The GC-MS analysis revealed the presence of 35 compounds in the essential oil of
C. ladanifer (
Figure 1). These compounds were divided into oxygenated sesquiterpenes (34.02%), oxygenated monoterpenes (33.14%), linear esters (10.38%), monoterpenes (9.11%), and sesquiterpenes (4.29%). The major constituents present in this EO were viridiflorol (17.64%),
trans-pinocarveol (11.02%), bornylacetate (9.38%), and ledol (8.85%) (
Table 2). The percentage of these constituents is higher than those found by Boukil et al. (oxygenated hydrocarbons (13.27%), oxygenated sesquiterpenes (2.57%), and monoterpenic ester (5.86%))
[19]. The same authors found that the main components from the fresh leaves of
C. ladanifer were verticiol (18.16%), camphene (17.70%),
n-butylcyclohexane (5.95%), and 3-carene (5.23%)
[19]. These findings indicate that the time of harvest has a significant impact on the chemical composition obtained. The results of various chemical analysis studies on
C. ladanifer essential oil carried out previously showed that the main constituents of
C. ladanifer leaf essential oil from Northern Morocco were viridiflorol (19.6%), bornyl acetate (16.7%), and camphene (12.3%)
[30]. Zidane et al. characterized
C. ladanifer from Eastern Morocco and indicated the presence of camphene (15.5%), borneol (11.1%), 2,2,6-trimethylcyclohexanol (7.3%), 4-terpineol (6.3%), and α-pinene (4.2%) as the major compounds in the essential oil of this plant
[29]. In Algeria, it was found that the main constituents of this oil were 5,7-di-
epi-α-eudesmol (13.6%), borneol (12.5%), camphene (12.2%), δ-cadinene (7.6%), α-eudesmol (6.4%)%), 4-terpineol (5.7%) and α-pinene (4.2%)
[28]. In France, Verdeguer et al. characterized the chemical composition of the oil extracted from the leaves and stems of
C. ladanifer of Spanish origin but cultivated in Corsica by the presence of pinene (39%), viridiflorol (11.8%), ledol (3.3%) and bornyl acetate (3.1%)
[33]. In Portugal, the chemical composition of
C. ladanifer oil shows the presence of three sesquiterpenes alcohols, viridiflorol (13.6–17.4%), globulol (3.1–5.0%), and an unknown alcohol sesquiterpene (2.7–6.0%), as well as diterpene alcohol 15-
nor-labdan-8-ol (1.7–5.2%)
[34]. In Spain, the composition of the essential oil of
C. ladanifer cultivated in central Spain, revealed its richness in oxygenated compounds, with
trans-pinocarveol (20.00%), bornyl acetate (7.03%), and terpinen-4-ol (6.37%) as the main monoterpene compounds. Viridiflorol (13.59%) and ledol (4.36%) were the main constituents of the oxygenated sesquiterpene fraction. Large amounts of α-pinene (4.70%) were found in the hydrocarbon fractions. From this comparison, it seems that Moroccan
C. ladanifer essential oil composition is closer to that of Corsica with Spanish origin. The chemical composition of
C. ladanifer essential oil varies considerably depending on the source, plant material, and extraction method. As a result, based on the intended product during the exploitation of the species, a selection of organs, vegetative stage, and area proves to be extremely helpful in promoting the acquisition of very accurate chemotypes.
Figure 1. GC Chromatogram of the essential oil of C. ladanifer.
Table 2. The compounds identified in the essential oil of C. ladanifer after analysis by GC/MS on column DB-5.
No. |
Compounds |
Formulas |
Percentage |
IK Calculated |
IK (ADAMS) |
1 |
α-Pinene |
C | 10 | H | 16 |
2.43 |
922 |
939 |
2 |
TIC 75 μg |
R |
CIP 5 μg |
S |
p | -Cymene |
CEF 30 μg |
R | C | 10 | H | 14 |
6.11 |
1004 |
1024 |
VAN 30 μg |
S |
3 |
( | Z | )-vertocitral C |
C | 9 | H | 14 | O |
0.63 |
1028 |
1080 |
4 |
p | -Cymenene |
C | 10 | H | 14 |
demonstrated full resistance to the tested antibiotics, it demonstrated an inhibition diameter of 35 ± 0.27 when the EO was used, indicating a good and promising effect. Our results are superior to those found by Benayad et al. (
S. aureus (28 mm),
A. Baumannii (24 mm), and
E. coli (18 mm)) (plant harvested in May)
[11]. Same note for results obtained by Boukil et al. (
S. aureus (14 mm), and
E. coli (9 mm)) (plant harvested in August)
[19]. As an outcome, harvesting the plant at the flowering stage is correlated to a potent antibacterial power.
Figure 2. Bacterial strain growth inhibition zone of C. ladanifer essential oil.
Table 4. Diameter of the inhibition zone of C. ladanifer essential oil against the four pathogenic strains.
|
S. aureus |
E. coli |
A. baumannii |
S. Typhi |
C. ladanifer | 5 μL (EO) |
55 ± 0.22 |
42 ± 0.11 |
35 ± 0.27 |
30 ± 0.25 |
0.57 |
1065 |
1091 |
5 |
α-Campholenal |
C | 10 | H | 16 | O |
1.34 |
1093 |
1126 |