ABSTRACT
Ribosome-inactivating proteins (RIPs) are rRNA N-glycosylases from plants (EC 3.2.2.22) that inactivate ribosomes thus inhibiting protein synthesis. The antiviral properties of RIPs have been investigated for more than four decades. However, interest in these proteins is rising due to the emergence of infectious diseases caused by new viruses and the difficulty in treating viral infections. On the other hand, there is a growing need to control crop diseases without resorting to the use of phytosanitary products which are very harmful to the environment and in this respect, RIPs have been shown as a promising tool that can be used to obtain transgenic plants resistant to viruses. The way in which RIPs exert their antiviral effect continues to be the subject of intense research and several mechanisms of action have been proposed. The purpose of this review is to examine the research studies that deal with this matter, placing special emphasis on the most recent findings.
Subject(s)
Antiviral Agents/pharmacology , Pest Control, Biological , Plant Diseases/prevention & control , Plants, Genetically Modified/enzymology , Protein Synthesis Inhibitors/pharmacology , Ribosome Inactivating Proteins/pharmacology , Toxins, Biological/pharmacology , Virus Diseases/drug therapy , Viruses/drug effects , Animals , Antiviral Agents/isolation & purification , Humans , Plant Diseases/genetics , Plant Diseases/virology , Plants, Genetically Modified/genetics , Plants, Genetically Modified/virology , Protein Synthesis Inhibitors/isolation & purification , Ribosome Inactivating Proteins/isolation & purification , Toxins, Biological/isolation & purification , Virus Diseases/metabolism , Virus Diseases/virology , Viruses/metabolism , Viruses/pathogenicityABSTRACT
Background: The corona virus disease 2019 (COVID-19) pandemic has highlighted the fact that there are few effective antiviral agents for treating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Although the very recent development of vaccines is an extremely important breakthrough, it remains unclear how long-lived such vaccines will be. The development of new agents therefore remains an important goal. Purpose: Given the multifaceted pathology of COVID-19, a combinatorial formulation may provide an effective treatment. BEN815, a natural nutraceutical composed of extracts from guava leaves (Psidium guajava), green tea leaves (Camellia sinensis), and rose petals (Rosa hybrida), had previously shown to have a therapeutic effect on allergic rhinitis. We investigated whether BEN815 possesses anti-inflammatory, antiviral and antioxidant activities, since the combination of these effects could be useful for the treatment of COVID-19. Study design: We examined the anti-inflammatory effects of BEN815 and its principal active components quercetin and epigallocatechin gallate (EGCG) in lipopolysaccharide (LPS)-induced RAW264.7 cells and in an LPS-challenged mouse model of endotoxemia. We also assessed the antioxidant activity, and antiviral effect of BEN815, quercetin, and EGCG in SARS-CoV-2-infected Vero cells. Methods: The principal active ingredients in BEN815 were determined and quantified using HPLC. Changes in the levels of LPS-induced pro-inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α were measured by ELISA. Changes in the expression levels of cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) were analyzed using western blotting. Antioxidant assay was performed using DPPH and ABTS assay. SARS-CoV-2 replication was measured by immunofluorescence staining. Results: BEN815 significantly suppressed the induction of IL-6 and TNF-α as well as COX-2 and iNOS in LPS-induced RAW264.7 cells. In addition, BEN815 protected against LPS-challenged endotoxic shock in mice. Two major constituents of BEN815, quercetin and EGCG, reduced the induction of IL-6 and TNF-α as well as COX-2 and iNOS synthase in LPS-induced RAW264.7 cells. BEN815, quercetin, and EGCG were also found to have antioxidant effects. Importantly, BEN815 and EGCG could inhibit SARS-CoV-2 replications in Vero cells. Conclusion: BEN815 is an anti-inflammatory, antiviral, and antioxidant natural agent that can be used to prevent and improve inflammation-related diseases, COVID-19.
ABSTRACT
Nowadays, viral infection is considered a major cause of mortality all over the world such as covid-19 pandemic. In this context, searching for antiviral agents are major researchers interests. In this study, essential oils (EO) of Lavandula angustifolia (lavender) and Salvia officinalis (salvia) were subjected to combat avian influenza H5N1 virus. Laboratory trials were performed to identify Lavender and salvia EOs and evaluate their antioxidant, anti-inflammatory and antiviral activity against an avian influenza H5N1 virus. EOs were prepared by the hydrodistillation of air-dried plants and analyzed by GC-MS methods. The results revealed that salvia has the highest EOs yield 1.3% than lavender 1%. The dominant constituents of lavender EO were linalyl acetate and linalool while camphor and α-thujone were the dominant compounds of salvia. Both oils exhibited antioxidant activity in DPPH and ABTS and total antioxidant capacity assays. The results suggest the use of salvia and lavender EOs as effective natural anti-inflammatory, antioxidant and antiviral agents.