Abstract
Wild Rhododendron tomentosum Harmaja shoots were collected from four localities of Estonia. Essential oils, isolated from dried samples by simultaneous distillation and extraction, were analysed using GC-FID and Gas chromatography–mass spectrometry methods. The yields of oils were in the range 0.14–0.87%. A total of 72 constituents, accounting for over 95% of the total oil yield, were identified. The major components in the all four oils studied were palustrol (15.9–53.5%), ledol (11.8–18.3%), γ-terpineol (0–31.2%), p-cymene (0.1–13.9%), lepalone (0.7–6.5%), lepalol (1.0–6.5%) and cyclocolorenone (1.0–6.4%). Two different chemotypes of R. tomentosum were found in Estonia and one of them was rich in palustrol (41.0–53.5%) and ledol (14.6–18.3%). The second chemotype, for the first time, was rich in γ-terpineol (24.7–31.2%) and contained less of palustrol (15.9–16.7%) and ledol (11.8–12.8%), but more p-cymene (12.5–13.9%). Also, γ-terpineol was identified for the first time in the oils of R. tomentosum.
Acknowledgement
The authors gratefully acknowledge Mati Müürisepp, Ph.D., for performing GC–MS analysis.