Thymol derivatives from a root culture of Inula helenium.

A root culture of Inula helenium L. was established from leaf explants of aseptic seedlings. An ethanol extract from the lyophilised roots was fractionated using different chromatographic techniques (CC, TLC). The main secondary metabolites found in the root culture were two thymol derivatives: 10-isobutyryloxy-8,9-epoxy-thymol isobutyrate (1) and 10-isobutyryloxy-6-methoxy-8,9-epoxy-thymol isobutyrate (2). The compounds were identified by spectral methods. Quantification of compound 1 in plant material was done by analytical RP-HPLC.