Green tea's most important polyphenol may fight flu viruses

September 07, 2005

The flu virus has two enzymes that it uses to spread infection. The first enzyme called hemagglutinin allows the flu virus to attach to our cells and gain entry into them. The second enzyme known as neuraminidase allows the young virus particles to spread from cell to cell allowing a full blown flu infection. These enzymes are so important to the ability of the flu to spread infection that the individual flu strains are identified by these enzymes. The more these enzymes change from flu strain to flu strain the worse and more dangerous is the newly minted infection.

In this study different polyphenols from Green Tea (EGCG, EGC, and ECG) were tested for their ability to inhibit influenza virus replication and to assess any direct viral killing ability. In this study both EGCG and ECG were potent inhibitors of virus replication in all viruses tested including both type A influenza viruses currently found in people (A/H1N1 and A/H3N2) and influenza B virus. Both EGCG and ECG inhibited hemagglutinin enzyme activity with EGCG being stronger. Both EGCG and ECG inhibited viral RNA synthesis (this inhibits viral replication). Both EGCG and ECG inhibited neuraminidase activity. The study is published in the August 29th, 2005 issue of the journal Antiviral Research.

Commentary by Jerry Hickey, R.Ph.

Ergothioneine is an antioxidant that I have been following for some time but until now there hasn't been a satisfactory source of this wonderful nutrient. It is a very powerful antioxidant that neutralizes hydroxyl and peroxynitrate free radicals, blocks mutagen formation, increases the rate of detoxification in the liver, helps protect the skin from the suns ultraviolet radiation, protects the mitochondria, and lowers the risk of developing cataracts.

L-Theanine protects the liver from alcohol toxicity

Once alcohol is absorbed it quickly travels throughout the body and is distributed to all tissues. It is not used as food or fuel until the liver metabolizes it to acetate or ketone bodies. In the liver an enzyme called alcohol dehydrogenase converts alcohol to acetaldehyde. Acetaldehyde is eventually converted to acetate and then ketone bodies which are used as fuel or stored as fat. Aldehyde dehydrogenase is a detoxifying enzyme that often works in conjunction with alcohol dehydrogenase. Aldehyde dehydrogenase reduces levels of destructive aldehydes generated by alcohol and other toxins. Another more sinister alcohol metabolizing enzyme known as CYP2E1 is increased after chronic drinking. This enzyme is connected to the long term destructive effects of alcohol. The amount of alcohol that can be metabolized (detoxified) per hour is determined genetically and varies from person to person depending on the amount of their liver metabolizing enzymes. Alcohol is obviously metabolized more slowly than it is consumed.

Alcohol has a destructive effect on the liver by reducing glutathione levels and also by generating a large volume of oxidizing free radicals. Recently, researchers have discovered that L-Theanine reduces the toxicity of chemotherapeutic drugs in the liver by improving liver glutathione levels and preventing drug induced liver irritation and toxicity. Alcohol also produces free radicals, reduces the level of glutathione, and increases the level of lipid peroxidation in the liver causing liver toxicity and increasing liver damage. In this study it was found that L-Theanine increased the rate of metabolism of alcohol in laboratory animals. The animals on L-Theanine had lower blood levels of alcohol one hour after consumption than the animals not supplemented with L-Theanine. L-Theanine improved alcohol detoxifying enzyme levels: both alcohol dehydrogenase and aldehyde dehydrogenase levels were higher in the Theanine supplemented animals. L-Theanine also reduced the level of the CYP2E1 enzyme generated by alcohol intake - this is the enzyme linked to tissue destruction. This infers that L-Theanine may decrease the long term destructive effects of alcohol abuse. L-Theanine also decreased the lipid peroxidation caused by alcohol, and restored it down to normal levels. L-Theanine may prevent alcohol associated liver damage. The study is published in the current issue of the Biological and Pharmaceutical Bulletin.