Progress in Essential Oils: Silver Fir or Abies alba oil

An oil produced from the needles and small branches of silver, white or European silver fir (or even silver spruce or white spruce) originates from Abies alba Mill., a European tree that can grow to the height of 150ft (ca.46 m.) a dbh (diameter at breast height) of 20ft (ca. 6.0m.). It can be found in the mountainous regions of eastern, western, southern and central Europe from the Carpathians in the East to the Pyrenees and from the Balkan Peninsula to northern Greece. Over the centuries the species has been reduced due to over exploitation, deforestation and afforestation with faster growing exotic trees.

More recently, forest management practices across Europe arrested this decline (Konnert and Bergmann, 1995). Abies alba is a significant timber tree in Western and Central Europe. In the past, it was used for the mast in sailing ships, while it is now commonly used in the manufacture of plywood and veneer because it is evenly grained and easy to work. An oil is produced from the needles and twigs in yields of 0.25–0.35%. At one time, an oil known as Templin oil was also produced from the cones of A. alba; however, because of the similarity between the needle/twig and the cone oils, templin oil is rarely produced these days. Also, from a pureist standpoint, it was extremely difficult—if not impossible—to differentiate the two oils and guarantee templin oil was produced only from the cones.

A survey of the literature reveals Baerheim Svendsen and Karlsen (1967) analyzed a sample of Edeltannenadelöls (the German name for A. alba oil) and found it contained santene, tricyclene, α-pinene, α-thujene, α-fenchene, camphene, β-pinene, δ-3-carene, sabinene, α-phellandrene, myrcene, α-terpinene, limonene, β-phellandrene, δ-terpinene, (E)- β-ocimene, p-cymene, (Z)- β-ocimene, 1,8-cineole and terpinolene in the monoterpene hydrocarbon fraction. Tsankova and Ognyanov (1968) confirmed an oil of A. alba produced in Bulgaria contained the following monterpene hydrocarbons:

santene (1.2%)

α-pinene (21.2%)

camphene (9.3%)

β-pinene (26.2%)

limonene + β-ocimene^* (33.2%)

p-cymene (9.0%)

^*correct isomer not determined

They also found the oil contained a number of sesquiterpene hydrocarbons such an α-ylangene, longifolene, β-caryophyllene, γ-muurolene, α-muurolene, β- selinene, δ-cadinene, γ-cadinene and a calamenene isomer, although not quantitative data for these components was presented.

An absolute produced in Bulgaria from the needles of A. alba was analyzed by Nicolov et al. (1972). The compounds found in this extract were as follows:

α-pinene (23.3%)

camphene (0.3%)

β-pinene (15.8%)

sabinene (0.3%)

myrcene + δ-3-carene (0.4%)

α-phellandrene (0.3%)

limonene (14.5%)

β-phellandrene (0.8%)

1,8-cineole (0.7%)

γ-terpinene + p-cymene + terpinolene (0.6%)

camphor (1.5%)

bornyl acetate + terpinen-4-ol (5.9%)

borneol + α-terpineol (8.7%)

Nicolov et al. (1976) determined that an oil of A. alba of Bulgarian origin contained santene, α-pinene, limonene, bornyl acetate and lauric aldehyde (dodecanal), although not quantitative data was presented.

Manville et al. (1977) examined the tree-to-tree variation of the major constituents of Abies alba needle oils produced in the laboratory from twigs and needles obtained from the former Czechoslovakia. Additionally, the author’s compared these oils with a commercial oil. The oil compositions are shown in T-1.

Scheffer (1978) analyzed the monoterpene hydrocarbon fraction of A. alba needle oil. He found it contained the following hydrocarbons:

cyclofenchene (0.2%)

bornylene (0.5%)

santene (1.8%)

tricyclene (1.8%)

α-pinene (23.6%)

α-thujene (<0.1%)

β-fenchene (0.2%)

α-fenchene (2.0%)

camphene (21.1%)

β-pinene (8.7%)

sabinene (0.2%)

δ-3-carene (0.1%)

myrcene (1.0%)

α-phellandrene (0.2%)

α-terpinene (0.7%)

limonene (34.2%)

β-phellandrene (1.3%)

γ-terpinene (0.3%)

p-cymene (1.0%)

terpinolene (1.1%)

Penka and Cermák (1979) explored the potential for Czechoslovakia to produce a silver fir oil from the by-products of the existing logging business. The authors recommended the production of oil should commence with the introduction of mobile distillation systems. The needle oils were found to possess santene, α-pinene, camphene, β-pinene, δ-3-carene and p-cymene as constituents.

Stefanescu (1979) determined that the needle oil of A. alba, produced in Romania, contained α-pinene, β-pinene, α-phellandrene, δ-3-carene, limonene, γ-terpinene, bornyl acetate borneol, isoborneol, α-terpineol, α-muurolol and some cadinene isomers.

Srinivas (1986) used GC\MS only to determine that a commercial oil of A. alba contained the following constituents:

tricyclene (0.1%)

α-thujene (2.1%)

α-pinene (22.2%)

camphene (19.5%)

β-pinene (7.3%)

myrcene (1.8%)

p-cymene (1.5%)

1,4-cineole (0.6%)

limonene (12.0%)

linalool (0.2%)

α-terpineol (0.7%)

bornyl acetate (20.7%)

The author also reported a volatile nor-camphene (3.7%) was found in the oil; however, the identity of compound could not be confirmed by this reviewer.

A lab-distilled oil produced in 0.3% yield of A. alba was analyzed by Chalchat et al. (1986) using (GC-FID) and GC\MS. The constituents characterized in this oil were:

santene (0.9%)

tricyclene (0.8%)

α-pinene (31.7%)

camphene (5.8%)

β-pinene (3.0%)

sabinene (0.1%)

δ-3-carene (0.3%)

myrcene (1.0%)

limonene (34.1%)

γ-terpinene (0.1%)

p-cymene (0.1%)

terpinolene (0.3%)

δ-elemene (1.0%)

α-ylangene (0.4%)

α-copaene (0.1%)

linalyl acetate (1.2%)

bornyl acetate (1.3%)

β-caryophyllene (4.2%)

terpinen-4-ol (0.2%)

α-himachalene (0.4%)

α-terpineol (0.2%)

α-terpinyl acetate (0.5%)

α-patchoulene(0.3%)

β-himachalene (2.6%)

allo-aromadendrene (0.2%)

γ-patchoulene (0.6%)

γ-cadinene (0.3%)

δ-cadinene (0.5%)

cadina-1,4-diene (0.1%)

neryl acetate (0.1%)

α-muurolol (0.1%)

T-muurolol (0.1%)

^*correct isomer not identified

Trace amounts (<0.05%) of α-terpinene, β-phellandrene, (Z)-β-ocimene, α-santalene, camphor, geranyl acetate and α-cadinol were also found in this oil. The authors also reported identifying a sesquiterpenoid compound (3,6,10,10)-tetramethyl-tricyclo [7.2.0] 2-undecene), although this identity has not been confirmed.

The chemical composition of fir needle oil produced on the lab-scale from needles and twigs of A. alba was compared with a commercial oil. The analysis of these two oils by Kubeczka and Schultze (1987) can be seen in T-2.

Neubeller (1990) examined the needle waxes and major needle volatiles of A. alba. He found the leaf waxes for seven year-old trees were C_14–C₃₅ with the predominant waxes being C₂₃, C₂₅, C₂₇, C₃₁. The major volatiles were found to be α-pinene, camphene, β-pinene and limonene (predominant volatile).

Vskot and Coufalikova (1990) examined the effect of harvest time on the oil composition of four major constituents of A. alba growing in Czechoslovakia. They found these compounds varied from March to December as follows:

α-pinene (3.1–12.4%)

phellandrene^* (4.8–16.7%)

limonene (16.1–25.9%)

bornyl acetate (3.7–12.8%)

^* correct isomer not identified

Merkx and Baerheim Svendsen (1990) determined that the needles of A. alba contained the following glycosidically bound volatile compounds:

(Z)-3-hexenol

benzyl alcohol

hexanol

1-octen-3-ol

3-octanol

2-phenethylalcohol

They found that (Z)-3-hexenol was the major bound volatile compound.

A sample of silver fir oil (A. alba) of Polish origin was found by Gora et al. (1997) to contain the following major components:

α-pmene (31.8%)

camphene (16.2%)

β-pinene (15.0%)

limonene (16.8%)

bornyl acetate (4.1%)

A lab-distilled oil of A. alba needles collected from the southern Balkans was analyzed by Roussis et al (1997) using GC-FID and GC/MS. The constituents characterized in this study were as follows:

α-pinene (10.9%)

camphene (15.3%)

β-pinene (19.8%)

limonene (16.0%)

α-fenchyl acetate (14.2%)

globulol (1.5%)

As a follow-up to this report, Roussis et al (2000) reported a more detailed analysis of A. alba oil produced from needles collected from the Mt. Goc region of Serbia. Using the same method of analysis as before, the authors determined the oil possessed the following composition:

α-thujene (2.8%)

α-pinene (10.9%)

camphene (15.3%)

β-pinene (19.8%)

myrcene (1.1%)

α-phellandrene (0.9%)

α-terpinene (0.2%)

limonene (11.0%)

β-ocimene^* (0.2%)

γ-terpinene (0.2%)

terpinolene (0.9%)

linalool (0.1%)

α-fenchyl alcohol (<0.1%)

terpinen-4-ol (0.1%)

α-terpineol (0.2%)

methyl thymol (0.1%)

α-fenchyl acetate (14.2%)

linalyl acetate (0.1%)

α-terpinyl acetate (0.4%)

neryl acetate (0.1%)

geranyl acetate (0.2%)

β-caryophyllene (4.0%)

α-ionone^* (0.4%)

aristolene (0.7%)

γ-elemene (0.5%)

α-humulene (1.9%)

γ-gurjunene (0.3%)

germacrene D (0.8%)

γ-cadinene (0.8%)

δ-cadinene (0.9%)

globulol (1.5%)

β-eudesmol (0.3%)

kaur-15-ene (<0.1%)

An oil of A. alba from needleless young branches collected in Montenegro was analyzed by Chalchat et al. (2001) using GC-FID and GC\MS. The oil was found to contain the following constituents:

santene (1.5%)

tricyclene (2.1%)

α-pinene (17.3%)

camphene (16.7%)

β-pinene (32.8%)

sabinene (0.1%)

myrcene (1.0%)

limonene (6.1%)

β-phellandrene (4.9%)

p-cymene (0.1%)

terpinolene (0.3%)

α-campholenal (0.1%)

α-longipinene (0.2%)

camphor (0.2%)

α-gurjunene (0.4%)

pinocarvone (0.1%)

longifolene (0.6%)

bornyl acetate (9.0%)

β-caryophyllene (1.3%)

cryptone (0.1%)

α-humulene (0.6%)

(E)-β-farnesene (0.2%)

γ-muurolene (0.3%)

borneol + α-terpineol (2.1%)

γ-cadinene (1.1%)

α-selinene (0.1%)

δ-cadinene (0.4%)

caryophyllene oxide

Trace amounts (< 0.05%) of γ-terpinene, α-copaene, α-himachalene, trans-pinocarveol, (Z)-β-farnesene, β-selinene, α-muurolene, β-bisabolene and myrtenol were also characterized in this oil.

The volatile constituents of a needle oil of A. alba of Romanian origin were found by Marculescu and Gleizes (2001) to be norbornene (probably santene), cyclofenchene (probably tricyclene), α-pinene, camphene, β-pinene, myrcene, β-terpinene (incorrect identification), limonene, β-phellandrene, γ-terpinene, δ-3-carene (misidentified), α-longipinene, α-cubebene (requires corroboration), β-caryophyllene, α-humulene, β-cubebene (requires corroboration, β-selinene, β-cadinene (misidentification, β-bisabolene, α-campholenal, β-terpineol (misidentification or artefact), camphor, borneol, terpinen-4-ol, linalyl propionate (requires corroboration), bornyl acetate, γ-terpineol (does not occur naturally), menthyl acetate (misidentification). (E)-nerolidol and agarospirol (requires corroboration).

Ochocka et al. (2002) used chiral GC to determine the enantiomeric ratios of four major monoterpene hyrocarbons in the needle oils of A. alba of Polish and Austrian origin and a cone oil of Austrian origin. These results are presented in T-3.

Rohloff and Langleite (2005) analyzed the needle oils of the Pinaceae and Cupressaceae, which are produced commercially. Using GC\MS only as their analytical method the oil of A. alba was found to contain the following constituents:

tricyclene (4.9%)

α-pinene (13.8%)

camphene (12.8%)

β-pinene (3.5%)

δ-3-carene (1.1%)

myrcene (1.9%)

limonene (41.8%)

β-phellandrene (1.3%)

bornyl acetate (6.9%)

borneol (0.4%)

Duquesnoy et al. (2007) examined the lab-distilled oils of A. alba were produced from 53 single mature trees collected throughout Corsica. The authors used GC-FID, GC\MS, ¹³C-NMR and chemometric analysis to examine the oils. They found that the oils could be subdivided into two groups based on their major constituents as can be seen in T-4.

In addition, the authors characterized sabinene, 1,8-cineole, (E)-β-ocimene, p-cymenene, longicyclene, trans-calamenene, caryophyllene oxide and manoyl oxide in one or both of the two oil types.

Harangi (2007) confirmed the presence of β-caryophyllene, and himachala-2,4-diene as constituents of A. alba oil.

A commercial oil of A. alba that was purchased in Korea was subjected to analysis using GC/MS only by Yang et al. (2009). The constituents supposedly characterized in this oil were:

4-hydroxy-4-methyl-2-pentanone (0.1%)

2,3-dimethylbicyclo[2.2.1]hept-2-ene (1.6%)

δ-3-carene (13.9%)

camphene (2.1%)

β-phellandrene (2.1%)

β-pinene (0.5%)

tricyclene (12.9%)

p-cymene (0.6%)

α-terpinene (1.2%)

borneol (1.7%)

bornyl acetate (30.3%)

aromadendrene (0.1%)

α-humulene (0.2%)

β-caryophyllene (2.2%)

β-elemene (0.7%)

valencene (0.1%)

α-bisabolene (0.1%)

The above analysis is a typical example of the use of the computer to identify(most were misidentified base on their elution order) the constituents of an oil which because of its bornyl acetate content(assuming correct identification of at least this compound) could not even be a Silver fir oil.

Wajs et al. (2010) used GC/MS-FID to examine the oil composition of the seeds and cones of A. alba harvested from trees growing on the Bieszczady mountain (S.E. Poland) and Lodz (Central Poland) The results of this study are summarized in T-5.

As can be seen (4R)- (-)-limonene was the predominant enantiomer (by Chiral GC) in the oils. In addition, trace (0.05%) amounts of tricyclene, α-thujene, sabinene, (E)-β-ocimene, γ-terpinene, fenchone, trans-p-menth-2-en-1-ol, cis-p-mentha-2,8-dien-1-ol, menthol, citronellol, neral, (Z)-anethole, trans-carvone epoxide, geraniol, (E)-anethole, thymol, bornyl acetate, carvacrol, eugenol, α-terpinyl acetate, bicycloelemene, citronellyl acetate, α-longipinene, geranyl acetate, β-cubebene, β-gurjunene, himachala-2,4-diene, aromadendrene, selina-4(15),7-diene, γ-muurolene, α-amorphene, germacrene D, β-selinene, α-muurolene, cubebol, α-cadinene, α-calacorene, elemol, (E)-nerolidol, longiborneol, humulene epoxide II, T-cadinol, T-muurolol, cubenol, apiole, a farnesol isomer, (E)-trans-bergamotol, (E,E)-farnesyl acetate, manoyl oxide, 13-epi-manoyl oxide, abieta-7,13-diene and abietal were found in the seed oils. In contrast, only tricyclene, sabinene, β-phellandrene, (E)-β-ocimene, γ-terpinene, trans-p-menth-2-en-1-ol, bornyl acetate, α-longipinene, α-calacorene, elemol and α-cadinol were found as trace constituents of the cone oil.

A commercial sample of A. alba oil of Romanian origin that was screened for its antimicrobial characteristics was determined by Serban et al. (2011) to contain the following major constituents:

α-pinene (27.0%)

camphene (13.5%)

β-pinene (30.9%)

limonene (12,4%)