TNF and rheumatoid arthritis: Our research team discovered coumarin monomer compound Q-1 (praecoxin) in the previous study on Tiekuaizi, which can inhibit MAPK and NF-κB signaling pathways and reduce the expressions of inflammatory factors such as IL-6 and TNF-α, and it can also inhibit the cell proliferation of human rheumatoid arthritis (RA) fibroblast-like synovial cell lines, exerting an anti-rheumatoid arthritis effect (Wu et al., 2021).