New Study: Antiviral Activity Found in Green Tea

AHA Publisher — Mon, 29 Mar 2021 07:00:06 +0000

Jocelyn Solis-Moreira via News-Medical – Adding to its long list of health benefits, new research finds antiviral activity from green tea. In a new study, one of its ingredients, epigallocatechin gallate (EGCG), blocked severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from binding to human angiotensin-converting enzyme 2 (ACE2) receptors and can subsequently prevent infection of human lung cells. This action was also observed in the SARS-CoV-2 variants of concern (VOC). Green tea is one of the most consumed beverages in many countries across Asia. It has high anti-inflammatory and anti-oxidative properties that could help reduce the risk of developing severe COVID-19 symptoms. The researchers wrote: Taken together, our data as well as the findings just reported by others[48-50] indicate the possibility that consumption of green tea or its active ingredient EGCG is beneficial for preventing or reducing SARS-CoV-2 transmission and infection…Given its low toxicity, antiinflammation, antioxidant, and anti-SARS-CoV-2 variant properties, use of GTB or EGCG is likely to minimize the SARS-CoV-2 spread, ameliorate symptoms and disease severity.” The study “Epigallocatechin Gallate from Green Tea Effectively Blocks Infection of SARS-CoV-2 and New Variants by Inhibiting Spike Binding to ACE2 Receptor” is available as a preprint on the bioRxiv* server, while the article undergoes peer review. Designing the Research Study The team created several pseudoviruses that contained S proteins with a single mutation (K417N, E484K, N501Y, D614G) or with full-set mutations of the newly emerged variants (B.1.1.7, B.1.351, and B.1.429). They transfected the pseudoviruses into HEK293T-hACE2 cells. The wild-type S or D614G S was able to cause infection as observed by increased luciferase activity. Although, convalescent plasma of COVID-19 patients was successful in blocking both of these pseudoviruses. The transfected cells showed little cytotoxicity to green tea beverages, indicating it was safe to use. Viral Inhibition Caused by a Green Tea Beverage Green tea effectively prevented infection from the wild-type SARS-CoV-2 or D614G and the COVID-19 variants B.1.429 found in California and B.1.351 found in South Africa — in a dose-dependent manner. Researchers also found green tea beverages prevented other coronaviruses‘ infection as observed when tested against HCoV OC43 in HCT-8 cells. The researchers next looked to see what was in green tea that was causing these antiviral effects. Catechins — EGCG, EGC, ECG, and EC — were studied because they are green tea’s active ingredients. The results showed three catechins: EGCG, EGC, and ECG, dose-dependently blocked a pseudovirus infection caused by the wild-type SARS-CoV-2 strain. Upon closer inspection, the researchers deduced EGCG as the most potent inhibitor for viral infection. EGCG makes up more than 50% of catechins found in green tea beverages. In addition, exposing EGCG to mutated strains such as D614G, K417N, E484K, and N501Y suppressed its ability to cause infection. The researchers also found EGCG inhibited viral infection of cells containing variants of concern, including B.1.17, B.1.351, and B.1.429. EGCG was tested on infected human lung epithelial cells, where they discovered it could suppress SARS-CoV-2 before and after infection. Although, the inhibitory activity was greater when cells were pretreated with EGCG before SARS-CoV-2 infection. Catechin’s antiviral activity was also effective in preventing infection from other related coronaviruses. EGCG was the most effective in suppressing HCoV OC43, while EC was the least effective. EGCG Prevents Inhibition by Blocking SARS-CoV-2 Binding to ACE2 Receptor EGCG was most effective in stopping the viral entry of SARS-CoV-2 in human cells before infection — although it was also somewhat effective during infection. The researchers found it blocked viral entry by preventing the S1 subunit — which has the highest binding affinity — to ACE2. EGCG also decreased binding of the S2 subunit, although it already had a little binding affinity to ACE2. The researchers concluded: We found that the recombinant RBD could bind to ACE2 with EC50 of 4.08 ng/mL, while EGCG significantly decreased the binding affinity of RBD (4.7-fold) with EC50 of 19.19 ng/mL. In addition, EGCG also diminished the binding affinity of full-length S to ACE2 by 2.5-fold (EC50: 43.48 to 107.6 ng/mL). The inhibitory effect of EGCG on RBD or full-length S binding to ACE2 was dose-dependent.” *Important Notice bioRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information. To read the original article click here.

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Australian Scientists Develop a Nasal Spray That Could Stop SARS-CoV-2 Infection

AHA Publisher — Thu, 01 Oct 2020 07:00:21 +0000

Angela Betsaida B. Laguipo, BSN via News-Medical Net – As the coronavirus disease (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continues to wreak havoc globally, scientists race to develop an effective medicine or vaccine to fight the infection. With more than 33.5 million people infected since the pandemic started in December 2019, finding a treatment for those infected is crucial to stemming its spread. Now, a biotech company in Australia, Ena Respiratory, said that a nasal spray it is developing might help boost the human immune system to fight flu and common colds, significantly reduced the growth of the coronavirus in a recent study in animals. The potential nasal spray may not only help treat COVID-19 but also prevent it. The Nasal Spray The novel product, called INNA-051, is being developed by Ena Respiratory, and laboratory experiments have shown that it reduced viral replication by as much as 96 percent in the animal study. Spearheaded by Public Health England’s (PHE) Deputy Director, Professor Miles Carroll, the new study described the potential treatment and has been published in the open-source preprint server bioRxiv*. Used as a nasal spray, it aims to boost the natural immune system of the body to fight common colds and flu. It works by triggering the innate immune system, which is the body’s first line of defense against infection from a pathogen. When the drug has enhanced the immune system, it also prevented the infection and replication of SARS-CoV-2 in the laboratory. The Study Respiratory tract diseases, including those that cause flu, common colds, and the coronavirus infection, represent major ongoing global health threats. These viruses have caused outbreaks to pandemics, endangering the lives of those who are at higher risk, such as children, older adults, and those who are immunocompromised. The SARS-CoV-2 infection is actively spreading worldwide, and it spreads quickly from one person to another through close contact and respiratory droplets. One of the biggest threats of the current pandemic is that several people infected with the virus are asymptomatic, which means that they do not know that they carry the virus. As a result, they are called silent spreaders. The research team from the National Infection Service, Public Health England (PHE) wanted to develop the nasal spray to prevent the replication of the virus in the nasal area, the most common point of entry of the virus. To test the nasal spray, the team obtained nasal wash and throat swab samples four days before the viral challenge. Upon analyzing the viral RNA in nasal wash samples, the team confirmed infection in all treatment groups, with lower viral RNA levels seen in the INNA-051 treatment. The team has found that prophylactic intra-nasal administration of INNA-051 in the SARS-CoV-2 ferret infection model has reduced levels of viral RNA in the nose and throat. “The results of our study support clinical development of a therapy based on prophylactic TLR2/6 innate immune activation in the URT to reduce SARS-CoV-2 transmission and provide protection against COVID-19,” the team wrote in the paper. Further, the research team added that the prophylactic approach is important to people at a high risk of community transmission or development of the severe disease from COVID-19, such as older adults, people with comorbidities, and those who are immunocompromised. “We’ve been amazed by just how effective our treatment has been. By boosting the natural immune response of the ferrets with our treatment, we’ve seen a rapid eradication of the virus,” Christophe Demaison, the Ena Respiratory Managing Director, said. “If humans respond similarly, the benefits of treatment are two-fold. Individuals exposed to the virus would most likely rapidly eliminate it, with the treatment ensuring that the disease does not progress beyond mild symptoms. This is particularly relevant to vulnerable members of the community. In addition, the rapidity of this response means that the infected individuals are unlikely to pass it on, meaning a swift halt to community transmission,” he added. *Important Notice bioRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information. This article has been modified. To read the original article click here.

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New Study: Antiviral Activity Found in Green Tea

Australian Scientists Develop a Nasal Spray That Could Stop SARS-CoV-2 Infection