Variability of volatiles in Pinus cembra L. within and between trees from a stand in the Salzburg Alps (Austria) as assessed by essential oil and SPME analysis

Abstract

Pinus cembra L. is a coniferous European mountain range tree rich in oleoresins and essential oils. Twig tips with needles are the most common tree parts used to obtain essential oils. As the whole tree contains volatiles, the essential oil composition from different parts was studied, including twig tips with needles from the bottom, the top and the cone bearing branches, cones, twigs without needles from the lower and upper part of the crown as well as wood and bark from the trunk. The variability in essential oil composition between these plant parts and between individual trees has been studied using multivariate statistical analyses. α-Pinene was present in all samples, being highest in cones (49.3%) and lowest in sapwood (0.7%). Twig tips with needles from different parts of the crown had similar essential oil composition with α-pinene (43.9–48.3%), β-phellandrene (13.1–17.2%), β-pinene (6.6–9.3%), germacrene D (5.1–6.8%) and limonene (4.1–6.1%) as main compounds. Twig essential oils had usually more β-phellandrene (23.9–29.8%) than α-pinene (23.3–24.3%) and also appreciable amounts of β-pinene (13.5–15.1%) and limonene (11.9–17.9%). Cone essential oils contained mainly α-pinene, β-pinene (20.1%) and limonene (13.9%). The essential oils from wood and bark were rich in diterpenes as cembratrienol (4.9–21.4%), cembrene (4.8–14.3%) and methyl daniellate (2.7–6.8%). Sapwood distillates contained also notable amounts of alkane derivatives. Finally, the solvent free SPME technique has been employed to analyse the volatiles in the plant parts. For needles and cones the observed patterns were in good accordance with the compositions of the respective essential oils.

Diversity of Essential Oils and the Respective Hydrolates Obtained from Three Pinus cembra Populations in the Austrian Alps

“…Finally, six oxidized sesquiterpenes could be identified; they occur at low levels, together representing less than 1.4% of the oil, each usually below 0.4%. Diterpenoids were not present in the actual essential oils, in contrast to essential oils obtained in a laboratory scale Clevenger type hydrodistillation device, which after three hours contained small amounts of diterpenes [11,13]. The main compounds, α-pinene, β-phellandrene, β-pinene, and germacrene D were found in all samples.…”

“…The analytical column used did not separate limonene from β-phellandrene. Previous experiences report that P. cembra essential oil contains more β-phellandrene than limonene [9,13]. β-Pinene (7.0-9.0%) was a further remarkable monoterpene hydrocarbon, while the percentages of camphene and myrcene remained below 2-3%.…”

“…The content of volatiles varies widely within the P. cembra tree. While unripe cones are rich in essential oils (2.4-3.0%) the wood is very low in these compounds [10,13]. For needles and branches, essential oil contents range from 0.46 to 0.66% in plants growing in Poland [10], to 1.1 to 2.5% from Austrian plants [13], and 2.45% in trees from Romania [8].…”

“…Former research demonstrated that essential oil composition clearly differed between the needles and the twigs and branches. Needles had more α-pinene and germacrene D than the twig tips, but less limonene, β-phellandrene, and β-pinene [10,13]. Therefore, the composition of a commercially produced essential oil is strongly dependent on the ratio of twigs to needles in the distilled raw material.…”

Liquid and Vapor Phase of Four Conifer-Derived Essential Oils: Comparison of Chemical Compositions and Antimicrobial and Antioxidant Properties

“…Similar composition was described by Lis et al [ 32 ], where the needle oil was dominated by α-pinene (48.4%), limonene (7.5%), and β-phellanderene (3.1%); α-pinene was also the major component (69.14%) in needle EO of P. cembra growing in Romania [ 33 ]. The composition of the EO from twig tips with needles of the P. cembra L. growing in Salzburg Alps was represented by α-pinene (43.9–48.3%), β-phellandrene (13.1–17.2%), and β-pinene (6.6–9.3%) [ 34 ]. Pinus cembra needles EO from Slovakia consisted of α-pinene (53.2%), limonene (11.4%), and β-phellandrene (9.4%) [ 35 ].…”