Green Tea Chemical May Prevent HIV Infection
Flavenoid Unique to Green Tea Inhibits Spread of AIDS-causing Virus
May 21, 2009
Flavenoids and Green Tea
The flavenoid epigallocatechin-3-gallate (EGCG) is found in high concentration in green tea. Several studies in Europe, the US and Japan have demonstrated that EGCG can interrupt two different biochemical pathways by which HIV insinuates itself.
Flavenoids (aka bioflavenoids) are members of a family of chemicals naturally found in many plants. Best known for their antioxidant properties, flavenoids also exhibit anti-allergic, anti-inflammatory, anti-microbial and anti-cancer activity.
Green Tea and Sexually-Transmitted HIV
Writing in the May 18, 2009, online edition of the Proceedings of the National Academy of Sciences, researchers at Germany's University of Heidelberg and the Heinrich-Pette Institute for Experimental Virology and Immunology in Hamburg, found that human semen contains a factor -- dubbed semen-derived enhancer of virus infection (SEVI)--that escorts HIV to the front door of the cells it likes to infect and "consistently enhances HIV-1 infection." The EGCG in green tea apparently inhibits SEVI activity and degrades it, thus limiting HIV infection. The study's authors said "EGCG appears to be a promising supplement to antiretroviral microbicides to reduce sexual transmission of HIV-1." The German researchers said the use of green tea EGCG in topical vaginal creams would "provide a simple and affordable prevention method" to guard against HIV transmission, especially in poorer areas.
Green Tea: A Molecular HIV Blocker
A 2006 joint study between the University of Sheffield, United Kingdom, and Baylor College of Medicine, Texas, examined the effects of EGCG in laboratory test tubes. Results were published in the Journal of Allergy and Clinical Immunology. Professor Mike Williamson, one of the researchers from the Department of Molecular Biology and Biotechnology at the University of Sheffield found that EGCG stopped the HIV virus from binding to the body's immune cells by getting there first. EGCG blocks the HIV-1 virus from entering the immune system cells that it subverts and destroys as part of the AIDS process. The EGCG molecule itself binds to the same exact site--the CD4 molecule--to which gp120, the "docking module" of HIV, attaches. "Our research shows that drinking green tea could reduce the risk of becoming infected by HIV, and could also slow down the spread of HIV." Prof Williamson warned that green tea is not a cure, and neither is it a safe way to avoid infection. The study merely suggests that EGCG "has potential use as adjunctive therapy in HIV-1 infection".
Japanese research published in 2003 into the HIV-preventive characteristics of EGCG indicated that while the flavenoid held promise, huge doses would be needed for a therapeutic benefit. But Baylor's Dr. Christina Nance and her team found that "physiological levels" of EGCG --the amount in just a cup or two of green tea -- inhibited HIV binding by 40%, and that "the natural anti-HIV agent EGCG is a candidate as an alternative therapy in HIV-1 therapy."
Green Tea is Superior to Black
Black tea leaves contain EGCG, but in much lower quantities. Black tea leaves are fermented, a process in which many of the catechins (flavenoids) are oxidized to darker-colored molecules called theaflavin and thearubigen.
 |
