# Chemical Composition, Antioxidant Potential, and Antibacterial Activity of Essential Oil Cones of TunisianCupressus sempervirens

Authors: Aicha Ben Nouri; Wissal Dhifi; Sana Bellili; Hanene Ghazghazi; Chedia Aouadhi; Ameur Chérif; Mohamed Hammami; Wissem Mnif
Journal: Journal of Chemistry
 (2015)

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## Abstract

The extraction yield of the essential oil (EO) extracted by hydrodistillation from the cones of TunisianCupressus sempervirens L. was of 0.518%. The chemical composition was analyzed by GC-MS. Results showed that this essential oil was mainly composed of monoterpene hydrocarbons (65%) with α-pinene as the major constituent (47.51%). Its antioxidant activity was ascertained by evaluating the total antioxidant capacity and also by evaluating its inhibitory effect against DPPH and ABTS radicals. In addition, it showed a strong antioxidant power against the DPPH (IC50 = 151 µg/mL) and ABTS (IC50 = 176.454 µg/mL) radicals scavenging. Moreover, its antibacterial activity was tested against different species of pathogenic bacteria (three Gram-positive and eight Gram-negative bacteria). The bacterial strains susceptible to the evaluated oil were Bacillus subtilis, Escherichia coli, Klebsiella oxytoca, Morganella morganii, Shigella, and Vibrio cholerae.


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## Body

## 1. Introduction

Cupressus (Cupressaceae), comprising twelve species, is distributed in North America, the Mediterranean region, and subtropical Asia at high altitudes [1]. The geographic area ofCupressus genus is limited to the northern hemisphere and many species have been studied [2, 3]. In Tunisia, only one species of the genusCupressus,Cupressus sempervirens L. [4], was native.Cupressus sempervirens L. is a medicinal plant. The dried leaves of this plant are used as an emmenagogue and for stomach pain [5] as well as for diabetes [6]. Its dried fruit plant is used for inflammation treatment [7], toothache, and laryngitis [8] and also as a contraceptive [9], astringent, and antiphrastic drug [10]. The dried seed of this tree has been used for wounds, ulcers, bruises, sores, pimples, pustules, skin eruptions, and erysipelas [11].Cupressus sempervirens essential oil is used externally for headache, colds, cough, and bronchitis [12].Studies on phytochemical compounds ofCupressus sempervirens L. revealed that it contains active constituents such as flavonoids (cupressuflavone, amentoflavone, rutin, quercitrin, quercetin, and myricitrin), phenolic compounds (anthocyanidin, catechins flavones, flavonols and isoflavones, tannins, and catechol), and essential oils (EO) [13, 14]. It has been demonstrated that principals active fromCupressus sempervirens L. display antiseptic, aromatherapeutic, astringent, balsamic, and anti-inflammatory activities [15].Cupressus sempervirens L. antimicrobial activity has been reported in several studies [14, 16].Even studies have focused on chemistry and biological activities ofCupressus sempervirens L. leaves originating from different areas in the world [14, 16, 17]; there is no report concerning this species (cones) in Tunisia. The aim of this study is to ascertain the chemical composition of the EO of TunisianCupressus sempervirens L. cones and to evaluate its antioxidant and antibacterial activities.


## 2. Materials and Methods

### 2.1. Plant Material

Cones (the aerial parts) ofCupressus sempervirens L. were collected from Sidi Thabet (North of Tunisia) in March 2014. The botanical identification was achieved by Pr. Mohammed Chaeib from the Faculty of Sciences of Sfax-Tunisia. Female cones were dried at room temperature for 7 days and used for analyses. Voucher specimens of the plants were deposited in the Herbarium of this laboratory.


### 2.2. Extraction of the Essential Oil

Cupressus sempervirens cones were dried at room temperature. After that, 100 g of dry matter was used for essential oil extraction by hydrodistillation in a Clevenger apparatus for four hours. The resulting essential oil recovered is dried by anhydrous sodium sulphate and then stored at 4°C for further analysis.


### 2.3. Analysis of the Essential Oil

Cupressus sempervirens L. essential oil composition was investigated by GC and GC/MS. The analytical GC was carried out on an HP5890-series II gas chromatograph (Agilent Technologies, California, USA) equipped with Flame Ionization Detectors (FID) under the following conditions: the fused silica capillary column, apolar HP-5, and polar HP Innowax (30 m × 0.25 mm ID, film thickness of 0.25 mm). The oven temperature was held at 50°C for 1 min, then programmed at rate of 5°C/min to 240°C, and held isothermal for 4 min. The carrier gas was nitrogen at a flow rate of 1.2 mL/min; injector temperature: 250°C; detector: 280°C; the volume injected: 0.1 mL of 1% solution (diluted in hexane). The percentages of the constituents were calculated by electronic integration of FID peak areas without the use of response factor correction. GC/MS was performed in a Hewlett-Packard 5972 MSD System. An HP-5 MS capillary column (30 m × 0.25 mm ID, film thickness of 0.25 mm) was directly coupled to the mass spectrometry. The carrier gas was helium, with a flow rate of 1.2 mL/min. Oven temperature was programmed (50°C for 1 min, then 50–240°C at 5°C/min) and subsequently held isothermal for 4 min; injector port: 250°C; detector: 280°C; split ratio: 1 : 50; volume injected: 0.1 mL of 1% solution (diluted in hexane); mass spectrometer: HP5972 recording at 70 ev scan time: 1.5 s; mass range: 40–300 amu. Software adopted to handle mass spectra and chromatograms was ChemStation. The identification of the compounds was based on mass spectra (compared with Wiley 275.L, 6th edition mass spectral library). Further confirmation was done from Retention Index data generated from a series of alkanes retention indices (relative to C9–C28 on the HP-5 and HP-20M columns) [18].


### 2.4. Antioxidant Activities

#### 2.4.1. Evaluation of Total Antioxidant Capacity

The total antioxidant capacity is based on the reduction of Mo (VI) to Mo (V) by the oil and the formation of a phosphate subsequent green/Mo (V) complex at acid pH [19]. In a reaction volume of 1 mL was added to different concentrations of tested oil and standard sulfuric acid (0.6 M), sodium phosphate (28 mM), and ammonium molybdate (4 mM). The solutions were then incubated in a water bath at 95°C for 1 hour. After cooling to room temperature, the optical density is measured at 695 nm. Each fraction was analyzed in triplicate.


#### 2.4.2. DPPH Radical-Scavenging Activity

The ability of our essential oil to reduce the DPPH was measured according to the method described by Tuberoso [20]. For each concentration, one milliliter was added to 0.25 mL of ethanolic solution of DPPH. The mixture was stirred vigorously and then incubated at room temperature for 30 min in the dark. The absorbance illustrating the power of the extract to reduce the free radical DPPH to the yellow-colored diphenylpicrylhydrazine was measured at 520 nm. So, antiradical activity is expressed as IC50 (μg mL−1), the extract dose required to induce a 50% inhibition. The ability to scavenge the DPPH radical was calculated using the following equation: DPPH scavenging effect = [(A0-A1)/A0]×100, where A0 and A1 were the absorbance of the control and the sample after 30 min, respectively. Each experiment was analyzed in triplicate.


#### 2.4.3. ABTS Assay

For ABTS assay, we used the method described by Hayouni et al. [21]. The stock solutions included 7 mM ABTS∙+ and 2.45 mM potassium persulfate solution. The working solution was then prepared by mixing the two stock solutions in equal quantities and allowing them to react for 12 h at room temperature in the dark. The solution was then diluted by mixing 1 mL ABTS∙+ solution with 50 mL methanol to obtain an absorbance of 0.7±0.02 units at 734 nm using the spectrophotometer 6305 UV-VIS. Fresh ABTS∙+ solution was prepared for each assay. 50 μL of each concentration of the essential oil is added with 950 μL of ABTS∙+ solution, allowed to react in the dark and then we follow the kinetics of this mixture every 5 min for 30 min. Then the absorbance was measured at 734 nm. Antiradical activity is expressed as IC50 (μg mL−1), the extract dose required to induce a 50% inhibition. A low IC50 value corresponds to a high antioxidant activity of plant extract. Results are expressed in μg Trolox equivalents (TE)/mg dry mass. The percentage inhibition of the ABTS cation radical by the samples was calculated according to the following formula: Inhibition percentage (% inhibition) =(A0-At)/(A0×100), where A0 is absorbance of control sample (t=0h) and At is absorbance of a tested sample in 5 or 30 min.


### 2.5. Antimicrobial Activities

#### 2.5.1. Microorganisms

The tested microorganisms include Gram-positive bacteria,Staphylococcus aureus ATCC 29213,Bacillus subtilis ATCC 6633, andBacillus cereus ATCC 11778, and Gram-negative bacteria:Escherichia coli ATCC 8739,Klebsiella oxytoca CECT 8207,Salmonella salamae ATCC43972,Salmonella typhi ATCC 25241,Morganella morganii ATCC 25830,Salmonella anatum ATCC9270,Vibrio cholerae CECT 8265, andShigella ATCC 29930.


#### 2.5.2. Disk-Diffusion Assay

Antibacterial activity was evaluated using the method described by Choi et al. (2006) [22]. The principle of this method is to use Whatman paper discs of 6 mm in diameter. The discs were impregnated with essential oil diluted in hexane. A disc soaked in hexane was used as negative control. These discs are then deposited on the surface of a middle swab with a bacterial suspension to an optical density of 0.5 McFarlend standard. We used the bacterial strains for the culture medium Muller-Hinton. At the end of the incubation, 24 hours at 37°C, the diameters of the zone of inhibition were measured.


#### 2.5.3. Minimum Inhibitory Concentration

A broth microdilution was used to determine the minimum inhibitory concentration (MIC). The tests were performed in Muller-Hinton Broth. The essential oil was dissolved in Tween 80. A serial doubling of tested oil was prepared in a 96-well microtiter plate over the range 78μg/mL–1 mg/mL. In each well containing a concentration was added 100 μL of bacterial suspension of 10 6 (0.5 MacFarlen standard). We incubated plates overnight at 37°C and then measured the optical density at 620 nm.


## 2.1. Plant Material

Cones (the aerial parts) ofCupressus sempervirens L. were collected from Sidi Thabet (North of Tunisia) in March 2014. The botanical identification was achieved by Pr. Mohammed Chaeib from the Faculty of Sciences of Sfax-Tunisia. Female cones were dried at room temperature for 7 days and used for analyses. Voucher specimens of the plants were deposited in the Herbarium of this laboratory.


## 2.2. Extraction of the Essential Oil

Cupressus sempervirens cones were dried at room temperature. After that, 100 g of dry matter was used for essential oil extraction by hydrodistillation in a Clevenger apparatus for four hours. The resulting essential oil recovered is dried by anhydrous sodium sulphate and then stored at 4°C for further analysis.


## 2.3. Analysis of the Essential Oil

Cupressus sempervirens L. essential oil composition was investigated by GC and GC/MS. The analytical GC was carried out on an HP5890-series II gas chromatograph (Agilent Technologies, California, USA) equipped with Flame Ionization Detectors (FID) under the following conditions: the fused silica capillary column, apolar HP-5, and polar HP Innowax (30 m × 0.25 mm ID, film thickness of 0.25 mm). The oven temperature was held at 50°C for 1 min, then programmed at rate of 5°C/min to 240°C, and held isothermal for 4 min. The carrier gas was nitrogen at a flow rate of 1.2 mL/min; injector temperature: 250°C; detector: 280°C; the volume injected: 0.1 mL of 1% solution (diluted in hexane). The percentages of the constituents were calculated by electronic integration of FID peak areas without the use of response factor correction. GC/MS was performed in a Hewlett-Packard 5972 MSD System. An HP-5 MS capillary column (30 m × 0.25 mm ID, film thickness of 0.25 mm) was directly coupled to the mass spectrometry. The carrier gas was helium, with a flow rate of 1.2 mL/min. Oven temperature was programmed (50°C for 1 min, then 50–240°C at 5°C/min) and subsequently held isothermal for 4 min; injector port: 250°C; detector: 280°C; split ratio: 1 : 50; volume injected: 0.1 mL of 1% solution (diluted in hexane); mass spectrometer: HP5972 recording at 70 ev scan time: 1.5 s; mass range: 40–300 amu. Software adopted to handle mass spectra and chromatograms was ChemStation. The identification of the compounds was based on mass spectra (compared with Wiley 275.L, 6th edition mass spectral library). Further confirmation was done from Retention Index data generated from a series of alkanes retention indices (relative to C9–C28 on the HP-5 and HP-20M columns) [18].


## 2.4. Antioxidant Activities

### 2.4.1. Evaluation of Total Antioxidant Capacity

The total antioxidant capacity is based on the reduction of Mo (VI) to Mo (V) by the oil and the formation of a phosphate subsequent green/Mo (V) complex at acid pH [19]. In a reaction volume of 1 mL was added to different concentrations of tested oil and standard sulfuric acid (0.6 M), sodium phosphate (28 mM), and ammonium molybdate (4 mM). The solutions were then incubated in a water bath at 95°C for 1 hour. After cooling to room temperature, the optical density is measured at 695 nm. Each fraction was analyzed in triplicate.


### 2.4.2. DPPH Radical-Scavenging Activity

The ability of our essential oil to reduce the DPPH was measured according to the method described by Tuberoso [20]. For each concentration, one milliliter was added to 0.25 mL of ethanolic solution of DPPH. The mixture was stirred vigorously and then incubated at room temperature for 30 min in the dark. The absorbance illustrating the power of the extract to reduce the free radical DPPH to the yellow-colored diphenylpicrylhydrazine was measured at 520 nm. So, antiradical activity is expressed as IC50 (μg mL−1), the extract dose required to induce a 50% inhibition. The ability to scavenge the DPPH radical was calculated using the following equation: DPPH scavenging effect = [(A0-A1)/A0]×100, where A0 and A1 were the absorbance of the control and the sample after 30 min, respectively. Each experiment was analyzed in triplicate.


### 2.4.3. ABTS Assay

For ABTS assay, we used the method described by Hayouni et al. [21]. The stock solutions included 7 mM ABTS∙+ and 2.45 mM potassium persulfate solution. The working solution was then prepared by mixing the two stock solutions in equal quantities and allowing them to react for 12 h at room temperature in the dark. The solution was then diluted by mixing 1 mL ABTS∙+ solution with 50 mL methanol to obtain an absorbance of 0.7±0.02 units at 734 nm using the spectrophotometer 6305 UV-VIS. Fresh ABTS∙+ solution was prepared for each assay. 50 μL of each concentration of the essential oil is added with 950 μL of ABTS∙+ solution, allowed to react in the dark and then we follow the kinetics of this mixture every 5 min for 30 min. Then the absorbance was measured at 734 nm. Antiradical activity is expressed as IC50 (μg mL−1), the extract dose required to induce a 50% inhibition. A low IC50 value corresponds to a high antioxidant activity of plant extract. Results are expressed in μg Trolox equivalents (TE)/mg dry mass. The percentage inhibition of the ABTS cation radical by the samples was calculated according to the following formula: Inhibition percentage (% inhibition) =(A0-At)/(A0×100), where A0 is absorbance of control sample (t=0h) and At is absorbance of a tested sample in 5 or 30 min.


## 2.4.1. Evaluation of Total Antioxidant Capacity

The total antioxidant capacity is based on the reduction of Mo (VI) to Mo (V) by the oil and the formation of a phosphate subsequent green/Mo (V) complex at acid pH [19]. In a reaction volume of 1 mL was added to different concentrations of tested oil and standard sulfuric acid (0.6 M), sodium phosphate (28 mM), and ammonium molybdate (4 mM). The solutions were then incubated in a water bath at 95°C for 1 hour. After cooling to room temperature, the optical density is measured at 695 nm. Each fraction was analyzed in triplicate.


## 2.4.2. DPPH Radical-Scavenging Activity

The ability of our essential oil to reduce the DPPH was measured according to the method described by Tuberoso [20]. For each concentration, one milliliter was added to 0.25 mL of ethanolic solution of DPPH. The mixture was stirred vigorously and then incubated at room temperature for 30 min in the dark. The absorbance illustrating the power of the extract to reduce the free radical DPPH to the yellow-colored diphenylpicrylhydrazine was measured at 520 nm. So, antiradical activity is expressed as IC50 (μg mL−1), the extract dose required to induce a 50% inhibition. The ability to scavenge the DPPH radical was calculated using the following equation: DPPH scavenging effect = [(A0-A1)/A0]×100, where A0 and A1 were the absorbance of the control and the sample after 30 min, respectively. Each experiment was analyzed in triplicate.


## 2.4.3. ABTS Assay

For ABTS assay, we used the method described by Hayouni et al. [21]. The stock solutions included 7 mM ABTS∙+ and 2.45 mM potassium persulfate solution. The working solution was then prepared by mixing the two stock solutions in equal quantities and allowing them to react for 12 h at room temperature in the dark. The solution was then diluted by mixing 1 mL ABTS∙+ solution with 50 mL methanol to obtain an absorbance of 0.7±0.02 units at 734 nm using the spectrophotometer 6305 UV-VIS. Fresh ABTS∙+ solution was prepared for each assay. 50 μL of each concentration of the essential oil is added with 950 μL of ABTS∙+ solution, allowed to react in the dark and then we follow the kinetics of this mixture every 5 min for 30 min. Then the absorbance was measured at 734 nm. Antiradical activity is expressed as IC50 (μg mL−1), the extract dose required to induce a 50% inhibition. A low IC50 value corresponds to a high antioxidant activity of plant extract. Results are expressed in μg Trolox equivalents (TE)/mg dry mass. The percentage inhibition of the ABTS cation radical by the samples was calculated according to the following formula: Inhibition percentage (% inhibition) =(A0-At)/(A0×100), where A0 is absorbance of control sample (t=0h) and At is absorbance of a tested sample in 5 or 30 min.


## 2.5. Antimicrobial Activities

### 2.5.1. Microorganisms

The tested microorganisms include Gram-positive bacteria,Staphylococcus aureus ATCC 29213,Bacillus subtilis ATCC 6633, andBacillus cereus ATCC 11778, and Gram-negative bacteria:Escherichia coli ATCC 8739,Klebsiella oxytoca CECT 8207,Salmonella salamae ATCC43972,Salmonella typhi ATCC 25241,Morganella morganii ATCC 25830,Salmonella anatum ATCC9270,Vibrio cholerae CECT 8265, andShigella ATCC 29930.


### 2.5.2. Disk-Diffusion Assay

Antibacterial activity was evaluated using the method described by Choi et al. (2006) [22]. The principle of this method is to use Whatman paper discs of 6 mm in diameter. The discs were impregnated with essential oil diluted in hexane. A disc soaked in hexane was used as negative control. These discs are then deposited on the surface of a middle swab with a bacterial suspension to an optical density of 0.5 McFarlend standard. We used the bacterial strains for the culture medium Muller-Hinton. At the end of the incubation, 24 hours at 37°C, the diameters of the zone of inhibition were measured.


### 2.5.3. Minimum Inhibitory Concentration

A broth microdilution was used to determine the minimum inhibitory concentration (MIC). The tests were performed in Muller-Hinton Broth. The essential oil was dissolved in Tween 80. A serial doubling of tested oil was prepared in a 96-well microtiter plate over the range 78μg/mL–1 mg/mL. In each well containing a concentration was added 100 μL of bacterial suspension of 10 6 (0.5 MacFarlen standard). We incubated plates overnight at 37°C and then measured the optical density at 620 nm.


## 2.5.1. Microorganisms

The tested microorganisms include Gram-positive bacteria,Staphylococcus aureus ATCC 29213,Bacillus subtilis ATCC 6633, andBacillus cereus ATCC 11778, and Gram-negative bacteria:Escherichia coli ATCC 8739,Klebsiella oxytoca CECT 8207,Salmonella salamae ATCC43972,Salmonella typhi ATCC 25241,Morganella morganii ATCC 25830,Salmonella anatum ATCC9270,Vibrio cholerae CECT 8265, andShigella ATCC 29930.


## 2.5.2. Disk-Diffusion Assay

Antibacterial activity was evaluated using the method described by Choi et al. (2006) [22]. The principle of this method is to use Whatman paper discs of 6 mm in diameter. The discs were impregnated with essential oil diluted in hexane. A disc soaked in hexane was used as negative control. These discs are then deposited on the surface of a middle swab with a bacterial suspension to an optical density of 0.5 McFarlend standard. We used the bacterial strains for the culture medium Muller-Hinton. At the end of the incubation, 24 hours at 37°C, the diameters of the zone of inhibition were measured.


## 2.5.3. Minimum Inhibitory Concentration

A broth microdilution was used to determine the minimum inhibitory concentration (MIC). The tests were performed in Muller-Hinton Broth. The essential oil was dissolved in Tween 80. A serial doubling of tested oil was prepared in a 96-well microtiter plate over the range 78μg/mL–1 mg/mL. In each well containing a concentration was added 100 μL of bacterial suspension of 10 6 (0.5 MacFarlen standard). We incubated plates overnight at 37°C and then measured the optical density at 620 nm.


## 3. Results and Discussion

### 3.1. Chemical Composition

The extraction yield of the EO from the cones of TunisianCupressus sempervirens L. was of 0.518%. The coupling analysis of GC/MS and GC-FID/KI revealed 67 compounds (Figure 1). The major compound was α-pinene (47.51%). It was followed by δ-3-carene, α-terpinyl acetate, β-caryophyllene, and α-cedrol whose proportions were 7.40, 4.11, 4.53, and 4.99%, respectively (Table 1). These results are in accordance with those reported by Boukhris et al. (2012) [17] forCupressus sempervirens L. collected from the random gardens in Sfax, Tunisia, and characterized by α-pinene (37.14%), δ-3-carene (19.67%), limonene (5.43%), and α-terpinolene (4.69%) as the most abundant volatiles. Furthermore, Riahi et al. (2012) [23] reported a yield of 0.92% for TunisianCupressus sempervirens L. It is higher than that obtained for AlgerianC. sempervirens (0.26%) [14] and comparable to that of the Cameroon species (1%) [24].Table 1
Essential oil composition from cones ofCupressus sempervirens.
Number
Volatile compound
RIa
RIb
Amount (% of whole EO)
Methods of identification
1
Tricyclene
924
1015
0.14
MS, RI
2
α-Pinene
939
1032
47.51
MS, RI, Co-GLC
3
α-Fenchene
953
1044
0.74
MS, RI
4
Camphene
954
1076
0.15
MS, RI, Co-GLC
5
Sabinene
976
1132
0.6
MS, RI, Co-GLC
6
β-Pinene
980
1118
1.53
MS, RI, Co-GLC
7
β-Myrcene
994
1174
1.28
MS, RI, Co-GLC
8
δ-3-Carene
1011
1159
7.4
MS, RI, Co-GLC
9
α-Terpinene
1018
1188
0.11
MS, RI, Co-GLC
10
p-Cymene
1026
1280
0.2
MS, RI, Co-GLC
11
m-Cymene
1023
1278
1.12
MS, RI, Co-GLC
12
Limonene
1030
1203
1.75
MS, RI, Co-GLC
13
β-Phellandrene
1006
1176
0.13
MS, RI
14
(Z)-b-Ocimene
1040
1246
0.14
MS, RI
15
(E)-b-Ocimene
1050
1266
0.12
MS, RI
16
g-Terpinene
1062
1266
0.12
MS, RI, Co-GLC
17
α,p-Dimethylstyrene
1080
1452
0.15
MS, RI
18
Fenchone
1087
1406
0.13
MS, RI
19
Terpinolene
1088
1290
0.6
MS, RI, Co-GLC
20
Sabinol
1210
1800
0.24
MS, RI
21
Borneol
1165
1719
0.31
MS, RI
22
Terpinen-4-ol
1018
1188
0.97
MS, RI, Co-GLC
23
α-Terpineol
1189
1706
0.17
MS, RI, Co-GLC
24
Carvacrol, methyl ether
1244
1586
0.07
MS, RI, Co-GLC
25
Bornyl acetate
1295
1597
2.75
MS, RI
26
α-Terpinyl acetate
1350
1677
4.11
MS, RI
27
Terpinyl-4 acetate
1333
1709
0.39
MS, RI
28
δ-Elemene
1337
1479
0.24
MS, RI
29
α-Cubebene
1352
1468
0.93
MS, RI
30
α-Ylangene
1372
1493
0.9
MS, RI
31
α-Copaene
1376
1497
1.72
MS, RI, Co-GLC
32
β-Bourbonene
1385
1535
0.15
MS, RI
33
β-Elemene
1391
1600
0.12
MS, RI
34
Longifolene
1413
1575
0.2
MS, RI
35
β-Cubebene
1348
1456
0.69
MS, RI
36
α-Gurjunene
1408
1529
0.37
MS, RI
37
β-Caryophyllene
1415
1612
4.53
MS, RI
38
β-Gurjunene
1432
1612
0.2
MS, RI
39
α-Cedrene
1411
1568
0.14
MS, RI
40
Aromadendrene
1439
1628
0.29
MS, RI
41
α-Humulene
1454
1687
0.64
MS, RI, Co-GLC
42
Alloaromadendrene
1474
1661
0.54
MS, RI
43
Germacrene D
1480
1696
1.14
MS, RI, Co-GLC
44
α-Muurolene
1477
1704
0.15
MS, RI
45
δ-Cadinene
1517
1773
0.11
MS, RI
46
cis-Calamenene
1543
1837
0.16
MS, RI
47
Cadina-1,4-diene
1552
1768
0.12
MS, RI
48
β-Bisabolene
1508
1740
1.73
MS, RI
49
Spathulenol
1576
2144
0.21
MS, RI
50
α-Cedrol
1597
2021
4.99
MS, RI, Co-GLC
51
T-Cadinol
1642
2187
0.25
MS, RI
52
α-Acorenol
1630
2163
0.34
MS, RI
53
β-Acorenol
1637
2212
0.31
MS, RI
54
epi-α-Cadinol
1640
2170
0.11
MS, RI
55
α-Muurolol
1642
2209
0.73
MS, RI
56
β-Eudesmol
1650
2257
0.68
MS, RI
57
α-Eudesmol
1641
2216
0.17
MS, RI
58
α-Cadinol
1649
2255
0.55
MS, RI
59
Cadalene
1674
2200
0.09
MS, RI
60
Sandaracopimara-8(14),15-diene
1960
2255
0.04
MS, RI
61
Manoyl oxide
2010
2396
0.07
MS, RI
62
Isopimara-9-(11),15-diene
1906
2175
0.05
MS, RI
63
Abietadiene
2054
2530
0.05
MS, RI
64
Manool
1989
2376
0.38
MS, RI
65
Kaurene
2048
2399
0.13
MS, RI
66
Totarol
2280
2314
0.31
MS, RI
67
Ferruginol
2295
2330
0.23
MS, RI
Total  (%) 97.69
RI: Retention Index; MS: mass spectrometry; Co-GLC: coinjection.
%: percentage calculated by GC-FID on nonpolar HP-5 capillary column.
aApolar HP-5 MS column.
bPolar HP Innowax column.Figure 1
Essential oil chromatogram from cones ofCupressus sempervirens.The major components of TunisianCupressus sempervirens L. as reported by Riahi et al. (2012) [23] were α-terpinolene (24.44%), 3-carene (18.60%), α-limonene (11.61%), terpinen-4-ol (10.56%), β-myrcene (4.89%), camphor (4.62%), and β-linalool (4.23%). For essential oils of mostCupressus species, α-pinene and 3-carene were cited as the major compounds [25]. However in our sample α-pinene component is absent. Results by Tapondjou et al. (2005) revealed that the oil fromCupressus sempervirens L. in Cameroon mainly consists of α-pinene (9.9%), terpinen-4-ol (11.2%), and sabinene (14.8%).Moreover,α-pinene and γ-terpinene accounted, respectively, for 39.5 and 11.56% of the whole essential oil ofCupressus sempervirens L. cones originating from Greece [26]. The cone essential oil of EgyptianCupressus sempervirens L. showed antibacterial activity [27]. It is in contradiction with the results reported by Chéraif et al. (2005) [28]. Indeed, α-pinene is present in the essential oil ofCupressus sempervirens L. leaves at a low rate (20%) compared with that of cone essential oil. In addition, the proportion of δ-3-carene is important (22.9%) in the essential oil branches ofCupressus sempervirens L. by comparison with that of cones (7.40%). Limonene is of the order of 5.1% in the essential oils branches ofCupressus sempervirens L. Its rate is lower in cones essential oil (1.75%). The same results have been reported for α-terpinyl acetate whose rates were of 7.5% and 4.11%, respectively, in branches and cones. Furthermore, β-caryophllene was detected as trace in twigs whereas its rate was of 4.53% in cones. Among volatiles, α-terpinolene was present in the branches essential oil with an amount of 9.4%. However, it was absent in cones essential oil.Loukis et al. (1991) [26] reported that α-pinene and γ-terpinene accounted, respectively, for 39.5 and 11.56% of the whole essential oil ofCupressus sempervirens L. cones originating from Greece.Emami et al. (2004) [29] detected 42 compounds in the essential oil of conesCupressus sempervirens L. originating from Egypt. They reported a yield of 0.26% for leaves essential oil. Tognolini et al. (2006) [30] reported that the α-pinene is the major compound. This is the second monoterpene hydrocarbon predominant compound according to the results of Sacchetti et al. (2005) [31]. Furthermore, the most abundant volatile compounds in the essential oil of TurkishCupressus sempervirens L. are α-pinene and Δ-3-carene. Obviously, the composition of essential oils is significantly influenced by the organ. It is also influenced by many other factors including environmental factors such as rainfall, sunlight, soil, and climatic conditions and agronomic factors such as the date of harvest and the density of the culture.


### 3.2. Antioxidant Activities

Considering the many aspects of antioxidants and their reactivity, several tests are applied as antioxidants. Among them, the total antioxidant capacity, DPPH, and ABTS radicals scavenging tests are used to determine the antioxidant power of essential oil.The chemical complexity of essential oils, often a mixture of dozens of compounds with different functional groups, polarity, and antioxidant activity, may lead to scattered results, depending on the test employed [31].


#### 3.2.1. Total Antioxidant Capacity

The total antioxidant activity ofCupressus sempervirens L. is expressed as Trolox equivalent. The phosphomolybdenum method is based on the reduction of Mo (VI) with Mo (V) by the antioxidant compounds and the formation of a green phosphate/Mo complex (V). Our results showed that the antioxidant activity is proportional to the extract concentration (0.0434 μg ET/g DW) (Figure 2). Baykan Erel et al. (2012) [32] studied the antioxidant activity of essential oils of six species of Artemisia. It was noted that only essential oil ofArtemisia absinthium andArtemisia arborescens has a total antioxidant activity with values, respectively, in the order of 2.89 mg ET/g DW and 3.39 mg ET/g DW.Figure 2
Total antioxidant capacity from cones essential oil ofCupressus sempervirens.


#### 3.2.2. DPPH Radical-Scavenging Activity

Free radical-scavenging activities of the tested oil and positive control (Trolox) are presented in Figure3. In fact,Cupressus sempervirens L. essential oil remarkably reduced the concentration of DPPH free radical and transformed its stable, purple color into the yellow-colored DPPH-H with an efficiency IC50 = 151 μg/mL. The effect of antioxidant on DPPH radical scavenging was thought to be due to its hydrogen-donating ability. DPPH radical is a stable free radical and accepts an electron or hydrogen radical to become a stable diamagnetic molecule [33].Figure 3
Scavenging of DPPH radical from cones essential oil ofCupressus sempervirens.In two antioxidants screening studiesCupressus sempervirens L. was reported to display moderate radical-scavenging effect against DPPH [31, 34]. The leaf methanolic extract of EgyptianCupressus sempervirens L. had strong DPPH radical-scavenging activity as reported by Ibrahim et al. (2009) [35].Needless to say, potency of antioxidant activity of a substance is correlated with the applied method. In a study on some Iranian conifers the leaf and fruit MeOH extracts ofCupressus sempervirens L. were highly effective in ferric thiocyanate (FTC) and thiobarbituric acid (TBA) methods [36]. Nevertheless, activity of these extracts was also changeable according to the method.


#### 3.2.3. ABTS Assay

Essential oil ofCupressus sempervirens L. had an antioxidant according to the DPPH test. The results relative to ABTS radical cation scavenging confirmed the previous result. In fact, IC50 obtained at the end of this test is 176.454 μg/mL (Figure 4). Ghazghazi et al. (2010) [37] obtained, by studying the essential oil samples ofR. canina of Feija and Ain Draham (North of Tunisia) during the test of the ABTS, IC50 values of 159.0 μg/mL and 201.8 μg/mL, respectively. From these results we can conclude that the essential oil ofCupressus sempervirens L. has a strong antioxidant against ABTS cation. The antioxidant activity of essential oil could be assigned to the synergistic effects of two or more of its components. In this context, Lu and Foo (2001) [38] reported that most natural antioxidant compounds often work synergistically to produce a broad spectrum of antioxidant properties that create an effective defense system against free radicals.Cupressus sempervirens L. essential oil consists of a very complex mixture of various chemical classes (Table 1), which may produce either synergistic or antagonistic effects on the process of lipid oxidation [39].Figure 4
Scavenging of ABTS radical from cones essential oil ofCupressus sempervirens.


### 3.3. Antibacterial Activity

The antibacterial test allowed us to determine the sensitive strains to the essential oil ofCupressus sempervirens L. The screening of this activity was firstly determined by the disk-diffusion method on agar for predicting the inhibitory activity of the oil on the growth of a bacterial culture. Our results showed that the evaluated oil had significant antibacterial effect. In fact, among twelve tested strains, six were sensitive to this oil (Table 2). Gram-negative bacteria (Klebsiella oxytoca,Vibrio cholerae,Shigella, andE. coli) were the most sensitive strains with the MIC values that do not exceed 125 μg/mL of essential oil (Table 2). This finding was in agreement with other findings. For example, the cone EO of EgyptianCupressus sempervirens L. showed antibacterial activity [27]. Chéraif et al. (2005) [28] tested the antibacterial activity of essential oilCupressus sempervirens L. on Gram-positive and Gram-negative bacteria and found that this essential oil has a moderate activity against tested bacteria. It is important to mention that the activity was more pronounced for Gram-positive than Gram-negative bacteria. Similarly, Mazari et al. (2010) [14], when studying the biological activities of essential oils ofCupressus sempervirens L. andJuniperus phoenicea, reported that both oils constitute sources of antimicrobial agents. There are often large variations in the intensity of the antimicrobial activities against Gram-negative and Gram-positive bacteria.Table 2
Antibacterial activity from essential oil cones ofCupressus sempervirens.
Microorganisms
Concentration (mg/mL)
Negative control
1
0.5
0.25
0.125
0.0625
0.0312
0.0156
0.0078
Bacillus subtilis ATCC 6633
−
−
−
+
+
+
+
+
+
Escherichia coli ATCC 8739
−
−
−
−
+
+
+
+
+
Klebsiella oxytoca CECT 8207
−
−
−
−
+
+
+
+
+
Morganella morganii  ATCC 25830
−
−
+
+
+
+
+
+
+
Shigella ATCC 29930
−
−
−
−
+
+
+
+
+
Vibrio cholerae CECT 8265
−
−
−
−
−
+
+
+
+The EO ofCupressus sempervirens L. presented antibacterial activity against Gram-positive and Gram-negative bacteria, showing the biggest inhibition withB. subtilis andE. coli. Additionally, the cypress essential oil was found to have moderate antimicrobial activity when compared to vancomycin (30 mcg) and erythromycin (15 mcg) as antibiotics [40].The antibacterial activity could be affected by the solubility of the oil, the diffusion range in the agar and the evaporation [41, 42]. In addition, the antibacterial activities of the essential oils suggest their usefulness in the treatment of various infectious diseases caused by the tested bacteria.It is well known that Gram-negative bacteria are more resistant to essential oil compound antibacterial properties than Gram-positive bacteria because of hydrophobic lipopolysaccharide in the outer membrane which provides protection against different agents [43]; however, the obtained results indicated that the evaluated oil possesses selective antibacterial activity and its effect was pronounced against Gram-negative bacteria compared to Gram-positive ones.


## 3.1. Chemical Composition

The extraction yield of the EO from the cones of TunisianCupressus sempervirens L. was of 0.518%. The coupling analysis of GC/MS and GC-FID/KI revealed 67 compounds (Figure 1). The major compound was α-pinene (47.51%). It was followed by δ-3-carene, α-terpinyl acetate, β-caryophyllene, and α-cedrol whose proportions were 7.40, 4.11, 4.53, and 4.99%, respectively (Table 1). These results are in accordance with those reported by Boukhris et al. (2012) [17] forCupressus sempervirens L. collected from the random gardens in Sfax, Tunisia, and characterized by α-pinene (37.14%), δ-3-carene (19.67%), limonene (5.43%), and α-terpinolene (4.69%) as the most abundant volatiles. Furthermore, Riahi et al. (2012) [23] reported a yield of 0.92% for TunisianCupressus sempervirens L. It is higher than that obtained for AlgerianC. sempervirens (0.26%) [14] and comparable to that of the Cameroon species (1%) [24].Table 1
Essential oil composition from cones ofCupressus sempervirens.
Number
Volatile compound
RIa
RIb
Amount (% of whole EO)
Methods of identification
1
Tricyclene
924
1015
0.14
MS, RI
2
α-Pinene
939
1032
47.51
MS, RI, Co-GLC
3
α-Fenchene
953
1044
0.74
MS, RI
4
Camphene
954
1076
0.15
MS, RI, Co-GLC
5
Sabinene
976
1132
0.6
MS, RI, Co-GLC
6
β-Pinene
980
1118
1.53
MS, RI, Co-GLC
7
β-Myrcene
994
1174
1.28
MS, RI, Co-GLC
8
δ-3-Carene
1011
1159
7.4
MS, RI, Co-GLC
9
α-Terpinene
1018
1188
0.11
MS, RI, Co-GLC
10
p-Cymene
1026
1280
0.2
MS, RI, Co-GLC
11
m-Cymene
1023
1278
1.12
MS, RI, Co-GLC
12
Limonene
1030
1203
1.75
MS, RI, Co-GLC
13
β-Phellandrene
1006
1176
0.13
MS, RI
14
(Z)-b-Ocimene
1040
1246
0.14
MS, RI
15
(E)-b-Ocimene
1050
1266
0.12
MS, RI
16
g-Terpinene
1062
1266
0.12
MS, RI, Co-GLC
17
α,p-Dimethylstyrene
1080
1452
0.15
MS, RI
18
Fenchone
1087
1406
0.13
MS, RI
19
Terpinolene
1088
1290
0.6
MS, RI, Co-GLC
20
Sabinol
1210
1800
0.24
MS, RI
21
Borneol
1165
1719
0.31
MS, RI
22
Terpinen-4-ol
1018
1188
0.97
MS, RI, Co-GLC
23
α-Terpineol
1189
1706
0.17
MS, RI, Co-GLC
24
Carvacrol, methyl ether
1244
1586
0.07
MS, RI, Co-GLC
25
Bornyl acetate
1295
1597
2.75
MS, RI
26
α-Terpinyl acetate
1350
1677
4.11
MS, RI
27
Terpinyl-4 acetate
1333
1709
0.39
MS, RI
28
δ-Elemene
1337
1479
0.24
MS, RI
29
α-Cubebene
1352
1468
0.93
MS, RI
30
α-Ylangene
1372
1493
0.9
MS, RI
31
α-Copaene
1376
1497
1.72
MS, RI, Co-GLC
32
β-Bourbonene
1385
1535
0.15
MS, RI
33
β-Elemene
1391
1600
0.12
MS, RI
34
Longifolene
1413
1575
0.2
MS, RI
35
β-Cubebene
1348
1456
0.69
MS, RI
36
α-Gurjunene
1408
1529
0.37
MS, RI
37
β-Caryophyllene
1415
1612
4.53
MS, RI
38
β-Gurjunene
1432
1612
0.2
MS, RI
39
α-Cedrene
1411
1568
0.14
MS, RI
40
Aromadendrene
1439
1628
0.29
MS, RI
41
α-Humulene
1454
1687
0.64
MS, RI, Co-GLC
42
Alloaromadendrene
1474
1661
0.54
MS, RI
43
Germacrene D
1480
1696
1.14
MS, RI, Co-GLC
44
α-Muurolene
1477
1704
0.15
MS, RI
45
δ-Cadinene
1517
1773
0.11
MS, RI
46
cis-Calamenene
1543
1837
0.16
MS, RI
47
Cadina-1,4-diene
1552
1768
0.12
MS, RI
48
β-Bisabolene
1508
1740
1.73
MS, RI
49
Spathulenol
1576
2144
0.21
MS, RI
50
α-Cedrol
1597
2021
4.99
MS, RI, Co-GLC
51
T-Cadinol
1642
2187
0.25
MS, RI
52
α-Acorenol
1630
2163
0.34
MS, RI
53
β-Acorenol
1637
2212
0.31
MS, RI
54
epi-α-Cadinol
1640
2170
0.11
MS, RI
55
α-Muurolol
1642
2209
0.73
MS, RI
56
β-Eudesmol
1650
2257
0.68
MS, RI
57
α-Eudesmol
1641
2216
0.17
MS, RI
58
α-Cadinol
1649
2255
0.55
MS, RI
59
Cadalene
1674
2200
0.09
MS, RI
60
Sandaracopimara-8(14),15-diene
1960
2255
0.04
MS, RI
61
Manoyl oxide
2010
2396
0.07
MS, RI
62
Isopimara-9-(11),15-diene
1906
2175
0.05
MS, RI
63
Abietadiene
2054
2530
0.05
MS, RI
64
Manool
1989
2376
0.38
MS, RI
65
Kaurene
2048
2399
0.13
MS, RI
66
Totarol
2280
2314
0.31
MS, RI
67
Ferruginol
2295
2330
0.23
MS, RI
Total  (%) 97.69
RI: Retention Index; MS: mass spectrometry; Co-GLC: coinjection.
%: percentage calculated by GC-FID on nonpolar HP-5 capillary column.
aApolar HP-5 MS column.
bPolar HP Innowax column.Figure 1
Essential oil chromatogram from cones ofCupressus sempervirens.The major components of TunisianCupressus sempervirens L. as reported by Riahi et al. (2012) [23] were α-terpinolene (24.44%), 3-carene (18.60%), α-limonene (11.61%), terpinen-4-ol (10.56%), β-myrcene (4.89%), camphor (4.62%), and β-linalool (4.23%). For essential oils of mostCupressus species, α-pinene and 3-carene were cited as the major compounds [25]. However in our sample α-pinene component is absent. Results by Tapondjou et al. (2005) revealed that the oil fromCupressus sempervirens L. in Cameroon mainly consists of α-pinene (9.9%), terpinen-4-ol (11.2%), and sabinene (14.8%).Moreover,α-pinene and γ-terpinene accounted, respectively, for 39.5 and 11.56% of the whole essential oil ofCupressus sempervirens L. cones originating from Greece [26]. The cone essential oil of EgyptianCupressus sempervirens L. showed antibacterial activity [27]. It is in contradiction with the results reported by Chéraif et al. (2005) [28]. Indeed, α-pinene is present in the essential oil ofCupressus sempervirens L. leaves at a low rate (20%) compared with that of cone essential oil. In addition, the proportion of δ-3-carene is important (22.9%) in the essential oil branches ofCupressus sempervirens L. by comparison with that of cones (7.40%). Limonene is of the order of 5.1% in the essential oils branches ofCupressus sempervirens L. Its rate is lower in cones essential oil (1.75%). The same results have been reported for α-terpinyl acetate whose rates were of 7.5% and 4.11%, respectively, in branches and cones. Furthermore, β-caryophllene was detected as trace in twigs whereas its rate was of 4.53% in cones. Among volatiles, α-terpinolene was present in the branches essential oil with an amount of 9.4%. However, it was absent in cones essential oil.Loukis et al. (1991) [26] reported that α-pinene and γ-terpinene accounted, respectively, for 39.5 and 11.56% of the whole essential oil ofCupressus sempervirens L. cones originating from Greece.Emami et al. (2004) [29] detected 42 compounds in the essential oil of conesCupressus sempervirens L. originating from Egypt. They reported a yield of 0.26% for leaves essential oil. Tognolini et al. (2006) [30] reported that the α-pinene is the major compound. This is the second monoterpene hydrocarbon predominant compound according to the results of Sacchetti et al. (2005) [31]. Furthermore, the most abundant volatile compounds in the essential oil of TurkishCupressus sempervirens L. are α-pinene and Δ-3-carene. Obviously, the composition of essential oils is significantly influenced by the organ. It is also influenced by many other factors including environmental factors such as rainfall, sunlight, soil, and climatic conditions and agronomic factors such as the date of harvest and the density of the culture.


## 3.2. Antioxidant Activities

Considering the many aspects of antioxidants and their reactivity, several tests are applied as antioxidants. Among them, the total antioxidant capacity, DPPH, and ABTS radicals scavenging tests are used to determine the antioxidant power of essential oil.The chemical complexity of essential oils, often a mixture of dozens of compounds with different functional groups, polarity, and antioxidant activity, may lead to scattered results, depending on the test employed [31].


### 3.2.1. Total Antioxidant Capacity

The total antioxidant activity ofCupressus sempervirens L. is expressed as Trolox equivalent. The phosphomolybdenum method is based on the reduction of Mo (VI) with Mo (V) by the antioxidant compounds and the formation of a green phosphate/Mo complex (V). Our results showed that the antioxidant activity is proportional to the extract concentration (0.0434 μg ET/g DW) (Figure 2). Baykan Erel et al. (2012) [32] studied the antioxidant activity of essential oils of six species of Artemisia. It was noted that only essential oil ofArtemisia absinthium andArtemisia arborescens has a total antioxidant activity with values, respectively, in the order of 2.89 mg ET/g DW and 3.39 mg ET/g DW.Figure 2
Total antioxidant capacity from cones essential oil ofCupressus sempervirens.


### 3.2.2. DPPH Radical-Scavenging Activity

Free radical-scavenging activities of the tested oil and positive control (Trolox) are presented in Figure3. In fact,Cupressus sempervirens L. essential oil remarkably reduced the concentration of DPPH free radical and transformed its stable, purple color into the yellow-colored DPPH-H with an efficiency IC50 = 151 μg/mL. The effect of antioxidant on DPPH radical scavenging was thought to be due to its hydrogen-donating ability. DPPH radical is a stable free radical and accepts an electron or hydrogen radical to become a stable diamagnetic molecule [33].Figure 3
Scavenging of DPPH radical from cones essential oil ofCupressus sempervirens.In two antioxidants screening studiesCupressus sempervirens L. was reported to display moderate radical-scavenging effect against DPPH [31, 34]. The leaf methanolic extract of EgyptianCupressus sempervirens L. had strong DPPH radical-scavenging activity as reported by Ibrahim et al. (2009) [35].Needless to say, potency of antioxidant activity of a substance is correlated with the applied method. In a study on some Iranian conifers the leaf and fruit MeOH extracts ofCupressus sempervirens L. were highly effective in ferric thiocyanate (FTC) and thiobarbituric acid (TBA) methods [36]. Nevertheless, activity of these extracts was also changeable according to the method.


### 3.2.3. ABTS Assay

Essential oil ofCupressus sempervirens L. had an antioxidant according to the DPPH test. The results relative to ABTS radical cation scavenging confirmed the previous result. In fact, IC50 obtained at the end of this test is 176.454 μg/mL (Figure 4). Ghazghazi et al. (2010) [37] obtained, by studying the essential oil samples ofR. canina of Feija and Ain Draham (North of Tunisia) during the test of the ABTS, IC50 values of 159.0 μg/mL and 201.8 μg/mL, respectively. From these results we can conclude that the essential oil ofCupressus sempervirens L. has a strong antioxidant against ABTS cation. The antioxidant activity of essential oil could be assigned to the synergistic effects of two or more of its components. In this context, Lu and Foo (2001) [38] reported that most natural antioxidant compounds often work synergistically to produce a broad spectrum of antioxidant properties that create an effective defense system against free radicals.Cupressus sempervirens L. essential oil consists of a very complex mixture of various chemical classes (Table 1), which may produce either synergistic or antagonistic effects on the process of lipid oxidation [39].Figure 4
Scavenging of ABTS radical from cones essential oil ofCupressus sempervirens.


## 3.2.1. Total Antioxidant Capacity

The total antioxidant activity ofCupressus sempervirens L. is expressed as Trolox equivalent. The phosphomolybdenum method is based on the reduction of Mo (VI) with Mo (V) by the antioxidant compounds and the formation of a green phosphate/Mo complex (V). Our results showed that the antioxidant activity is proportional to the extract concentration (0.0434 μg ET/g DW) (Figure 2). Baykan Erel et al. (2012) [32] studied the antioxidant activity of essential oils of six species of Artemisia. It was noted that only essential oil ofArtemisia absinthium andArtemisia arborescens has a total antioxidant activity with values, respectively, in the order of 2.89 mg ET/g DW and 3.39 mg ET/g DW.Figure 2
Total antioxidant capacity from cones essential oil ofCupressus sempervirens.


## 3.2.2. DPPH Radical-Scavenging Activity

Free radical-scavenging activities of the tested oil and positive control (Trolox) are presented in Figure3. In fact,Cupressus sempervirens L. essential oil remarkably reduced the concentration of DPPH free radical and transformed its stable, purple color into the yellow-colored DPPH-H with an efficiency IC50 = 151 μg/mL. The effect of antioxidant on DPPH radical scavenging was thought to be due to its hydrogen-donating ability. DPPH radical is a stable free radical and accepts an electron or hydrogen radical to become a stable diamagnetic molecule [33].Figure 3
Scavenging of DPPH radical from cones essential oil ofCupressus sempervirens.In two antioxidants screening studiesCupressus sempervirens L. was reported to display moderate radical-scavenging effect against DPPH [31, 34]. The leaf methanolic extract of EgyptianCupressus sempervirens L. had strong DPPH radical-scavenging activity as reported by Ibrahim et al. (2009) [35].Needless to say, potency of antioxidant activity of a substance is correlated with the applied method. In a study on some Iranian conifers the leaf and fruit MeOH extracts ofCupressus sempervirens L. were highly effective in ferric thiocyanate (FTC) and thiobarbituric acid (TBA) methods [36]. Nevertheless, activity of these extracts was also changeable according to the method.


## 3.2.3. ABTS Assay

Essential oil ofCupressus sempervirens L. had an antioxidant according to the DPPH test. The results relative to ABTS radical cation scavenging confirmed the previous result. In fact, IC50 obtained at the end of this test is 176.454 μg/mL (Figure 4). Ghazghazi et al. (2010) [37] obtained, by studying the essential oil samples ofR. canina of Feija and Ain Draham (North of Tunisia) during the test of the ABTS, IC50 values of 159.0 μg/mL and 201.8 μg/mL, respectively. From these results we can conclude that the essential oil ofCupressus sempervirens L. has a strong antioxidant against ABTS cation. The antioxidant activity of essential oil could be assigned to the synergistic effects of two or more of its components. In this context, Lu and Foo (2001) [38] reported that most natural antioxidant compounds often work synergistically to produce a broad spectrum of antioxidant properties that create an effective defense system against free radicals.Cupressus sempervirens L. essential oil consists of a very complex mixture of various chemical classes (Table 1), which may produce either synergistic or antagonistic effects on the process of lipid oxidation [39].Figure 4
Scavenging of ABTS radical from cones essential oil ofCupressus sempervirens.


## 3.3. Antibacterial Activity

The antibacterial test allowed us to determine the sensitive strains to the essential oil ofCupressus sempervirens L. The screening of this activity was firstly determined by the disk-diffusion method on agar for predicting the inhibitory activity of the oil on the growth of a bacterial culture. Our results showed that the evaluated oil had significant antibacterial effect. In fact, among twelve tested strains, six were sensitive to this oil (Table 2). Gram-negative bacteria (Klebsiella oxytoca,Vibrio cholerae,Shigella, andE. coli) were the most sensitive strains with the MIC values that do not exceed 125 μg/mL of essential oil (Table 2). This finding was in agreement with other findings. For example, the cone EO of EgyptianCupressus sempervirens L. showed antibacterial activity [27]. Chéraif et al. (2005) [28] tested the antibacterial activity of essential oilCupressus sempervirens L. on Gram-positive and Gram-negative bacteria and found that this essential oil has a moderate activity against tested bacteria. It is important to mention that the activity was more pronounced for Gram-positive than Gram-negative bacteria. Similarly, Mazari et al. (2010) [14], when studying the biological activities of essential oils ofCupressus sempervirens L. andJuniperus phoenicea, reported that both oils constitute sources of antimicrobial agents. There are often large variations in the intensity of the antimicrobial activities against Gram-negative and Gram-positive bacteria.Table 2
Antibacterial activity from essential oil cones ofCupressus sempervirens.
Microorganisms
Concentration (mg/mL)
Negative control
1
0.5
0.25
0.125
0.0625
0.0312
0.0156
0.0078
Bacillus subtilis ATCC 6633
−
−
−
+
+
+
+
+
+
Escherichia coli ATCC 8739
−
−
−
−
+
+
+
+
+
Klebsiella oxytoca CECT 8207
−
−
−
−
+
+
+
+
+
Morganella morganii  ATCC 25830
−
−
+
+
+
+
+
+
+
Shigella ATCC 29930
−
−
−
−
+
+
+
+
+
Vibrio cholerae CECT 8265
−
−
−
−
−
+
+
+
+The EO ofCupressus sempervirens L. presented antibacterial activity against Gram-positive and Gram-negative bacteria, showing the biggest inhibition withB. subtilis andE. coli. Additionally, the cypress essential oil was found to have moderate antimicrobial activity when compared to vancomycin (30 mcg) and erythromycin (15 mcg) as antibiotics [40].The antibacterial activity could be affected by the solubility of the oil, the diffusion range in the agar and the evaporation [41, 42]. In addition, the antibacterial activities of the essential oils suggest their usefulness in the treatment of various infectious diseases caused by the tested bacteria.It is well known that Gram-negative bacteria are more resistant to essential oil compound antibacterial properties than Gram-positive bacteria because of hydrophobic lipopolysaccharide in the outer membrane which provides protection against different agents [43]; however, the obtained results indicated that the evaluated oil possesses selective antibacterial activity and its effect was pronounced against Gram-negative bacteria compared to Gram-positive ones.


## 4. Conclusion

According to our results, the essential oil of cypress cones is very rich inα-pinene which is its major component. This compound is followed by Δ-3-carene, α-terpinyl acetate, β-caryophyllene, and cedrol. This composition is different from those found in other studies, and this difference may be due to climatic factors.Furthermore, the evaluation of the antioxidant activity by chemical tests (total antioxidant capacity, DPPH, and ABTS) revealed a variable behavior of the essential oil against the used radicals. Moreover, IC50 values calculated are very low such that this reflects the high antioxidant power: they are of 176.45 and 151 μg/mL for ABTS and DPPH tests, respectively. The evaluation of the antibacterial activity of the tested essential oil showed that it possesses a significant activity. These promising results allow us to expand our studies to ascertain other activities of this essential oil such as antiparasitic, antifungal, and anticholinesterase activities.



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*Source: 538929-2015-10-01.xml*