A tea cup may hold the potential to protect humans from bioterrorist threats according to an article published in the March, 2008 issue of the Society for Applied Microbiology's journal Microbiologist.
Professor Les Baillie from Welsh School of Pharmacy at Cardiff University and Dr Theresa Gallagher of the University of Maryland Biotechnology Institute in Baltimore describe how compounds found in Camellia sinensis, the plant whose leaves are commonly used to produce tea, possess the ability to inhibit the activity of several strains of infectious bacteria, including Legionella pneumophila, by stimulating intracellular antibacterial activity. Extracts from the plant also have a direct antimicrobial action at concentrations found in a standard cup of tea.
In addition to targeting the microorganisms themselves, tea compounds have been found to inhibit the biological activity of the toxins they produce. Neurotoxins produced by Clostridium tetani and Clostridium botulinum (a potential bioterrorism agent) are inhibited by thearubigins found in black tea, which are generated during the fermentation of green tea leaves. Thearubigins are believed to exert their effect prior to the cells' uptake of these toxins. Similarly, epigallocatechin gallate (EGCG), one of the active compounds upon which much of the current tea research has been centered, inhibits the activity of the lethal toxin produced by Bacillus anthracis (anthrax), which can fatally infect humans.
In the current study, the researchers compared the ability of varying strengths of black tea and coffee to kill a strain of anthrax bacteria over a three hour period. Although not all bacterial organisms were inactivated by tea due to the presence of a small number of spores, tea was considerably more potent than coffee at inhibiting B. anthracis. Similar results were observed when two cultures of B. cereus were tested. Surprisingly, increasing the concentration of tea beyond that found in a standard brewed cup decreased its antibacterial activity, and the addition of milk completely blocked tea's ability to inhibit anthrax.
"In the event that we are faced with a potential bio-terror attack, individuals may want to forgo their dash of milk at least until the situation is under control," Dr Baille suggested.
When asked if green tea would be equally effective, Dr Baille told Life Extension, "It is very likely that green tea would be as effective as black tea against Bacillus anthracis due to the presence of EGCG. We did not look at green tea due to the fact that our beverage of choice at the time was English breakfast tea."
"Our research sought to determine if English Breakfast tea was more effective than a commercially available American medium roast coffee at killing anthrax," Dr Baille stated. "We found that special components in tea such as polyphenols have the ability to inhibit the activity of anthrax quite considerably."
"Given the ability of tea to bring solace and steady the mind, and to inactivate Bacillus anthracis and its toxin, perhaps the Boston Tea Party was not such a good idea after all," he concluded.
Related Health Concern: Bacterial infections
Tea (black, green, or oolong) is a good source of free radical-scavenging antioxidants (Trevisanato SI et al 2000). Other infection-fighting chemicals were heightened in cells of tea drinkers, leading researchers to conclude that drinking tea primed the immune system to fight infection (Bukowski JF et al 1999; Kamath AB et al 2003).
These results have been borne out in many clinical studies. Elements of tea, called catechins, have been widely studied for their ability to prevent bacterial infection. One such study examined catechins' ability to prevent infection in the prostate gland in rats. This condition, known as chronic bacterial prostatitis, is extremely common in men. Researchers found that tea catechins were able to reduce both bacterial growth and inflammation in the rats' prostate glands. Morever, the catechins worked well as an adjuvant therapy for ciprofloxacin, the standard antibiotic treatment for this condition. Researchers suggested that tea catechins, which have shown additional antibacterial effects and synergistic properties with antibiotics, be considered to help manage chronic bacterial prostatitis (Lee YS et al 2005).
In another interesting study, researchers infused plastic film with tea catechins, then tested this surface for antibacterial properties. They found that the catechin-infused film was significantly resistant to bacteria such as E. coli and suggested that implants and catheters made from catechin-infused plastic might be able to help reduce infection during invasive procedures (Maeyama R et al 2005).
Catechins are thought to boost immunity by enhancing resistance to infection and selectively modulating the formation of cytokines, which are associated with inflammation, among other things. Researchers have also hypothesized that hydrogen peroxide generated by the catechins may also be responsible for its antibacterial properties (Arakawa H et al 2004). In a laboratory study of immune cells taken from heavy smokers, tea catechins were shown to help the immune cells recover their function (Yamamoto Y et al 2004).