Chemical Composition of Essential Oils of Grindelia squarrosa and
Katalin Veresa, Orsolya Rozaa, Eszter Laczkó-Zöldb and Judit Hohmanna,*
aDepartment of Pharmacognosy, Faculty of Pharmacy, University of Szeged, Eötvös str. 6.,
H-6720 Szeged, Hungary
bDepartment of Pharmacognosy, University of Medicine and Pharmacy, Targu Mures,
Gheorghe Marinescu str. 38, 540139 Târgu Mureș, Romania
Received: December 12th, 2013; Accepted: December 18th, 2013
The essential oils of Grindelia squarrosa (Pursh) Dunal and G. hirsutula Hook. & Arn. cultivated in Romania were isolated by hydrodistillation. The essential
oils were analyzed by a combination of GC-FID and GC-MS. The identification of the constituents was achieved from their retention indices and comparison
of their MS data with computer library database and literature data. The fifty identified constituents accounted for 72.1-81.3% of the oils. The oils were found
to contain α-pinene, β-pinene, limonene, borneol, bornyl acetate and germacrene D as main constituents. The oils obtained from the two species showed small
differences in chemical composition. However, menthol, menthone and pulegone were detected only in the essential oil of G. hirsutula.
Keywords: Grindelia squarrosa, Grindelia hirsutula, Asteraceae, Essential oil composition, GC-FID, GC-MS.
The genus Grindelia Willd. (Asteraceae) comprises about 60
species, all of which are native to North and Central America and
chiefly concentrated in warm-temperate regions. Several species are
cultivated as ornamentals in Europe .
Grindeliae herba is traditionally used as an adjuvant for treatment of
catarrhs of the upper respiratory tract, and as an antispasmodic and
expectorant . Indigenous peoples of the Americas traditionally
used buds of Grindelia species in the treatment of asthma
and bronchitis. Grindeliae herba, derived from G. squarrosa and
G. robusta, was included in the US Pharmacopoeia in 1893 and
later in the German and French Pharmacopoeias . The ESCOP
Monographs also added G. humilis Hook. et Arn. and G. camporum
Greene to the definition of Grindeliae herba .
The essential oil, accumulated in the aerial parts, has a proposed
role in the beneficial effects of the herb, with α-pinene, β-pinene
and limonene as the main compounds. Three studies have been
conducted concerning the essential oil composition of G. squarrosa,
all of them using plant material from Germany [3-5]. On the other
hand, the chemical constituents of the essential oil from G. hirsutula
(syn. G. humilis) was evaluated earlier only once, using plant
material from Egypt .
In our study, the essential oil compositions of G. squarrosa and
G. hirsutula, cultivated in Targu Mures in Romania, were
examined. The essential oil contents of the herbs were relatively
low (0.1%). The compositions of the essential oils were
determined by GC-FID and GC-MS techniques. Table 1 presents
the results of the qualitative and quantitative analyses.
The fifty-six identified constituents accounted for 72.1-81.3% of the
oils. These oils contained α-pinene, β-pinene, limonene, borneol,
bornyl acetate and germacrene D as main constituents. The oils
showed small differences in chemical composition. However,
menthol, menthone and pulegone were detected only in the essential
oil of G. hirsutula.
Compared with literature data, there were substantial differences in
the essential oil composition of G. hirsutula cultivated in Egypt and
Romania. In our study, the limonene content was considerably
higher than in the previously published assessment (7.0% vs 0.2%).
The spathulenol (5.5% vs 0.7%) and borneol (3.3% vs 0.2%)
contents were also substantially higher, while the germacrene D
(4.2% vs 11.9%) yield was lower than expected, and (2E,8E)-
tridecadiene-4,6-diin-10-ol was absent despite the high ratio
(10.5%) reported by El-Shamy et al. .
The α-pinene content (8.3% vs 16.1-35.5%) in G. squarrosa was
considerably lower, but the bornyl acetate level (10.8% vs 0.2-
1.4%) was more than nine times higher than reported earlier. The
spathulenol content (5.4% vs tr-0.2%) also exceeded the previously
published ratio [3-5].
Our study underlines the importance of geographical parameters in
the composition of herbal essential oils.
Plant material: The plant material was gathered from the perennial
populations of G. squarrosa and G. hirsutula cultivated in Targu
Mures, Romania. The aerial parts of the plants were collected
during the flowering stage in July 2010. The comminuted plant
materials were stored at room temperature until processing.
Voucher specimens (No. 820 and No. 821) have been deposited at
the Department of Pharmacognosy (Faculty of Pharmacy,
University of Szeged).
Isolation of the essential oil: The dried flowering shoots were cut
and hydrodistilled for 2 h, according to the method in the European
Pharmacopoeia 6.0 . The obtained essential oils were dried over
anhydrous sodium sulfate, filtered and stored at –18ºC until tested
and analyzed. The yields were calculated based on the dry weight of
the plant materials.
NPC Natural Product Communications 2014
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2 Natural Product Communications Vol. 9 (0) 2014 Veres et al.
Table 1: Chemical composition of essential oils from herbs of two Grindelia species.
Compoundsa RIb % in samples Identification
G. squarrosa G. hirsutula
E-Salvene 876 0.3 0.3 c
α-Thujene 924 0.2 0.2 c
α-Pinene 938 8.3 .6.2 c, d
Camphene 956 1.9 0.9 c
Thuja-2,4(10)-diene 960 0.9 0.5 c
β-Pinene 985 1.5 2.3 c, d
Myrcene 992 1.6 1.8 c
p-Cymene 1027 0.5 0.4 c
Limonene 1035 8.1 7.0 c, d
1,8-Cineol 1040 - 0.2 c, d
2,2,6-Trimethylcyclohexanone 1045 1.1 1.2 c
cis-Ocimene 1046 - tr c
Benzene acetaldehyde 1058 0.4 0.4 c
trans-Ocimene 1060 tr tr c
3-Methyl-2-cyclohexen-1-on 1061 tr tr c
cis-Vertocitral C 1090 tr tr c
p-Cymenene 1101 tr tr c
Perillene 1113 tr tr c
α-Campholenal 1139 1.2 0.7 c
cis-p-Mentha-2,8-dien-1-ol 1148 tr tr c
trans-Pinocarveol 1153 0.8 0.4 c
trans-Sabinol 1157 3.6 1.8 c
Camphor 1159 0.4 0.3 c, d
Menthon 1168 - 2.7 c
Borneol 1186 3.5 3.3 c, d
Menthol 1190 - 1.7 c, d
p-Methyl-acetophanone 1203 0.5 0.4 c
Myrtenal 1212 1.6 1.0 c
Verbenone 1224 2.8 0.9 c
trans-Carveol 1233 1.0 0.7 c
Pulegone 1253 - 2.1 c
Carvone 1260 0.7 0.6 c, d
trans-Chrysanthenyl acetate 1264 1.8 0.5 c
Bornyl acetate 1293 10.8 3.6 c
trans-Sabinyl acetate 1308 tr tr c
α-Ylangene 1378 tr tr c
α-Copaene 1382 tr tr c
Modheph-2-ene 1389 tr 0.4 c
Methyl eugenol 1419 0.3 0.3 c
β-Caryophyllene 1427 1.1 1.2 c, d
trans-α-Ionone 1447 0.3 0.4 c
cis-β-Farnesene 1453 0.3 0.7 c
α-Humulene 1464 0.5 0.6 c
cis-Thujopsadiene 1477 0.3 0.4 c
-Muurolene 1484 0.2 0.3 c
ar-Curcumene 1490 tr tr c
Germacrene D 1494 2.4 4.2 c
Compoundsa RIb % in samples Identification
G. squarrosa G. hirsutula
β-Selinene 1498 1.1 0.9 c
10,11-Epoxy-calamenene 1524 3.6 4.1 c
Dihydro agarofuran 1542 0.6 0.8 c
Germacrene B 1570 1.6 1.8 c
Spathulenol 1592 5.4 5.5 c, d
Caryophyllene oxide 1597 4.9 3.4 c, d
Salvia-4(14)-en-1-one 1608 0.7 0.9 c
Humulene epoxide II 1627 2.2 1.9 c
Muurola-4,10(14)-dien-1-β-ol 1645 2.3 2.2 c
Identified components 81.3 72.1
aCompounds listed in sequence of elution from a CB-5 MS column.
bRetention indices calculated against C9 to C24 n-alkanes on a DB-5 MS column.
cComparison of mass spectra with MS libraries and retention indices.
dComparison with authentic compound
Gas chromatography: The GC-FID analysis was carried out with
an HP 5890 Series II gas chromatograph (FID), using a 30 m × 0.35
mm × 0.25 µm HP-5 fused silica capillary column. The temperature
program was from 60°C to 210°C at 3°C min-1, and from 210°C to
250°C (2 min hold) at 5°C min-1. The detector and injector
temperature was 250°C and the carrier gas was N2, with split
Gas chromatography-mass spectrometry: GC-MS analysis was
performed with a FINNIGAN GCQ ion trap bench-top mass
spectrometer. All conditions were as above except that the carrier
gas was He at a linear velocity of 31.9 cm.s-1 and the capillary
column was a DB-5MS (30 m × 0.25 mm × 0.25 µm). The positive
ion electron ionization mode was used, with a mass range of 40-400
Compounds identification: Identification of the compounds was
based on comparisons with published MS data  and a computer
library search (the database was delivered together with the
instrument), and also by comparison of their retention indices with
those of authentic compounds (Extrasynthese, Genay, France) and
with literature values. Retention indices were calculated mainly
from the GC-MS analysis results .
Acknowledgments - This study was supported by the European
Union and co-funded by the European Social Fund (TÁMOP-
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