavonoids, secondary metabolites widely present in plant tissues with antioxidant and anti-microbial functions, to inhibit key proteins involved in coronavirus infective cycle, such as PLpro, 3CLpro, NTPase/helicase. Due to their pleiotropic activities and lack of systemic toxicity, flavonoids and their derivative may represent target compounds to be tested in future clinical trials to enrich the drug arsenal against coronavirus infections.
In vitro and some animal models have shown that quercetin, a polyphenol derived from plants, has a wide range of biological actions including anti-carcinogenic, anti-inflammatory and antiviral activities; as well as attenuating lipid peroxidation, platelet aggregation and capillary permeability. This review focuses on the physicochemical properties, dietary sources, absorption, bioavailability and metabolism of quercetin, especially main effects of quercetin on inflammation and immune function. According to the results obtained both in vitro and in vivo, good perspectives have been opened for quercetin. Nevertheless, further studies are needed to better characterize the mechanisms of action underlying the beneficial effects of quercetin on inflammation and immunity.
Abstract: Genes required for SARS-CoV-2 entry into human cells, ACE2 and FURIN, were employed as baits to build genomic-guided molecular maps of upstream regulatory elements, their expression and functions in the human body, and pathophysiologically relevant cell types. Repressors and activators of the ACE2 and FURIN genes were identified based on the analyses of gene silencing and overexpression experiments as well as relevant transgenic mouse models. Panels of repressors (VDR; GATA5; SFTPC; HIF1a) and activators (HMGA2; INSIG1; RUNX1; HNF4a; JNK1/c-FOS) were then employed to identify existing drugs manifesting in their effects on gene expression signatures of potential coronavirus infection mitigation agents. Using this strategy, vitamin D and quercetin have been identified as putative 2019 coronavirus disease (COVID-19) mitigation agents. Quercetin has been identified as one of top-scoring candidate therapeutics in the supercomputer SUMMIT drug-docking screen and Gene Set Enrichment Analyses (GSEA) of expression profiling experiments (EPEs), indicating that highly structurally similar quercetin, luteolin, and eriodictyol could serve as scaffolds for the development of efficient inhibitors of SARS-CoV-2 infection. In agreement with this notion, quercetin alters the expression of 98 of 332 (30%) of human genes encoding protein targets of SARS-CoV-2, thus potentially interfering with functions of 23 of 27 (85%) of the SARS-CoV-2 viral proteins in human cells. Similarly, Vitamin D may interfere with functions of 19 of 27 (70%) of the SARS-CoV-2 proteins by altering expression of 84 of 332 (25%) of human genes encoding protein targets of SARS-CoV-2. Considering the potential effects of both quercetin and vitamin D, the inference could be made that functions of 25 of 27 (93%) of SARS-CoV-2 proteins in human cells may be altered. GSEA and EPEs identify multiple drugs, smoking, and many disease conditions that appear to act as putative coronavirus infection-promoting agents. Discordant patterns of testosterone versus estradiol impacts on SARS-CoV-2 targets suggest a plausible molecular explanation of the apparently higher male mortality during the coronavirus pandemic. Estradiol, in contrast with testosterone, affects the expression of the majority of human genes (203 of 332; 61%) encoding SARS-CoV-2 targets, thus potentially interfering with functions of 26 of 27 SARS-CoV-2 viral proteins. A hypothetical tripartite combination consisting of quercetin/vitamin D/estradiol may affect expression of 244 of 332 (73%) human genes encoding SARS-CoV-2 targets. Of major concern is the ACE2 and FURIN expression in many human cells and tissues, including immune cells, suggesting that SARS-CoV-2 may infect a broad range of cellular targets in the human body. Infection of immune cells may cause immunosuppression, long-term persistence of the virus, and spread of the virus to secondary targets. Present analyses and numerous observational studies indicate that age-associated vitamin D deficiency may contribute to the high mortality of older adults and the elderly. Immediate availability for targeted experimental and clinical interrogations of potential COVID-19 pandemic mitigation agents, Biomedicines 2020, 8, 129; doi:10.3390/biomedicines8050129 www.mdpi.com/journal/biomedicines Biomedicines 2020, 8, 129 2 of 26 namely vitamin D and quercetin, as well as of the highly selective (Ki, 600 pm) intrinsically specific FURIN inhibitor (a1-antitrypsin Portland (a1-PDX), is considered an encouraging factor. Observations reported in this contribution are intended to facilitate follow-up targeted experimental studies and, if warranted, randomized clinical trials to identify and validate therapeutically viable interventions to combat the COVID-19 pandemic. Specifically, gene expression profiles of vitamin D and quercetin activities and their established safety records as over-the-counter medicinal substances strongly argue that they may represent viable candidates for further considerations of their potential utility as COVID-19 pandemic mitigation agents. In line with the results of present analyses, a randomized interventional clinical trial evaluating effects of estradiol on severity of the coronavirus infection in COVID19+ and presumptive COVID19+ patients and two interventional randomized clinical trials evaluating effects of vitamin D on prevention and treatment of COVID-19 were listed on the ClinicalTrials.gov website
There are currently no antiviral drugs with proven efficacy nor are there vaccines for its prevention. Unfortunately, the scientific community has little knowledge of the molecular details of SARS-CoV-2 infection. The drugs we are chosen are used as clinical trials for antiviral and there is no proven guide for specificity and effectiveness against the virus so the results are different Now the clinical trials and research authorities are work speedily to target the most proven treatment for the virus so anything is infantile until now. the covid-19 with time be more explained by scientists it is steroid response disease and cause thromosis and cytokine storm , the aim of the study to inhibit viral replication and decrease the severity of the disease as antiviral and anticytokine storm , antithrombosis Zinc is a mineral element needed to regulate adaptive immune cells\\\\\\\\\\\\\\\' functions. Higher level of intracellular zinc showed to increase intracellular pH; which affect on RNA-dependent RNA polymerase and decrease replication mechanism of RNA viruses. Therefore, drugs that described as zinc ionophores could be used with zinc supplement to act as antiviral against many RNA viruses including SARS-CoV-2 Quercetin is natural compound act as zinc ionophore to cause zinc influx intracellular.
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