Salah-uddin Ahmed, from the University of Michigan Health System, told attendees at Experimental Biology 2007 in Washington, D.C. yesterday that the tea extract may also suppress the inflammatory products in the connective tissue of people with rheumatoid arthritis.
"Our research is a very promising step in the search for therapies for the joint destruction experienced by people who have rheumatoid arthritis," said Ahmed.
The results add to an ever-growing body of science linking consumption to a wide range of health benefits, including lower risk of certain cancers, weight loss, heart health, and protection against Alzheimer's.
Green tea contains between 30 and 40 per cent of water-extractable polyphenols, while black tea (green tea that has been oxidized by fermentation) contains between 3 and 10 per cent.
The four primary polyphenols found in fresh tealeaves are epigallocatechin gallate (EGCG), epigallocatechin, epicatechin gallate, and epicatechin.
The research, which has not been seen in its entirety by NutraIngredients.com, focused on synovial fibroblasts - cells that form a lining of the tissue surrounding the capsule of the joints - from patients with rheumatoid arthritis.
These fibroblasts were subsequently cultured in a growth medium and incubated with EGCG.
The pro-inflammatory cytokine interleukin-1 beta (IL-1beta) was then added to the culture medium.
IL-1beta is an immune system protein reported to play an important role in causing joint destruction in people with rheumatoid arthritis.
Ahmed told attendees that when untreated cells were stimulated with IL-1beta, a cascade of events occurred that resulted in production of the bone-destructive molecules interleukin-6 (IL-6) and cyclooxygenase-2 (COX-2).
However, when the cells were incubated with EGCG the production of IL-6 and COX-2 was not observed.
The scientists revealed that work is ongoing with lab tests focusing on the inhibitory role of EGCG in gene expression.
Animal studies will be used to test if EGCG can provide similar therapeutic or preventive effects against rheumatoid arthritis.
Positive results could form a strong foundation for future testing of the green tea extract in humans with rheumatoid arthritis, said Ahmed.
This study could be good news for the tea extract market.
European demand for tea extracts is currently surging, having reached 500 metric tonnes by 2003.
This has seen companies such as DSM, with its Teavigo boasting 95 per cent purity of EGCG, and Taiyo International, with its Sunphenon claiming more than 90 per cent purity, position themselves firmly in specific catechin markets.
Approximately seven million people in the UK alone are reported to have long-term health problems associated with arthritis.
Around 206 million working days were lost in the UK in 1999-2000, equal to £18bn (€26bn) of lost productivity.
Source: Experimental Biology 2007 , Washington, D.C,
29 April 2007 Authors: S.-U. Ahmed, A. Pakozdi and A. Koch