Aroma volatiles of rhizomes and roots of cultivated Rhodiola rosea L

In a 3-year project, 5 different clones of rose root (Rhodiola rosea L.) collected from coastal and mountain regions of Norway have been cultivated at the Apelsvoll Research Centre, Division Kise. Rhizomes and roots of female and male plants have been analysed by headspace solid-phase microextraction procedure (HS-SPME) and gas chromatography coupled with mass spectrometry. As reported earlier, terpenic and alipathic volatiles were detected as the main aroma compounds contributing to the characteristic rose-like fragrance of the underground parts of R. rosea. (E)-Pinocarveol (21.8 %) was detected as the main terpenic volatile in the roots of 3-year old plants, as well as cumic alcohol and myrtenol, whereas geraniol, cinnamaldehyde and cinnamyl alcohol showed highest concentrations in the tuberous rhizomes. These results were confirmed by recent HS-SPME analyses (May 2002) of fresh samples of cultivated rose root from Mid-Norway4 with (E)-pinocarveol and myrtenol as the main compounds in the roots (22.6 % and 19.6 %, respectively). The volatiles of rhizomes were dominated by geraniol (42.1 %) and decanol (36.9 %). Although the drying process (48 h at 35°C) resulted in significantly reduced concentrations, the relative distribution of aroma volatiles was almost unaffected. Only slight differences where observed when comparing 3-year old female and male plants from Apelsvoll Research Centre analysed by HS-SPME. Higher amounts of phenyl propanoids (cinnamyl alcohol, cinamaldehyde), oxygen-containing terpenes (cumic alcohol, cuminaldehyde) and alipathic volatiles (octanol and decanol) were detected in rhizomes and roots of R. rosea, whereas higher concentrations of characteristic volatiles such as myrtenol, geraniol and phenylethyl alcohol were observed in female plants. The essential oil analysis of steam-distilled samples from dried plant material of 2-year old clones (2001) from Apelsvoll Research Centre showed that rhizomes consisted mainly of oxygen-containing terpenes such as geraniol (51.9 %), myrtenol (10.4 %) and the phenyl propanoid cinnamyl alcohol (9.1 %). Straight-chain aliphatic alcohols and acids occurred in minor amounts (10.8 %). These results will be supplemented by further investigations of male and female rose root plants in the summer of 2002, to gain further information about rose root essential oil as a potential source for the production of fragrance and perfume essences.