In previous studies, Kunanusornchai et al.[21] found that oral administration of COS (10 mg/kg/day) induced AMP-activated protein kinase activation, and suppressed TNF-α-induced iNOS and COX-2 expression in rabbit and human synovitis cells, indicating that COS suppressed synovitis through AMP-activated protein kinase activation. Here, TNF is linked to synovitis.