The study analyses a potent anti-inflammatory compound derived from green tea. Researchers found that the compound called pigallocatechin-3-gallate (EGCG) -inhibited the production of several molecules in the immune system, that contribute to inflammation and joint damage in people with rheumatoid arthritis.

The compound from green tea also was found to 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 Salah-uddin Ahmed, Ph.D., lead researcher on the study.

To conduct the research, the scientists isolated cells called synovial fibroblasts from the joints of patients with rheumatoid arthritis. These fibroblasts cells that form a lining of the tissue surrounding the capsule of the joints were cultured in a growth medium and incubated with the green tea compound.

The fibroblasts were then stimulated with pro-inflammatory cytokine IL-1?¨°, a protein of the immune system known to play an important role in causing joint destruction in people with rheumatoid arthritis.

The researchers looked at whether the green tea compound has the capability to block the activity of two potent molecules, IL-6 and cyclooxygenase-2 (COX-2), which also are actively involved in causing bone erosion in the joints of people with rheumatoid arthritis.

When untreated cells were stimulated with IL-1?¨°, a sequence of molecular events occurred that resulted in production of the bone-destructive molecules. But, the scientists found that pre-incubation with EGCG was capable of inhibiting the production of these molecules. EGCG also inhibited the production of prostaglandin E2, a hormone-like substance that causes inflammation in the joints.

The cell signaling pathways that regulate levels of these immune system molecules under both normal and rheumatoid arthritis situations are well studied, and the researchers were able to trace the effects of the green tea compound infusion to see that it worked by inhibiting these pathways.

Ahmed said that these studies suggest that EGCG or molecules that could be derived synthetically from the EGCG found in green tea may be of therapeutic value by inhibiting the joint destruction in rheumatoid arthritis.