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Cream with green tea extract hinders HIV transmission: study
 
 
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WASHINGTON (AFP) - A chemical found in green tea helps inhibit sexual transmission of the virus which causes AIDS, said a study Tuesday that recommends using the compound in vaginal creams to supplement antiretrovirals.
 
Medical experts at Germany's University of Heidelberg said the compound could be a low-cost arrow in the quiver of medical weapons to fight the spread of HIV in research-poor countries.
 
The researchers said they determined that the green tea polyphenol, or vegetable tannin, called epigallocatechin-3-gallate (EGCG) is capable of neutralizing a protein in sperm which serves as a vector for viral transmission during sex.
 
EGCG degrades what is known as a semen-derived enhancer of virus infection, or SEVI, described in the study as "an important infectivity factor of HIV."
 
Writing in the online edition of the Proceedings of the National Academy of Sciences, the researchers said they "recently identified a peptide fraction in human semen that consistently enhanced HIV-1 infection."
 
SEVIs capture viral elements and attach them to the surface of target cells, enhancing cell fusion and decreasing a cell's ability to repel viral threats.
 
EGCG "targets SEVI for degradation" and "abrogates semen-mediated enhancement of HIV-1 infection in the absence of cellular toxicity," said the researchers, some of whom work at the university's Heinrich-Pette-Institute for Experimental Virology and Immunology.
 
Because of its effects on semen-based HIV transmission threats, the study's authors said "EGCG appears to be a promising supplement to antiretroviral microbicides to reduce sexual transmission of HIV-1."
 
With the vast majority of the world's 33 million people with HIV infected through heterosexual sex, and as 96 percent of new infections occur in poor and developing nations, researchers said the use of green tea EGCG in topical creams would "provide a simple and affordable prevention method" to guard against HIV transmission.
 
Green tea, which originated in China and is widely consumed in Asia, the Middle East and growing numbers of western countries, is already popular for its antioxidant qualities.
 

The main green tea polyphenol epigallocatechin-3-gallate counteracts semen-mediated enhancement of HIV infection
 
PNAS May 2009
 
Ilona Haubera,1, Heinrich Hohenberga, Barbara Holstermanna, Werner Hunsteinb, and Joachim Haubera aHeinrich-Pette-Institute for Experimental Virology and Immunology, Martinistrasse 52, D-20251 Hamburg, Germany; and bFaculty of Medicine, University of Heidelberg, Schlosswolfsbrunnenweg 41, D-69118 Heidelberg, Germany Edited by Peter K. Vogt, The Scripps Research Institute, La Jolla, CA, and approved April 2, 2009 (received for review November 20, 2008)
 
Peptide fragments, derived from prostatic acidic phosphatase, are secreted in large amounts into human semen and form amyloid fibrils. These fibrillar structures, termed semen-derived enhancer of virus infection (SEVI), capture HIV virions and direct them to target cells. Thus, SEVI appears to be an important infectivity factor of HIV during sexual transmission. Here, we are able to demonstrate that epigallocatechin-3-gallate (EGCG), the major active constituent of geen tea, targets SEVI for degradation. Furthermore, it is shown that EGCG inhibits SEVI activity and abrogates semen-mediated enhancement of HIV-1 infection in the absence of cellular toxicity. Therefore, EGCG appears to be a promising supplement to antiretroviral microbicides to reduce sexual transmission of HIV-1.
 
 
 
 
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