Yarrow by Parts: An Ethnobotanical, Pharmacological, and Metabolomics Analysis of One of North America's Most Important Medicinal Plants

 

Achillea millefolium, also known as Yarrow, is a flowering plant in the family Asteraceae with a global distribution and long history as a herbal medicine. Meta-analysis of ethnobotanical data reveals that Yarrow is highly selected by North American Indigenous groups for medicinal use, in general, and as treatment of pulmonary and orthopedic symptoms, in particular. These ethnobotanical applications are reflected by the presence of bioactive compounds with known anti-inflammatory, antimicrobial, and anxiolytic properties. However, while distinct plant parts appear preferentially selected for specific applications, the phytochemistry and bioactivity of different Yarrow tissues remains poorly studied. Accordingly, we tested extracts of Yarrow root, leaf, stem and flower in a battery of bioassays targeting inflammation, the endocannabinoid system, and glucose metabolism. Flower and root extracts were consistently identified as the most active and were respectively enriched in flavonoids and alkylamides. Mass spectrometry-based metabolomics was then used to investigate phytochemical differences of between root, leaf, stem and flower samples collected throughout the growing season. Multivariate statistical analysis showed separation between the plant parts and enabled the putative identification of metabolites selectively detected in each individual plant part were putatively identified. Supporting In support of ethnobotanical reports of distinct medicinal properties, the four structural parts of A. millefolium showed distinct pharmacological and chemical profiles, with flowers, roots, and their active metabolites warranting additional study.