The composition of the essential oils from stems, leaves, and flowers of
Phlomis aucheri, stems, leaves and roots of
Teucrium polium and leaves of
Ajuga chamaecistus, are listed in
Table 1,
2 and
3, respectively, in which the percentage and relative retention indices of components are given.
As it is shown from
Table 1, in
P. aucheri we identified 46 compounds representing 91.58%, 40 constituents representing 91.04% and 40 components representing 89.53% of the stem, leaf and flower oils, respectively. The main component in three oils was germacrene D (11.10%, 28.31% and 21.06%), respectively. Other notable constituents were
β- caryophyllene (5.58%, 4.96% and15.93%) and bicyclogermacrene (6.30%, 8.86% and 7.63%), respectively.
(E)- Anethole (24.58%) was the other main component in the stem oil of the plant and not detected in the leaf and flower oils. As can be seen from the above information, all three oils were rich in regard to sesquiterpenes (51.52%, 78.52% and 85.16%), respectively. The
monoterpene fraction was relatively small, representing only 12.32%, 8.88% and 1.70%, respectively. In the stem oil of P. aucheri, considerable percentage of non terpenoid compounds, compairing to other parts of the plant oils, were identified (27.74%). In an earlier study, Javidnia et al. analyzed the essential oil of the aerial parts of P. aucheri collected in Fars province. The oil was found to be rich in caryophllyene oxide (33.5%), β- caryophyllene (27.0%) andβ-selinene (9.9%) (44).
Only a few reports on the analysis of essential oils of Phlomis species have been published.
Water distilled essential oils from aerial parts of P. persica and P. olivieri, which are endemic to Iran, have been the subject of our previous studies. The major components of both oils were germacrene D (38.2% and 26.4%) and bicyclogermacrene (16.3% and 12.7%), respectively.
Both oils consisted mainly of sesquiterpene hydrocarbons (
45). Also we reported the oil composition of
P. pungens. The major constituents of the oil of the plant were germacrene D (24.5%), bicyclogermacrene (14.1%), α-pinene (13.5%) and (E) -
β- farnesene (13.4%) (
46).
Camparison of the present results with those of our previous investigation of oils of the Phlomis genus showed that they are also dominated by sesquiterpenes.
Germacrene D has been identified in other species of
Phlomis, including
P. cancellata (
47),
P. bracteosa (
48),
P. armeniaca (
49),
P. chorassanica (
50),
P. herba-venti (
51),
P. bruguieri (
52,
53),
P. lanceolata,
P. anisoonata (
53) and
P. linearis (
54).
As it is shown from
Table 2, 45 components representing 96.84%, 41 constituents representing 98.48% and 20 compounds representing 88.7% were identified in the oils of stem, leaf and root of
T. polium, respectively.
The main components in all three oils were α-muurolol (25.02%, 20.03% and19.53%), α-cadinol (15.72%, 8.11%, and 13.01%) and β-caryophyllene (10.86%, 10.11% and 10. 64%), respectively.
Other notable compounds were in stem oil; caryophyllene oxide (6.49%), elemol (5.53%) and hexadecanoic acid (5.17%), in leaf oil, (z) nerolidol (7.13%) and β- pinene (6.65%), in root oil; hexadecanoic acid (16.37%).
According to these results, the composition of the stem, leaf and root oils of T. polium show significant similarity for the concentration of the main components. All three oils were rich in regard to sesquiterpenes (80.89%, 75.58% and 59.96%), respectively.
The monoterpene fraction of the stem and leaf oils was relatively small, representing (6.73% and 21.45%) of the total oils, resepectively. In the root oil of the plant we could not find any trace of monoterpenes. In the root oil of T.polium, considerable percentage of non terpenoid compounds, compared to other parts of the plant oils, were identified (28.74%).
Water distilled oil obtained from the aerial parts of
T. persicum, which is endemic to Iran, have been the subject of our previous studies. epi-
α-Cadinol (23.2%) and
α-pinene (17.3%) were the main components among the thirty-one constituents characterized in the oil of
T. persicum representing 95.9% of the total components detected (
55). The oil of
T. gnaphalodes was characterized by higher amounts or
β-caryophyllene (12.1%), sabinene (8.8%) and
trans- pinocarveol (7.8%) (
53).
As it is shown from the
Table 3, in
A. chamaecistus oil, 68 components, which representing about 92.6% of the total composition, were identified. The leaf oil of
A. chamaecistus consists of 14 monoterpene hydrocarbons (26.38%), 12 oxygenated monoterpenes (16.25%), 17 sesquiterpene hy- drocarbons (24.21%), 8 oxygenated sesquiterpenes (11.36%), and 17 non terpenoid compounds (14.40%). The major components of this oil were (z)-
β- ocimene (12.11%) and germacrene D (10.11%) followed by spathulenol (6.10%) and bornyl acetate (6.08%).
The leaf oil of A. chamaecistus was rich in regard to both monoterpenes (42.63%) and sesquiterpenes (35.57%).
The qualitative and quantitative variation between our results and our previous reports (
40) for the constituents of the oil from aerial parts may be attributed to the different environment conditions and different methods of extraction of the oils.
The oils of the genus
Ajuga have been the subject of only a few studies. The oil of
A. chamaecistus subsp. tomentella contained thymol (34.5%) and exo- fenchol (15.6%) as the major components (
56).
The oil of
A. chamaecistus subsp. scoparia was characterized by higher amounts of
p-cymene (34.5%),
β- pinene (18.0%),
α- phellandrene (17.8%) and
α- pinene (15.2%) were major constituents (
57) .
The major constituents of the aerial parts of
A. chamaepitys ssp. chamaepitys were
β-pinene (34.3%) and
α-pinene (16.1%) (
58). The dominant compounds in
A. bombycina were
β- pinene (28.2%) and
α- pinene (18.5%) (
59).