Role of phytochemicals treatments in managing rheumatoid arthritis (review article)

Abstract

Non-steroidal anti-inflammatory drugs are one of the symptomatic treatment options for rheumatoid arthritis (RA). However, these medications are known to have multiple adverse effects. Although biological medications target molecular pathways involved in the inflammatory process of RA, there is a lack of long-term safety data. This review aims to present the novel insights of recent studies investigating medicinal plants, phytochemicals and their pharmacological activities against RA. Punicalagin reduces release of LPS-induced nitric oxide, TNF-α, and IL-6 by suppressing NF-κB and MAPK signaling pathways that are responsible for apoptosis of chondrocytes. Anthocyanins decrease the number of Th17 cells and suppress Th17 cells differentiation in vivo and in vitro. Also, anthocyanins inhibit osteoclasts via downregulation of cytokines including IL-1, IL-6, IL-17, and TNF-α in vitro. Oral ellagic acid in arthritic rats considerably decreases paw edema and levels of chitinase-3-like protein-1, which is induced via the NF-κB pathway and overexpression of which is associated with the inflammatory process of RA in chondrocytes and synovial tissue. Punicic acid reduces MMP9 gene expression, associated with the activation of NF-κB, which may mediate its anti-inflammatory effect in osteoarthritis. Although to date natural products are mainly used as nutraceuticals, the treatment of RA by medicinal plants needs more investigation to fully explore their potential as pharmacological agents in the treatment of autoimmune inflammatory diseases.