Ursolic acid, a natural pentacyclic triterpenoid found in various plants (such as rosemary, apples, and holy basil), has garnered research interest for its potential anti-inflammatory properties relevant to rheumatoid arthritis (RA). Preclinical studies have demonstrated that ursolic acid can inhibit inflammatory mediators, reduce oxidative stress, and modulate immune cell function. In vitro experiments show its capacity to suppress the expression of pro-inflammatory cytokines (e.g., TNF-α, IL-1β, IL-6) and inhibit the NF-κB pathway, both of which play central roles in RA pathogenesis. Animal models of arthritis have shown that ursolic acid administration can reduce joint inflammation and slow disease progression.

Despite promising preclinical results, there is currently a lack of robust clinical evidence in humans to confirm its efficacy or safety for treating RA. No large-scale randomized controlled trials have investigated the effects of ursolic acid in RA patients. Thus, while the scientific rationale is supported by mechanistic and animal studies, translation to clinical application remains unproven. The use of ursolic acid for RA is not rooted in traditional medicine, but rather in modern scientific exploration. Its use for RA should therefore be considered experimental, with a low evidence rating due to the absence of human trials.