Pineapple weed and its uses

Pineapple weed (Matricaria discoidea) was introduced to Britain from Oregon in the late 19th century and spread rapidly. It is now an abundant annual weed of waysides and waste places, its cone-shaped flower heads a familiar sight from June to September.

When crushed, the flowers give off an odour resembling ripe apples or pineapples, and it is thought that either this, or the fact that the flowers resemble a pineapple in appearance, is responsible for the plant’s common name.The flowers have an agreeable fruity taste before they are fully ripe, and have been added to salads, as well as being used, either fresh or dried, as an infusion.

A close relative of camomile, pineapple weed has been used in folk medicine for centuries. The name matricaria is derived from the Latin matrix (uterus), and camomiles have been used for a host of gynaecological disorders. Other uses for pineapple weed have been as a sedative, an anti-inflammatory, an antispasmodic and an anthelmintic.

Analysis of the essential oil of the pineapple weed shows that the major constituent is myrcene, a chemical important in the perfumery industry. Because of its pleasant odour, it is often used directly, but it is highly valued as an intermediate in fragrance production.

Another constituent is the coumarin herniarin, which has shown a range of biological activities, including haemostatic and anthelmintic properties. Research has also demonstrated antimicrobial activity, with extracts of pineapple weed causing inhibition of aggregation of  Escherichia coli cells in vitro.

The pharmacopoeia of the former Soviet Union permitted the substitution, for external use only, of pineapple weed for German camomile (Matricaria recutita), a herbal medicine popular in the Baltic states. According to the pharmacopoeia, the inflorescence has an antispasmodic and anti-inflammatory effect.

An Estonian study carried out in 2006 compared the chemical composition of German camomile, the country’s most popular medicinal plant, with that of pineapple weed. The researchers concluded that the spasmolytic effects of each plant were comparable, and toxicity studies suggested that pineapple weed was suitable for internal use.