Chemical Composition of the Tuber Essential Oil from Helianthus tuberosus L. (Asteraceae)

Helianthus tuberosus L. (Jerusalem artichoke) is cultivated in Europe and other parts of the world as a food crop and ornamental plant. The volatile oils of the aerial parts of H. tuberosus were investigated more than 30 years ago, but no study could be found to date on the constituents of the tuber essential oil. Herein, the first characterization by GC-FID, GC/MS, and C-13-NMR analyses of a hydrodistilled essential oil of Jerusalem artichoke tubers was reported. Fresh plant material collected in Serbia (Sample A) and a commercial sample (Sample B) yielded only small amounts of oil (0.0014 and 0.0021% (w/w), resp.). In total, 195 constituents were identified, representing 88.2 and 93.6% of the oil compositions for Samples A and B, respectively. The main constituents identified were beta-bisabolene (1; 22.9-30.5%), undecanal (0-12.7%), alpha-pinene (7.6-0.8%), kauran-16-ol (2; 6.9-9.8%), 2-pentylfuran (0.0-5.7%), and (E)-tetradec-2-enal (0.0-4.9%). Several rare compounds characteristic for Helianthus ssp. were also detected: helianthol A (6; 2.1-1.9%), dihydroeuparin (10; 0.0-2.3%), euparin (9; 0.0-0.4%), desmethoxyencecalin (7; traces - 0.2%), desmethylencecalin (8; 0.0-0.4%), and an isomer of desmethylencecalin (0.0%-traces). The essential oils isolated from the tuber and the aerial parts share the common major component 1.