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Essential oils (EOs) are known to inhibit the growth of a wide range of microorganisms. Particularly interesting is the possible use of EOs to treat multidrug-resistant cystic fibrosis (CF) pathogens. We tested the essential oil (EO) from Origanum vulgare for in vitro antimicrobial activity, against three of the major human opportunistic pathogens responsible for respiratory infections in CF patients; these are methicillin-resistant Staphylococcus aureus, Stenotrophomonas maltophilia and Achromobacter xylosoxidans. Antibiotic susceptibility of each strain was previously tested by the standard disk diffusion method. Most strains were resistant to multiple antibiotics and could be defined as multi-drug-resistant (MDR).The antibacterial activity of O. vulgare EO (OEO) against a panel of 59 bacterial strains was evaluated, with MIC and MBC determined at 24, 48 and 72 hours by a microdilution method. The OEO was effective against all tested strains, although to a different extent. The MBC and MIC of CEO for S. aureus strains were either lower or equal to 0.50%, v/v, for A. xylosoxidans strains were lower or equal to 1% and 0.50%, v/v, respectively; and for S. maltophilia strains were lower or equal to 0.25%, v/v. The results from this study suggest that CEO might exert a role as an antimicrobial in the treatment of CF infections.
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Department of Organic Chemistry, University of Granada,
Campus de Fuente Nueva, s/n, 18071, Granada, Spain
Department STEBICEF,
University of Palermo, Viale delle Scienze,
Parco d’Orleans II - 90128 Palermo, Italy
National Engineering Laboratory for TCM Standardization Technology,
Shanghai Institute of Materia Medica, Chinese Academy of Sciences,
Shanghai 201203, P. R. China
G.B. Elyakov Pacific Institute of Bioorganic Chemistry,
Far Eastern Branch, Russian Academy of Sciences,
Pr. 100-letya Vladivostoka 159, 690022,
Vladivostok, Russian Federation
School of Pharmacy,
Tokyo University of Pharmacy and Life Sciences,
Horinouchi 1432-1, Hachioji, Tokyo 192-0392, Japan
Department of Chemistry, University of Wollongong,
Wollongong, New South Wales, 2522, Australia
Department of Chemistry, Texas Christian University,
Forts Worth, TX 76129, USA
Department of Chemistry, The University of Alabama in Huntsville,
Huntsville, AL 35809, USA
Faculty of Pharmaceutical Sciences, Hokuriku University,
Ho-3 Kanagawa-machi, Kanazawa 920-1181, Japan
Institute of Pharmaceutical Science
Faculty of Life Sciences & Medicine
King’s College London, Britannia House
7 Trinity Street, London SE1 1DB, UK
Prof. Viqar Uddin Ahmad
Karachi, Pakistan
Prof. Giovanni Appendino
Novara, Italy
Prof. Yoshinori Asakawa
Tokushima, Japan
Prof. Roberto G. S. Berlinck
São Carlos, Brazil
Prof. Anna R. Bilia
Florence, Italy
Prof. Josep Coll
Barcelona, Spain
Prof. Geoffrey Cordell
Chicago, IL, USA
Prof. Fatih Demirci
Eskişehir, Turkey
Prof. Francesco Epifano
Chieti Scalo, Italy
Prof. Ana Cristina Figueiredo
Lisbon, Portugal
Prof. Cristina Gracia-Viguera
Murcia, Spain
Dr. Christopher Gray
Saint John, NB, Canada
Prof. Dominique Guillaume
Reims, France
Prof. Duvvuru Gunasekar
Tirupati, India
Prof. Hisahiro Hagiwara
Niigata, Japan
Prof. Judith Hohmann
Szeged, Hungary
Prof. Tsukasa Iwashina
Tsukuba, Japan
Prof. Leopold Jirovetz
Vienna, Austria
Prof. Phan Van Kiem
Hanoi, Vietnam
Prof. Niel A. Koorbanally
Durban, South Africa
Prof. Chiaki Kuroda
Tokyo, Japan
Prof. Hartmut Laatsch
Gottingen, Germany
Prof. Marie Lacaille-Dubois
Dijon, France
Prof. Shoei-Sheng Lee
Taipei, Taiwan
Prof. Imre Mathe
Szeged, Hungary
Prof. M. Soledade C. Pedras
Saskatoon, Canada
Prof. Luc Pieters
Antwerp, Belgium
Prof. Peter Proksch
Düsseldorf, Germany
Prof. Phila Raharivelomanana
Tahiti, French Polynesia
Prof. Luca Rastrelli
Fisciano, Italy
Prof. Stefano Serra
Milano, Italy
Dr. Bikram Singh
Palampur, India
Prof. John L. Sorensen
Manitoba, Canada
Prof. Johannes van Staden
Scottsville, South Africa
Prof. Valentin Stonik
Vladivostok, Russia
Prof. Ping-Jyun Sung
Pingtung, Taiwan
Prof. Winston F. Tinto
Barbados, West Indies
Prof. Sylvia Urban
Melbourne, Australia
Prof. Karen Valant-Vetschera
Vienna, Austria
The School of Pharmacy & Biomedical Sciences,
University of Portsmouth,
Portsmouth, PO1 2DT U.K.
Essential Oil from Origanum vulgare Completely Inhibits the Growth
of Multidrug-Resistant Cystic Fibrosis Pathogens
Giovanna Pesaventoa,§, Valentina Magginib,§, Isabel Maidac, Antonella Lo Nostroa, Carmela Calonicoa,
Chiara Sassolia, Elena Perrinc, Marco Fondic , Alessio Mengonic, Carolina Chiellinid, Alfredo Vannaccib,
Eugenia Gallob, Luigi Gorib, Patrizia Boganic, Anna Rita Biliae, Silvia Campanaf, Novella Ravennif,
Daniela Dolcef, Fabio Firenzuolib and Renato Fanib,*
aDept. of Health Sciences, University of Florence, Viale G. B. Morgagni, 48, I- 50134 Florence, Italy
bCenter for Integrative Medicine, Careggi University Hospital, University of Florence, Florence, Italy
cDept. of Biology, University of Florence, Via Madonna del Piano 6, I-50019 Sesto Fiorentino (Florence), Italy
dConsiglio per la ricerca in agricoltura e l’analisi dell’economia agraria, centro di ricerca per l’Agrobiologia e
la Pedologia (CRA-ABP) Piazza D'Azeglio 30, I-50121 – Firenze, Italy
eDept. of Chemistry Ugo Schiff, University of Florence, Via Ugo Schiff 6, I-50019 Sesto Fiorentino (Florence),
fDept. of Paediatric Medicine Anna Meyer Children's University Hospital, Florence, Italy
§These authors contributed equally to this study
Received: November 6th, 2015; Accepted: April 11st, 2016
Essential oils (EOs) are known to inhibit the growth of a wide range of microorganisms. Particularly interesting is the possible use of EOs to treat multidrug-
resistant cystic fibrosis (CF) pathogens. We tested the essential oil (EO) from Origanum vulgare for in vitro antimicrobial activity, against three of the major
human opportunistic pathogens responsible for respiratory infections in CF patients; these are methicillin-resistant Staphylococcus aureus, Stenotrophomonas
maltophilia and Achromobacter xylosoxidans. Antibiotic susceptibility of each strain was previously tested by the standard disk diffusion method. Most strains
were resistant to multiple antibiotics and could be defined as multi-drug-resistant (MDR).The antibacterial activity of O. vulgare EO (OEO) against a panel of
59 bacterial strains was evaluated, with MIC and MBC determined at 24, 48 and 72 hours by a microdilution method. The OEO was effective against all tested
strains, although to a different extent. The MBC and MIC of OEO for S. aureus strains were either lower or equal to 0.50%, v/v, for A. xylosoxidans strains
were lower or equal to 1% and 0.50%, v/v, respectively; and for S. maltophilia strains were lower or equal to 0.25%, v/v. The results from this study suggest
that OEO might exert a role as an antimicrobial in the treatment of CF infections.
Keywords: Essential Oils, Origanum vulgare, Multidrug resistance, Cystic Fibrosis, Methicillin-resistant Staphylococcus aureus, Stenotrophomonas
maltophilia, Achromobacter xylosoxidans.
Leading causes of morbidity and mortality in cystic fibrosis (CF)
are respiratory tract infections caused by human pathogens such as
methicillin resistant Staphylococcus aureus (MRSA),
Stenotrophomonas maltophilia and Achromobacter xylosoxidans
[1]. In the United States, the prevalence of MRSA, S. maltophilia,
and A. xylosoxidans in CF patients is in the order of 22.6%, 15.8%
and 6%, respectively. Two studies in Italy have reported a
prevalence of 16% of A. xylosoxidans infection [2] and of 7% for
MRSA [3]. These bacteria often show an increasing level of
multidrug resistance (MDR) hampering the treatment of CF-
associated infections with conventional antimicrobial therapies [1].
Thus, new therapeutic strategies need to be discovered. Much
attention is paid to bioactive compounds derived by plants that are
known to possess antimicrobial properties and are used in
traditional medicine to treat several diseases. In particular, essential
oils (EOs) play an important role in the protection of plants and
have been empirically used for centuries to treat upper respiratory
tract infections such as pharyngitis, bronchitis and sinusitis [4].
Furthermore, in many cases the EO activity results from the
complex interaction between the different classes of compounds
such as phenols, aldehydes, ketones, alcohols, esters, ethers and
hydrocarbons found in EOs [5]. It is likely that it will be more
difficult for bacteria to develop resistance to the multi-component
EOs than to common antibiotics, which are often composed of only
a single molecular entity [6], since several molecular targets would
need to adapt to overcome the effects of the oil [7].
The activity of EOs against bacteria, fungi and viruses has been
tested in many studies and indeed, many bacteria, especially
pathogens, exhibit high sensitivity to EOs mainly extracted from
thyme, oregano and cloves [8-10]. We have previously performed a
preliminary analysis of EOs from six aromatic medicinal plants
(Eugenia caryophyllata, Origanum vulgare, Rosmarinus officinalis,
Lavandula hybrida, Melaleuca alternifolia and Thymus vulgaris)
revealing that, despite their different chemical composition, all of
them were able to inhibit the growth of representative strains of
members of the Burkholderia cepacia complex (Bcc) [11].
The antibacterial activity of Origanum vulgare EO (OEO) has been
attributed to the phenolic components, such as thymol and carvacrol
[5], which are able to inhibit some pathogenic bacterial strains,
including Escherichia coli, and serovars enteritidis, choleraesuis,
and typhimurium of Salmonella enterica [12]. Previous studies have
reported that OEO shows antimicrobial activity both in vitro and
in vivo against S. aureus [13-16]. On the basis of current literature
the OEO could represent a good compromise between potential
NPC Natural Product Communications 2016
Vol. 11
No. 6
861 - 864
862 Natural Product Communications Vol. 11 (6) 2016 Pesavento et al.
Table 1: Bacterial strains tested in this work.
ecies Strain Ori
in Reference S
ecies Strain Ori
in Reference
This work
. x
losoxidans* 1 CF
This work
5 CF
21 CF
6 CF
34 CF
9 CF
39 CF
11 CF
41 CF
12 CF
42 CF
13 CF
43 CF
15 CF
45 CF
16 CF
48 CF
17 CF
49 CF
20 CF
50 CF
23 CF
52 CF
24 CF
53 CF
25 CF
54 CF
26 CF 55 CF
27 CF
56 CF
28 CF
60 CF
32 CF
61 CF
33 CF
62 CF
63 CF
S. malto
hilia* 1 CF
This work
S. malto
hilia* 12 CF
This work
2 CF
13 CF
3 CF
14 CF
4 CF
15 CF
5 CF
16 CF
6 CF
17 CF
7 CF
19 CF
8 CF
20 CF
10 CF
21 CF
11 CF
22 CF
* Strains isolated from CF patient (CF) at the Anna Meyer Children’s Hospital
(Florence, Italy). 1 sputum; 2 throat swab; 3 bronchial
antibacterial activity [8, 9, 11, 17] and tolerability [18] if properly
formulated in specific drug delivery systems [19]. The aim of this
work was to investigate the antimicrobial potential of O. vulgare
EO, whose composition was previously determined [11], on a panel
of 59 MDR strains belonging to three of the major groups of CF
opportunistic pathogens (i.e. MRSA, Stenotrophomonas
maltophilia, and Achromobacter xylosoxidans) estimating the
bacteriostatic or bactericidal activity.
As a first step of the investigation, the molecular and/or phenotypic
characterization of all the 59 representatives of the bacterial panel
was performed revealing that the bacterial isolates of each species
corresponded to different strains (data not shown). Then, the
antibiotic resistance profile of each strain was determined using a
panel of different antibiotics (Tables S1-S3). Most of the strains
were resistant to multiple antibiotics (belonging to at least two
major classes of antibiotics) and can be therefore defined as MDR
according to the definition of the American Cystic Fibrosis
Foundation [20]. In particular:
i) A. xylosoxidans strains (Table S1) showed a resistant rate
higher than 60% for almost all categories of antibiotic tested:
between β-lactams antibiotics only the combination piperacillin/
tazobactam, imipenem and meropenem showed lower resistance
percentages. The resistant rates for colistin and minocycline were
62.5% and 50%, respectively. The percentage of antibiotics to
which each strain was resistant ranged from 50% to 100%.
ii) S. maltophilia strains (Table S2) showed a resistant rate
higher than 78% for β-lactams, aminoglycosides and
fluoroquinolones antibiotics. The resistant rates for the combination
trimethoprim/sulfamethoxazole and minocycline were 45% and
5.56%, respectively. The percentage of antibiotics to which each
strain was resistant ranged between 50% and 100%.
iii) Staphylococcus aureus strains (Table S3) were highly
resistant to β-lactams and macrolides. The resistant rate for
fluoroquinoles and lincosamides was around 74% and 83%
respectively, whilst the other rates were lower than 50% up to 0%
for linezolid, tigecyclin, trimethoprim/sulphamethoxazole and
vancomycin. One strain was resistant to teicoplanin. The percentage
of antibiotics to which each strain was resistant ranged from 31.2%
to 66.7%.
Subsequently, the antimicrobial activity of different concentrations
of OEO was tested for each of the 59 strains listed in Table 1 by
determining both MIC and MBC. Data obtained at 48 h of
incubation in the presence of OEO are shown in Tables S1-S3 and
summarized in Table 2. OEO exhibited antibacterial activity against
all the 59 bacterial strains to a different extent.
Several MRSA and A. xylosoxidans strains had MIC of 0.50% and
0.25%, v/v, EO at 48 h of incubation. Results were consistent also
at 24 h and 72 h (Table 2).
Quite interestingly, the analysis of MBC data revealed that the OEO
had a strong bactericidal activity, which in most cases was
consistent with the MIC values observed.
In general, OEO showed its inhibitory and microbicidal activity
against human pathogens, even at low concentration: after 48 h,
0.5%, v/v, OEO was able to inhibit the growth of 100% of A.
xylosoxidans, S. maltophilia, and MRSA, and to kill 100% of S.
maltophilia and of MRSA and 95% of A. xylosoxidans.
In particular, the analysis of data from Table 2 revealed that after
i) S. maltophilia strains were more sensitive than those
belonging to the other genera: no strain exhibited MIC and MBC
higher than 0.125%, v/v. The lowest OEO percentages still active
were 0.015% and 0.03, v/v, for MIC and MBC, respectively.
ii) Achromobacter strains were mostly inhibited and killed
by OEO concentrations of 0.25% and 0.50%, v/v.
iii) MRSA had MIC and MBC values ranging from 0.5% to
0.125%, v/v, of OEO.
Data obtained in this work revealed that all the 59 tested strains
were sensitive to OEO, even though to different extents. Overall the
sensitivity of S. maltophilia strains was higher than that exhibited
by MRSA and A. xylosoxidans strains. Moreover, there was no
correlation between the MDR patterns and sensitivity to the OEO of
strains belonging to the same species/group. Indeed, strains with a
(very) different MDR profile exhibited a very similar degree of
sensitivity to the OEO.
MBC values were in most cases completely consistent with the MIC
values of the same strain and indicated that the OEO had a strong
bactericidal activity on each of the 59 strains tested. Since the
strains belong to very different bacterial species/genera (both Gram
positive and Gram negative) the finding of such a broad activity of
OEO might suggest that OEO has the same cellular target(s) on
such widely different species. It is likely that the antibacterial
activity of OEO is due to the combined effect of several bioactive
molecules of the EO complex. Moreover, and quite interestingly, in
spite of the large number of experiments carried out in this work, no
mutant strain resistant to the EO tested was isolated. This finding
strongly suggests the possibility that the antimicrobial activity of
OEO is exerted toward multiple cellular targets. If this is so, the
simultaneous blocking of the activity of different molecular targets
should strongly decrease the probability of the appearance of a
mutant able to resist the essential oils, as happens for most of the
common antibiotics. For example, S. aureus is known for its
involvement in CF and nosocomial infections and is frequently
resistant to several antibiotics. OEO has been reported to reduce
lipase and coagulase activity of S. aureus [21]. The lack of
appearance of resistant strains to concentrations much lower than
2% OEO (maximum MBC value after 24 h) represents a very
interesting finding that might pave the way to the use of OEO to
fight the infections in CF patients.
Antimicrobial activity of Origanum vulgare essential oil Natural Product Communications Vol. 11 (6) 2016 863
Table 2: MIC and MBC in the twenty strains of A. xylosoxidans, S. maltophilia and MRSA.
EO concentration
(% v/v)
MIC (mg/L) (O.D.) MBC
24h 48h 72h 24h 48h 72h
Number % Number % Number %Number % Number % Number %
A. xylosoxidans
1.000 0 0 0 0 0 0 0 0 1 5 1 5
0.500 1 5 7 35 7 35 7 35 8 40 8 40
0.250 14 70 12 60 12 60 11 55 11 55 11 55
0.125 5 25 1 5 1 5 2 10 0 0 0 0
0.060 0 0 0 0 0 0 0 0 0 0 0 0
0.030 0 0 0 0 0 0 0 0 0 0 0 0
S. maltophilia
1.000 0 0 0 0 0 0 0 0 0 0 0 0
0.500 0 0 0 0 0 0 0 0 0 0 0 0
0.250 1 5 0 0 0 0 3 15 0 0 0 0
0.125 7 35 9 45 9 45 12 60 5 25 5 25
0.060 3 15 0 0 1 5 4 20 6 30 4 20
0.030 8 40 10 50 9 45 1 5 9 45 11 55
0.015 0 0 1 5 1 5 0 0 0 0 0 0
0.007 1 5 0 0 0 0 0 0 0 0 0 0
1.000 0 0 0 0 0 0 0 0 0 0 0 0
0.500 5 26.3 5 26.3 5 26.3 7 36.8 5 26.3 5 26.3
0.250 8 42.1 8 42.1 8 42.1 7 36.8 8 42.1 8 42.1
0.125 6 31.6 6 31.6 6 31.6 5 26.4 6 31.6 6 31.6
0.060 0 0 0 0 0 0 0 0 0 0 0 0
0.030 0 0 0 0 0 0 0 0 0 0 0 0
Finally, the development of new inhaled antibiotics (or
antimicrobial-like drugs) could be of great importance to improve
the efficacy of the treatment of CF patients [22]. It is easy to
imagine that an essential oil could be developed into an inhalation
apparatus for use in patients with respiratory infections, as
previously reported for basil, rosemary and eucalyptus [23-25].
Nevertheless, toxicological screenings are mandatory before
suggesting a possible clinical use and possible additive/synergistic
effects should be investigated since EO combinations and/or EOs
plus antibiotics could boost their bactericidal effect, lowering the
concentrations needed, and minimizing in turn the risk of side
Bacterial strains and growth conditions: The panel of 59 bacterial
strains (20 for S. maltophilia and A. xylosoxidans and 19 for
MRSA) tested in this work is reported in Table 1. The bacterial
strains were isolated from different CF patients and each strain was
maintained at -80°C under glycerol (25%, v/v) stock, and grown on
Columbia blood agar (Thermo Scientific, Oxoid SpA, Strada
Rivoltana, 20090 Rodano (MI) - Italy) at 37°C for 24 h.
Identification and typing of bacterial strains: Bacterial strains
were identified using Matrix Assisted Laser Desorption Ionization
Time-of-Flight (Maldi-Tof VITEK MS, bioMérieux Italia Spa,
Antibiotic resistance profiling: Susceptibility was evaluated to
clinically-relevant antibiotics, specific for each pathogen [26-29]
and selected across different antimicrobial families. Minimum
Inhibitory Concentration (MIC) was evaluated for S. maltophilia by
E-Test, and for A. xylosoxidans and MRSA by an automated system
(Vitek 2, bioMérieux Italia Spa, Italy). Results were interpreted
according to the available EUCAST (b) breakpoint tables or CLSI’s
Origanum vulgare essential oil: The O. vulgare EO, extracted by
steam distillation, was purchased from Prodotti Phitocosmetici Dott.
Vannucci di Vannucci Daniela e C. Sas, Prato, Italy. The
composition of the OEO used in this work has been already
reported [11]. MIC and MBC were determined in TSB added with
the EO in concentrations two-fold diluted from 2% to 0.007%, v/v,
and the same volume of dimethylsulphoxide (DMSO, Carlo Erba
Reagenti SpA, Milano, Italy), sterilized by filtration through filters
with a pore diameter of 0.22 µm (Sartorius Italy Srl, Monza e
Brianza, Italy).
Determination of MIC and MBC of O. vulgare EO: Determination
of MIC, in broth micro-dilutions, was performed as described in
standard protocols. Microtiter plates containing serial dilutions of
the OEO were inoculated with aliquots of 100 μL of bacterial
suspensions containing approximately 2×106 CFU/mL in a final
volume of 200 μL. The negative control contained 200 μL of TSB,
whereas the two positive controls contained TSB and DTSB (1% of
DMSO) inoculated with 100 μL of the bacterial suspension
respectively. A further negative control was set up using an
antibiotic able to inhibit the growth of the tested bacteria; different
antibiotics might be used according to the different resistance
pattern of the tested bacteria [26-29]. Microplates were incubated at
37°C aerobically. After incubation, the Infinite 200 PRO multimode
reader (Tecan), was used to detect density (using OD600).
From each tube, at time "0" a 10 μL aliquot of the suspension was
spread on TSA plates and incubated at 37°C aerobically; afterwards,
the number of CFU was determined. The effect of OEO on bacteria
was monitored at 24 h intervals up to 72 h by seeding 10 μL of the
suspensions on TSA plates. Data obtained allowed the
establishment of the bactericidal/bacteriostatic activity of OEO vs
each organism, in terms of MIC, intended as the lowest
concentration of OEO able to inhibit completely the growth of
microorganisms in tubes and on plates. The MBC was defined as
the concentration of OEO that killed at least 99.9% of the inoculum.
All assays were performed in triplicate. Colony growth was verified
even for each control. MIC and MBC were determined after
incubation for 24, 48 and 72 h.
Statistical analyses: Means, standard deviations of bacterial counts
and graphics were obtained through Microsoft Office Excel 2007
(Microsoft S.r.l., Milano, Italy).
Supplementary data: Details on the antibiotic resistance profile,
Origanum vulgare essential oil MIC and MBC of each strain are
also available.
Acknowledgments - This work was supported by Ente Cassa di
Risparmio di Firenze (project 2013.0657).
864 Natural Product Communications Vol. 11 (6) 2016 Pesavento et al.
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Natural Product Communications Vol. 11 (6) 2016
Published online (
A Validated HPLC Method for Simultaneous Determination of Caffeoyl Phenylethanoid Glucosides and
Flavone 8-C-glycosides in Haberlea rhodopensis
Dimitrina Zheleva-Dimitrova, Paraskev Nedialkov and Ulrich Giresser 791
A Novel Heterodimer from Crotalaria ferruginea
Yi-Hong Zou, Xin Liu, Ye-Na Liu, Gui-Hua Tang and Sheng Yin 793
New 2-(2-Phenylethyl)chromone Derivatives and Inhibitors of Phosphodiesterase (PDE) 3A from Agarwood
Takuji Sugiyama, Yuji Narukawa, Shunsuke Shibata, Ryo Masui and Fumiyuki Kiuchi 795
Influence of Different Carbohydrates on Flavonoid Accumulation in Hairy Root Cultures of Scutellaria baicalensis
Chang Ha Park, Young Seon Kim, Xiaohua Li, Haeng Hoon Kim, Mariadhas Valan Arasu, Naif Abdullah Al-Dhabi,
Sook Young Lee and Sang Un Park 799
Pyran-2-one Derivatives from the Roots of Croton crassifolius
Weihuan Huang, Jiajian Wang, Yeyin Liang, Yaolan Li and Guocai Wang 803
New Isocoumarins and Related Metabolites from Talaromyces flavus
Jun-Wei He, Huai-Shuang Xu, Li Yang, Wei-Wei He, Chuan-Xi Wang, Feng Lin, Yang-Yun Lian, Bo-Hang Sun and Guo-Yue Zhong 805
A New Neolignan, and the Cytotoxic and Anti-HIV-1 Activities of Constituents from the Roots of Dasymaschalon sootepense
Sakchai Hongthong, Chutima Kuhakarn, Thaworn Jaipetch, Pawinee Piyachaturawat, Surawat Jariyawat, Kanoknetr Suksen,
Jitra Limthongkul, Narong Nuntasaen and Vichai Reutrakul 809
New Phenyl Propanoids from Cryptocarya bracteolata
Nurdin Saidi, Hiroshi Morita, Marc Litaudon, Mohd. Azlan Nafiah, Khalijah Awang and Mustanir 815
Anti-inflammatory Constituents from the Aerial Parts of Iris minutiaurea
Kyeong Wan Woo, Ki Ho Lee, Ji Hun Jang, Min Suk Kim, Hyun Woo Cho, Jung Hee Cho and Byeongkwan An 817
New Aminonaphthoquinone from the Sea Urchins Strongylocentrotus pallidus and Mesocentrotus nudus
Elena A. Vasileva, Natalia P. Mishchenko, Pavel A. Zadorozhny and Sergey A. Fedoreyev 821
Proteomic Analysis of the Antibacterial Mechanism of Action of Juglone against Staphylococcus aureus
Jiayi Wang, Zixue Wang, Rina Wu, Donghua Jiang, Bing Bai, Dehong Tan, Tingcai Yan, Xiyun Sun, Qi Zhang, and Zhaoxia Wu 825
A Pair of New Polyketide Enantiomers from Three Endolichenic Fungal Strains Nigrospora sphaerica, Alternaria alternata,
and Phialophora sp.
Jun-Wei He, Chuan-Xi Wang, Li Yang, Guo-Dong Chen, Dan Hu, Liang-Dong Guo, Xin-Sheng Yao and Hao Gao 829
Insight into the Presence of Stilbenes in Medicinal Plants Traditionally Used in Croatian Folk Medicine
Ivana Generalić Mekinić, Danijela Skroza, Ivica Ljubenkov and Višnja Katalinić 833
Two New Isomers of Palmityl-4-hydroxycinnamate from Flowers of Taraxacum Species
Matej Dudáš, Mária Vilková, Tibor Béres, Miroslav Repčák and Pavol Mártonfi 837
Chemical Composition, Herbicidal and Antifungal Activity of Satureja cuneifolia Essential Oils from Spain
David García-Rellán, Mercedes Verdeguer, Adele Salamone, María Amparo Blázquez and Herminio Boira 841
Composition of the Leaf Essential Oil of Phoebe formosana from Taiwan and its in vitro Cytotoxic, Antibacterial, and
Antifungal Activities
Yu-Chang Su and Chen-Lung Ho 845
Effects of Plant Density on the Number of Glandular Trichomes and on Yield and Quality of Essential Oils from Oregano
Teresa Tuttolomondo, Salvatore La Bella, Claudio Leto, Giuseppe Bonsangue, Raffaele Leone, Maria Cristina Gennaro,
Giuseppe Virga, Rosalinda Inguanta and Mario Licata 849
Antioxidant and Anti-inflammatory Activities of Essential Oils of Actinodaphne macrophylla and A. pruinosa (Lauraceae)
Wan Mohd Nuzul Hakimi Wan Salleh and Farediah Ahmad 853
Chemical Composition, Antioxidant and Cytotoxic Activities of Essential Oil of the Inflorescence of Anacamptis coriophora
subsp. fragrans (Orchidaceae) from Tunisia
Ridha El Mokni, Saoussen Hammami, Stefano Dall’Acqua, Gregorio Peron, Khaled Faidi, Jeremy Phillip Braude,
Houcine Sebei and Mohamed Hédi El Aouni 857
Essential Oil from Origanum vulgare Completely Inhibits the Growth of Multidrug-Resistant Cystic Fibrosis Pathogens
Giovanna Pesavento, Valentina Maggini, Isabel Maida, Antonella Lo Nostro, Carmela Calonico, Chiara Sassoli, Elena Perrin,
Marco Fondi, Alessio Mengoni, Carolina Chiellini, Alfredo Vannacci, Eugenia Gallo, Luigi Gori, Patrizia Bogani, Anna Rita Bilia,
Silvia Campana, Novella Ravenni, Daniela Dolce, Fabio Firenzuoli and Renato Fani 861
In Vitro Trials of Dittrichia graveolens Essential Oil Combined with Antibiotics
Dragoljub L. Miladinović, Budimir S. Ilić, Branislava D. Kocić, Marija S. Marković and Ljiljana C. Miladinović 865
Phytochemistry, Bioactivity and Potential Impact on Health of Juglans: the Original Plant of Walnut
Dongdong Bi, Yicheng Zhao, Rui Jiang, Yan Wang, Yuxin Tian, Xiaoyi Chen, Shaojuan Bai and Gaimei She 869
Natural Product Communications
Volume 11, Number 6
Original Paper
Pubinernoid A and Apo-9'-fucoxanthinone, Secondary Metabolites from a Gorgonian Coral Pinnigorgia sp.
Hsin-Huan Chang, Yu-Chia Chang, Wu-Fu Chen, Tsong-Long Hwang, Lee-Shing Fang, Zhi-Hong Wen, Yu-Hsin Chen,
Yang-Chang Wu and Ping-Jyun Sung 707
A New Non-glucosidic Iridoid from the Roots of Strychnos nux-blanda
Jirapast Sichaem, Suttira Khumkratok, Pongpun Siripong and Santi Tip-pyang 709
New Cytotoxic Guaianolides from Centaurea aegyptiaca
Hanan G. Sary, Abdel Nasser B. Singab and Khaled Y. Orabi 711
Artemisinic Acid Serves as a Novel ORCA3 Inducer to Enhance Biosynthesis of Terpenoid Indole Alkaloids in
Catharanthus roseus Cambial Meristematic Cells
Mingxuan Wang, Jiachen Zi, Jianhua Zhu, Shan Chen, Pu Wang, Liyan Song and Rongmin Yu 715
New Antiplasmodial Diterpenes from Gutierrezia sarothrae
Qingxi Su, Seema Dalal, Michael Goetz, Maria B. Cassera and David G. I. Kingston 719
A New Cassane-type Diterpene from the Seed of Caesalpinia sappan
Hai Xuan Nguyen, Nhan Trung Nguyen, Phu Hoang Dang, Phuoc Ho Thi, Mai Thanh Thi Nguyen, Mao Van Can,
Dya Fita Dibwe, Jun-ya Ueda, Kinzo Matsumoto and Suresh Awale 723
Two New Oleanane-type Triterpenoids from Methanolyzed Saponins of Momordica cochinchinensis
Rong Fan, Rong-Rong Cheng, Hong-Tao Zhu, Dong Wang, Chong-Ren Yang, Min Xu and Ying-Jun Zhang 725
Isolation of a New Homomonoterpene from Madhuca pasquieri and Effect of Isolated Compounds on NO Production
Le Son Hoang, Manh Hung Tran, Van Thu Nguyen, Quynh Mai Thi Ngo, Joo-Sang Lee, Seong-Soo Rho, Jeong Ah Kim,
Jeong-Hyung Lee, Mi Hee Woo and Byung Sun Min 729
New Bioactive Semisynthetic Derivatives of 31-Norlanostenol and Obtusifoliol from Euphorbia officinarum
Maria Bailen, Mourad Daoubi Khamlichi, Ahmed Benharref, Rafael A. Martinez-Diaz and Azucena Gonzalez-Coloma 733
Variation of Ginsenosides in Ginseng of Different Ages
Jian-Ming He, Yi-Zhen Zhang, Jian-Ping Luo, Wen-Ju Zhang and Qing Mu 739
Colochiroside E, an Unusual Non-holostane Triterpene Sulfated Trioside from the Sea Cucumber Colochirus robustus and
Evidence of the Impossibility of a 7(8)-Double Bond Migration in Lanostane Derivatives having an 18(16)-Lactone
Alexandra S. Silchenko, Anatoly I. Kalinovsky, Sergey A. Avilov, Pelageya V. Andryjaschenko, Pavel S. Dmitrenok,
Ekaterina A. Yurchenko, Igor Yu. Dolmatov, Salim Sh. Dautov, Valentin A. Stonik and Vladimir I. Kalinin 741
Two New Steroidal Aglycones from Roots of Cynanchun paniculatum
Jia-wen Zhao, Feng-yang Chen, Li-juan Gao, Shi-fang Xu, Yi-ping Ye and Xiao-yu Li 747
Steroid Sulfates from Ophiuroids (Brittle Stars): Action on Some Factors of Innate and Adaptive Immunity
Anna K. Gazha, Lyudmila A. Ivanushko, Eleonora V. Levina, Sergey N. Fedorov, Tatyana S. Zaporozets, Valentin A. Stonik and
Nataliya N. Besednova 749
Cytotoxicity of Naturally Occurring Isoquinoline Alkaloids of Different Structural Types
Jakub Chlebek, Ivo Doskočil, Daniela Hulcová, Kateřina Breiterová, Marcela Šafratová, Radim Havelek, Klára Habartová,
Anna Hošťálková, Tereza Volštátová and Lucie Cahlíková 753
Hypoglycemic and Antioxidant Activities of the Water Extract of Aquilaria crassna Leaves in Streptozotocin-Nicotinamide-
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Suchada Manok, Bunleu Sungthong, Hitoshi Sato, Erika Sugiyama and Vilasinee Hirunpanich Sato 757
In Vitro Antifungal Activity of Kampo Medicine Water Extracts against Trichophyton rubrum
Xia Da, Hitoshi Takahashi, Kyaw Zaw Hein and Eishin Morita 763
Guarea kunthiana Bark Extract Enhances the Antimicrobial Activities of Human and Bovine Neutrophils
Natalja Jerjomiceva, Hisham Seri, Ragheda Yaseen, Nicole de Buhr, William N. Setzer, Hassan Y. Naim and
Maren von Köckritz-Blickwede 767
Red Wine Inhibits Aggregation and Increases ATP-diphosphohydrolase (CD39) Activity of Rat Platelets in Vitro
Elisabetta Caiazzo, Idolo Tedesco, Carmela Spagnuolo, Gian Luigi Russo, Armando Ialenti and Carla Cicala 771
How the Addition of Spices and Herbs to Virgin Olive Oil to Produce Flavored Oils Affects Consumer Acceptance
Manel Issaoui, Guido Flamini, Sondess Souid, Alessandra Bendini, Sara Barbieri, Ines Gharbi, Tullia Gallina Toschi,
Pier Luigi Cioni and Mohamed Hammami 775
Erythrina edulis (Pajuro) Seed Protein: A New Source of Antioxidant Peptides
Arturo Intiquilla, Karim Jiménez-Aliaga, Amparo I. Zavaleta, Inés Arnao, Carmen Peña, Elizabeth L. Chávez-Hidalgo and
Blanca Hernández-Ledesma 781
Cloning and Functional Analysis of Three Chalcone Synthases from the Flowers of Safflowers Carthamus tinctorius
Junichi Shinozaki, Hiromichi Kenmoku, Kenichi Nihei, Kazuo Masuda, Masaaki Noji, Katsuhiro Konno, Yoshinori Asakawa and
Kohei Kazuma 787
Continued inside backcover
... This study is a further confirmation that the presence of eucalyptol (and terpenes in general) is crucial for the antimicrobial activity of the EO. Thymol and carvacrol have been investigated for their antimicrobial properties by Pesavento and coworkers [69], who reported the antimicrobial activity of Origanum vulgare EO on opportunistic respiratory pathogens. In this work, 59 bacterial strains belonging to Staphylococcus aureus, Stenotrophomonas maltophilia, and Achromobacter xylosoxidans species were subjected to the treatment with Origanum vulgare EO [69]. ...
... Thymol and carvacrol have been investigated for their antimicrobial properties by Pesavento and coworkers [69], who reported the antimicrobial activity of Origanum vulgare EO on opportunistic respiratory pathogens. In this work, 59 bacterial strains belonging to Staphylococcus aureus, Stenotrophomonas maltophilia, and Achromobacter xylosoxidans species were subjected to the treatment with Origanum vulgare EO [69]. All strains resulted to be highly susceptible, even in the treatment with low EO concentrations. ...
... Interestingly, the selected strains belonged to different bacterial species or genera, and it emerged that none of them muted becoming resistant: these findings suggested that the broad activity of Origanum vulgare EO could be achieved through the interaction with multiple cellular targets, thus minimizing the possible occurrence of mutant-resistant strains. These results encourage a possible use of Origanum vulgare EO in the treatment of multidrug-resistant cystic fibrosis (CF) pathogens, as suggested by the authors [69]. ...
Full-text available
Essential oils are being studied for more than 60 years, but a growing interest has emerged in the recent decades due to a desire for a rediscovery of natural remedies. Essential oils are known for millennia and, already in prehistoric times, they were used for medicinal and ritual purposes due to their therapeutic properties. Using a variety of methods refined over the centuries, essential oils are extracted from plant raw materials: the choice of the extraction method is decisive, since it determines the type, quantity, and stereochemical structure of the essential oil molecules. To these components belong all properties that make essential oils so interesting for pharmaceutical uses; the most investigated ones are antioxidant, anti-inflammatory, antimicrobial, wound-healing, and anxiolytic activities. However, the main limitations to their use are their hydrophobicity, instability, high volatility, and risk of toxicity. A successful strategy to overcome these limitations is the encapsulation within delivery systems, which enable the increase of essential oils bioavailability and improve their chemical stability, while reducing their volatility and toxicity. Among all the suitable platforms, our review focused on the lipid-based ones, in particular micro- and nanoemulsions, liposomes, solid lipid nanoparticles, and nanostructured lipid carriers.
... Different studies showed that MDR pathogens were sensitive to some EOs, including O. vulgare and T. vulgaris. 8,10,[30][31][32] This observation is consistent with our findings that there is The results are expressed as the mean of the diameters in mm of 3 replicates for each strain (±standard deviation). * The differences are statistically different (P-value <0.01). ...
... with the following antimicrobials and concentrations (μg): ampicillin (A, 10), amoxicillin/clavulanic acid 2:1 (AMC, 30), chloramphenicol (C, 30), ceftazidime (CAZ, 10), cyprofloxacin (CIP, 5), colistin (CST,10), enrofloxacin (ENR,5), triple sulfa (SSS,250), cefotaxime (CTX, 5), gentamicin (G, 10), kanamycin (K, 30), cefalotin (KF, 30), nalidixic acid (NAL, 30), streptomycin (S, 10), trimethoprim-sulfamethoxazole (SXT, 1.25/23.75), and tetracycline (T,30). Data were analyzed following the CLSI guideline instructions.36 ...
Full-text available
Antimicrobial resistance has become a global threat to public health. There is a critical need to find new antimicrobial substances from natural sources. The aim of this study was to investigate the antimicrobial activity of essential oils (EOs) obtained from Origanum vulgare, Thymus serpyllum, Thymus vulgaris, and Melaleuca alternifolia against multidrug resistant strains of Salmonella isolated from samples of diverse animal origin. The strains were biochemically identified, serotyped, and characterized for their antimicrobial resistance profiles. The antimicrobial activity of the EOs against the strains was evaluated using the Kirby-Bauer diffusion method, followed by determination of the minimal inhibitory concentration and minimum bactericidal concentrations. The EOs of T. serpyllum and O. vulgare, which contain carvacrol as the main compound, show excellent antimicrobial activity.
... In this scenario, essential oils represent ideal candidates because they may act as anti-virulence or antipathogenic agents [12,14,16]. EOs are complex mixtures of different classes of organic compounds and have been empirically used in traditional medicine, including for the treatment of uncomplicated upper respiratory tract infections [47,48]. Some EOs include essentially terpenoids and phenolic compounds that are known to impair the virulence by interference with bacterial quorum sensing mechanisms [31]. ...
Full-text available
Pseudomonas aeruginosa is an opportunistic pathogen responsible for nosocomial infections, and is often involved in airway infections of cystic fibrosis (CF) patients. P. aeruginosa virulence is related to its ability to form biofilm, trigger different types of motilities, and produce toxins (for example, bacterial pigments). In this scenario, essential oils (EOs) have gained notoriety for their role in phenotype modulation, including virulence modulation. Among different EOs previously analyzed, herein we investigated the activity of Coridothymus capitatus EO (CCEO) against specific virulence factors produced by P. aeruginosa isolated from CF patients. CCEO showed inhibition of new biofilm formation and reduction in mature biofilm in about half of the tested strains. On selected strains, SEM analysis provided interesting information regarding CCEO action in a pre-adhesion assay. CCEO treatment showed a dramatic modification of the extracellular matrix (ECM) structure. Our results clearly showed a drastic reduction in pyocyanin production (between 84% and 100%) for all tested strains in the presence of CCEO. Finally, CCEO was also able to strongly affect P. aeruginosa swarming and swimming motility for almost all tested strains. In consideration of the novel results obtained on clinical strains isolated from CF patients, CCEO may be a potential candidate to limit P. aeruginosa virulence.
... Some possess antimicrobial activities, and are thus commonly used as self-medication to treat mild respiratory infections (Inouye et al., 2001). Noteworthily, an increasing number of studies suggest that EOs could be useful as adjunctive therapy in cystic fibrosis (CF) patients chronically infected with Haemophilus influenzae (Balazs et al., 2019), Staphylococcus aureus, Stenotrophomonas maltophilia, Achromobacter xylosoxidans (Pesavento et al., 2016), or Pseudomonas aeruginosa (Ragno et al., 2020). For instance, extracts of bay, cinnamon, clove, pimento, thyme, rosemary, oregano and lemongrass have been reported to inhibit in vitro the growth of P. aeruginosa, a major pathogen in CF lung (Hammer et al., 1999;Swamy et al., 2016). ...
Full-text available
Essential oils (EOs) or their components are widely used by inhalation or nebulization to fight mild respiratory bacterial infections. However, their interaction with antibiotics is poorly known. In this study we evaluated the effects of citral, the main component of lemongrass oil, on in vitro susceptibility of Pseudomonas aeruginosa to antibiotics. Exposure of strain PA14 to subinhibitory concentrations of citral increased expression of operons encoding the multidrug efflux systems MexEF-OprN and MexXY/OprM, and bacterial resistance to anti-pseudomonal antibiotics including imipenem (twofold), gentamicin (eightfold), tobramycin (eightfold), ciprofloxacin (twofold), and colistin (≥128-fold). Use of pump deletion mutants showed that in addition to efflux other mechanisms were involved in this citral-induced phenotype. Determination of Zeta potential suggested that citral impairs the cell surface binding of aminoglycosides and colistin used at low concentrations (≤10 μg/mL). Moreover, experiments based on Raman spectroscopy and high-resolution mass spectrometry demonstrated formation of a Schiff base between the aldehyde group of citral and amino-groups of tobramycin and colistin. Chemical synthesis of tobracitryl, the imine compound resulting from condensation of citral and tobramycin, confirmed the loss of antibiotic activity due to adduct formation. Altogether these data point to the potential risk concern of self-medication with EOs containing citral in patients suffering from P. aeruginosa chronic lung infections and being treated with aerosols of aminoglycoside or colistin.
... Altintas et al. 2013;Freires et al. 2015;Martins et al. 2015). Indeed, it has been shown that essential oils from different medicinal plants, such as Lavandula officinalis, Origanum vulgare and Thymus (Maida et al. 2014;Pesavento et al. 2016;Checcucci et al. 2017;Maggini et al. 2017b), possess strong antimicrobial activity against different human pathogens resistant to a plethora of antibiotics. The plant VOCs could also boost the antibiotic efficacy as a result of an intracellular mechanism of action, as demonstrated using Burkholderia cepacia mutants affected in efflux pumps (Perrin et al. 2018). ...
Symbiosis involving two (or more) prokaryotic and/or eukaryotic partners is extremely widespread in nature and it has performed, and is still performing, a key role in the evolution of several biological systems. The interaction between symbiotic partners are based on the emission and perception of a plethora of molecules, including Volatile Organic Compounds (VOCs), synthesized by both prokaryotic and eukaryotic (micro)organisms. VOCs acquire increasing importance since they spread above-and below-ground and act as info-chemicals regulating a very complex network. In this work we have reviewed what is known about the VOCs synthesized by fungi prior and during the interaction(s) with their partners (either prokaryotic or eukaryotic) and their possible role(s) in establishing and maintaining the symbiosis. Lastly, we have also described the potential applications of fungal VOCs from different biotechnological perspectives, including medicinal, pharmaceutical, and agronomical ones.
Background: Antibiotic resistance in cystic fibrosis (CF) is a well-known phenomenon. However, the comprehensive epidemiological impact of antibiotic resistance in CF is not clearly documented. So, this meta-analysis evaluated the proportion rates of carbapenem resistance (imipenem, meropenem, and doripenem) in CF based on publication date (1979-2000, 2001-2010, and 2011-2021), continents, pathogens, and antimicrobial susceptibility testing (AST). Methods: We searched studies in PubMed, Scopus, and Web of Science (until April 2021). Statistical analyses were conducted using STATA software (version 14.0). Results: The 110 studies included in the analysis were performed in 25 countries and investigated 13,324 pathogens associated with CF. The overall proportion of imipenem, meropenem, and doripenem resistance in CF were 43% (95% CI 36-49), 48% (95% CI 40-57), 28% (95% CI 23-33), and 45% (95% CI 32-59), respectively. Our meta-analysis showed that trends of imipenem, meropenem, and doripenem-resistance had gradual decreases over time (1979-2021). This could be due to the limited clinical effectiveness of these antibiotics to treat CF cases over time. Among the opportunistic pathogens associated with CF, the highest carbapenem resistance rates were shown in Stenotrophomonas maltophilia, Burkholderia spp., Pseudomonas aeruginosa, and Staphylococcus aureus. The highest and lowest carbapenem resistance rates among P. aeruginosa in CF patients were shown against meropenem (23%) and doripenem (39%). Conclusions: We showed that trends of carbapenem resistance had decreased over time (1979-2021). This could be due to the limited clinical effectiveness of these antibiotics to treat CF cases over time. Plans should be directed to fight biofilm-associated infections and prevent the emergence of mutational resistance. Systematic surveillance for carbapenemase-producing pathogens in CF by molecular surveillance is necessitated.
Full-text available
Origanum vulgare L. (O. vulgare) is an important medicinal herb of the family Lamiaceae. In the current study, we explained the critical evaluation of traditional uses, the phytochemistry and the antimicrobial properties of O. vulgare and its subspecies, with a focus on the mechanisms of actions of the most important phytochemicals from O. vulgare subspecies. The most important phytochemicals of O. vulgare are volatile (essential oil) and non-volatile phenolic compounds (phenolic acids & flavonoids). The constituents of the O. vulgare essential oil (EO) include high percentages of thymol and carvacrol with excellent antimicrobial activity alone or in combination with other antibiotics. Interesting results have been reported the remarkable antimicrobial activities of infusion or tea products of O. vulgare with a high amount of EO against multidrug‐resistant bacterial and fungal microorganism (such as Escherichia coli, Staphylococcus aureus, Candida albicans and Pseudomonas aeruginosa). The most important antibacterial mechanisms of O. vulgare are enzyme inhibition, efflux pump inhibition, ATP depletion, biofilm formation inhibition and cytoplasmic membrane damage. The antimicrobial activity of the hirtum subspecies has been confirmed in different in-vitro and in-vivo studies. The present review confirms the clinical and preclinical research showing the O. vulgare and its subspecies antimicrobial effects.
Full-text available
Bacterial biofilm plays a pivotal role in chronic Staphylococcus aureus (S. aureus) infection and its inhibition may represent an important strategy to develop novel therapeutic agents. The scientific community is continuously searching for natural and “green alternatives” to chemotherapeutic drugs, including essential oils (EOs), assuming the latter not able to select resistant strains, likely due to their multicomponent nature and, hence, multitarget action. Here it is reported the biofilm production modulation exerted by 61 EOs, also investigated for their antibacterial activity on S. aureus strains, including reference and cystic fibrosis patients’ isolated strains. The EOs biofilm modulation was assessed by Christensen method on five S. aureus strains. Chemical composition, investigated by GC/MS analysis, of the tested EOs allowed a correlation between biofilm modulation potency and putative active components by means of machine learning algorithms application. Some EOs inhibited biofilm growth at 1.00% concentration, although lower concentrations revealed different biological profile. Experimental data led to select antibiofilm EOs based on their ability to inhibit S. aureus biofilm growth, which were characterized for their ability to alter the biofilm organization by means of SEM studies.
Malvastrum coromandelianum (L.) Garcke is a subshrub of the Malvaceae family with various medicinal properties. The objective of this study was to investigate the chemical composition, antibacterial, cytotoxic and antioxidant activities of the essential oil isolated from the aerial parts of M. coromandelianum. The chemical composition was identified by GC/FID and GC/MS analysis. Fifty compounds were identified, representing 98.5 % of the oil. The major constituents were identified as palmitic acid (19.2 %), hexahydrofarnesyl acetone (5.2 %), linoleic acid (4.8 %), β-caryophyllene (3.5 %) and cedren-8-en-15-ol (3.1 %). The antibacterial activity was evaluated by the disc agar diffusion and micro-broth dilution assays. The results demonstrated that the essential oil exhibited significant antibacterial activity against Staphylococcus aureus, Bacillus subtilis and Escherichia coli with MIC values of 0.156 mg/mL, 0.156 mg/mL and 0.078 mg/mL, respectively. In addition, a moderate cytotoxic effect was observed against HepG2 and MCF-7 cell lines with IC50 values of 116.40 μg/mL and 120.27 μg/mL according to the MTT assay. The essential oil was also evaluated for antioxidant effects by DPPH, ABTS and FRAP assays, which showed a weak antioxidant activity.
Full-text available
Stenotrophomonas maltophilia has both the pathogenic potential and the ability to cause food spoilage, and is characterized by multi-resistance to many antibiotics. Essential oils (EOs) have been reported as good antimicrobial agents. In this study, seven EOs were selected to evaluate the antibacterial effect against foodborne spoilage S. maltophilia 4–1 by disk diffusion method, broth dilution method, and fumigation treatment. The chemical compositions of EOs were analyzed via gas chromatography–mass spectrometry injecting with both gas and liquid, hoping to reveal the relationship between active compounds and antibacterial activity. The results indicated that litsea cubeba oil (LCO) exhibited a strong inhibitory effect with minimum bactericidal concentration (MBC) value of 0.125% (v/v), and only LCO showed bacteriostatic effect in fumigation treatment within the tested range. Its key active component, citral, was responsible for the antibacterial property by causing damage and rupture of cell membrane determined using fluorescent dyes and field emission scanning electron microscope. The minimum inhibitory concentration and MBC of citral against S. maltophilia 4–1 was determined to be 0.25% (v/v) and 0.5% (v/v), respectively. This study reveals the high efficiency of EOs to inhibit bacteria in terms of key active component, and provides an alternative to reduce the resistant bacteria.
Full-text available
Essential oils are complex blends of a variety of volatile molecules such as terpenoids, phenol-derived aromatic components, and aliphatic components having a strong interest in pharmaceutical, sanitary, cosmetic, agricultural, and food industries. Since the middle ages, essential oils have been widely used for bactericidal, virucidal, fungicidal, antiparasitical, insecticidal, and other medicinal properties such as analgesic, sedative, anti-inflammatory, spasmolytic, and locally anaesthetic remedies. In this review their nanoencapsulation in drug delivery systems has been proposed for their capability of decreasing volatility, improving the stability, water solubility, and efficacy of essential oil-based formulations, by maintenance of therapeutic efficacy. Two categories of nanocarriers can be proposed: polymeric nanoparticulate formulations, extensively studied with significant improvement of the essential oil antimicrobial activity, and lipid carriers, including liposomes, solid lipid nanoparticles, nanostructured lipid particles, and nano- and microemulsions. Furthermore, molecular complexes such as cyclodextrin inclusion complexes also represent a valid strategy to increase water solubility and stability and bioavailability and decrease volatility of essential oils.
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Cystic fibrosis (CF) patients have chronic airway infection and frequent exposure to antibiotics, which often leads to the emergence of resistant organisms. Achromobacter xylosoxidans is a new emergent pathogen in CF spectrum. From 2005 to 2010 we had an outbreak in A. xylosoxidans prevalence in our CF center, thus, the present study was aimed at deeply investigating virulence traits of A. xylosoxidans strains isolated from infected CF patients. To this purpose, we assessed A. xylosoxidans genome variability by randomly amplified polymorphic DNA (RAPD), biofilm production, antibiotic resistances, and motility. All A. xylosoxidans strains resulted to be biofilm producers, and were resistant to antibiotics usually employed in CF treatment. Hodge Test showed the ability to produce carbapenemase in some strains. Strains who were resistant to β-lactamics antibiotics, showed the specific band related to metal β-lactamase (blaIMP-1), and some of them showed to possess the integron1. Around 81% of A. xylosoxidans strains were motile. Multivariate analysis showed that RAPD profiles were able to predict Forced Expiratory Volume (FEV1%) and biofilm classes. A significant prevalence of strong biofilm producers strains was found in CF patients with severely impaired lung functions (FEV1% class 1). The outbreak we had in our center (prevalence from 8.9 to 16%) could be explained by an enhanced adaptation of A. xylosoxidans in the nosocomial environment, despite of aggressive antibiotic regimens that CF patients usually undergo.
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In this work we have checked the ability of the essential oils extracted from six different medicinal plants (Eugenia caryophyllata, Origanum vulgare, Rosmarinus officinalis, Lavandula officinalis, Melaleuca alternifolia, and Thymus vulgaris) to inhibit the growth of 18 bacterial type strains belonging to the 18 known species of the Burkholderia cepacia complex (Bcc). These bacteria are opportunistic human pathogens that can cause severe infection in immunocompromised patients, especially those affected by cystic fibrosis (CF), and are often resistant to multiple antibiotics. The analysis of the aromatograms produced by the six oils revealed that, in spite of their different chemical composition, all of them were able to contrast the growth of Bcc members. However, three of them (i.e., Eugenia caryophyllata, Origanum vulgare, and Thymus vulgaris) were particularly active versus the Bcc strains, including those exhibiting a high degree or resistance to ciprofloxacin, one of the most used antibiotics to treat Bcc infections. These three oils are also active toward both environmental and clinical strains (isolated from CF patients), suggesting that they might be used in the future to fight B. cepacia complex infections.
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Clove essential oil, used as an antiseptic in oral infections, inhibits Gram-negative and Gram-positive bacteria as well as yeast. The influence of clove essential oil concentration, temperature and organic matter, in the antimicrobial activity of clove essential oil, was studied in this paper, through the determination of bacterial death kinetics. Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa were the microorganisms selected for a biological test. To determine the temperature effect, they were assayed at 21° and 37° C. The concentration coefficient was determined with 0.4%, and 0.2% of essential oil. The influence of the presence of organic matter was determined with 0.4% of essential oil. The results obtained demonstrated that Escherichia coli were more sensitive even though the essential oil exerted a satisfactory action in three cases. In the three microbial species, 0.4% of essential oil at 21° C have reduced the bacterial population in 5 logarithmic orders. Organic matter reduces the antibacterial activity even though the bactericide efficacy was not lost. Clove essential oil can be considered as a potential antimicrobial agent for external use.
With the aim to expand the olive oil market to a larger number of consumers who are not familiar with the sensory characteristics of virgin olive oil, the use of novel products known as "flavored olive oils", obtained by adding different kind of spices and aromatic herbs, is spreading in many countries. In order to test consumer acceptability of this type of product, in a country (Tunisia) in which virgin olive oil is regularly consumed, flavored olive oils were prepared by adding aromatic extracts of thyme, oregano, a mix of herbs (used as pizza seasoning), rosemary, and basil to a monovarietal Chemlali virgin olive oil and a consumer test on 206 subjects was performed. Selected quality parameters (free acidity, peroxide number, oxidative stability, specific absorption at K-232 nm and K-270 nm) were also measured and no significant variations were detected. Slight differences were found concerning the content of minor compounds (chlorophylls, carotenoids and total phenols). On the other hand, notable differences were seen in the profiles of volatile compounds, which appeared to be responsible for the observed variability in consumer acceptance. Although the unflavored oil was more appreciated than the flavored ones, among the latter, thyme flavored olive oil was the most appreciated.
The flowers of safflowers (Carthamus tinctorius L.) are very important as they are the sole source of their distinct pigments, i.e. carthamus-red and -yellows, and have historically had strong connections to the cultural side of human activities such as natural dyes, rouge, and traditional medicines. The distinct pigments are quinochalcone C-glucosides, which are found specifically in the flowers of C. tinctorius. To investigate the biosynthetic pathways of quinochalcone C-glucosides, de novo assembly of the transcriptome was performed on the flowers using an Illumina sequencing platform to obtain 69,312 annotated coding DNA sequences. Three chalcone synthase like genes, CtCHS1, 2 and 3 were focused on and cloned, which might be involved in quinochalcone C-glucosides biosynthesis by establishing the C6-C3-C6 chalcone skeleton. It was demonstrated that all the recombinant CtCHSs could recognize p-coumaroyl-CoA, caffeoyl-CoA, feruloyl-CoA, and sinapoyl-CoA as starter substrates. This is the first report on the cloning and functional analysis of the three chalcone synthase genes from the flowers of C. tinctorius.