Phytochemical variation within populations of Echinacea angustifolia (Asteraceae)

Quantitative evaluation of phytochemical diversity in Echinacea angustifolia DC. populations from different natural geographic areas supports the existence of distinct natural chemotypes within the species. Consumers, growers and manufacturers of phytomedicines are interested in chemotype identification for prediction of phytochemical content in cultivar development. Six month old E. angustifolia roots, grown from nine different wild seed sources in a controlled environment, were extracted into 70% ethanol and 28 reported phytochemicals were measured by HPLC separation. Two-way ANOVA between the nine populations revealed quantitative differences (p<0.05) in the caffeic acid derivatives 2,3-O-dicaffeoyl tartaric acid (cichoric acid), 2-O-caffeoyl tartaric acid (caftaric acid), 1,3-dicaffeoyl-quinic acid (cynarin), echinacoside and ten reported alkamides. Canonical discriminant analysis determined the phytochemical variables which contributed the most towards chemotype distinction for five of the nine populations: undeca-2E,4Z-diene-8,10-diynoic acid-2-methylbutylamide*, dodeca-2E,4E-dienoic acid isobutylamide*, dodeca-2E-ene-8,10-diynoic acid isobutylamide**, hexadeca-2E,9Z-diene-12,14-diynoic acid isobutylamide*, cichoric acid**, caftaric acid*, and echinacoside** (*p<0.0001, **p<0.05). Five of those compounds were also significantly associated with latitudinal variation by regression analyses (p<0.05). (C) 2002 Published by Elsevier Science Ltd.