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The aim of this work was to investigate the antibacterial properties of geranium oil obtained from Pelargonium graveolens Ait. (family Geraniaceae), against one standard S. aureus strain ATCC 433000 and seventy clinical S. aureus strains. The agar dilution method was used for assessment of bacterial growth inhibition at various concentrations of geranium oil. Susceptibility testing of the clinical strains to antibiotics was carried out using the disk-diffusion and E-test methods. The results of our experiment showed that the oil from P. graveolens has strong activity against all of the clinical S. aureus isolates-including multidrug resistant strains, MRSA strains and MLS(B)-positive strains-exhibiting MIC values of 0.25-2.50 μL/mL.
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Molecules 2012, 17, 10276-10291; doi:10.3390/molecules170910276
molecules
ISSN 1420-3049
www.mdpi.com/journal/molecules
Article
Antimicrobial Activity of Geranium Oil against Clinical Strains
of Staphylococcus aureus
Monika Bigos 1, Małgorzata Wasiela 1, Danuta Kalemba 2 and Monika Sienkiewicz 1,*
1 Medical and Sanitary Microbiology Department, Medical University of Lodz, Hallera Sq. 1,
Lodz 90-647, Poland; E-Mails: monika.bigos@umed.lodz.pl (M.B.);
malgorzata.wasiela@umed.lodz.pl (M.W.)
2 Institute of General Food Chemistry, Lodz University of Technology, Stefanowskiego Str., 4/10,
Lodz 90-924, Poland; E-Mail: danuta.kalemba@p.lodz.pl; Tel./Fax: +48-42-631-3428
* Author to whom correspondence should be addressed; E-Mail: monika.sienkiewicz@umed.lodz.pl;
Tel./Fax: +48-42-639-3198.
Received: 28 June 2012; in revised form: 12 August 2012 / Accepted: 14 August 2012 /
Published: 28 August 2012
Abstract: The aim of this work was to investigate the antibacterial properties of geranium
oil obtained from Pelargonium graveolens Ait. (family Geraniaceae), against one standard
S. aureus strain ATCC 433000 and seventy clinical S. aureus strains. The agar dilution
method was used for assessment of bacterial growth inhibition at various concentrations of
geranium oil. Susceptibility testing of the clinical strains to antibiotics was carried out using
the disk-diffusion and E-test methods. The results of our experiment showed that the oil
from P. graveolens has strong activity against all of the clinical S. aureus isolates—
including multidrug resistant strains, MRSA strains and MLSB-positive strains—exhibiting
MIC values of 0.25–2.50 μL/mL.
Keywords: antibacterial activity; geranium oil; MIC; multidrug resistant strains;
Staphylococcus aureus
1. Introduction
Bacteria that belong to the Staphylococcus genus constitute one of the most important
epidemiological problems of contemporary invasive medicine. S. aureus has the strongest virulence
potential among all the staphylococcal species. It may become a part of human bacterial flora
OPEN ACCESS
Molecules 2012, 17 10277
(S. aureus nasal carriage) but increases the risk of the infection development, both nosocomial and
community-acquired [1–3]. Since 1960 methicillin-resistant S. aureus, MRSA, has become one of the
key pathogens responsible for health care associated infections that are usually difficult to treat [4].
There are a few reasons why S. aureus strains are able to exist persistently within the hospital
environment. Their simultaneous resistance to several groups of antimicrobial agents including
beta-lactam antibiotics, aminoglycosides, lincosamides, tetracyclines, and also quinolones and
rifampin, seriously restricts the possible ways to treat staphylococcal infections [5]. Glycopeptides are
then the drugs of choice, but S. aureus strains, especially methicillin resistant ones, may lose
susceptibility to vancomycin (full or intermediate resistance to vancomycin) [6]. Patients belonging to
the extreme age groups, immunocompromised and critically ill, usually need increasingly invasive
methods of the diagnostics and therapy, what facilitates the infection development, mainly if they are
or become colonized with S. aureus strains [7,8]. In consequence, the resulting increased morbidity
and mortality as well as the extended hospital stays have an adverse influence on the whole hospital
budget [9].
Essential oils derived from aromatic plants have many biological properties and can be used to
prevent and treat human systemic diseases, including infectious diseases. They have been reported as
exceptionally good therapeutic agents for chemoprevention, cancer suppression, antidiabetic activity
and lowering serum cholesterol and triglycerides [10]. Many of them have the high activity against
Gram-positive and Gram-negative bacteria, as well as against viruses and fungi. Due to their content of
anti-infective agents essential oils may be applied in the fighting against the drug-resistant bacteria and
for prevention of the resistance formation of pathogenic microbes. Essential oils, mainly from plants of
the Lamiaceae and Apiaceae families, have been added to food, not only as flavouring agents but also
as preservatives [11–13].
The Pelargonium (Geraniaceae) genus is represented by many essential oil producing species
inter alia: P. graveolens, P. odoranissimum, P. zonale and P. roseum. Geranium oil is obtained from
leaves, flowers and stalks by steam or hydrodistillation. The therapeutic effects of the oil find
application in the treatment of dysentery, diarrhoea, biliary conditions, gastric ulcers, diabetes, cancer
and skin diseases. The main constituents responsible for biological activity are citronellol, geraniol,
linalool, isomenthone, nerol and citronellyl formate [14–16]. Due to these components the essential oil
from P. graveolens has a strong antibacterial effect, with low Minimal Inhibitory Concentration (MIC)
values against S. aureus (0.72 mg/mL), and also against Bacillus cereus (0.36 mg/mL) and B. subtilis
(0.72 mg/mL) [17]. Interestingly, the possibility to use the combinations of different oils or
combinations of oils with antibiotics can be also a supplementary therapy. It was found that geranium
oil has the ability to reduce the antibiotic effective MIC with norfloxacin against standard S. aureus strains.
The overuse of antimicrobial chemotherapeutic agents, unfortunately typical of modern medicine, is
evident and cannot be glossed over in silence. Thus the search for effective and safe medicines that
could be used to treat staphylococcal infections is on. We have decided to determine if the essential oil
derived from Pelargonium graveolens Ait. has antibacterial properties against clinical S. aureus
isolates, what could make it an alternative or complementary to antistaphylococcal prophylactics or
antibiotic therapy.
Molecules 2012, 17 10278
2. Results
2.1. Chemical Composition of Geranium Oil
The analysis of the tested essential oil derived from Pelargonium graveolens Ait. revealed that
citronellol (26.7%) and geraniol (13.4%) were the main components. Among sixty seven constituents
identified in the geranium oil other prevailing compounds like nerol (8.7%), citronellyl formate
(7.1%), isomenthone (6.3%), linalool (5.2%), and 10-epi-γ-eudesmol (4.4%) were present. The whole
chemical composition of the tested oil is shown in Table 1.
Table 1. Chemical composition of geranium oil of Pelargonium graveolens Ait.
Number Compound % (relative) RI
1 α-Pinene 0.7 929
2 β-Pinene tr 979
3 Myrcene 0.1 983
4 Car-2-ene tr 986
5 α-Phellandrene 0.1 996
6 p-Cymene 0.1 1,012
7 β-Phellandrene tr 1,020
8 Limonene 0.2 1,021
9 (Z)-β-Ocimene tr 1,028
10 (E)-β-Ocimene 0.1 1,039
11 cis-Linlool oxide (f) 0.3 1,058
12 trans-Linlool oxide (f) 0.1 1,072
13 Terpinolene tr 1,079
14 Linalool 5.2 1,086
15 cis-Rose oxide 1.4 1,097
16 trans-Rose oxide 0.6 1,113
17 α-Cyclogeraniol tr 1,127
18 Isopulegol 0.1 1,130
19 Menthone 1.6 1,133
20 Isomenthone 6.3 1,144
21 Isomenthol 0.1 1,168
22 α-Terpineol 0.3 1,173
23 Estragole 0.1 1,177
24 Citronellol 26.7 1,217
25 Nerol 8.7 1,220
26 Geraniol 13.4 1,243
27 Geranial 1.1 1,246
28 Citronellyl formate 7.1 1,261
29 Neryl formate 0.1 1,264
30 Geranyl formate 2.5 1,283
31 Bicycloelemene Citronellyl acetate 0.4 1,334
32 α-Cubebene 0.2 1,349
33 Geranyl acetate 0.4 1,361
Molecules 2012, 17 10279
Table 1. Cont.
Number Compound % (relative) RI
34 α-Copaene 0.5 1,377
35 β-Bourbonene 1.1 1,385
36 1,5-di-epi-Bourbonene 0.2 1,388
37 α-Gurjunene 0.1 1,411
38 β-Caryophyllene 1.5 1,419
39 Citronellyl propionate 0.3 1,425
40 β-Copaene 0.2 1,428
41 Guaia-6,9-diene 0.3 1,439
42 4aH,10aH-Guaia-1(5),6-diene 0.1 1,442
43 4bH,10aH-Guaia-1(5),6-diene 0.5 1,445
44 Geranyl propionate 1.0 1,452
45 Alloaromadendrene 0.2 1,459
46 7aH,10bH-Cadina-1(6),4-diene 0.2 1,469
47 γ-Muurolene 0.1 1,471
48 Germacrene D 1.0 1,477
49 γ-Selinene 0.1 1,479
50 β-Selinene 0.2 1,482
51 Bicyclogermacrene 0.7 1,491
52 α-Muurolene 0.2 1,496
53 Dihydroagarofuran 0.1 1,500
54 γ-Cadinene 0.6 1,509
55 trans-Calamenene 0.3 1,510
56 δ-Cadinene 0.9 1,515
57 Zonarene 0.2 1,518
58 Cadina-1,4-diene 0.1 1,525
59 Selina-4(15),7(11)-diene 0.2 1,530
60 Geranyl butyrate 1.4 1,537
61 Phenylethyl tiglate 0.7 1,554
62 Geranyl isovalerate 0.1 1,582
63 10-epi-γ-Eudesmol 4.4 1,613
64 γ-Eudesmol 0.1 1,620
65 Geranyl tiglate 1.0 1,675
66 Geranyl ester I 0.2 1,694
67 Geranyl ester II 0.1 1,730
RI—Retention Index; tr < 0.05%.
2.2. Susceptibility to Antibiotics among the Clinical S. aureus Strains
Overall, drug susceptibility of 70 S. aureus strains was analysed. Bacterial isolates came from
various clinical materials: swabs from the nasal cavity—eight strains (Table 2), skin lesion—nine
strains (Table 3), postoperative wounds—eight strains (Table 4), intubation tube—14 strains (Table 5),
conjunctival sack—six strains (Table 6), throat—11 strains (Table 7), and from the stools—14 strains
(Table 8). The detailed susceptibility to the tested antimicrobial agents of all the clinical strains is
shown in the seven tables shown below. Resistance to methicillin was found in 31 bacterial isolates
Molecules 2012, 17 10280
(44.3%) in comparison to 39 methicillin-susceptible strains (55.7%). These results were fully
confirmed by E-tests: the minimal inhibitory concentration (MIC) value for cefoxitin ranged from
8 µg/mL to 256 µg/mL for MRSA and from 1.5 µg/mL to 3 µg/mL for MSSA isolates. Most MRSA
strains were isolated from the nasal cavity (six out of eight strains), intubation tubes (10 out of
14 strains), and the throat (four out of 11 strains) (Tables 2, 5 and 7). The majority of bacterial strains
proved to be resistant to penicillin (57 strains, 81.4%). Nineteen of them turned out to be resistant only
to this antibiotic. As expected, MRSA strains showed considerably higher resistance to drugs other
than β-lactam antibiotics comparing to methicillin sensitive S. aureus strains (MSSA): 24 strains and
10 strains, respectively. Full resistance to β-lactam antibiotics as the only mechanism of drug
resistance was confirmed in seven bacterial isolates (10.0%). Resistance to ciprofloxacin, gentamicin,
tetracycline, and chloramphenicol was found in five strains (7.1%), six strains (8.6%), nine strains
(12.9%), and four strains (5.7%), respectively. One S. aureus isolate displayed intermediate
susceptibility to tetracycline. Twenty six S. aureus strains (37.1%) were simultaneously resistant to
erythromycin and clindamycin, showing inducible or constitutive resistance to macrolide-lincosamide-
streptogramin B (MLSB resistance): 14 and 11 strains, respectively, while only one bacterial isolate
displayed both these mechanisms. Most MLSB-positive strains were methicillin-resistant: inducible
MLSB resistance was found in nine MRSA strains, whereas constitutive MLSB mechanism was present
in 11 MRSA strains. The tested S. aureus strains were entirely susceptible to tigecycline, rifampin,
trimethoprim-sulphamethoxazole, linezolid, fusidic acid, quinupristine-dalfopristine, vancomycin
(MIC < 2µg/mL), and daptomycin (MIC < 1 µg/mL). Ten bacterial isolates (14.3%) proved to be
susceptible to all the antistaphylococcal agents studied.
Table 2. Characteristics of S. aureus strains isolated from the nasal cavity.
No.
MIC of
geranium
essential oil
[µL/mL]
Susceptibility to antibiotics Total
FOX
MIC
[
µg
/mL]
P
CIP
CN
E
DA
QD
TE
TGC
C
FD
LZD
RA
VA
DPC
SXT
R I S
1. 0.75 R 24 R S S R R S S S S S S S S S S 4 0 12
2. 1.75 R 24 R S S R R S S S S S S S S S S 4 0 12
3. 0.25 S 2 R S S R R S S S S S S S S S S 3 0 13
4. 1.00 R 16 R S S R R S S S S S S S S S S 4 0 12
5. 1.50 R 8 R S S S S S R S R S S S S S S 4 0 12
6. 1.00 R 8 R S R R R S I S S S S S S S S 5 1 10
7. 1.00 S 3 R S S R R S S S S S S S S S S 3 0 13
8. 1.00 R 32 R R R R R S S S S S S S S S S 6 0 10
FOX—cefoxitin; P—penicillin; CIP—ciprofloxacin; CN—gentamicin; E—erythromycin;
DA—clindamycin; QD—quinupristine-dalfopristine; TE—tetracycline; TGC—tigecycline;
C—chloramphenicol; FD—fusidic acid; LZD—linezolid; RA—rifampin; VA—vancomycin;
DPC—daptomycin; SXT—cotrimoxazole; R—resistance; I—intermediate susceptibility;
S—susceptibility.
Molecules 2012, 17 10281
Table 3. Characteristics of S. aureus strains isolated from skin lesions.
No.
MIC of
geranium
essential oil
[µL/mL]
Susceptibility to antibiotics Total
FOX
MIC
[µg/mL]
P
CIP
CN
E
DA
QD
TE
TGC
C
FD
LZD
RA
VA
DPC
SXT
R I S
1. 0.25 S 3 R S S S S S S S S S S S S S S 1 0 15
2. 1.00 S 3 R S S S S S S S S S S S S S S 1 0 15
3. 1.00 S 2 R S S S S S S S S S S S S S S 1 0 15
4. 1.00 S 1.5 R S S S S S S S S S S S S S S 1 0 15
5. 0.25 S 3 R S S S S S S S S S S S S S S 1 0 15
6. 1.25 S 3 R S S S S S S S S S S S S S S 1 0 15
7. 1.50 R 32 R S S R R S S S S S S S S S S 4 0 12
8. 1.00 R 12 R S R R R S S S S S S S S S S 5 0 11
9. 1.00 R 12 R S S R R S S S R S S S S S S 5 0 11
FOX—cefoxitin; P—penicillin; CIP—ciprofloxacin; CN—gentamicin; E—erythromycin;
DA—clindamycin; QD—quinupristine-dalfopristine; TE—tetracycline; TGC—tigecycline;
C—chloramphenicol; FD—fusidic acid; LZD—linezolid; RA—rifampin; VA—vancomycin;
DPC—daptomycin; SXT— cotrimoxazole; R—resistance; S—susceptibility.
Table 4. Characteristics of S. aureus strains isolated from postoperative wounds.
No.
MIC of
geranium
essential oil
[µL/mL]
Susceptibility to antibiotics Total
FOX
MIC
[
µg
/mL]
P
CIP
CN
E
DA
QD
TE
TGC
C
FD
LZD
RA
VA
DPC
SXT
R I S
1. 1.00 S 3 R S S S S S S S S S S S S S S 1 0 15
2. 1.25 S 3 S S S S S S S S S S S S S S S 0 0 16
3. 2.25 R 8 R S S S S S R S S S S S S S S 3 0 13
4. 2.25 S 3 S S S S S S S S S S S S S S S 0 0 16
5. 1.00 S 3 R S S R R S S S S S S S S S S 3 0 13
6. 0.75 S 3 S S S R R S S S S S S S S S S 2 0 14
7. 1.50 R 8 R S S R R S R S R S S S S S S 6 0 10
8. 0.50 R 48 R S S S S S S S S S S S S S S 2 0 14
FOX—cefoxitin; P—penicillin; CIP—ciprofloxacin; CN—gentamicin; E—erythromycin;
DA—clindamycin; QD—quinupristine-dalfopristine; TE—tetracycline; TGC—tigecycline;
C—chloramphenicol; FD—fusidic acid; LZD—linezolid; RA—rifampin; VA—vancomycin;
DPC—daptomycin; SXT— cotrimoxazole; R—resistance; S—susceptibility.
Molecules 2012, 17 10282
Table 5. Characteristics of S. aureus strains isolated from intubation tubes.
No.
MIC of
geranium
essential oil
[µL/mL]
Susceptibility to antibiotics Total
FOX
MIC
[µg/mL]
P
CIP
CN
E
DA
QD
TE
TGC
C
FD
LZD
RA
VA
DPC
SXT
RI S
1. 0.25 S 3 R S S S S S S S S S S S S S S 1 0 15
2. 0.25 S 3 R S S S S S S S S S S S S S S 1 0 15
3. 1.00 R 96 R R S R R S S S S S S S S S S 5 0 11
4. 0.25 S 2 R S S S S S S S S S S S S S S 1 0 15
5. 1.50 R 24 R S S S S S S S S S S S S S S 2 0 14
6. 1.50 S 2 S S S S S S S S S S S S S S S 0 0 16
7. 0.25 R 16 R S S R R S S S S S S S S S S 4 0 12
8. 0.25 R 24 R S S S S S S S S S S S S S S 2 0 14
9. 0.75 R 24 R S S R R S S S S S S S S S S 4 0 12
10. 0.75 R 48 R S S S S S S S S S S S S S S 2 0 14
11. 2.50 R 8 R S S R R S R S R S S S S S S 6 0 10
12. 0.50 R 256 R R R R R S R S S S S S S S S 7 0 9
13. 1.50 R 128 R R S R R S S S S S S S S S S 5 0 11
14. 1.50 R 8 R S S S S S S S S S S S S S S 2 0 14
FOX—cefoxitin, P—penicillin; CIP—ciprofloxacin; CN—gentamicin; E—erythromycin;
DA—clindamycin; QD—quinupristine-dalfopristine; TE—tetracycline; TGC—tigecycline;
C—chloramphenicol; FD—fusidic acid; LZD—linezolid; RA—rifampin; VA—vancomycin;
DPC—daptomycin; SXT— cotrimoxazole; R—resistance; S—susceptibility.
Table 6. Characteristics of S. aureus strains isolated from the conjunctival sack.
No.
MIC of
geranium
essential oil
[µL/mL]
Susceptibility to antibiotics Total
FOX
MIC
[µg/mL]
P
CIP
CN
E
DA
QD
TE
TGC
C
FD
LZD
RA
VA
DPC
SXT
RI S
1. 0.25 R 32 R S S S S S S S S S S S S S S 2 0 14
2. 0.75 S 3 S S S S S S S S S S S S S S S 0 0 16
3. 0.75 S 3 R S S S S S S S S S S S S S S 1 0 15
4. 1.50 S 1.5 R S S S S S S S S S S S S S S 1 0 15
5. 1.00 S 2 S S S R R S S S S S S S S S S 2 0 14
6. 1.00 R 12 R S S R R S S S S S S S S S S 4 0 12
FOX—cefoxitin; P—penicillin; CIP—ciprofloxacin; CN—gentamicin; E—erythromycin;
DA—clindamycin; QD—quinupristine-dalfopristine; TE—tetracycline; TGC—tigecycline;
C—chloramphenicol; FD—fusidic acid; LZD—linezolid; RA—rifampin; VA—vancomycin;
DPC—daptomycin; SXT— cotrimoxazole; R—resistance; S—susceptibility.
Molecules 2012, 17 10283
Table 7. Characteristics of S. aureus strains isolated from the throat.
No.
MIC of
geranium
essential oil
[µL/mL]
Susceptibility to antibiotics Total
FOX
MIC
[µg/mL]
P
CIP
CN
E
DA
QD
TE
TGC
C
FD
LZD
RA
VA
DPC
SXT
RI S
1. 1.00 S 3 R S S S S S R S S S S S S S S 2 0 14
2. 0.25 S 1.5 S S S S S S S S S S S S S S S 0 0 16
3. 2.25 S 3 S S S S S S S S S S S S S S S 0 0 16
4. 1.00 S 3 S S S S S S S S S S S S S S S 0 0 16
5. 1.50 S 2 R S S S S S R S S S S S S S S 2 0 14
6. 0.75 S 3 S S R S S S S S S S S S S S S 1 0 15
7. 1.00 R 12 R S S R R S S S S S S S S S S 4 0 12
8. 0.75 S 3 R S S S S S S S S S S S S S S 1 0 15
9. 2.50 R 12 R S S R R S S S S S S S S S S 4 0 12
10. 2.50 R 32 R S R S S S R S S S S S S S S 4 0 12
11 1.00 R 48 R S S S S S R S S S S S S S S 3 0 13
FOX—cefoxitin; P—penicillin; CIP—ciprofloxacin; CN—gentamicin; E—erythromycin;
DA—clindamycin; QD—quinupristine-dalfopristine; TE—tetracycline; TGC—tigecycline;
C—chloramphenicol; FD—fusidic acid; LZD—linezolid; RA—rifampin; VA—vancomycin;
DPC—daptomycin; SXT— cotrimoxazole; R—resistance; S—susceptibility.
Table 8. Characteristics of S. aureus strains isolated from stools.
No.
MIC of
geranium
essential oil
[µL/mL]
Susceptibility to antibiotics Total
FOX
MIC
[µg/mL]
P
CIP
CN
E
DA
QD
TE
TGC
C
FD
LZD
RA
VA
DPC
SXT
RI S
1. 0.25 S 3 R S S S S S S S S S S S S S S 1 0 15
2. 0.25 S 3 R S S R R S S S S S S S S S S 3 0 13
3. 0.25 S 3 R S S S S S S S S S S S S S S 1 0 15
4. 0.25 R 64 R R S R R S S S S S S S S S S 5 0 11
5. 1.00 S 3 R S S S S S S S S S S S S S S 1 0 15
6. 0.75 S 2 R S S S S S S S S S S S S S S 1 0 15
7. 2.25 S 3 S S S S S S S S S S S S S S S 0 0 16
8. 2.00 S 3 S S S S S S S S S S S S S S S 0 0 16
9. 0.75 S 3 S S S S S S S S S S S S S S S 0 0 16
10. 1.00 S 3 R S S S S S S S S S S S S S S 1 0 15
11. 1.25 S 3 R S S S S S S S S S S S S S S 1 0 15
12. 1.50 S 2 R S S R R S S S S S S S S S S 3 0 13
13. 2.50 R 16 R S S S S S S S S S S S S S S 2 0 14
14. 1.00 R 32 R S S S S S S S S S S S S S S 2 0 14
FOX—cefoxitin; P—penicillin; CIP—ciprofloxacin; CN—gentamicin; E—erythromycin;
DA—clindamycin; QD—quinupristine-dalfopristine; TE—tetracycline; TGC—tigecycline;
C—chloramphenicol; FD—fusidic acid; LZD—linezolid; RA—rifampin; VA—vancomycin;
DPC—daptomycin; SXT—cotrimoxazole; R—resistance; S—susceptibility.
Molecules 2012, 17 10284
2.3. Susceptibility of the Clinical S. aureus Strains to the Geranium Oil
The geranium oil obtained from Pelargonium graveolens Ait. shows a very strong activity against
the standard S. aureus strain (ATCC 433000) and also against the examined S. aureus strains obtained
from the clinical materials. The values of MIC against clinical S. aureus strains ranged from 0.25 µL/mL
to 2.5 µL/mL. The growth of the standard S. aureus strain, ATCC 433,000, was inhibited by 0.25 µL/mL
of the tested oil. The majority of S. aureus strains studied: 47 out of 70, were sensitive to the oil
concentrations of 1.00 µL/mL or lower (Figure 1). These strains were isolated from: nasal cavity 6/8,
skin lesions 7/9, postoperative wounds 4/8, intubation tubes 9/14, conjunctival sack 5/6, throat 7/11
and stools 9/14 (Tables 2 and 8).
Figure 1. Susceptibility of the clinical S. aureus strains to the geranium oil.
In our study the geranium oil had a strong antimicrobial activity against clinical S. aureus strains
with different mechanisms of resistance. The lowest values of geranium essential oil MICs (0.25 µL/mL
and 0.5 µL/mL) inhibited the growth of both MRSA strains exhibiting high MICs for cefoxitin
(16–256 µg/mL) and MSSA isolates presenting the lowest MICs for cefoxitin (1.5–3 µg/mL) (Table 5).
However, MRSA strains exhibiting high MICs for cefoxitin (12–32 µg/mL) were also inhibited in
1.75 µL/mL and 2.50 µL/mL of the tested oil (Tables 2, 7 and 8). No correlation between MICs for
geranium oil and MICs for cefoxitin could be noticed.
The most effective against MRSA and MSSA clinical S. aureus strains were concentrations:
1.00 µL/mL (n = 21), 0.25 µL/mL (n = 14), 0.75 µL/mL (n = 10) and 1.50 µL/mL (n = 10) (Table 9).
Molecules 2012, 17 10285
Table 9. Resistance to cefoxitin in correlation with MICs of geranium oil among S. aureus strains.
Number of strains MIC of geranium oil [µL/mL]
0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50
MRSA 4 2 3 10 0 6 1 0 1 4
MSSA 10 0 7 11 3 4 0 1 3 0
Total 14 2 10 21 3 10 1 1 4 4
The effect of the geranium oil on S. aureus strains exhibiting MLSB mechanism of drug resistance
was also analysed. The growth of most such bacterial isolates was inhibited also in the presence of
1.00 µL/mL (n = 11), 0.25 µL/mL (n = 4) and 1.50 µL/mL (n = 4) of the tested oil (Table 10).
Table 10. MLSB resistance in correlation with MICs of geranium oil among S. aureus strains.
Number of strains with different
MLSB mechanisms
MIC of geranium oil [µL/mL]
0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50
Inducible MLSB 3 1 3 5 0 1 1 0 0 0
Constitutive MLSB 1 0 0 6 0 2 0 0 0 2
Constitutive and inducible MLSB 0 0 0 0 0 1 0 0 0 0
Total 4 1 3 11 0 4 1 0 0 2
Finally, the effect of the geranium oil on S. aureus strains resistant to antibiotics other than
β-lactams, macrolides and lincosamides was analysed. The growth of most bacterial strains resistant to
tetracycline, gentamicin, and ciprofloxacin was inhibited by the lower concentrations of the geranium
oil (1.50 µL/mL).
3. Discussion
Because of increasing concern over S. aureus resistance to beta-lactam and glycopeptide antibiotics,
especially among MRSA strains, new therapeutic options are being sought. The ‘golden age’ of
antibiotics has gone. Attempts are made to modify cephalosporins, carbapenems, glycopeptides,
quinolones, tetracyclines and other antibiotics to obtain compounds with new activity against
staphylococci. Only a few examples of antimicrobial agents administered against difficult to treat
staphylococcal infections may be mentioned, i.e., linezolid, quinupristine-dalfopristine, tigecycline,
glycopeptides (dalbavancin, telavancin, oritavancin), telithromycin, daptomycin, and ceftobiprole [18–20].
High costs of the therapies using the drugs listed above as well as the many side-effects associated
with their pharmacokinetics should incline us to look for other alternatives. In our opinion geranium
oil may be one of them. We have determined the susceptibility to this essential oil among 70 S. aureus
strains isolated from the nasal cavity, conjunctival sack, throat, skin lesions, postoperative wounds,
intubation tubes, and from stools. The tested strains exhibited various antibiotic susceptibility patterns
(Tables 2–8). Resistance to methicillin was found in 44.3% of all bacterial isolates. The percentage of
MLSB-positive S. aureus strains amounted to 37.1%. Susceptibility of both multidrug resistant and
fully susceptible clinical isolates to the tested oil was investigated. All S. aureus strains proved to be
susceptible to tigecycline, rifampin, trimethoprim-sulphamethoxazole, linezolid, fusidic acid,
quinupristine-dalfopristine, vancomycin, and daptomycin.
Molecules 2012, 17 10286
The obtained results, in accordance with the literature, show that geranium oil has antimicrobial
properties against all tested strains. The activity is due to the high content of alcoholic compounds with
antibacterial properties such as citronellol and geraniol, which account for over 40% of the ingredients
of the geranium oil [21,22].
The geranium oil obtained from Pelargonium graveolens Ait. shows a very strong activity against
the standard S. aureus strain (ATCC 433000) and also against the examined S. aureus strains coming
from clinical materials. Moreover, the effectiveness of the geranium oil in relation to multidrug
resistant S. aureus strains, even those resistant to β-lactam antibiotics and those showing macrolide-
lincosamide-streptogramin resistance (MLSB resistance), was revealed in our study. The values of MIC
against clinical S. aureus strains ranged from 0.25 µL/mL to 2.5 µL/mL. The growth of the standard
S. aureus strain, ATCC 433000, was inhibited by 0.25 µl/mL of the tested oil.
According to the literature, geranium oil showed growth inhibitory effect against methicillin-resistant
S. aureus ssp. aureus ATCC 700699 using the disk-diffusion method (30 L of tested oil per 13 mm
disk) with an inhibition zone of 26 mm [23]. Prabuseenivasan et al. [24] reported that oil obtained
from Pelargonium graveolens Ait. used at concentrations higher than 12.8 mg/mL inhibited the growth
of the S. aureus standard strain ATCC 25923. In our investigations geranium oil was active against
S. aureus ATCC 433000 at a much lower concentration of 0.25 µL/mL. Research on antimicrobial
properties of geranium oil alone and in combination with tea tree oil demonstrated its very strong
activity against non-typable MRSA strains and MRSA strains belonging to phage type 15 isolated
from the wounds of burn patients in a burns unit. The results of these experiments show that geranium
oil can be used in the treatment of MRSA infections which have created major problems for burn units
and also intensive care units [25]. Malik and Sink [26] in their investigations demonstrated very good
efficiency of the geranium oil against antibiotic sensitive and resistant bacterial strains isolated from
urinary tract infections of significant bacteriuria. S. aureus sensitive and resistant to kanamycin,
ampicillin and ciprofloxacin were used to check antibacterial activity of the geranium oil by the
disk-diffusion method using 10 L of the oil per 6 mm disk. The inhibition zone for S. aureus
(sensitive) was 26.5 mm and for S. aureus (resistant)—26.3 mm. The antibiotic sensitive and resistant
strains of S. aureus were inhibited at 8.96 mg/mL of the geranium oil. In our research, multidrug
resistant clinical strains isolated from different clinical materials were mainly sensitive to 1.00 µL/mL
or lower concentrations of geranium oil and even the most resistant strains were inhibited at 2.50 μL/mL.
In our investigation it has been found that geranium essential oil is effective against S. aureus
strains with different mechanisms of drug resistance. Geranium oil can be applied not only in the
treatment of dysentery, urinary tract and skin infections, but also in inflammation of the mouth, larynx,
pharynx caused by bacterial and fungal pathogens. It can be used as an effective air disinfectant and as
an additive to antiseptic preparations, and be used in the hospitals, nursing homes and clinics. The
application of essential oils in the treatment of human diseases, particularly infectious diseases caused
by multidrug resistant bacterial strains, may be an interesting alternative to synthetic drugs. Synergy of
action essential oils with antibiotics and chemotherapeutics presents an opportunity for significant
reductions of therapeutic doses, reduction of the adverse effects of antibiotic therapy and prevention
of antibiotic-resistant strain formation. Because of the therapeutic problems associated with
particularly resistant strains, essential oils can be useful in fighting against the microflora provoking
hospital-acquired infections. Doran et al. [27] have tested the antibacterial activity of geranium and
Molecules 2012, 17 10287
lemongrass essential oils against MRSA strains alone and in combination. The tests shown that
essential oil vapours inhibited the growth of antibiotic-sensitive and antibiotic-resistant bacteria, but
the effects were variable, depending on the exposure time and testing environment. Bearden et al. [28]
showed the antibacterial effectiveness of a combination of bezetonin chloride and volatile oils from tea
tree or thyme against MRSA strains isolated from wounds. Karpanen et al. [29] showed that essential
oils from tea tree eucalyptus and thyme, together with chlorhexidine digluconate, an antiseptic used in
dermatology, were effective against S. epidermidis pathogenic strains and proved thyme to be the most
effective. It shows not only inhibitory properties against the investigated bacteria but also prevents
biofilm formation. Concerning the application of oils, many studies have shown that essential oils
are well absorbed by nasal, oral, gastric, intestinal mucous membranes and the skin. The active
compounds in the oils are incorporated into cell membranes and influence enzyme and ion channel
function as well as receptor proteins. Oils are not accumulated in the human body and are neutralized
by binding to glucuronic acid and eliminated with urine [30]. The LD50 values for most essential oils
are greater than 5 g/kg body weight, while therapeutic doses are usually only a few drops per day.
Details—monographs of oils have been published in National Pharmacopeia, National Pharmacopeia,
ISO, WHO and Council of Europe, to ensure the availability of the necessary information about
essential oils: their source, concentration of active components, and therapeutic doses. The parameters
of geranium oil are clarified in ISO-4731. Although plant medicines are considered to be safe, the
possibility of overdoses and their interactions with synthetic drugs administered orally must be
considered. Investigations on essential oils’ mechanism of action and their components are currently
being carried out both in vitro and in vivo [31,32], but many products containing essential oils have
been already patented. Due to their antimicrobial properties they are used in the treatment of
respiratory, digestive system, and also in skin and oral infections. A number of essential oils have been
identified as effective antibacterials used in food to control natural spoilage processes and to prevent
the growth of microorganisms and also as additives to drugs and cosmetics [33].
4. Experimental
4.1. Essential Oil Analysis
A commercial essential oil from Pelargonium graveolens Ait. was purchased from the
manufacturer (POLLENA-AROMA Poland) and analyzed by GC-FID-MS in the Institute of General
Food Chemistry, Lodz University of Technology, using a Trace GC Ultra apparatus (Thermo Electron
Corporation) with FID and MS DSQ II detectors and FID-MS splitter (SGE). Operating conditions:
apolar capillary column Rtx-1ms (Restek), 60 m × 0.25 mm i.d., film thickness 0.25 µm; temperature
program, 50–300 °C at 4 °C/min; SSL injector temperature 280 °C; FID temperature 300 °C; split ratio
1:20; carrier gas helium at a regular pressure 200 kPa; FID temperature 260 °C; carrier gas, helium;
0.5 mL/min; split ratio 1:20. Mass spectra were acquired over the mass range 30–400 Da, ionization
voltage 70 eV; ion source temperature 200 °C.
Identification of components was based on the comparison of their MS spectra with those in a
laboratory-made MS library, commercial libraries (NIST 98.1, Wiley Registry of Mass Spectral Data,
8th Ed. and MassFinder 4) and with literature data [34,35] along with the retention indices on an
apolar column (Rtx-1, MassFinder 4) associated with a series of alkanes with linear interpolation
Molecules 2012, 17 10288
(C8-C26). A quantitative analysis (expressed as percentages of each component) was carried out by
peak area normalization measurements without correction factors.
4.2. Antibacterial Activity of Essential Oil
For testing of antibacterial activity a S. aureus ATCC 433000 strain that came from collection of
Medical and Sanitary Microbiology Department, Medical University of Lodz, was used. The clinical
S. aureus strains, collected in 2010, came from different materials taken from patients of five hospital
wards (internal medicine, surgical ward, otolaryngology, gastroenterology, and intensive care unit) of
the Polish Mother's Health Center in Lodz, Poland. Bacterial strains were isolated from the nasal
cavity, conjunctival sack, throat, skin lesions, postoperative wounds, intubation tubes, and stools.
S. aureus isolates involved in this study came from the patients requiring antistaphylococcal antibiotic
therapy due to the active infections (this applies to the strains isolated from the conjunctival sack,
throat, skin lesions, postoperative wounds, and intubation tubes) or the patients that were S. aureus
carriers (applies to the isolates from the nasal cavity and feces). The standard and clinical strains were
cultivated on Columbia agar medium and incubated at 37 °C for 48 h in aerobic conditions. Bacterial
suspensions with an optical density of 0.5 on a McFarland scale were prepared. A BioMérieux
densitometer was used.
The essential oil was diluted in ethanol. This solution was mixed with an agar medium to obtain
concentrations from 0.125 to 2.5 µL/mL and poured into Petri dishes [36]. Inoculum containing
1.5 × 108 CFU/mL (0.1 mL) per spot was seeded upon the surface of agar with various oil
concentrations, as well as upon that with no oil added (strain growth control). The MICs values were
determined after 24 h of incubation at 37 °C under aerobic conditions. The analysis of the antibacterial
activity of the oil was independently performed three times. Control media containing ethanol
(at concentrations used in the dilutions) did not inhibit the growth of bacterial strains.
4.3. Antibiotic Susceptibility of the Clinical S. aureus Strains
Antimicrobial susceptibility testing was performed in accordance with the criteria of the European
Committee on Antimicrobial Susceptibility Testing (EUCAST) [37]. The disk-diffusion method was
used to investigate the bacterial susceptibility to 14 antimicrobial agents: cefoxitin (FOX, 30 μg,
Oxoid), erythromycin (E, 15 μg, Oxoid), clindamycin (DA, 2 μg, Oxoid), tetracycline (TE, 30 μg,
Oxoid), tigecycline (TGC, 15 μg, Bio-Rad), chloramphenicol (C, 30 μg, Bio-Rad), ciprofloxacin (CIP,
5 μg, Oxoid), rifampin (RA, 5 μg, Bio-Rad), gentamicin (CN, 10 μg, Oxoid), trimethoprim-
sulphamethoxazole (SXT, 1.25/23.75 μg, Oxoid), linezolid (LZD, 30 μg, Oxoid), fusidic acid (FD, 10 μg,
Oxoid), and quinupristine-dalfopristine (QD, 15 μg, Oxoid); additionally susceptibility to penicillin
(P, 10 IU, Oxoid) was also tested. The following cut-off values for the disk-diffusion determination of
resistance (R) and susceptibility (S) have been used: cefoxitin (R < 22, S 22), penicillin (R < 26, S 26),
erythromycin (R < 18, S 21), clindamycin (R < 19, S 22), tetracycline (R < 19, S 22), tigecycline
(R < 18, S 18), chloramphenicol (R < 18, S 18), ciprofloxacin (R < 20, S 20), rifampin (R < 23,
S 26), gentamicin (R < 18, S 18), trimethoprim-sulphamethoxazole (R < 14, S 17), linezolid (R < 19,
S 19), fusidic acid (R < 24, S 24), quinupristine-dalfopristine (R < 18, S 21), according to
EUCAST criteria [33]. Susceptibility to vancomycin (VA256, BioMérieux) and daptomycin (DPC256,
Molecules 2012, 17 10289
BioMérieux) was carried out using the E-test method. This technique was also used to determine MIC
value for cefoxitin (FX256, BioMérieux). The following cut-off values for the E-test determination
of resistance have been used: cefoxitin (R > 4 µg/mL), vancomycin (R > 2 µg/mL), daptomycin
(R 1 µg/mL) [37]. Inducible and constitutive resistance to macrolide-lincosamide-streptogramin B
(MLSB resistance) was investigated using a double disk technique with erythromycin (15 μg) and
clindamycin (2 μg). Bacterial isolates were inoculated on Mueller-Hinton II Agar (bioMerieux) and
incubated in an aerobic atmosphere at 35 °C for 18 h (24 h for cefoxitin and vancomycin).
5. Conclusions
1. Geranium oil obtained from Pelargonium graveolens Ait. was active at concentrations of
0.25–2.50 μL/mL against multidrug resistant staphylococci of different origin.
2. No correlation was found between MICs values for geranium oil inhibiting the growth of
S. aureus strains and MICs values for cefoxitin.
3. The growth of most MLSB-positive S. aureus strains was inhibited in lower MICs values of the
tested oil.
Acknowledgements
The research reported in this publication has been funded through the Medical University of Lodz,
Poland (Grant No. 502-03/5-018-02/502-54-014) and has not been submitted elsewhere.
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... A number of phenolic compounds, flavonoids, vitamins, carotenoids, and anthocyanin compounds found in edible and non-edible flowers possess antioxidant properties (Bigos et al., 2012;Kalemba-Drożdż and Cierniak, 2019;Rop et al., 2012b). Furthermore, this secondary metabolite mitigates various oxidative stress-related chemicals in addition to acting as an antioxidant. ...
... The lower concentration of polar metabolites and cell wall constituents of gram negative pathogens might be other reasons of not getting inhibition zone using polar solvents. Petals of flowers and oil derived from different tissue of plants shown to have tremendous potential to inhibit well known gram positive and gram negative human pathogens and fungi that belongs to Genus Bacillus, Staphylococcus Pseudomonas, Mycobacterium, Klebseilla, Enterococcus, Escherichia, Salmonella, Candida, Aspergillus, and Coccidioides (Al-Snafi, 2013;Bigos et al., 2012;Chaleshtori et al., 2016;Kamil et al., 2020;Rafiq et al., 2016;Singh et al., 2012;Tosun et al., 2021)). The majority of scientific reports were based on the oil extracted from leaf, stem or flower and this oil represents concentrated form of metabolites. ...
... There have been several scientific evidences supporting to use these flowers petals for making antimicrobial formulation. Researchers have characterized major metabolites in Geranium (Bigos et al., 2012;Mangalagiri et al., 2021)),Cosmos (Salehan et al., 2013;Sia et al., 2020;Yusoff et al., 2014), Pansy (Khoshkam et al., 2016;Witkowska-Banaszczak et al., 2005), Calendula (Chaleshtori et al., 2016), Dianthus (Aliyazicioglu et al., 2017;Kamaluldeen and Al-defiery, 2021), Petunia (Kumar, 2015;Thenmozhi et al., 2011) using a variety of metabolic platforms and their findings with metabolites present therein as well as the antimicrobial potential have been supported by current research. ...
Article
In this work, the nutritional value and phytochemical content of the six annual flower petals such as Pansy (Viola wittorckiana), Dianthus (Dianthus chinensis), Cosmos (Cosmos bipinnatus), Calendula (Calendula officinalis), Petunia (Petunia hybrida), and Geranium (Pelargonium hortorum), were assessed. Gas Chromatography-Mass spectrometry (GC-MS) was utilized to characterize their metabolites in addition to assessing their antioxidant and antibacterial activities. Dianthus chinensis was found to have the highest concentrations among all six an-nuals' components, including total protein (19.5 gm/100 g), ascorbic acid (100 mg/100 g), anthocyanin (1.23 mg Cyn. H./g), total reducing capacity (9.47 mg GAE/g), and hydrolysable tannin (36.96 mg TAE/g). While TPC and TFC values in all of the studied flowers ranged from 13.94 to 107.9 mg catechol/g and 13.3 to 135.84 mg rutin /g, respectively. Maximum TPC was found in geranium flowers (107.9 mg catechol/g). The pansy was shown to have a minimum amount of total phenol (13.9 mg catechol/g). Calendula has the highest level of β-carotene (0.85 mg/g), whereas the cosmos has the highest amount of carotenoid (18.8 µg/g) and lycopene (0.55 µg/g) among the flowers. Petunia flowers showed the highest antioxidant activity (98.3 %), according to the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, followed by pansies (87.6 %), cosmos (65 %), geraniums (56.3 %), and calendula (46.4 %), with the exception of Dianthus. The concentration of micronutrients differed significantly among all six flowers which accumulated nutrients in descending order from (highest to lowest) Fe (1771 ppm) > Zn (143 ppm)>Cu (21.1 ppm) with maximum concentration obtained in Cosmos, Dianthus, and Calendula, respectively. It was found that Petunia extracts exhibited the highest antimicrobial properties, with a maximum growth inhibition zone against Salmonella typhi A (S. typhi A), S. typhi B, Enterobacter, and Pseudomonas with hexane extract, except for S. typhi. However, Dianthus extracts exhibited the highest growth inhibition zones against Enterobacter. Several bioactive metabolites were found in the petals during GC-MS analysis. Among others, notable metabolites include ß-Amyrin, Caryophyllene, 2,4-Di-tert-butylphenol, ß-Sitosterol, and Stig-masterol, while brewing samples include significant amounts of phenylethyl alcohol, indole, 4-Vinylphenol,.tau.-Muurolol, and 2-Methoxy-4-Vinylphenol. The results are significant information that may be utilized to promote the consumption of annual edible flowers and to recognize their usage as flower infusions or as tea supplements.
... Pelargonium has been renowned for its perfumery and aromatherapy properties. Besides being used in cosmetics, it is highly denuded to cure a number of diseases due to antibacterial, antifungal, antioxidant, anti-inflammatory and anticancer activities [1], [2], [3], [4], [5]. The aerial parts are used in folk medicine as a food and tea drinks additive and for relieving some gastrointestinal, topical, dental, and cardiovascular disorders and are effective in preventing haemorrhoids. ...
... Traditionally, Pelargonium propagated through cutting. However, this plant is susceptible to several diseases that cause extensive damage to the crop at all stages of growth and development Table (2,3,4) and could not be available throughout the year. Tissue culture offers an effective and alternate way for rapid and safe propagation. ...
Chapter
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This book is a comprehensive review of secondary metabolite production from plant tissue culture. The editors have compiled 12 meticulously organized chapters that provide the relevant theoretical and practical frameworks in this subject using empirical research findings. The goal of the book is to explain the rationale behind in vitro production of secondary metabolites from some important medicinal plants. Biotechnological strategies like metabolic engineering and the biosynthesis, transport and modulation of important secondary metabolites are explained along with research studies on specific plants. In addition to the benefits of secondary metabolites, the book also aims to highlight the commercial value of medicinal plants for pharmaceutical and healthcare ventures. Topics covered in this part include: 1. In vitro propagation and tissue culture for several plants including Withania somnifera (L.) Dunal, Aloe vera, Oroxylum indicum (L) Kurz, Ocimum basilicum L, Rhubarb, Tea, and many others (including plants in Northern India). 2. Genetic Improvement of Pelargonium 3. Bioactive Components in Senna alata L. Roxb 4. Plant tissue culture techniques The book caters to a wide readership. It primarily prepares graduate students, researchers, biotechnologists, giving them a grasp of the key methodologies in the secondary metabolite production. It is a secondary reference for support executives, industry professionals, and policymakers at corporate and government levels to understand the importance of plant tissue culture and maximizing its impact in the herbal industry.
... explored this activity across different phenologicl stages, revealing bactericidal efficacy with MIC values ranging from 0.15 to 2.5 μg/mL. Notably, others have exhibited potent activity against clinical S. aureus strains,36 with MIC values ranging from 0.25 to 2.5 μL/mL. Remarkably, 47 out of 70 clinical S. aureus strains displayed sensitivity to Pelargonium graveolens essential oil concentrations of 1.00 μL/mL or lower. ...
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Background Atopic dermatitis (AD) is a chronic inflammatory skin condition characterized by pruritus and skin barrier dysfunction. This study aims to evaluate the therapeutic potential of Pelargonium graveolens (Geraniaceae) in managing AD symptoms through its essential oil. Methods The chemical composition of Pelargonium graveolens flower essential oil (PFEO) was analyzed using gas chromatography-mass spectrometry (GC-MS). Its antimicrobial, antioxidant, and anti-inflammatory properties were assessed, along with the inhibitory effects of PFEO on key enzymes involved in skin repair: tyrosinase, elastase, and collagenase. An in vivo evaluation of a gel formulation containing PFEO was also conducted to assess its anti-inflammatory and analgesic efficacy. Results GC-MS analysis identified major compounds in PFEO, including Geraniol (22.83%), beta-citronellol (19.51%), naphthalenemethanol (15.36%), and Geranyl tiglate (9.38%), with minor constituents such as linalool (3.81%) and neryl formate (1.31%). PFEO exhibited bacteriostatic activity against various bacterial and fungal strains, including Pseudomonas aeruginosa , Staphylococcus aureus , Methicillin-Resistant Staphylococcus aureus (MRSA), Bacillus anthracis , Streptococcus pyogenes , Staphylococcus epidermidis , Candida albicans , and Malassezia spp. The essential oil also demonstrated significant antioxidant properties and inhibited key enzymes linked to skin alterations in AD. Conclusions PFEO shows promising therapeutic potential for managing symptoms of atopic dermatitis due to its antimicrobial, antioxidant, and anti-inflammatory properties, as well as its analgesic effects. The findings support further exploration of PFEO as a natural alternative in the treatment of AD.
... The inhibition zone increased with increasing concentration of EO for the studied pathogenic microorganisms (Listeria monocytogenes, Staphylococcus aureus, Salmonella typhimurium, and Escherichia coli). Bigos et al. (2012) reported that geranium oil has strong activity against all the clinical S. aureus isolates, including multidrug-resistant strains. Omara et al. (2014) investigated the effect of marjoram EO on the development of Salmonella species and E. coli in comparison to erythromycin and found that both were vulnerable to marjoram EO. ...
... The monoterpene alcohols β-citronellol and geraniol are the components present at the highest concentrations. According to our data, in the study of Bigos et al. [11] the primary constituents of Pelargonium graveolens Ait. were found to be citronellol (26.7%) and geraniol (13.4%). Other common compounds found in geranium EO included nerol (8.7%), citronellyl formate (7.1%), isomenthone (6.3%), linalool (5.2%), and 10-epi-γ-eudesmol (4.4%), among the sixty-seven constituents discovered. ...
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The essential oil of Pelargonium graveolens (PGEO) is identified in the literature as a rich source of bioactive compounds with a high level of biological activity. This study aimed to examine the chemical profile of PGEO as well as its antioxidant, antibacterial, antibiofilm, and insecticidal properties. Its chemical composition was analyzed using gas chromatography–mass spectrometry (GC-MS), achieving comprehensive identification of 99.2% of volatile compounds. The predominant identified compounds were β-citronellol (29.7%) and geraniol (14.6%). PGEO’s antioxidant potential was determined by means of DPPH radical and ABTS radical cation neutralization. The results indicate a higher capacity of PGEO to neutralize the ABTS radical cation, with an IC50 value of 0.26 ± 0.02 mg/mL. Two techniques were used to assess antimicrobial activity: minimum inhibitory concentration (MIC) and disk diffusion. Antimicrobial evaluation using the disk diffusion method revealed that Salmonella enterica (14.33 ± 0.58 mm), which forms biofilms, and Priestia megaterium (14.67 ± 0.58 mm) were most susceptible to exposure to PGEO. The MIC assay demonstrated the highest performance of this EO against biofilm-forming S. enterica (MIC 50 0.57 ± 0.006; MIC 90 0.169 ± 0.08 mg/mL). In contrast to contact application, the assessment of the in situ vapor phase antibacterial activity of PGEO revealed significantly more potent effects. An analysis of antibiofilm activity using MALDI-TOF MS demonstrated PGEO’s capacity to disrupt the biofilm homeostasis of S. enterica growing on plastic and stainless steel. Additionally, insecticidal evaluations indicated that treatment with PGEO at doses of 100% and 50% resulted in the complete mortality of all Harmonia axyridis individuals.
... S. aureus strains isolated from skin lesions were found to be sensitive to geranium oil at concentrations from 0.25 μl/ml to 1.5 μl/ml, and those from postoperative wounds at concentrations ranging from 0.5 μl/ml to 2.25 μl/ml. The largest number of MRSA and MSSA clinical strains, as well as those with the MLSB mechanism, were inhibited at a 1.0 μl/ml concentration of geranium oil (Bigos et al., 2012). ...
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Purpose: The purpose of the study was to evaluate the antibacterial properties of commercial geranium essential oil (Etja, Elbląg, Poland) against some Gram-positive and Gram-negative bacteria. To this intent, the antimicrobial susceptibility test was used (the Kirby–Bauer disk diffusion test for measuring zone diameters of bacterial growth inhibition). Methodology. Natural geranium essential oil (Etja, Elbląg, Poland) was used in the current study. The testing of the antibacterial activity of geranium essential oil was carried out in vitro by the Kirby-Bauer disc diffusion technique. In the current study, Gram-positive strains such as Enterococcus faecalis (Andrewes and Horder) Schleifer and Kilpper-Balz (ATCC® 51299™) (resistant to vancomycin; sensitive to teicoplanin), Enterococcus faecalis (Andrewes and Horder) Schleifer and Kilpper-Balz (ATCC® 29212™), Staphylococcus aureus subsp. aureus Rosenbach (ATCC® 29213™), Staphylococcus aureus subsp. aureus Rosenbach (ATCC® 25923™), Staphylococcus aureus (NCTC 12493™), and Gram-negative strains such as Pseudomonas aeruginosa (Schroeter) Migula (ATCC® 27853™), Escherichia coli (Migula) Castellani and Chalmers (ATCC® 25922™), and Escherichia coli (Migula) Castellani and Chalmers (ATCC® 35218™) strains were used for the assessment of antibacterial activity of geranium essential oil. Scientific novelty. The highest diameters of the inhibition zone around the growth of Gram-negative strains were obtained for Escherichia coli (Migula) Castellani and Chalmers (ATCC® 25922™) and E. coli (Migula) Castellani and Chalmers (ATCC® 35218™) strains. Diameters of the inhibition zone were increased by 47.6% (p < 0.05) and 84.1% (p < 0.05) compared to the control samples, respectively. Gram-positive strains were more sensitive to the impact of commercial geranium essential oil. The highest diameters of the inhibition zone around the growth of Gram-positive strains were obtained for Staphylococcus aureus subsp. aureus Rosenbach (ATCC® 29213™) and Staphylococcus aureus subsp. aureus Rosenbach (ATCC® 25923™). Diameters of the inhibition zone were increased by 95.1% (p < 0.05) and 67.7% (p < 0.05) compared to the control samples, respectively. Conclusions. This study demonstrated that commercial geranium essential oil possesses potential antimicrobial properties against Gram-positive bacteria, such as Enterococcus faecalis (Andrewes and Horder) Schleifer and Kilpper-Balz (ATCC® 51299™) and Enterococcus faecalis (Andrewes and Horder) Schleifer and Kilpper-Balz (ATCC® 29212™), S. aureus subsp. aureus Rosenbach (ATCC® 29213™) and S. aureus subsp. aureus Rosenbach (ATCC® 25923™) strains. Pseudomonas aeruginosa strain was resistant to commercial geranium essential oil. This study showed that this essential oil could be a potential preparation as a source of natural antibacterial properties.
... A number of different compounds were detected in the GC-MS analysis. Table 3 [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] shows the name of the compounds detected, their peak areas, type of metabolite and whether that type of metabolite had any previous record of antimicrobial activity. Fig. 3 shows the total chromatogram of the GC-MS. ...
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... Methanol, ethanol, acetone, and aqueous extracts of geranium fresh leaves have been analyzed in the past for anti-microbial ability against E. coli, S. aureus, P. aeruginosa and K. pneumonia and have shown inhibitory activities against the tested microbes (Pradeepa, Kalidas, & Geetha, 2016). However, in the current study the extracts did not show any antimicrobial ability, while geranium oil is a strong antioxidant and geraniol is the major antimicrobial agent present in the plant (Bigos, Wasiela, Kalemba, & Sienkiewicz, 2012;Singh, Kumar, Gupta, & Chaturvedi, 2012). Different extraction procedures such as subcritical extraction or Soxhlet extraction with various solvents need to be tested for the extraction of antimicrobial molecules from the after distilled biomass. ...
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Pelargonium graveolens commonly known as geranium crop has received attention by essential oil manufacturers. Geranium plant is propagated using plant tissue culture followed by its cultivation in the fields. Geranium oil extraction creates a large amount of post distilled geranium biomass (PDGB). The present study utilized this unexplored PDGB for extraction of antioxidant, anti-tyrosinase, and antimicrobial constituents for cosmetic applications and determining the extract’s safety. The PDGB of methanol extract and ethyl acetate extract exhibited good qualitative phytochemical profiles. Antimicrobial activity was found to be absent in both extracts. Ethyl acetate extract of PDGB exhibited the highest antioxidant activity in terms of DPPH free radical scavenging and tyrosinase inhibition. The IC50 for ethyl acetate extract and methanol extract were found to be 0.188 and 0.201 mg/ml, whereas for GO it was found to be 77.49 mg/ml. The tyrosinase inhibition was found to be significantly higher (p
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Antibiotic resistance, which has increased rapidly in recent years, is one of the leading public health threats. Studies indicate that this resistance problem, which is expressed in frightening numbers, will cause great loss of life, especially in the 2050s. Alternative methods are being investigated for effective antibiotics in the fight against resistance. Geranium belongs to the Geraniaceae family and contains about 800 species belonging to 6 genera on earth. Geranium species are widely used for constipation, digestive disorders, and diabetes. Within the scope of the study, methanol, ethyl acetate, ethanol and hexane extracts of Geranium sp. plant belonging to Rize province were prepared and their antimicrobial activities were investigated by agar well method against various Gram negative, Gram positive bacteria and two fungal species. Antiquorum sensing activity was determined using Chromobacterium violaceum strains. According to the results of the study, it was determined that the methanol etil acetate and ethanol extracts of Geranium sp. had antimicrobial activity. Additionally Geranium sp. had violacein inhibition activity. Findings show that the plant has antimicrobial and antiquorum sensing properties. Thus, it was concluded that the active compound potential of the plant is high and more detailed studies should be done.
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BACKGROUND The oral cavity harbors more than 700 species of bacteria, which play crucial roles in the development of various oral diseases including caries, endodontic infection, periodontal infection, and diverse oral diseases. AIM To investigate the antimicrobial action of Cymbopogon Schoenanthus and Pelargonium graveolens essential oils against Streptococcus mutans, Staphylococcus aureus, Candida albicans, Ca. dubliniensis, and Ca. krusei. METHODS Minimum microbicidal concentration was determined following Clinical and Laboratory Standards Institute documents. The synergistic antimicrobial activity was evaluated using the Broth microdilution checkerboard method, and the antibiofilm activity was evaluated with the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay. Data were analyzed by one-way analysis of variance followed by the Tukey post-hoc test (P ≤ 0.05). RESULTS C. schoenanthus and P. graveolens essential oils were as effective as 0.12% chlorhexidine against S. mutans and St. aureus monotypic biofilms after 24 h. After 24 h P. graveolens essential oil at 0.25% was more effective than the nystatin group, and C. schoenanthus essential oil at 0.25% was as effective as the nystatin group. CONCLUSION C. schoenanthus and P. graveolens essential oils are effective against S. mutans, St. aureus, Ca. albicans, Ca. dubliniensis, and Ca. krusei at different concentrations after 5 min and 24 h.
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Adams, R. P. 2007. Identification of essential oil components by gas chromatography/ mass spectrometry, 4th Edition. Allured Publ., Carol Stream, IL Is out of print, but you can obtain a free pdf of it at www.juniperus.org
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Background: To evaluate the antibacterial activity of 21 plant essential oils against six bacterial species. Methods: The selected essential oils were screened against four gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus vulgaris) and two gram-positive bacteria Bacillus subtilis and Staphylococcus aureus at four different concentrations (1:1, 1:5, 1:10 and 1:20) using disc diffusion method. The MIC of the active essential oils were tested using two fold agar dilution method at concentrations ranging from 0.2 to 25.6 mg/ml. Results: Out of 21 essential oils tested, 19 oils showed antibacterial activity against one or more strains. Cinnamon, clove, geranium, lemon, lime, orange and rosemary oils exhibited significant inhibitory effect. Cinnamon oil showed promising inhibitory activity even at low concentration, whereas aniseed, eucalyptus and camphor oils were least active against the tested bacteria. In general, B. subtilis was the most susceptible. On the other hand, K. pneumoniae exhibited low degree of sensitivity. Conclusion: Majority of the oils showed antibacterial activity against the tested strains. However Cinnamon, clove and lime oils were found to be inhibiting both gram-positive and gram-negative bacteria. Cinnamon oil can be a good source of antibacterial agents.
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Plants have been used for thousands of years to flavor and conserve food, to treat health disorders and to prevent diseases including epidemics. The knowledge of their healing properties has been transmitted over the centuries within and among human communities. Active compounds produced during secondary vegetal metabolism are usually responsible for the biological properties of some plant species used throughout the globe for various purposes, including treatment of infectious diseases. Currently, data on the antimicrobial activity of numerous plants, so far considered empirical, have been scientifically confirmed, concomitantly with the increasing number of reports on pathogenic microorganisms resistant to antimicrobials. Products derived from plants may potentially control microbial growth in diverse situations and in the specific case of disease treatment, numerous studies have aimed to describe the chemical composition of these plant antimicrobials and the mechanisms involved in microbial growth inhibition, either separately or associated with conventional antimicrobials. Thus, in the present work, medicinal plants with emphasis on their antimicrobial properties are reviewed.
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