The clinical advantages of cold-pressed non-raffinated evening primrose oil over refined preparations.

The non-triglyceride fraction of unrefined evening primrose oil has recently been shown to contain 3-O-trans-caffeoyl derivatives of betulinic, morolic, and oleanolic acid. These lipophilic pentacyclic triterpenes have free radical scavenging, cyclooxygenase and neutrophil elastase inhibitory activities, and are therefore likely to be of benefit to human health. However, biochemical assays have suggested that these lipophilic antioxidants only occur in trace amounts, if at all, in commercial samples of evening primrose oil. A newly available commercially available cold-pressed, non-raffinated evening primrose oil preparation was found to contain a pentacyclic triterpene ester. Given the potential benefits of the triterpene esters, it is suggested that such a cold-pressed, non-raffinated commercially available evening primrose oil product is likely to have greater health benefits than conventional evening primrose oil preparations.