IL6 and rheumatoid arthritis: Sabrina Fechtner has revealed that EGCG, epigallocatechin (EGC), and EC occupy the active site of the TAK1 kinase domain, with EGCG being the most dominant, interfering with the IL-1β signaling pathway that regulates the expression of IL-6, IL-8, and Cox-2 in primary human RA synovial fibroblasts (100).