Evaluation of the Farming Potential of Echinacea Angustifolia DC. Accessions Grown in Italy by Root-Marker Compound Content and Morphological Trait Analyses

The Echinacea genus includes a number of species that are commercially employed for the preparation of herbal products. Echinacea angustifolia DC. is one of these and is widely used, mainly for its immunomodulating properties, as it contains a wide range of compounds that belong to different chemical classes. In particular, echinacoside, cynarin and lipophylic alkylamides are the main specialized metabolites of the roots and can be considered to be marker compounds. In this work, 65 E. angustifolia accessions have been compared in a field trial in Italy, with the aim of investigating the variability/stability of the weight and chemical composition of their roots in order to identify the accessions that are most promising for future genetic-improvement programs. The morphological characteristics of the aerial parts have also been investigated. Seventeen samples were discarded due to germination or plantlet-development issues. Seven of the remaining accessions were identified as being different Echinacea species after a combined phytochemical and morphological evaluation. The morphological traits of the epigeal part, the root weight and the chemical composition data of the 41 confirmed E. angustifolia accessions were submitted to multivariate statistical analysis and a moderately homogenous sample distribution, with low selected-marker variability, was observed. Good echinacoside content was detected in almost all roots (>0.5%). However, two groups of accessions stood out because of their interesting features: One group possessed small roots, but had a high concentration of marker compounds, while another had highly developed roots and a good amount of marker compounds. These accessions can therefore be exploited for future selection work.

Keywords: cynarin; dodeca-2E,4E,8Z,10E/Z-tetraenoic isobutylamide; echinacoside; marker-compound quantification; morphological traits; root weight.