The Variability of the Essential Oil Composition of Wild Ledum palustre L. Shoots During Vegetation Period

The wild Ledum palustre L. was collected in the Samanis marsh (Utena region, Lithuania) from April through October 2007 on the same day of each month. Seven essential oils of shoots (without inflorescences and seeds) and one oil of inflorescence were obtained by hydrodistillation and analyzed by GC and GC/MS. Predominant constituents in all oils were ledol (21.0-32.2%) and palustrol (26.2-37.9%). The oils richest in ledol and palustrol were found in April and October. To evaluate the amounts of these compounds in the shoots, the percentages were related to the contents of the oils obtained from shoots. Calculated amounts of ledol and palustrol were largest in shoots during flowering in May. The inflorescence oil (11.4%) and shoot oil (7.5%) obtained from L. palustre during seed formation in June contained considerable amounts of myrcene. Cyclocolorenones (2.7-6.5%) were among six main constituents. Monoterpenoids 2-methyl-5-(3-furyl)-3-penten-2-ol, 5-(3-furyl)-2-methyl-1-penten-3-one (lepalone) and 5-(3-furyl)2-methyl-1-penten-3-ol (lepalol) were found in all oils. The largest amounts of furyl compounds were produced by L. palustre in September (9.5%) and October (14.7%). Sixty-nine identified compounds comprised 95.7-99.3% of the oils.