TNF and rheumatoid arthritis: Previous evidence showed that the use of NSAIDs, methotrexate, tumor necrosis factor, and bDMARDs (such as etanercept) did not add to the burden of kidney function of RA patients,38, 39 but only long‐term use of cyclosporine A and cyclophosphamide caused renal damage in patients with RA.40, 41 Although there are many drugs widely used in the clinic, new extraction methods to obtain natural products may also be beneficial to the treatment of RA with renal damage.42