A mechanistic review on medicinal plants used for rheumatoid arthritis in traditional Persian medicine.

Objectives: Rheumatoid arthritis (RA) is a chronic, inflammatory, autoimmune disease, which affects synovial tissue in multiple joints. Although conventional treatments of RA commonly alleviate the symptoms, high incidence of adverse reactions leads to research tendency towards complementary and alternative medicine. As various medicinal plants are traditionally used for the management of symptomatologies associated with RA in Persian medicine, we reviewed medicinal literature to confirm their efficacy in the management of RA.

Key Findings: Scientific evidence revealed that traditional medicaments exert beneficial effects on RA through several cellular mechanisms including downregulation of pro-inflammatory cytokines such as TNF-α, IL-6 and NF-κB, suppression of oxidative stress, inhibition of cartilage degradation with destructive metalloproteinases and enhancement of antioxidant performance. Various active constituents from different chemical categories including flavonols, lignans, coumarins, terpenes, glycosylflavons, dihydroflavonols, phytoestrogens, sesquiterpene lactones, anthraquinones, alkaloids and thymoquinones have been isolated from the medicinal plants.

Summary: The pharmacological mechanisms of the medicinal plants traditionally used for RA in Persian medicine are discussed in the current review. Further investigations are mandatory to focus on bioefficacy of these phytochemicals for finding novel natural drugs.