O. grandiflora L’Hér.; and others Onagraceae Evening star; King’s cure-all; suncup; sundrop Oenotherae biennis oleum Seed oil Essential fatty acids of the omega-6 series including linoleic acid (about 65–85%) and gamma-linolenic (gamolenic) acid (GLA) (about 7–14%) are the major constituents of evening primrose oil. Other fatty acids include oleic acid, α-linolenic acid, palmitic acid and stearic acid. The sterols β-sitosterol and campesterol and triterpene alcohols are also present (Montserrat-de la Paz et al. 2012; Pharmaceutical Press Editorial Team 2013; WHO 2004; Williamson et al. 2013). Many clinical studies have been carried out on evening primrose oil, with conflicting results. It may be helpful in some patients and when supplementation with essential fatty acids is needed. A Cochrane review assessed 19 studies that investigated oral evening primrose oil in the treatment of eczema, but found that it failed to significantly improve overall eczema symptoms compared to placebo (Bamford et al. 2013). An earlier review based on 10 studies of the use of evening primrose oil in atopic dermatitis also found no convincing evidence to support its use (Williams 2003). A more recent (uncontrolled) study investigated the dose-dependent effects on clinical symptoms and serum fatty acids of evening primrose oil in children and adolescents (aged 2–15 years) with atopic dermatitis. Patients were randomly divided into two groups: those receiving 160 mg evening primrose oil daily (n = 20) and those receiving 320 mg daily (n = 20) for 8 weeks. Serum fatty acid levels were significantly higher in the 320 mg group that the 160 mg group, and while both groups showed a reduction in Eczema Area Severity Index (EASI) scores after 8 weeks, the improvement was greater in the 320 mg group (Chung et al. 2013). A preliminary study found that topically applied evening primrose oil reduced inflammation at 5-azacitine injection sites of patients with myelodysplastic syndrome (Platzbecker et al. 2010). In a systematic review of randomised controlled trials assessing herbal treatments for alleviating symptoms of premenstrual syndrome, evening primrose oil was found to be no more effective than placebo (Dante and Facchinetti 2011). A six-week randomised, placebo-controlled clinical trial evaluated oral evening primrose oil (1000 mg daily) in reducing frequency, severity and duration of menopausal hot flushes in women aged 45–59 years. The results showed improvement in hot flushes for both intervention and control groups, with evening primrose outperforming placebo, although statistical significance was found only in comparison of severity of hot flushes (Farzaneh et al. 2013).
Evening Primrose (Oil)
Oenothera biennis L.
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Atopic dermatitis and eczema:
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