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Evening Primrose (Oenothera biennis) and Skin irritation: evidence and sources
inferred from emollient action
For educational purposes only, not medical advice. Always consult a qualified practitioner before using medicinal plants, especially alongside prescribed medication, during pregnancy, or for a serious condition.
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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.
1 source supporting Evening Primrose for Skin irritation. Includes scientific publications, books, monographs and traditional-use references.
Mechanistic basis
This use is associated with the plant's emollient / skin-soothing action. Further evidence for that pharmacology:
Evening primrose ( Oenothera L.) is a plant belonging to the family Onagraceae, in which the most numerous species is Oenothera biennis . Some plants belonging to the genus Oenothera L. are characterized by biological activity. Therefore, studies were conducted to determine the dependence of biological activity on the chemical composition of various parts of the evening primrose, mainly leaves, stems, and seeds. Common components of all parts of the Oenothera biennis plants are fatty acids, phenolic acids, and flavonoids. In contrast, primrose seeds also contain proteins, carbohydrates, minerals, and vitamins. Therefore, it is believed that the most interesting sources of biologically active compounds are the seeds and, above all, evening primrose seed oil. This oil contains mainly aliphatic alcohols, fatty acids, sterols, and polyphenols. Evening primrose oil (EPO) is extremely high in linoleic acid (LA) (70⁻74%) and γ-linolenic acid (GLA) (8⁻10%), which may contribute to the proper functioning of human tissues because they are precursors of anti-inflammatory eicosanoids. EPO supplementation results in an increase in plasma levels of γ-linolenic acid and its metabolite dihomo-γ-linolenic acid (DGLA). This compound is oxidized by lipoxygenase (15-LOX) to 15-hydroxyeicosatrienoic acid (15-HETrE) or, under the influence of cyclooxygenase (COX), DGLA is metabolized to series 1 prostaglandins. These compounds have anti-inflammatory and anti-proliferative properties. Furthermore, 15-HETrE blocks the conversion of arachidonic acid (AA) to leukotriene A₄ (LTA₄) by direct inhibition of 5-LOX. In addition, γ-linolenic acid suppresses inflammation mediators such as interleukin 1β (IL-1β), interleukin 6 (IL-6), and cytokine - tumor necrosis factor α (TNF-α). The beneficial effects of EPO have been demonstrated in the case of atopic dermatitis, psoriasis, Sjögren's syndrome, asthma, and anti-cancer therapy.
Oil crops have become increasingly farmed worldwide because of their numerous functions in foods and health. In particular, oil derived from the seeds of evening primrose ( Oenothera biennis ) (EPO) comprises essential fatty acids of the omega-6 (ω-6) series. It is well recognized to promote immune cells with a healthy balance and management of female ailments. The nutrients of interest in this oil are linoleic acid (LA, 70-74%) and γ-linolenic acid (GLA, 8-10%), which are polyunsaturated fatty acids (PUFA) that account for EPO's popularity as a dietary supplement. Various other chemicals in EPO function together to supply the body with PUFA, elevate normal ω-6 essential fatty acid levels, and support general health and well-being. The inclusive EPO biochemical analysis further succeeded in identifying several other components, i.e. , triterpenes, phenolic acids, tocopherols, and phytosterols of potential health benefits. This comprehensive review capitalizes on EPO, the superior product of O. biennis , highlighting the interrelationship between various methods of cultivation, extraction, holistic chemical composition, sensory characters, and medicinal value. Besides the literature review, this study restates the numerous health advantages of primrose oil and possible drug-EPO interactions since a wide spectrum of drugs are administered concomitantly with EPO. Modern techniques to evaluate EPO chemical composition are addressed with emphasis on the missing gaps and future perspectives to ensure best oil quality and nutraceutical benefits.