Introduction
Pesticides are indispensable in
agricultural production. They have been used by farmers to control weeds and
insects and their remarkable increases in agricultural products have been
reported. Pesticides pertains to substances used as insecticides, fungicides,
herbicides, rodenticides, molluscicides, and nematicides (Tudi et al.
2021). According to the FAOSTAT data (http://www.fao.org/faostat/en/ # data),
during the same year, Algeria imported 17.566.404 ton of pesticides of all
types (for agricultural and non-agricultural uses) the equivalent of
108,603.74*103 US $ of which only 237 ton (1.34%) were dangerous compounds
while the quantity of pesticides imported for agricultural use was about 4517
ton, of which 1740 ton (39%), 323 ton (7%) and 206 ton (≈ 5%) were
fungicides-bactericides, insecticides and herbicides, respectively (Bettiche et
al. 2021).
These chemicals are considered to be the most
effective means to combat pests, unfortunately they have harmful consequences.
On the one hand, at the level of the environment through the accumulation of
residues and soil pollution and on the other hand, the appearance and
generalization of resistance mechanisms in pathogens and the ecological
imbalance, due to the fact that these compounds of synthesis have a wide
spectrum of action. These chemicals destroy not only harmful agents but also
other populations in the ecosystem. In view of these harmful consequences, it
is important to find alternative solutions which will make it possible to
continue to fight against phytopathogens while reducing the use of chemicals.
These may involve the rationalization of agricultural practices, the use of
resistant plant varieties and / or the development of biopesticides )Fulgence et
al. 2021). Many recent studies have shown that crude extracts of plants
such as Datura metel (Jabeen et al. 2022), Sonchus oleraceous and
Ageratum conyzoides (Banaras et al. 2020, 2021), Cannabis
sativa (Khan and Javaid 2020), Chenopodium murale (Khan et al.
2021) and Cassia fistula (Akbar et al. 2014; Ferdosi et al. 2022) have the ability to
control various fungal pathogens such as Aspergillus flavipes, Penicillium
expansum, Sclerotium rolfsii and Macrophomina phaseolina. There are
many reports of isolation of pure compounds from plants such as lupeol acetate
and coumarin for the control of fungi
(Javed et al. 2021; Uroos et al. 2022) and compounds namely
holadysenterine from microorganisms for the control of weeds. In addition,
plant pathogens namely Ascochyta rabiei, Macrophomina phaseolina and Sclerotium rolfsii can
effectively be controlled by soil amendment with plant materials of D. metel
(Jabeen et al. 2021), Chenopodium album (Ali et al.
2020) and Withania
somnifera (Javaid
et
al. 2020).
Furthermore, biological control agents such as plant growth promoting
rhizobacteria (Sharf et al. 2021) and various species of fungi namely Trichoderma
harzianum, T. viride, T. pseudokoningii (Javaid et al. 2018;
Khan and Javaid 2021; Khan et al. 2021), A. versicolor and Penicillium italicum (Khan and Javaid 2022a, b) have
been identified for the control of soil-borne plant pathogens. The aim of the
present study was to assess the antimicrobial activity of essential oils of Pelargonium
graveolens and Juniperus phoenicea against various
pathogens of B. napus.
Materials
and Methods
Work
place
The experiment was
carried out at the level of TIFC (Experimental Station: Technical Institute of Field Crops), the laboratories of Djilali
Bounaama-Khemis Miliana University. According to director Ben Taiba Bilal, the
TIFC is a Public Administrative Establishment (PAE), with a scientific and
technical vocation, placed under the supervision of the Ministry of
Agriculture, Rural Development and Fisheries (MARDF) in 1965. This station is
one of nine stations of the Technical Institute of Field Crops. It is
responsible for the development of major cereals (winter and summer cereals,
food legumes, fodder and industrial crops). It is located on the national road
N°14 in the Wilaya of Ain Defla. Its area of action covers, in addition to the
Wilaya of Ain Defla, the Wilaya of Chlef.
Brassica
napus
Three untreated contaminated B.
napus plants were harvested from the TIFC Khemis Miliana field during
the month of March 2022. The samples were placed in plastic bags and
transported to the university laboratory where they were stored. The three B.
napus samples were
planted in plastic pots, in order to carry out the experiment on samples
of contaminated leaves.
Essential
oils
In this study, two
bottles of P. graveolens and J. phoenicea EO
(200 mL) were provided by Dr Saifi Mounir (Djilali Bounaama-Khemis Miliana
University). These rose geranium and phoenicia juniper er EOs were prepared at his Aromabiol Company
located in Bordj Bou Arreridj.
Isolation
and identification of microorganisms
The three contaminated rapeseed
plants were named as follows: plant 1 (P1), plant 2 (P2) and plant 3 (P3). A
small piece of a leaf of each contaminated plant was then cut and placed in 9
mL of sterile physiological water to prepare decimal dilutions. These mixtures
are called stock solutions (SM) (SM1: tube of P1, SM2 tube of P2 and SM3 tube
of P3). A series of 5 test tubes were used, each containing 9 mL of physiological
water. Dilutions were made from SM1 up to 10-5. The operation was
repeated for SM2 and SM3. The Petri dishes containing the nutrient and
Sabouraud agars were then incubated at 37°C for 24 h for the bacteria and at 25°C
for 4 days for the fungi. After incubation, each colony of fungi was
subcultured in the BSA medium and the bacteria in the NA medium. The purpose of
this operation was to obtain pure colonies which will facilitate macroscopic
and microscopic identification afterward (Mushtaq et al. 2022).
Physicochemical parameters of
essential oils
The physical indexes (refractive
index (IR), and pH) and chemical indexes (acid, saponification and ester) were
studied to determine the characteristics of essential oils (Ibipiriene et
al. 2022).
Determination of antimicrobial
activity
The aromatogram is a method for
evaluating whether an essential oil exhibits antifungal or antibacterial
activity, in vitro, against a fungus or bacterium. Blotting paper
discs 6 mm in diameter, previously impregnated with known quantities of
essential oil with dilutions (concentrates, 1/2, 1/4, 1/8 and 1/12) prepared
using DMSO (dimethyl sulfoxide) were then placed on the surface of the agar
previously inoculated with a bacterial and fungal culture. After incubation,
inhibition of fungal and bacterial growth was evidenced by the presence of a
clear halo around the oil-impregnated disc (Bouaouina et al. 2022).
Antioxidant activity of
essential oils
1,1-Diphenyl-2-pcrylhydrazyl
(DPPH) was dissolved in absolute ethanol at a rate of 2.5 mg in 100 mL. From a
stock solution of essential oil of 0.1 mg mL-1, dilute solutions of
different concentrations (100, 25, 50 and 75 µg mL-1) were prepared by successive double dilution in
ethanol. 50 μL of each extract as well as the positive control were added to 2 mL of
the ethanolic solution of DPPH. Mixtures were incubated in the dark at room
temperature for 30 min. The absorbances were measured at 517 nm, using a Thermo
brand Genesys 10 UV-Visible type spectrophotometer. Vitamin C (0.1 mg mL-1)
was used as a standard.
The evaluation of antioxidant activity using the DPPH method was
expressed as a percentage according to the following equation:
%20419-426_files/image002.png){kind=small}
Table 1: Count of colonies
obtained on nutrient agar from decimal dilutions
|
Samples Dilutions |
Number
of colonies (CFU mL-1) |
||||
|
10-1 |
10-2 |
10-3 |
10-4 |
10-5 |
|
|
Rapeseed plant 1 (P1) |
105 |
81 |
76 |
40 |
22 |
|
Rapeseed
plant 2 (P2) |
113 |
100 |
97 |
46 |
60 |
|
Rapeseed
plant 3(P3) |
90 |
69 |
59 |
44 |
30 |
Abs control: Absorbance of the control
reaction containing all the reagents except the oil (T = 0 min).
Abs extract: Absorbance of the sample
containing a dose of oil tested (T = 30 min). The value
of the IC50 inhibitory concentration represents the dose of
essential oils that neutralizes 50% of DPPH radicals (Munteanu and Apetrei
2021; Sethunga et al. 2022).
Essential
oil analysis by gas chromatography coupled with spectrometry
Gas Chromatography-Mass
Spectrometry (GC-MS) is a hyphenated analytical technique that combines the
separation properties of gas-liquid chromatography with the detection feature
of mass spectrometry to identify different substances within a test sample. GC
is used to separate the volatile and thermally stable substitutes in a sample
whereas GC-MS fragments the analyte to be identified on the basis of its mass (Ashish
et al. 2014).
The chromatographic analysis of essential oil was carried out with a gas
phase chromatograph type TQ 8030 coupled to a mass spectrometer. The
fragmentation is carried out by electron impact at 70 eV. The operating conditions were:
temperature column was from 40 to 250°C, the carrier gas was helium, the flow
rate of which was fixed at 3 mL min-1, injection mode was split mode
and the flow control mode with pressure of 49.5 KPa. The device was connected
to a computer system managing a Q3 Scan mass spectrum library to monitor the
progress of the chromatographic analyses, the volume of the injected sample was
0.5 µL of pure oil. The
identification of the constituents was made on the basis of the comparison of
their retention indices with those of the standard compounds of the
computerized database (Q3 Scan).
Results
Isolation and identification of
microorganisms
We observed from Table 1 that the
P2 sample contains between 60 and 113 CFU mL-1 compared to the other
rapeseed samples. Nutrient agar is a favorable medium for the growth of
bacteria that have contaminated rapeseed. There was the formation of orange,
yellow and white colonies as well as fungi. On Sabouraud agar, the fungi appear
black and white. We then did a second and a third subculture until we obtained
pure colonies. From the contaminated rapeseed leaves, we identified cocci (B1
and B3) and a bacilli (B2) under an optical microscope. All strains examined
possess the enzyme catalase. The latter decomposes the hydrogen peroxide into
water and oxygen which is released in the form of gaseous bubbles. The
identification of the biochemical characters of bacteria by the API 20 E
Gallery allowed us to know the biochemical characteristics of the three
isolated strains. The B1 and B3 strains correspond to the two species Klebsiella
oxytoca and K. pneumoniae, respectively. The B2 strain is
a Vibrio vulnificus.
Physical
indexes
The measured refractive index of P. graveolens
and J. phoenicea EOs vary between 1.467 and 1.468, respectively.
These indexes depend on the chemical composition which increases according to
the lengths of the chains of acids, their degrees of establishment and the
temperature. The value of the distilled water index is 1.33.
The IR of P. graveolens and J. phoenicea EOs is
high compared to that of distilled water. The pH is used to determine the
acidic, neutral or basic nature of a substance. The pH obtained indicates that
our essential oils are acidic (4.5 and 5).
Chemical
indexes
The acid number indicates the behavior and the
quantity of free acids present in our oils. We calculate the values
of the acid index and acidity of each oil, we obtain the values
5.6 and 2.8 mg g-1 of KOH for the essential oils of P.
graveolens and J. phoenicea, respectively. J. phoenicea
EO has a lower acid value compared to that of P. graveolens EO.
The acidity of P. graveolens oil is equal to 2.8% and that of
J. phoenicea 1.4%. The saponification index of the two oils are equal to 316.35 mg g-1
of KOH for J. phoenicea and 84.15 mg g-1 of KOH for P.
graveolens.
Neutralization of the acids released by hydrolysis in a basic medium
(saponification) of the esters contained in 1 g of gasoline makes it possible
to calculate the ester index (EI) using the following equation:
IE = IS-IA
For P. graveolens IE =
78.55 mg g-1 of KOH.
For J. phoenicea IE =
313.55 mg g-1 of KOH.
In vitro antimicrobial activity
According to Table 2, P. graveolens
and J. phoenicea EOs Table 2: Diameters of the
zones of inhibition in mm of the bacterial and fungal strains
|
EO of Pelargonium graveolens |
||||||
|
Microbial strains |
Inhibition zone diameters (mm) |
|||||
|
HE/DMSO (SM) |
1/2 dilution |
1/4 dilution |
1/8 dilution |
1/12 dilution |
control |
|
|
Alternaria alternata (P1) |
20 |
15 |
- |
- |
- |
- |
|
Alternaria alternata (P2) |
- |
- |
- |
- |
- |
- |
|
Alternaria alternata (P3B) |
- |
- |
- |
- |
- |
- |
|
Aspergillus niger (P3’W’) |
25 |
30 |
- |
- |
- |
- |
|
Klebsiella oxytoca (B1) |
- |
- |
- |
- |
- |
- |
|
Vibrio vulnificus(B2) |
15 |
12 |
14 |
20 |
- |
- |
|
Klebsiella pneumoniae spp. |
10 |
10 |
10 |
15 |
15 |
- |
|
EO of Juniperus phoenicea |
||||||
|
Alternaria alternata(P1) |
- |
- |
- |
- |
- |
- |
|
Alternaria alternata (P2) |
- |
- |
- |
- |
- |
- |
|
Alternaria alternata(P3B) |
- |
- |
- |
- |
- |
- |
|
Aspergillus niger (P3’W) |
- |
- |
- |
- |
- |
- |
|
Klebsiella oxytoca (B1) |
- |
- |
- |
- |
- |
- |
|
Vibrio vulnificus (B2) |
15 |
- |
10 |
- |
- |
- |
|
Klebsiella pneumoniae sspp. |
10 |
10 |
10 |
18 |
- |
- |
B1: Box
1; B2: Box 2; B3: Box3; P1: Plant 1; P2:
Plant 2; P3' N': Plant 3 Black; P3 ‘B’: Plant 3 White
%20419-426_files/image004.png)
Fig. 1: Antioxidant power of ascorbic acid or Vit C.
exhibited in vitro the
growth of certain microbial strains. If we take into consideration the
diameters of inhibition, the EO of P. graveolens was more active
on A. niger, Alternaria alternata, V. vulnificus
and K. pneumoniae. However, K. oxytoca showed a
great resistance towards the two EO. J. phoenicea EO has no
inhibiting effect on A. niger and A. alternata
fungi. On the other hand, V. vulnificus and K. pneumoniae
have a sensitivity towards the EO of J. phoenicea.
We can say also that our P. graveolens
EO has antifungal and antibacterial activity. This antagonistic effect results
by appearance of zones of inhibition whose diameters vary between 25 and 30 mm.
On the other hand, for fungi, no growth is observed with J. phoenicea
EO. While bacteria show sensitivity to this oil. These results in zones of
inhibition showed a diameter is between 10 and 18 mm.
Antioxidant
activity
From the graphic representations
drawn by the excel 2013, we were able to measure the IC50 value of
the two oils and ascorbic acid (Ac asc) or vitamin C (Fig. 1, 2 and 3).
The results of the antioxidant power of the EOs tested show that the
percentage of inhibition with P. graveolens EO is greater than
180% with a concentration of the order of 100 µg mL-1. For J. phoenicea EO and ascorbic acid,
the inhibition rate is estimated at 200 and 90%, with concentrations equal to
0.45 and 100 µg mL‑1,
respectively.
The IC50 value of each sample was calculated by the following
method:
For Ac asc: we use the equation
of Y = 108.67X
We had IC50 = 108.67X
50 = 108.67X
%20419-426_files/image006.png){kind=small}
IC50 of ascorbic acid
equals 0.46µg mL-1
For EO of P. graveolens:
Y = 193.35X
50 = 193.35X
%20419-426_files/image008.png){kind=small}
IC50 of P.
graveolens oil equals 0.25 µg mL-1
For EO of J. phoenicea: Y
= 212.88X
50 = 212.88X
%20419-426_files/image010.png){kind=small}
%20419-426_files/image012.png)
Fig. 2: Eo antioxidant power of P.
graveolens
%20419-426_files/image014.png)
Fig. 3: Eo antioxidant power
of J. phoenicea
%20419-426_files/image016.png)
Fig. 4: Chromatographic profile of essential oil of Pelargonium graveolens
IC50 of J. phoenicea oil
equals 0.23 µg mL-1
These results show that IC50 of J. phoenicea EO is
higher than that P. graveolens EO. The IC50 values
of the two oils are lower than that obtained for ascorbic acid
(0.46 µg mL-1).
Analysis
of P. graveolens essential oil by gas chromatography
In this part of work, we used a
gas chromatography device coupled with mass spectrometry, it is used to analyze
and identify chemical constituents of essential oil of P. graveolens
which gave a clear inhibitory effect of the microorganisms responsible for deterioration
of rapeseed leaves. The qualitative and quantitative analyzes of essential oil
made it possible to identify and quantify 19 major chemical compounds, which
were presented in Table 3 and Fig. 4. These identified compounds are listed in
order of their predominance. 6-octen-1-ol, 3,7-dimethyl appears as the major
constituent of EO (25.50%), followed by 2,6-octadien-1-ol3, 7-dimethyl-, (Z) -
(11.78%), eudesmol (8.57%), 6-octen-1-ol, 3,7-dimethyl-, acetate (7.81%),
1,6-octadien-3-ol, 3, 7-dimethyl-(4.60%) and cyclohexanone,
5-methyl-2-(1-mrthylethyl)-, trans-(4.32%) which represent 85.65% of the total
composition of our oil.
The rest of the chemical composition are minority constituents (14.35%).
Chemical analysis revealed 69 chemical constituents of P. graveolens
essential oil. Oxygenated compounds constitute an important part of the
chemical composition of oil compared to hydrocarbon compounds. The
chromatographic profile of absorbance as a function of time of our EO shows
that it has all the constituents necessary to make it a chemotype.
6-octen-1-ol, 3,7-dimethyl-appears as the major oil constituent (25.50%).
Discussion
Brassicaceae diseases caused by Alternaria
sp. can cause significant yield losses and are considered one of the most
critical disease complexes in the world, responsible, for example, for losses
of up to 47% in Indian mustard and even exceeding 70% in some species of Brassica
(Al-Lami
Table 3: Compounds identified
in essential oil of Pelargonium graveolens as determined by gas
chromatography analysis
|
Sr.
No |
Names
of compounds |
Molecular
formula |
Molecular
weight |
Retention
time (min) |
Peak area (%) |
|
1 |
6-Octen-1-ol, 3,7-dimethyl- |
C10H20O |
156.26 |
14.825 |
25.50 |
|
2 |
2,6-Octadien-1-ol,
3,7-dimethyl-, (Z)- |
C10H18O |
154.24 |
15.471 |
11.78 |
|
3 |
Eudesmol<gamma-> |
C15H26O |
222.37 |
23.907 |
8.57 |
|
4 |
6- Octen-1-ol, 3,7-dimethyl-,
acetate |
C12H22O2 |
198.30 |
15.948 |
7.81 |
|
5 |
1,6-Octadien-3-ol, 3,
7-dimethyl- |
C10H18O |
154.24 |
11.490 |
4.60 |
|
6 |
Cyclohexannone,
5-methyl-2-(1-methylethyl)-, trans- |
C10H18O |
154.24 |
13.241 |
4.32 |
|
7 |
2,6- Octadien-1-ol,
3,7-dimethyl-, formate, (E)- |
C11H18O2 |
182.25 |
16.497 |
2.89 |
|
8 |
Viridiflorene |
C15H24 |
204.35 |
21.219 |
2.79 |
|
9 |
1,6-Cyclidecadiene,1-methyl-5-methylene-8-(1-
methylethyl)-, [s-(e, e)] |
C15H24 |
204.35 |
20.914 |
2.22 |
|
10 |
2,6-Octadien-1-ol, 3,7-dimethyl-,
(Z)- |
C10H18O |
154.24 |
22.367 |
2.07 |
|
11 |
Viridiflorol |
C15H26O |
222.37 |
24.527 |
1.95 |
|
12 |
Linalylformate |
C11H18O2 |
182.26 |
25.226 |
1.68 |
|
13 |
Naphthalene,1,2,3,5,6,8a-hexahydro-4,7-dimethyl-1-(1-methylethyl)- |
C15H24 |
204.35 |
24.333 |
1.67 |
|
14 |
Phenylethyl tiglate 1 |
C13H16O2 |
204.26 |
22.997 |
1.62 |
|
15 |
Rose oxide |
C10H18O |
154.25 |
11.800 |
1.54 |
|
16 |
Caryophyllene |
C15H24 |
204.36 |
19.551 |
1.28 |
|
17 |
2,6,10- Dodecatrien-1-ol, 3,
7,11-trimethyl- |
C15H26O |
222.36 |
18.490 |
1.16 |
|
18 |
2,6-Octadien-1-ol,
3,7-dimethyl-, (Z)- |
C10H18O |
154.24 |
22.307 |
1.15 |
|
19 |
Naphthalene,
1,2,3,4,4a,5,6,8a-octahydro-7-methyl-4-methylene-1-(1-methyle) |
C15H24 |
204.35 |
21.601 |
1.05 |
|
20 |
Bicyclo[3.1.1]hept-2-ene, 2,6,6-trimetyl- |
C20H32 |
272.5 |
7.227 |
0.65 |
|
21 |
Cyclohexene,1-methyl-4-(1-methylethenyl)- |
C10H18 |
138.25 |
9.647 |
0.21 |
|
22 |
Eucalyptol |
C10H18O |
154.24 |
9.743 |
0.13 |
|
23 |
1,3,7-Octatriene, 3,7-dimethyl-, (E)- |
C10H16 |
136.23 |
9.841 |
0.09 |
|
24 |
1,3,6-Octatriene, 3,7-dimethyl-, (E)- |
C10H18 |
138.25 |
10.119 |
0.10 |
|
25 |
.Alpha.-methyl-.alpha.-[4-methyl
-3-pentenyl]oxiranemethanol |
C14H30O3Si |
274.47 |
10.813 |
0.09 |
|
26 |
Rose oxide |
C10H18O |
154.25 |
12.247 |
0.60 |
|
27 |
Cyclohexanone, 5-methy-2-(1-methylethyl)-, trans- |
C10H18O |
154.24 |
12.954 |
0.85 |
|
28 |
Cyclohexanol,
5-methyl-2-(1-methylethyl)-, [1r-(1.alpha.,2.beta.,5.alpi)] |
C10H20O |
156.26 |
13.727 |
0.20 |
|
29 |
3-Cyclohexene-1-methanol,
.alpha.,.alpha.,4-trimethyl- |
C12H20O2 |
196.29 |
13.903 |
0.39 |
|
30 |
2,6-Octadienal, 3,7-dimethyl- |
C10H16O |
152.24 |
15.137 |
0.28 |
|
31 |
2,6-Octadienal, 3,7-dimethyl- |
C10H16O |
152.24 |
15.849 |
0.42 |
|
32 |
2,6-Octadiene-1-ol, 3,7-dimethyl,acetate, (Z)- |
C12H20O2 |
196.28 |
16.085 |
0.11 |
|
33 |
2,6-Octadiene, 2,6-dimethyl |
C10H18 |
138.24 |
17.776 |
0.44 |
|
34 |
4-Isopropyl-3,7-dimethyl-3a,3b,4,5,6,7hexahydro-1H-Cyclopenta[2,3]C |
C15H24 |
204.35 |
17.843 |
0.17 |
|
35 |
Cyclobuta(1,2:3,4]dicylopentene,1,2,3,3A,3b,beta.,4,5,6,6a.beta.,6b.
|
C10H12 |
132.20 |
18.737 |
0.86 |
|
36 |
2-Bromopropionic acide, 2-phenylethyl ester |
C11H14O2 |
178.22 |
18.832 |
0.23 |
|
37 |
1H-cyclopenta(1,3)cyclopropa[1,2]benzene,octahydro-7-methyl-3-methylene-4- |
C15H24 |
204.35 |
19.742 |
0.13 |
|
38 |
6-Octen-1-ol, 3,7-dimethyl-, propanoate |
C13H24O2 |
212.32 |
19.831 |
0.43 |
|
39 |
1H-cyclopropa[a]naphthalene,1a,2,4,5,6,7,7a,7b-octahydro-1,1,7,7a-T |
C15H24 |
204.35 |
20.024 |
0.30 |
|
40 |
1,6Cyclodecadiene1-methyl-5-methylene-8-(1-methylethyl)-,
[s-(E,E)] |
C15H24 |
204.35 |
20.088 |
0.10 |
|
41 |
Gurjunene<alpha-> |
C15H24 |
204.35 |
20.178 |
0.48 |
|
42 |
1,4,8-Cycloundecatriene, 2,6,6,9-tetramethyl-,(E,E)- |
C15H24 |
204.35 |
20.317 |
0.37 |
|
43 |
Cadina-1(6),4-diene(10betah-) |
C15H24 |
204.35 |
20.710 |
0.28 |
|
44 |
Azulene,1,2,3,4,5,6,7,8-octahydro-1,4dimethyl-7-(1methylethylidene)-,
(1s- cI) |
C15H24 |
204.35 |
20.764 |
0.21 |
|
45 |
Naphthalene,decahydro-4a-methyl-1-methylene-7-(1-methylethenyl) |
C15H24 |
204.35 |
21.045 |
0.20 |
|
46 |
Nerolidyl acetate |
C17H28O2 |
264.4 |
21.381 |
0.33 |
|
47 |
Naphtalène,
1,2,3,4,4a,5,6,8a-octahydro-7-methyl-4-methylene-1-(1-methylet) |
C15H24 |
204.35 |
21.601 |
0.26 |
|
48 |
Citronellyl isobutyrate |
C14H26O2 |
226.35 |
21.686 |
0.84 |
|
49 |
4-Isopropyl-1,6-dimethyl-,2,3,7,8,8a-hexahydronaphtalene |
C15H24 |
204.35 |
21.837 |
0.25 |
|
50 |
Naphtalène,
1,2,3,4,4a,7-hexahydro-1,6-dimethyl-4-(1-methylethyl)- |
C15H24 |
204.35 |
21.981 |
0.15 |
|
51 |
5-Isopropyl-3,8-dimethyl-1,2,4,5,6,7-hexahydroazulene |
C33H37+ |
433.6 |
22.096 |
0.22 |
|
52 |
Cadala-1(10),3,8-triene |
C15H22 |
202.33 |
22.222 |
0.13 |
|
53 |
4-(5,5-Dimethylspiro[2,5]oct-4-yl)-3-buten-2-one |
C14H22O |
206.32 |
22.495 |
0.10 |
|
54 |
3-Hexyne, 2,2,5,5-tetramethyl |
C9H16 |
124.22 |
22.636 |
0.24 |
|
55 |
9-Isopropy-1-methyl-2-methylene-5-oxa-tricyclo[5.0.0
3,8]undecane |
C15H24O |
220.35 |
23.150 |
0.73 |
|
56 |
Neryl isovalerate |
C15H26O2 |
238.37 |
23.254 |
0.19 |
|
57 |
Azulene,1,2,3,3a,4,5,6,7-octahydro-1,4-dimethyl-7-(1-methylethyl)-, |
C15H24 |
204.35 |
23.326 |
0.19 |
|
58 |
1,1,4,7-Tetramethyldecahydro-1h-cyclopropa[e]azulen-4-ol |
C15H26O |
222.36 |
23.555 |
0.17 |
|
59 |
Citronellyl valerate |
C15H28O2 |
240.38 |
23.672 |
0.21 |
|
60 |
Muurolol<alpha-,epi-> |
C15H26O |
222.36 |
23.751 |
0.28 |
|
61 |
Di-epi-alpha-cedrene-(l) |
C15H24 |
204.35 |
24.004 |
0.25 |
|
62 |
2-Naphtalène méthanol,
1,2,3,4,4a,5,6,7-octahydro-.alpha.,.alpha.,4a,8-tetra |
C15H26O |
222.36 |
24.079 |
0.21 |
|
63 |
2-(6,10-Dimethylspiro[4,5]dec-6-en-2-yl)-2-propanol # |
C15H26O |
222.3 |
24.174 |
0.43 |
|
64 |
(-)Globulol |
C15H26O |
222.37 |
24.680 |
0.10 |
|
65 |
Citronellyl isobutyrate |
C14H26O2 |
226.35 |
24.884 |
0.17 |
|
66 |
Butanoic acid,
3,7-dimethyl-2,6-octadienylester, (E)- |
C14H24O |
208.33 |
25.524 |
0.23 |
|
67 |
Butanoic acid, 3,7-dimethyl-2,6-octadienyl
ester, (E)- |
C14H24O |
208.33 |
26.205 |
0.11 |
|
68 |
2-Pentadecagone, 6,10,14-trimethyl- |
C18H36O |
268.485 |
27.885 |
0.15 |
|
69 |
Butanoic acid,
3,7-dimethyl-2,6-octadienyl ester, (E)- |
C14H24O |
208.33 |
28.003 |
0.09 |
|
Total |
|
|
|
|
100 |
et al.
2019). The environmental factors of the culture area of B.napus
favored the development of this flora at the leaves. Temperature and humidity
are the primary environmental factors that favor the spread of plant diseases,
while mild, wet winters affect the survival of debris-borne fungi such as Alternaria
disease (Runno-Paurson et al. 2021). Pathogenic fungi of Alternaria
species produce many primary and secondary metabolites that are host-specific
and non-host-specific. These toxins have various negative impacts on cell
organelles including chloroplast, mitochondria, plasma membrane, nucleus, Golgi
bodies, etc. (Meena and Samal 2019). K.
pneumoniae and K. oxytoca are commonly found in carbohydrate-rich
wastewater, surface water, cooling water, soil, plant products, fresh
vegetables (Batt and Tortorello 2014; Rocha et al. 2022).
Vibrio
vulnificus is a potentially deadly natural pathogen present in
coastal waters. Sewage spills in coastal waters occur when infrastructure fails
due to severe storms or age, and can affect bacterial populations by altering
nutrient levels (Conrad and Harwood 2022). Our results are consistent with
those obtained by the Algerian study of Raho et al. (2017) in
which P. graveolens and J. phoenicea had an inhitory
effect in vitro. In other work of Stegmayer et al. (2022) P.
graveolens essential oil at a concentration of 250 ppm inhibited the growth
of phytopathogenic fungi Alternaria alternata (100%) in vitro.
Juniperus is a varied genus (about 75 species of Juniperus have
been reported) that has been used for traditional medicinal purposes. Many
species belonging to this botanical family have been used in traditional
medicine in Tunisia (Boujemaa et al. 2022).
P.
graveolens (geranium) originated from southern Africa and is widely cultivated
in several countries, mainly in Russia, Egypt, Algeria, Morocco, Congo, Japan
and India and some continents like Central America and Europe. Among several
extracts of P. graveolens that may be useful as bioactive natural plant
products; the essential oil has been reported to possess a wide range of
biological and pharmacological properties such as antioxidant, antibacterial,
antifungal, hypoglycemic, anti-inflammatory and anti-cancer properties
(Al-Mijalli et al. 2022). These activities could be related to the presence
of certain bioactive compounds including citronellol, geraniol and linalool as
major compounds (Okla et al. 2022). P. graveolens is
highly valued by industries for producing geranium essential oil. According to
BS ISO 4371-2012, P. graveolens essential oil from different
geographical origins should have geraniol (5–20%), citronellol (18–43%),
citronellyl formate (4–12%), geranyl formate (1–8%) and linalool (2–11%) as the
main components. The chemical profile of P. graveolens essential oil is
affected from its geographical origin (Mahboubi and Valian 2019). Concerning P.
graveolens EO at the vegetative stage, the total of the compounds
identified was 92.98, divided into three classes: monoterpene hydrocarbons
(20.84%), oxygenated monoterpenes (39.08%) and hydrocarbons sesquiterpenes
(25.41%) (Al-Mijalli et al. 2022). Cebi (2021) detected a
volatile compound from the essential oil of geranium (P. graveolens)
which accounted for 99.34% of the total essential oil composition. The most
abundant compounds were determined as citronellol (30.68%), geraniol (9.68%) and
citronella formate (9.90%).
The mechanism action of essential oil extracts is related to changes in
the permeability of the cell membrane. The fat-soluble nature of the extracts and
their easy overlap with cellular structures, which have lipid constituents due
to increased permeability of the cell membrane which due to electrolyte
imbalance and cell lysis and then death (Kadium et al. 2021). Many
biopesticides are based on plant extracts and secondary metabolites which,
during evolution, are thought to be involved in protecting plants against
biotic and abiotic stresses. Among secondary metabolites, alkaloids, phenols
and terpenoids are the most common. These substances can be extracted by plant
tissues by solvent or steam distillation, obtaining a complex mixture of
various molecules called “essential oil”. Many EOs are bioactive substances
with insecticidal activity against target pest species, including toxic and
repellent effects, developmental and behavioral alterations, and
sterility/infertility. EOs are traditional and ancient pest control tools;
several millennia ago, around 2000 BC. Medicinal plants were used in Asia, the
Middle East and North Africa to control stored grain pests. The interest of
using EOs as a control tool is linked to their low toxicity towards mammals, so
that these substances are used as food protectants not only against insects
(Palermo et al. 2021). In the work
of Edson et al. (2014), in fumigation tests, the essential oil of
P. graveolens caused 100% mortality of adults of B. tabaci,
biotype B at concentrations from 0.5 µg
L-1 in air. These results suggest that PG-EO and its related
monoterpenes are potentially applicable to develop effective natural product-based
pest-management compounds.
Conclusion
The essential oil of P. graveolens
can be used as a biopesticide of the microorganisms responsible for the
pathologies of B. napus plant.
Acknowledgements
The first author of this
publication thanks the director Ben Taiba Bilal of TIFC and Dr Saifi Mounir.
Author
Contributions
GH planned the experiment and
wrote first draft; KR, HR and BS performed the experiment.
Conflict
of interest
No conflict
Data Availability
The data presented in this study
will be available on request from the corresponding author.
Ethics Approval
Not applicable for this study.
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