Quantitative analysis of sesquiterpene lactones and thymol derivatives in extracts from Telekia speciosa

Abstract

A high-performance liquid chromatographic method based on a gradient elution and the application of core–shell type stationary phase was developed to estimate contents of sesquiterpene lactones and monoterpenoid thymol derivatives in the tissues of Telekia speciosa. The detection and quantification limits of the analytes were 0.05–0.29μgml−1 and 0.15–0.89μgml−1, respectively. Calibration curves showed good linearities (R2>0.9996) within the test ranges. Intra-day and inter-day precisions were satisfactory with RSD<2.6%. The recoveries of the standards tested ranged from 96 to 107%. The overall time of analysis was less than 35min. Using the method, seven major sesquiterpene lactones and one thymol derivative were quantified in different organs of the plant and plants of different origin. Aerial parts of T. speciosa accumulated miscellaneous sesquiterpene lactones, mainly of guaiane, pseudoguaiane, xanthane and eudesmane type, whereas roots of the plant contained almost exclusively isoalantolactone – an eudesmanolide of antiproliferative and anti-inflammatory activity (up to 1.2% dry weight). Flowers of T. speciosa proved to be an excellent source of xanthanolide – 8-epi-tomentosin (0.16–0.94%). Provenience of the plant material strongly influenced its biosynthetic potential.