Evening Primrose (Oenothera biennis) and Pain (general): evidence and sources

Background Evening primrose oil (EPO), extracted from the seeds of Oenothera biennis, has gained attention for its therapeutic effects in various inflammatory conditions. Method We performed a systematic search in multiple databases and defined the inclusion criteria based on the following PICOs: P: Patients with a form of inflammatory condition, I: EPO, C: Placebo or other therapeutic interventions, O: changes in inflammatory markers or patients' symptoms; S: randomized controlled trials. The quality of the RCTs was evaluated using Cochrane's RoB tool. Results Several conditions were investigated in the literature. In rheumatoid arthritis, mixed results were observed, with some studies reporting significant improvements in symptoms while others found no significant impact. EPO showed some results in diabetes mellitus, atopic eczema, menopausal hot flashes, and mastalgia. However, it did not demonstrate effectiveness in chronic hand dermatitis, tardive dyskinesia, psoriatic arthritis, cystic fibrosis, hepatitis B, premenstrual syndrome, contact lens-associated dry eyes, acne vulgaris, breast cyst, pre-eclampsia, psoriasis, or primary Sjogren's syndrome. Some results were reported from multiple sclerosis after EPO consumption. Studies in healthy volunteers indicated no significant effect of EPO on epidermal atrophy, nevertheless, positive effects on the skin regarding hydration and barrier function were achieved. Conclusion Some evidence regarding the potential benefits of EPO in inflammatory disorders were reported however caution is due to the limitations of the current survey. Overall, contemporary literature is highly heterogeneous and fails to provide strong recommendations regarding the efficacy of EPO on inflammatory disorders. Further high-quality studies are necessitated to draw more definite conclusions and establish O. biennis oil effectiveness as an assuring treatment option in alleviating inflammatory conditions.

Diets rich in arachidonic acid (20:4n-6) lead to the formation of 2-series prostaglandins (PGs) and 4-series leukotrienes (LTs), with proinflammatory effects. Nonsteroidal antiinflammatory drugs are used in rheumatoid arthritis to inhibit cyclooxygenase (prostaglandin-endoperoxide synthase), thereby decreasing production of 2-series PGs. Lipoxygenase activity remains intact, however, allowing LT production (eg, synthesis of LTB(4), a potent inflammatory mediator) to continue. Altering the essential fatty acid (EFA) content of the diet can modify some of these effects. Ingestion of a diet rich in evening primrose oil elevates concentrations of dihomo-gamma-linolenic acid (DGLA; 20:3n-6), which results in the production of 1-series PGs, eg, PGE(1). DGLA itself cannot be converted to LTs but can form a 15-hydroxyl derivative that blocks the transformation of arachidonic acid to LTs. Increasing DGLA intake may allow DGLA to act as a competitive inhibitor of 2-series PGs and 4-series LTs and thus suppress inflammation. The results of in vitro and animal work evaluating EFAs in inflammatory situations are encouraging, which has stimulated clinical workers to evaluate these compounds in rheumatoid arthritis. Several well-controlled, randomized clinical studies have now been completed in which various EFAs were evaluated as treatments. The results of most of these studies suggest some clinical benefit to these treatments; these data are reviewed here.

Background Cyclical mastalgia, which is characterized by cyclic breast pain associated with the menstrual cycle, is a common condition among premenopausal women. Despite their prevalence, effective treatment options remain limited. Evening primrose oil (EPO) and vitamin E have been proposed as potential therapies for cyclical mastalgia; however, their efficacy remains uncertain, particularly when used in combination. Objective This study aimed to evaluate the efficacy of EPO, vitamin E, and their combination in alleviating breast pain associated with cyclical mastalgia through a randomized controlled trial. Methods Premenopausal women (n=126) with cyclical mastalgia were recruited from gynecology clinics and randomized to receive EPO (1000 mg twice daily), vitamin E (400 mg once daily), their combination, or a placebo for six months. Randomization was performed using computer-generated random numbers. Participants were assessed at baseline and monthly intervals for six months. The primary outcome was the change in breast pain severity measured using a validated pain questionnaire such as the short-form McGill Pain Questionnaire. The secondary outcomes included changes in breast pain characteristics, adverse effects, and treatment adherence. Results A total of 126 participants participated in this study. The combination of EPO and vitamin E demonstrated superior efficacy in reducing breast pain severity compared with individual treatments and placebo (p Conclusion Combination therapy with EPO and vitamin E appears to be an effective treatment option for cyclical mastalgia, offering superior pain relief compared with individual treatments and placebo.