Yarrow (Achillea millefolium L. s.l.): pharmaceutical quality of commercial samples

Yarrow (Achillea millefolium L. s.l.) is traditionally used against inflammatory and spasmodic gastrointestinal complaints, hepato-biliary disorders, as an appetite enhancing drug, against skin inflammations and for wound healing due to its antiphlogistic, choleretic and spasmolytic properties. The main pharmacologically active principles were shown to be the essential oil (antimicrobial), proazulenes and other sesquiterpene lactones (antiphlogistic), dicaffeoylquinic acids (choleretic) and flavonoids (antispasmodic). In order to assess the pharmaceutical quality of the drug we evaluated the content of these bioactive compounds in 40 commercial drug samples. The essential oil and the proazulenes were analysed according to the European Pharmacopoeia, whereas the content of dicaffeoylquinic acids and flavonoids was determined by solid phase extraction (SPE)-HPLC. This comprehensive survey revealed that the quality of the drug material was very heterogenous, and only 50% of the samples met the standards of the European Pharmacopoeia. Moreover, this study gives information about the content of phenolic compounds in the drug and allowed to establish tentative reference values which may be used as additional parameters in the quality control of the drug.