IntroductionHeartleaf oxeye [Telekia speciosa (Schreb.) Baumg., Asteraceae, tribe Inuleae, basionym -Buphtalmum speciosum Schreb.] is a perennial plant native to Southeastern Europe and Asia Minor. It is the only species belonging to the genus Telekia Baumg. [1], which, accordingly to recent molecular phylogenetic studies based on both cpDNA and ITS sequence analysis [2] is closely related to Carpesium spp. and a group of resiniferous taxa of Inula L., including Inula helenium -a well known medicinal plant. Likewise the roots of the resiniferous Inula species, roots of T. speciosa contain essential oil with eudesmane-type sesquiterpene lactones as major constituents. Except for sesquiterpene lactones of eudesmanolide and pseudoguaianolide type, the plant reportedly contains xanthanolides, terpenoid cyclopropenone derivatives, polyacetylene, thymol and nerol derivatives [3][4][5][6]. Data on medicinal uses of T. speciosa are sparse, however, biological activity of secondary metabolites produced by the plant have gained some interest. Except for widely investigated alantolactone and isoalantolactone, other sesquiterpene lactones -telekin and 2,3-dihydroaromaticin have also shown marked antiproliferative activity against human cancer cell lines in vitro [7,8]. Moreover, 2,3-dihydroaromaticin is a potent inhibitor of lipopolisaccharide induced nitric oxide synthesis and a moderate inhibitor of the transcription factor NF-κB activation [9,10].Telekin affected activity of some antioxidant and drug-metabolizing enzymes in rat liver and kidney [11,12]. In a recently published report on antiproliferative and direct cytotoxic activity of extracts from T. speciosa an interference of these preparations with cell proliferation in vitro has been proven [13].The aim of the present study was to achieve in vitro multiplication of T. speciosa shoots and to investigate secondary metabolism of the culture as a potential source of biologically active compounds.
Material and methods
Plant materialSeeds of Telekia speciosa (Schreb.) Baumg. were delivered by Botanical Garden in Nantes (France). Multiple shoots of the plant were collected from in vitro cultures maintained in our laboratory. As a reference material, aerial parts of Telekia speciosa (Schreb.) were harvested in July-August from plants grown in the Garden of Medicinal Plants, Institute of Pharmacology, Polish Academy of Sciences, Kraków, where a voucher specimen (10/08) was deposited. The plants were obtained by acclimatization of in vitro regenerated plantlets and were collected in the second year of their vegetation outside.
AbstractMultiple shoots of Telekia speciosa were cultivated on MS medium containing 4.44 µM BAP and 0.54 µM NAA, solidified with agar. After eight weeks of culture the shoots were harvested and extracted with methanol. From the methanol extract one pseudoguaianolide -2,3-dihydroaromaticin and three thymol derivatives: 8-hydroxy-9,10-diisobutyryloxythymol, 10-isobutyryloxy-8,9-epoxythymyl isobutyrate and 10-(2-methylbutyryloxy)-8,9-epoxythymyl isobuty...