FIELD-CULTIVATED MEDICINAL PLANTS OF ACHILLEA MILLEFOLIUM GROUP: A SOURCE OF BIOACTIVE COMPOUNDS.

Medicinal plants of Achillea millefolium group in Bulgarian wild flora are widely used in both traditional medicine and pharmaceutical, cosmetic and nutritive industries. They are intensively collected from the natural habitats, thus leading to a number of negative effects, such as ecological risk of extinction of native sources and high heterogeneity of the collected market samples. We explored the possibilities for field cultivation of wild A. millefolium group species as a promising approach to produce homogenous samples of valuable plants without damage to the natural environment. Our preliminary studies have identified as promising two species of A. millefolium group in Bulgaria - A. collina and A. asplenifolia. The species A. collina and A. asplenifolia, each with two populations, were studied, while cv. "Proa", bred for field cultivation, was used as a standard. Seeds were collected from the natural habitats and those of cv. Proa were purchased from the firm "Pharmasaat GmbH", Germany. Seedlings were produced in a greenhouse and then transferred to the experimental field of the Institute of Plant Physiology and Genetics near Sofia. Plants were harvested at full blossoming stage. Essential oil yield and chamazulene content in the oil, contents of total flavonoids and chlorogenic (3-O-caffeoyl quinic) acid as well as antiradical and antioxidant activities in flower heads were determined. Principal Component Analysis (PCA) of data was performed. The results showed that field-grown plants of the studied A. millefolium group species produced significant amounts of bioactive compounds, particularly flavonoids and chlorogenic acid which highly correlated with the antiradical activity. PCA pointed to the relatedness of populations within each species, and the distant positions of the species. The populations of A. asplenifolia were distinguished by higher contents of total flavonoids, essential oil, chamazulene and chlorogenic acid as well as by higher antiradical and antioxidant activities as compared to A. collina, while being closer by all parameters to cv. "Proa". The data point to A. asplenifolia as a promising species for field cultivation. [ABSTRACT FROM AUTHOR]