Interest in the seed oil of the evening primrose plant lies in its essential fatty acid content, in particular in the linoleic acid (LA) and gamolenic acid (GLA) content. Both of these compounds are prostaglandin precursors and dietary gamolenic acid supplementation has been shown to increase the ratio of non-inflammatory to inflammatory prostaglandin compounds.
Evening primrose oil has been used as a food supplement for many years. LA and gamolenic acid are both essential fatty acids (EFAs), with LA representing the main EFA in the diet, whilst gamolenic acid is found in human milk, in oats and barley, and in small amounts in a wide variety of common foods.
Evening primrose oil (EPO) was licensed in the UK for the treatment of atopic eczema, and cyclical and non-cyclicalmastalgia, but product licences for two products were withdrawnin 2002 due to a lack of data sufficient to support efficacy in these conditions. Other conditions in which evening primrose oilhas been used include premenstrual syndrome, psoriasis, multiplesclerosis, hypercholesterolaemia, rheumatoid arthritis, Raynaud'sphenomenon, Sjögren's syndrome, postviral fatigue syndrome,asthma and diabetic neuropathy.
