AHR and arthritic joint disease: Tetrandrine can enhance the ubiquitination and degradation of spleen tyrosine kinase (Syk) through AhR/non-receptor tyrosine kinase/c-Cbl signaling pathway and regulate the expression of Syk and phospholipase-Cγ, thereby inhibiting osteoclastogenesis and bone destruction in arthritis (90, 91).