Oenothera: a precious plant for our health

Oenothera biennis is an herbaceous plant, commonly known as Evening Primrose, Enagra, Beauty of the Night, or also Rapunzel, Donkey Herb, and Gardener’s Ham; belonging to the Onagraceae family.

The origin of the name Oenothera can be explained in various ways: one derives from the Greek “onos,” meaning donkey, while “théra” means food, hence the food of donkeys. Meanwhile, “biennis” signifies biennial, referring to its vegetative cycle.

Native to North America, it arrived in Europe in the 1600s as an ornamental plant and later as an edible plant (flowers and leaves). Currently, it is mainly found in Northern Italy, in riverbeds or on beaches.

As its etymology suggests, it is biennial; in the first year, it produces a basal rosette of leaves, and in the second year, the stem emerges, reaching up to 150 cm.

The basal leaves are oblong-oval, notched, and adorned with red spots, while the stem leaves are alternate, with a short petiole or sessile, and oblong-lanceolate in shape.

The flowers are yellow, with four petals measuring 24-30 mm, gathered in terminal racemes.

The fruit consists of a subcylindrical capsule that opens at maturity, releasing many gray-brown seeds of irregular shape. These seeds constitute the main drug, but the roots, aerial parts, and flowers are also used.

Cold-pressing the seeds produces a vegetable oil rich in linoleic acid, gamma-linolenic acid, and essential fatty acids of the omega-6 series. Its action targets prostaglandins, resulting in anti-inflammatory activity.

Several studies have demonstrated that Evening Primrose oil can yield results in the treatment of dermatological conditions such as atopic dermatitis, acne, urticaria, psoriasis, and be supportive in certain autoimmune diseases like rheumatoid arthritis and multiple sclerosis, as well as premenstrual syndrome and asthma. It has hypocholesterolemic, platelet anti-aggregating, peripheral circulation-improving, and hypolipidemic actions. Lastly, it is used in cosmetics for its high elasticity-enhancing power.

It is taken internally in the form of capsules.

The roots contain mucilages, tannins, and mineral salts and can be taken as an infusion against whooping cough.

The aerial parts contain gums, waxes, phytosterols, and glucides, possessing sedative, antispasmodic, and anticonvulsant properties; they are taken as a decoction or through infusion.

The flowers contain mucilages, waxes, and yellow pigments, having sedative properties in cases of cough and whooping cough.

In English, it is called Evening Primrose because the flowers open in the evening and remain open for two consecutive nights.

ANJA LATINI

 Registered Herbalist at RNEP No. GLT0018S