Screening of selected essential oils for antibacterial activity in vapour phase

The purpose of the study was to determine the chemical composition and antibacterial activity of Lippia multiflora Moldenke essential oils (EOs) collected in different regions of Angola. Antibacterial activity was evaluated using the agar wells technique and vapour phase test. Analysis of the oils by GC/MS identified thirty-five components representing 67.5 to 100% of the total oils. Monoterpene hydrocarbons were the most prevalent compounds, followed by oxygenated monoterpenes. The content of the compounds varied according to the samples. The main components were Limonene, Piperitenone, Neral, Citral, Elemol, p-cymene, Transtagetone, and Artemisia ketone. Only one of the eleven samples contained Verbenone as the majority compound. In the vapour phase test, a single oil was the most effective against all the pathogens studied. The principal component analysis (PCA) and hierarchical cluster analysis (HCA) of components of the selected EOs and inhibition zone diameter values of agar wells technique allowed us to identify a variability between the plants from the two provinces, but also intraspecific variability between sub-groups within a population. Each group of essential oils constituted a chemotype responsible for their bacterial inhibition capacity. The results presented here suggest that Angolan Lippia multiflora Moldenke has antibacterial properties and could be a potential source of antimicrobial agents for the pharmaceutical and food industry.

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Antibacterial activity comparison of several Portuguese Thymus essential oils

Planta Medica ◽

10.1055/s-0029-1234925 ◽

2009 ◽

Vol 75 (09) ◽

Author(s):

SA Dandlen ◽

AC Figueiredo ◽

LG Pedro ◽

JG Barroso ◽

MG Miguel ◽

...

Keyword(s):

Antibacterial Activity ◽

Essential Oils ◽

Activity Comparison

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Chemical composition and antibacterial activity of essential oils from different populations of Artemisia incana (Asteraceae) from Iran

Planta Medica ◽

10.1055/s-0029-1234456 ◽

2009 ◽

Vol 75 (09) ◽

Author(s):

M Atri ◽

A Chehregani ◽

S Yousefi ◽

F Jalal

Keyword(s):

Antibacterial Activity ◽

Chemical Composition ◽

Essential Oils ◽

Different Populations

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Chemical Composition and Antibacterial Activity of Essential Oils of Three Medicinal Plants from Algerian Semi-Arid Climatic Zone

Phytothérapie ◽

10.3166/phyto-2019-0150 ◽

2018 ◽

Vol 16 (S1) ◽

pp. S155-S163 ◽

Cited By ~ 2

Author(s):

S. Mehalaine ◽

O. Belfadel ◽

T. Menasria ◽

A. Messaili

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Pseudomonas Aeruginosa ◽

Antibacterial Activity ◽

Chemical Composition ◽

Essential Oil ◽

Essential Oils ◽

Rosmarinus Officinalis ◽

Salvia Officinalis ◽

Thymus Algeriensis

The present study was carried out to determine, for the first time, the chemical composition and antibacterial activity of essential oils derived from the aerial parts of three aromatic plants Thymus algeriensis Boiss & Reut, Rosmarinus officinalis L., and Salvia officinalis L. growing under semiarid conditions. The essential oils were chemically analyzed and identified by gas chromatography (GC) and GC/ mass spectrometry (GC/MS) and their antimicrobial activity was individually evaluated against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa using both agar disk diffusion and agar dilution methods. The major constituents of Thymus algeriensis essential oil were identified as camphor (13.62%), 1,8-cineol (6.00%), borneol (5.74%), viridiflorol (4.00%), and linalool (3.93%). For Rosmarinus officinalis essential oil, 48 compounds were characterized, of which the main constituents were camphor (17.09%), Z-β-ocimene (10.88%), isoborneol (9.68%), α-bisabolol (7.89%), and borneol (5.11%). While, Salvia officinalis essential oil was characterized by β-thujone (16.44%), followed by viridiflorol (10.93%), camphor (8.99%), 1,8-cineol (8.11%), trans-caryophyllene (5.85%), and α-humulene (4.69%) as the major components. Notably, results from antibacterial screening indicated that Thymus algeriensis and Salvia officinalis essential oils exhibited a strong inhibitory effect against both Escherichia coli and Staphylococcus aureus compared to Rosmarinus officinalis essential oil. Further, less activity was recorded against Pseudomonas aeruginosa for the three tested essential oils.

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Chemical Composition, Antibacterial, Insecticidal and Anti-Oxidant Activities of Three Acantholimon Species (A. atropatanum, A. gilliatii and A. tragacanthium)

The Natural Products Journal ◽

10.2174/2210315509666190117153456 ◽

2020 ◽

Vol 10 (3) ◽

pp. 272-278

Author(s):

Ardalan Pasdaran ◽

Satyajit D. Sarker ◽

Lutfun Nahar ◽

Azadeh Hamedi

Keyword(s):

Antibacterial Activity ◽

Chemical Composition ◽

Essential Oil ◽

Essential Oils ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Main Compound ◽

Aerial Parts ◽

Anti Oxidant ◽

Gas Chromatography Mass Spectroscopy

Background: The essential oil from the Acantholimon genus have been an integral part of the traditional food additive in Middle East. Most of the plants in Acantholimon genus have not been studied scientifically. The aim of this study is to investigate the chemical composition, antibacterial, insecticidal and anti-oxidant activities of three Acantholimon species including Acantholimon atropatanum, A. gilliatii and A. tragacanthium. Method: The essential oils of the aerial parts were extracted by hydrodistillation. Chemical constitutions were identified by gas chromatography- mass spectroscopy technique, also their toxicities were assessed against the two important grain products pests, Oryzeaphilus mercator and Tribolium castaneum. Antibacterial activity was assessed against the three foodborne bacteria that include Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus based on the disc diffusion assay. Free-radical-scavenging property was identified based on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. Results: 2-hexahydrofarnesyl acetone was the main compound in A. gilliatii and A. tragacanthium, whilst farnesyl acetone, heptacosane and germacrene D were the principal components of A. atropatanum essential oil. These oils exhibited 40-90% mortality of O. mercator and/or T. castaneum at a dose of 12 μl/l air after 48h of exposure, and exhibited significant free-radicalscavenging property (RC50 = 3.7 × 10-3 - 8.3 × 10-3 mg/ml). The oils of A. tragacanthium and A. gilliatii showed a weaker antibacterial activity compared to A. atropatanum. Conclusion: A. atropatanum, A. gilliatii and A. tragacanthium essential oils had significant insecticidal and anti-oxidant properties. They also showed week to moderate antibacterial activity against P. aeruginosa and S. aureus.

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Evaluation of the in vitro antibacterial activity of some essential oils and their blends against Staphylococcus spp. isolated from episodes of sheep mastitis

RENDICONTI LINCEI ◽

10.1007/s12210-021-00991-5 ◽

2021 ◽

Author(s):

Filippo Fratini ◽

Margherita Giusti ◽

Simone Mancini ◽

Francesca Pisseri ◽

Basma Najar ◽

...

Keyword(s):

Antibacterial Activity ◽

Essential Oils ◽

Diffusion Method ◽

Minimal Bactericidal Concentration ◽

Coagulase Negative Staphylococci ◽

Disk Diffusion Method ◽

In Vitro Antibacterial Activity ◽

High Concentrations ◽

Thymus Serpyllum

AbstractStaphylococcus aureus and coagulase-negative staphylococci are among the major causes of mastitis in sheep. The main goal of this research was to determine the in vitro antibacterial activity of several essential oils (EOs, n 30), then five of them were chosen and tested alone and in blends against staphylococci isolates. Five bacteria were isolated from episodes of ovine mastitis (two S. aureus and three S. xylosus). Biochemical and molecular methods were employed to identify the isolates and disk diffusion method was performed to determine their antimicrobial-resistance profile. The relative percentage of the main constituents in the tested essential oils and their blends was detected by GC-EIMS analysis. Antibacterial and bactericidal effectiveness of essential oils and blends were evaluated through minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). All of them showed sensitivity to the used antimicrobials. The EOs with the highest antibacterial activity were those belonging to the Lamiaceae family characterized by high concentrations of thymol, carvacrol and its precursor p-cymene, together with cinnamon EO, rich in cinnamaldehyde. In terms of both MIC and MBC values, the blend composed by Thymus capitatus EO 40%, Cinnamomum zeylanicum EO 20%, Thymus serpyllum EO 20% and Satureja montana EO 20% was found to be the most effective against all the isolates. Some essential oils appear to represent, at least in vitro, a valid tool against ovine mastitis pathogens. Some blends showed a remarkable effectiveness than the single oils, highlighting a synergistic effect in relation to the phytocomplex.

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Ginger Essential Oils-Loaded Nanoemulsions: Potential Strategy to Manage Bacterial Leaf Blight Disease and Enhanced Rice Yield

Molecules ◽

10.3390/molecules26133902 ◽

2021 ◽

Vol 26 (13) ◽

pp. 3902

Author(s):

Abdullahi Adamu ◽

Khairulmazmi Ahmad ◽

Yasmeen Siddiqui ◽

Intan Safinar Ismail ◽

Norhayu Asib ◽

...

Keyword(s):

Antibacterial Activity ◽

Electron Microscope ◽

Essential Oils ◽

Disease Severity ◽

Rice Yield ◽

Cell Structure ◽

Leaf Blight ◽

Bacterial Leaf Blight ◽

Control Treatment ◽

Promising Alternative

The bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most serious rice diseases, causing huge yield losses worldwide. Several technologies and approaches have been opted to reduce the damage; however, these have had limited success. Recently, scientists have been focusing their efforts on developing efficient and environmentally friendly nanobactericides for controlling bacterial diseases in rice fields. In the present study, a scanning electron microscope (SEM), transmission electron microscope (TEM), and a confocal laser scanning microscope (CLSM) were utilized to investigate the mode of actions of ginger EOs on the cell structure of Xoo. The ginger EOs caused the cells to grow abnormally, resulting in an irregular form with hollow layers, whereas the dimethylsulfoxide (DMSO) treatment showed a typical rod shape for the Xoo cell. Ginger EOs restricted the growth and production of biofilms by reducing the number of biofilms generated as indicated by CLSM. Due to the instability, poor solubility, and durability of ginger EOs, a nanoemulsions approach was used, and a glasshouse trial was performed to assess their efficacy on BLB disease control. The in vitro antibacterial activity of the developed nanobactericides was promising at different concentration (50–125 µL/mL) tested. The efficacy was concentration-dependent. There was significant antibacterial activity recorded at higher concentrations. A glasshouse trial revealed that developed nanobactericides managed to suppress BLB disease severity effectively. Treatment at a concentration of 125 μL/mL was the best based on the suppression of disease severity index, AUDPC value, disease reduction (DR), and protection index (PI). Furthermore, findings on plant growth, physiological features, and yield parameters were significantly enhanced compared to the positive control treatment. In conclusion, the results indicated that ginger essential oils loaded-nanoemulsions are a promising alternative to synthetic antibiotics in suppressing Xoo growth, regulating the BLB disease, and enhancing rice yield under a glasshouse trial.

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