The Efficacy of Evening Primrose in Rheumatoid Arthritis: a Systematic Review

Considering the different side effects of the long-time conventional anti-rheumatic drugs prescribed for the treatment of rheumatoid arthritis, numerous studies have focused on herbal medicines to reduce inflammation in autoimmune diseases. Although the beneficial properties of evening primrose on rheumatoid arthritis have been determined, the results of the studies have not been systematically reported. The present review has investigated the effects of evening primrose on rheumatoid arthritis systematically. We searched the following electronic databases until March 2023: PubMed, the Cochrane Library, the China National Knowledge Infrastructure, Scopus, ProQuest, Google Scholar electronic databases, allied and complementary medicine database (AMED), and scientific information database (SID) databases for relevant studies. We excluded non-English articles and those not meeting our criteria. We chose all of the correlated original clinical, animal, and in vitro studies. Each article was assessed critically for the possible risk of bias. Thirteen articles were analyzed. Animal and in vitro research confirmed the desired effects of evening primrose on clinical, inflammatory, oxidative, and immunologic factors in rheumatoid arthritis. Also, the results of clinical studies showed the change and improvement of inflammatory and oxidative biomarkers in rheumatoid arthritis. Evening primrose could control rheumatoid arthritis in multiple ways such as decreasing inflammation, inhibiting oxidative stress, and modulating the immune system. This article provides convincing evidence to support the efficacy of evening primrose in rheumatoid arthritis and explains the significance of future clinical trials. Further large-scale high-quality randomized controlled trials (RCTs) assessing the efficacy of evening primrose on rheumatoid arthritis as a primary outcome variable are recommended.