Research on Essential Oils

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Research on Essential Oils - Study 1

Pharmazie. 2001 Apr;56(4):343-7.Antiviral activity of Australian tea tree oil and eucalyptus oil against herpes simplex virus in cell culture.

Schnitzler P, Schön K, Reichling J.

Department of Virology, Hygiene Institute, University of Heidelberg, Germany.

The antiviral effect of Australian tea tree oil (TTO) and eucalyptus oil (EUO) against herpes simplex virus was examined. Cytotoxicity of TTO and EUO was evaluated in a standard neutral red dye uptake assay. Toxicity of TTO and EUO was moderate for RC-37 cells and approached 50% (TC50) at concentrations of 0.006% and 0.03%, respectively. Antiviral activity of TTO and EUO against herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) was tested in vitro on RC-37 cells using a plaque reduction assay. The 50% inhibitory concentration (IC50) of TTO for herpes simplex virus plaque formation was 0.0009% and 0.0008% and the IC50 of EUO was determined at 0.009% and 0.008% for HSV-1 and HSV-2, respectively. Australian tea tree oil exhibited high levels of virucidal activity against HSV-1 and HSV-2 in viral suspension tests. At noncytotoxic concentrations of TTO plaque formation was reduced by 98.2% and 93.0% for HSV-1 and HSV-2, respectively. Noncytotoxic concentrations of EUO reduced virus titers by 57.9% for HSV-1 and 75.4% for HSV-2. Virus titers were reduced significantly with TTO, whereas EUO exhibited distinct but less antiviral activity. In order to determine the mode of antiviral action of both essential oils, either cells were pretreated before viral infection or viruses were incubated with TTO or EUO before infection, during adsorption or after penetration into the host cells. Plaque formation was clearly reduced, when herpes simplex virus was pretreated with the essential oils prior to adsorption. These results indicate that TTO and EUO affect the virus before or during adsorption, but not after penetration into the host cell. Thus TTO and EUO are capable to exert a direct antiviral effect on HSV. Although the active antiherpes components of Australian tea tree and eucalyptus oil are not yet known, their possible application as antiviral agents in recurrent herpes infection is promising.

PMID: 11338678 [PubMed - indexed for MEDLINE]

Research on Essential Oils - Study 2

Nat Prod Commun. 2009 Nov;4(11):1605-10.Chemical composition and antimicrobial activity of essential oil of Bupleurum montanum and B. plantagineum.

Laouer H, Hirèche-Adjal Y, Prado S, Boulaacheb N, Akkal S, Singh G, Singh P, Isidorov VA, Szczepaniak L.

Laboratory of Natural Resources Valorization, Department of Biology, Ferhat Abbas University, Setif, Algeria. hocine_laouer@hotmail.com

The hydrodistilled oils from the aerial parts of Bupleurum montanum and B. plantagineum, which are endemic to North Africa, including Algeria, were analyzed by gas chromatography-mass spectrometry (GC-MS). Ninety-eight compounds were detected in the oil of B. montanum, representing 98.6% of the total oil, and 68 in the oil of B. plantagineum, representing 99.8% of the total. Megastigma-4,6-(E),8(2)-triene was the major constituent of B. montana oil (25.3%). Other important compounds were myrcene, alpha-pinene and benzyl tiglate. Conversely, the major constituents of the oil of B. plantagineum were alpha-pinene (31.9%), cis-chrysanthenyl acetate (28.2%), and myrcene (24.8%), followed by the monoterpene hydrocarbon limonene (5.1%). The mutagenic, antiplasmodial and antimicrobial activities of the essential oils were individually evaluated against eleven microorganisms, using the agar diffusion method, by determination of MIC values. The investigated oils exhibited moderate antimicrobial activity. Maximum activity of the oils was observed against Nocardia asteroides, Staphylococcus aureus and Enterococcus faecalis. Fungicidal activity against Candida albicans was also found for both oils.

PMID: 19968000 [PubMed - in process]

Research on Essential Oils - Study 3

J Perianesth Nurs. 2009 Dec;24(6):348-55.The use of the essential oil lavandin to reduce preoperative anxiety in surgical patients.

Braden R, Reichow S, Halm MA.

United Hospital, St Paul, MN, USA.

Preoperative anxiety is prevalent in surgical patients who may require anxiety medications, thus impacting preoperative teaching and patient satisfaction. No studies were found in a comprehensive search on the effect of essential oils on anxiety in the preoperative setting. The purpose of this experimental study was to investigate whether the essential oil lavandin is more effective than standard care in reducing preoperative anxiety. A convenience sample of 150 adult patients were randomly assigned to either control (standard care), experimental (standard care plus essential oil lavandin), or sham (standard care plus jojoba oil) groups. Visual analog scales were used to assess anxiety on admission and OR transfer. Controlling for baseline anxiety and pain, the lavandin group had significantly lower anxiety on OR transfer, suggesting that lavandin is a simple, low-risk, cost-effective intervention with the potential to improve preoperative outcomes and increase patient satisfaction. Future studies should test the effects of lavandin in the postoperative phase and in specific populations with documented high anxiety.

PMID: 19962101 [PubMed - in process]

Research on Essential Oils - Study 4

J Food Sci. 2009 Sep;74(7):M390-7.Antibacterial effects of allspice, garlic, and oregano essential oils in tomato films determined by overlay and vapor-phase methods.

Du WX, Olsen CW, Avena-Bustillos RJ, McHugh TH, Levin CE, Mandrell R, Friedman M.

Processed Foods Research, Western Regional Research Center, US Dept of Agriculture, Agricultural Research Service, 800 Buchanan St, Albany, CA 94710, USA.

Physical properties as well as antimicrobial activities against Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes of allspice, garlic, and oregano essential oils (EOs) in tomato puree film-forming solutions (TPFFS) formulated into edible films at 0.5% to 3% (w/w) concentrations were investigated in this study. Antimicrobial activities were determined by 2 independent methods: overlay of the film on top of the bacteria and vapor-phase diffusion of the antimicrobial from the film to the bacteria. The results indicate that the antimicrobial activities against the 3 pathogens were in the following order: oregano oil > allspice oil > garlic oil. Listeria monocytogenes was less resistant to EO vapors, while E. coli O157:H7 was more resistant to EOs as determined by both overlay and vapor-phase diffusion tests. The presence of plant EO antimicrobials reduced the viscosity of TPFFS at the higher shear rates, but did not affect water vapor permeability of films. EOs increased elongation and darkened the color of films. The results of the present study show that the 3 plant-derived EOs can be used to prepare tomato-based antimicrobial edible films with good physical properties for food applications by both direct contact and indirectly by vapors emanating from the films.

PMID: 19895486 [PubMed - in process]

Research on Essential Oils - Study 5

J Food Sci. 2009 Sep;74(7):M358-63.Chemical composition and antimicrobial and antioxidant activities of Mentha (longifolia L. and viridis) essential oils.

Mkaddem M, Bouajila J, Ennajar M, Lebrihi A, Mathieu F, Romdhane M.

Laboratoire de Modélisation Analyse et Commande des Systèmes, Ecole Natl d'Ingénieurs de Gabès, Rue Omar elkhattab-ZRIG-6029 Gabès, Tunisie.

The study was aimed to investigate essential oil chemical composition (gas chromatography/flame ionization detection [GC-FID] and gas chromatography/mass spectrometry [GC-MS]) and antioxidant (1,1-diphenyl-2-picrylhydrazyl free radical (DPPH) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonate [ABTS] assays) and antimicrobial (Gram-positive and Gram-negative bacteria, fungi, and yeast) activities of essential oils extracted from leaves of Mentha longifolia L. and Mentha viridis. GC-MS analysis revealed that M. longifolia was constituted by pulegone (54.41%) as a major component followed by isomenthone (12.02%), 1,8-cineole (7.41%), borneol (6.85%), and piperitenone oxide (3.19%). M. viridis was rich in carvone (50.47%), 1,8-cineole (9.14%), and limonene (4.87%). The antioxidant activity by ABTS assay showed IC(50) values of 476.3 +/- 11.7 and 195.1 +/- 4.2 mg/L for M. longifolia and M. viridis, respectively, the DPPH assays have resulted in a moderate IC(50) (>8000 mg/L and 3476.3 +/- 133 mg/L for M. longifolia and M. viridis, respectively). Antimicrobial activity showed that Listeria monocytogenes and Klebsiella pneumoniae bacteria were more inhibited by the 2 essential oils tested. Escherichia coli was least susceptible. A strong activity was also observed on fungi and yeasts. Carvone, thymol, and piperitone oxide have not been detected in Tunisian M. longifolia. Camphor is reported for the 1st time for M. viridis. Antioxidant and antibacterial activities were correlated to chemical composition.

PMID: 19895481 [PubMed - in process]

Research on Essential Oils - Study 6

Pak J Pharm Sci. 2009 Oct;22(4):421-4.Antibacterial activity of oregano (Origanum vulgare Linn.) against gram positive bacteria.

Saeed S, Tariq P.

Department of Microbiology, University of Karachi, Karachi-75270, Pakistan. sabahatsaeed2003@yahoo.com

The present investigation is focused on antibacterial potential of infusion, decoction and essential oil of oregano (Origanum vulgare) against 111 Gram-positive bacterial isolates belonging to 23 different species related to 3 genera. Infusion and essential oil exhibited antibacterial activity against Staphylococcus saprophyticus, S. aureus, Micrococcus roseus, M. kristinae, M. nishinomiyaensis, M. lylae, M. luteus, M. sedentarius, M. varians, Bacillus megaterium, B. thuringiensis, B. alvei, B. circulans, B. brevis, B. coagulans, B. pumilus, B. laterosporus, B. polymyxa, B. macerans, B. subtilis, B. firmus, B. cereus and B. lichiniformis. The infusion exhibited maximum activity against B. laterosporus (17.5 mm mean zone of inhibition+/-1.5 Standard deviation) followed by B. polymyxa (17.0 mm+/-2.0 SD) and essential oil of oregano exhibited maximum activity against S. saprophyticus (16.8 mm+/-1.8 SD) followed by B. circulans (14.5 mm+/-0.5 SD). While all these tested isolates were found resistant to decoction of oregano.

PMID: 19783523 [PubMed - indexed for MEDLINE]

Research on Essential Oils - Study 7

Forsch Komplementmed. 2009 Apr;16(2):79-90. Epub 2009 Apr 3.Essential oils of aromatic plants with antibacterial, antifungal, antiviral, and cytotoxic properties--an overview.

Reichling J, Schnitzler P, Suschke U, Saller R.

Institute of Pharmacy and Molecular Biotechnology, Department of Biology, University of Heidelberg, Im Neuenheimer Feld 364, Heidelberg, Germany. Juergen.Reichling@urz.uni-heidelberg.de

The abundant use of anti-infective agents resulted in the emergence of drug-resistant bacteria, fungi, and viruses. To overcome the increasing resistance of pathogenic microbes, a variety of medicinal plants have been screened worldwide for their antimicrobial properties. The aim is to find new, effective antimicrobial agents with novel modes of actions. Essential oils derived from aromatic medicinal plants have been reported to exhibit exceptionally good antimicrobial effects against bacteria, yeasts, filamentous fungi, and viruses. The progress of this expanding scientific field will be documented by the most important results published in the last decade. Copyright (c) 2009 S. Karger AG, Basel.

PMID: 19420953 [PubMed - indexed for MEDLINE]

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