Green tea agent fights HIV infection
in HIV infection and could one day be used as a new anti-HIV drug,
suggests a new study this week. Japanese researchers report that
the extract, already believed to prevent cancer and heart disease,
stops HIV from binding to healthy immune cells.
The main active agent in green tea, EGCG, prevents the first step in HIV infection and could one day be used as a new anti-HIV drug, suggests a new study this week.
Epigallocatechin gallate, or EGCG, is the most abundant catechin in green tea and thought to be responsible for the numerous health benefits attributed to the beverage, including prevention of cancer and cardiovascular disease.
New research by Dr Kuzushige Kawai and colleagues from the University of Tokyo show that EGCG also inhibits the binding of HIV to human T cells, the first step in HIV infection. The study is the first to describe this effect of the green tea catechin on the attachment of HIV to human T cells.
Writing in this month's issue of the Journal of Allergy and Clinical Immunology, the researchers report on laboratory studies that found EGCG to block the binding of HIV envelope glycoprotein to human CD4 molecules on human T cells. The CD4 molecule acts as a binding target for HIV vesicles and plays an important role in the aggressive infection process.
The authors write that EGCG showed a strong affinity for the CD4 molecule, and by binding them, could effectively prevent the binding of the HIV glycoprotein envelope. These findings open new doors for the clinical application of EGCG as an anti-HIV drug.
Further research into the potential preventative effects of the green tea catechin EGCG on HIV infection is being conducted by researchers at the National Center for Macromolecular Imaging at Baylor College of Medicine, Houston, Texas, and the Department of Molecular Biology and Biotechnology at the University of Sheffield in England.
In an editorial accompanying the Kawai study, Dr William T. Shearer and colleagues from Baylor report on the use of advanced computer programmes to better define the nature and power of the binding effects of EGCG to the CD4 molecule.
"It might be possible to locate the precise EGCG binding spot on the CD4 molecule and compare that spot to where the HIV glycoprotein normally binds, in an attempt to explain the exciting discovery of Dr Kawai," said Dr Shearer. "Molecular modeling of a drug form of EGCG for HIV infection might be a further development of these investigations."
The researchers warned that the concentrations of EGCG used in their laboratory studies are many times over the blood concentration that could be achieved by normal green tea consumption. But the current findings call for additional research into the clinical application of green tea catechin as an anti-HIV drug.
There is currently only one HIV entry inhibitor prescription drug on the market, launched by pharma leader Roche earlier this year. Treatment with the drug costs around €20, 000 annually.
