Antimicrobial Activity Of Essential Oils Research Articles

Harnessing Nature's Arsenal: Investigating the Antibacterial Efficacy of Commercial Essential Oils against Staphylococcus Strains Isolated from Poultry Meat.

Pathogens prevalent in the food supply chain provide a significant worldwide risk to both human health and the economy. Poultry meat, a staple in global diets, serves as a reservoir for bacterial contamination. Staphylococcus, a gram-positive bacterium belonging to family Staphylococcaceae has been identified as a potential causative agent of food borne illnesses. The presence of antibiotic-resistant Staphylococcus strains in poultry products raises concerns about the transmission of resistance genes through the food chain, necessitating thorough investigations into alternative antimicrobial agents for effective bacterial control. Essential oils (EOs) hold profound importance in terms of their known and potential application. This study focuses on the evaluation of commercial essential oils and their effectiveness against Staphylococcus strains isolated from poultry meat. Briefly, 150 raw chicken meat samples were collected, and Staphylococcus spp. was identified based on morphological and cultural characteristics. Antibiogram analysis and essential oils activity was determined by disc diffusion and agar well diffusion assay respectively. Results showed that 27 (18%) samples tested positive for Staphylococcus spp, out of which S. aureus was identified in 25 isolates (16.66%). The antibiogram profile reveals that three antibiotics namely, gentamicin, vancomycin and ciprofloxacin were the most effective antibiotics showing sensitivity against 74.07%, 70.37% and 62.96% of the isolates respectively. Moreover, amongst the tested essential oils cinnamon oil and clove oil exhibited the highest antimicrobial activities ZOI ranges from 19-41mm and 19-33 mm respectively. While focusing on the evaluation of antimicrobial activity of essential oils, the study endeavors to aid in development of sustainable strategies for mitigating bacterial contamination in the food industry.

Chemical Composition and Antimicrobial Activity of Essential Oils and Hydrosols from Oregano, Sage and Pennyroyal against Oral Pathogens

In this study, the chemical composition of essential oils (EOs) extracted from Origanum vulgare ssp. hirtum Lamiaceae, (oregano), Salvia officinalis Lamiaceae (sage), Mentha pulegium Lamiaceae (pennyroyal), and respective hydrosols (HSs) has been investigated by Gas Chromatography–Mass Spectrometry (GC-MS). The antimicrobial activity was assessed against two oral pathogens: Gram-positive bacterium Streptococcus mutans and the fungus Candida albicans by determination of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal/Fungicidal concentration (MBC/MFC). Three-fold diluted solutions were dispensed into each well of a 96-well microtiter plate and, after incubation, MIC was determined by visual monitoring. The MBC/MFC was determined by transferring a small quantity of sample contained in each replicate well of the microtiter plates to appropriate culture media using a microplate replicator. The EOs of the tested herbs showed antimicrobial properties, especially the EO oil of O. vulgare, which exerted the highest antimicrobial activity. HSs of S. officinalis and M. pulegium exerted no antimicrobial activity, in contrast to oregano HS, which displayed strong antimicrobial activity. In all cases, a higher number of compounds were detected in EOs than in the corresponding HSs. The major compounds of sage EO were detected to be α-thujone (25.1%), 1,8-cineole (15.8%) and β-pinene (10.0%), while the HS was characterized by the presence of 1,8-cineole (32.6%), borneol (22.6%) and α-thujone (22.4%). Pennyroyal EO and HS consists mainly of pulegone (62.1 and 50.6%, respectively). Carvacrol was the major component present in EO (63%) and HS (97.3%) of oregano, probably contributing to the antimicrobial activity. Further research is needed in order to elucidate the antimicrobial mechanisms of specific compounds present in essential oils and hydrosols of Lamiaceae grown in Greece against oral pathogens.

Antimicrobial activities of essential oils from three species of citrus fruits against six infectious tropical bacteria: implications for the care and control of common bacterial tropical diseases in developing countries

The burden of bacterial infections and the failure of antimicrobial agents are increasing worldwide, especially in sub-Saharan Africa. This raises the need for novel therapeutic agents to combat bacterial infectious diseases. The sensitivity of several common pathogenic bacteria to essential oils from the peels of three species of citrus plants was investigated. Essential oils (EOs) were extracted from the fresh and dried peels of the citrus species using standard techniques. The antimicrobial activities of the EOs were determined using agar well diffusion and broth microdilution methods, and the activities of the EOs were compared to those of twelve conventional antibiotics. The results showed that the essential oils had high inhibitory effects. The minimum inhibitory concentrations (MICs) of the EOs ranged between 0.025 and 0.15 mg/ml. The activities of the EOs against the tested microorganisms were comparable to those of conventional antibiotics. Processing techniques did not affect the antibacterial activities of the EOs. Thus, the essential oils from the citrus species used against the investigated microorganisms were comparable to conventional antibiotics, and these findings showed that the oils could be widely applied in the health and pharmaceutical industries, where they could help in combating the menace of bacterial infections and therapeutic failure from drug resistance worldwide and especially in developing countries with limited resources available to combat these infections.

Comparison of antimicrobial activities of oregano, lavender, sage, anise and clove extracts obtained by supercritical fluid carbon dioxide extraction and essential oils obtained by hydrodistillation

ABSTRACT The aim of the study was to compare the extraction yields, chemical compositions and antimicrobial activities of essential oils obtained by hydrodistillation (HD) and volatile extracts obtained by supercritical fluid extraction extraction (SFE) from oregano (Origanum onites), lavender (Lavandula angustifolia), sage (Salvia officinalis), anise (Pimpinella anisum) and clove (Syzygium aromaticum). Essential oil compounds (EOCs) of the obtained materials from both techniques (HD and SFE) were determined by GC-MS/FID. Agar well diffusion method was used for the determination of antimicrobial activities on five different foodborne microorganisms (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli Enterococcus faecalis and Klebsiella pneumoniae). According to the results; extraction yields of SFE were found to be higher than HD for all tested aromatic plants. Active ingredient ratios (carvacrol, camphor, anethole, eugenole and linalol) varied depending on the extraction methods. SFE extracts were higher antimicrobial activity than HD essential oils, except clove extract on E. faecalis.

Gram-negative rough mutants used as test bacteria can increase sensitivity of direct bioautography

AbstractCurrently, the antimicrobial activity of essential oils (EOs) is an outstanding research field due to antibiotic resistance of microorganisms. Thin-layer chromatography‒direct bioautography (TLC‒DB) is an effective, fast method to find components with antimicrobial activity in a mixture of plant compounds, e.g., in EOs. The volatility and hydrophobic characters of EOs require special experimental conditions, and disc diffusion assay is not appropriate to explore the antimicrobial activity of them. The aim of this study was to use “R” mutants, which are more sensitive to synthetic antimicrobial drugs, in DB to increase the sensitivity of this method. Our hypothesis was that these mutants show sensitivity to some EOs (thyme, clove, and peppermint) as well. The chemical composition of our tested EOs was measured with gas chromatography‒mass spectrometry (GC‒MS). The main compounds (39.8% thymol, 78.8% eugenol, and 50.4% menthol) of EOs showed notable antibacterial activity in TLC‒DB. Based on our results, we suggest to use Salmonella minnesota Re595 rough strain as test bacterium in bioautography, because it showed the highest sensitivity to the tested antibiotics (gentamicin and cephalexin) and EOs. Furthermore, this rough mutant could make TLC‒DB more faster, because only 4 h incubation time was enough to detect the inhibition zones of the active compounds used in this study.

Chemical Components and Antimicrobial Activity of Essential Oil from Curcuma vitellina

Chemical Components and Antimicrobial Activity of Essential Oil from Curcuma vitellina

Comparative Study of Antibacterial Activity between Selected International and Indian Essential Oils against Selected Pathogenic Bacteria

In recent years, the rapid growth in Antimicrobial resistance (AMR) has become a global concern. Essential oils derived from plants that include bioactive components with proven antioxidative and antibacterial activities could be a potential solution to arrest this problem. In this study, antibacterial activities of DoTERRA essential oils such as Onguard, Clove, Teatree, Lavender and Eucalyptus were evaluated with Indian essential oils against clinical pathogenic bacteria. The GC-MS study revealed that cineole, terpinene, eucalyptol, and eugenol were the most prevalent bioactive components in these essential oils. The purity of the essential oils was confirmed with zeta potential and white light absorption spectrophotometer and shows that the Zeta potential of all the essential oils ranges from -51.4 to 0 mV. Using agar well diffusion and Micro broth dilution procedures, the antimicrobial activity of essential oils of clove, lavender, tea tree, eucalyptus, and On-Guard (combined) was assessed against several multi-drug-resistant bacteria. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of essential oils in aqueous and micellar solutions were determined by Micro broth dilution techniques. The most effective antibacterial essential oils were clove, tea tree, and On guard (a blended essential oil with a predominance of Limonene and Eugenol). The current research could result in development of formulas that contain micelle or colloid suspensions of whole essential oils such as clove, On-Guard, or Tea-Tree oil to aid in antimicrobial treatment.

Synergistic effects of essential oils and phenolic extracts on antimicrobial activities using blends of Artemisia campestris, Artemisia herba alba, and Citrus aurantium.

This study explores the synergistic antibacterial effects of essential oils (EOs) and phenolic extracts from three plants against foodborne pathogenic bacteria. The present work aimed to investigate the synergistic effects of the binary and the ternary combinations of extracts using different blend proportions of the following plant extracts: Artemisia campestris (AC), Artemisia herba alba (AHA), and Citrus aurantium (CA). The antimicrobial activities of EOs and phenolic extracts were determined and evaluated against five strains. For the EOs, the results of the DIZ showed the existence of synergism for different combinations of binary blends, such as AC/AHA or AHA/CA against Escherichia coli, and AC/CA against Enterobacter faecalis. In addition, ternary blends of AC:AHA:CA at a ratio of 1/6:2/3:1/6 exhibited a synergy effect, as measured by the CI, against E. coli. On the other hand, for the phenolic extracts, synergistic effects were noticed for binary blends of AC/CA at different ratios against E. coli, E. faecalis, and Pseudomonas aeruginosa strains. Similarly, ternary blends of phenolic extracts presented synergy against E. coli, E. faecalis, P. aeruginosa strains, and even C. albicans. In this case, the blending ratios were crucial determining factors for maximizing the synergy effect. The study established that the proportion of a single drug could play an essential role in determining the bioefficacy of a drug combination treatment. Therefore, the results showed the importance of studying the modulation of antibacterial activities based on the proportions of extracts in the mixture and finding the range of proportions (as determined by SLMD) that have a synergistic/additive/antagonistic effect with no or low side effects, which can be used in a food preservation system.

Chemical composition and antimicrobial activity of essential oils from six lavender (Lavandula angustifolia Mill.) cultivars

Chemical composition and antimicrobial activity of essential oils from six lavender (Lavandula angustifolia Mill.) cultivars

Chemical composition and antimicrobial activity of essential oil of Alpinia menghaiensis S.Q. Tong & Y.M. Xia in S.Q. Tong from Vietnam

The chemical constituents and antimicrobial activity of the essential oil isolated from the rhizomes of Alpinia menghaiensis S.Q. Tong & Y.M. Xia in S.Q. Tong from Vietnam was studied and reported. The techniques of gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC/MS) were used to characterize the chemical constituents of the essential oil while the microdilution assay was used to evaluate the antimicrobial activity. The main compounds identified in the rhizome essential oil consist of β-pinene (46.5%), β-phellandrene (25.7%) and α-pinene (8.5%). The studied essential oil inhibited the growth of Pseudomonas aeruginosa ATCC27853 with minimum inhibitory concentrations (MIC) value of 15.32 μg/mL ±0.01, and median inhibitory concentration (IC50) value of 32.0 ±0.01 μg/mL. The essential oil also displayed activity against Staphylococcus aureus ATCC25923 (MIC 31.57 ±0.01 μg/mL) and Bacillus cereus ATCC14579 (MIC, 34.21 μg/mL ±0.01 μg/mL), and IC50 value of 64.0 ±0.01 μg/mL. This is the first report on the rhizome oil composition, as well as the antimicrobial of essential oils from A. menghaiensis. The paper discusses further the comparative analysis of essential oils from A. menghaiensis.

Chemical components and antimicrobial activity of essential oil from leaf of Aristolochia balansae Franch.

Aristolochia balansae Franch. belonging to Aristolochiasubgenus Siphisia (Aristolochiaceae) is rarely distributed in Northern Vietnam. This study is the first time to determine the chemical composition and antimicrobial activity from essential oils of leaves collected in Ba Thuoc district, Thanh Hoa province in November 2021. The essential oils from the leaves of A. balansae were obtained by hydrodistillation using Clevenger-type apparatus and analysed by gas chromatography coupled with mass spectrometry. The yield of the essential oil was 0.15% of fresh weight, the essential oil is light yellow, lighter than water. Sixty-three components were identified, which present 78.58% of the total composition of the leaf’s essential oil. The main components were sesquiterpenes and oxygenated sesquiterpenes. The constituents occurring in higher amounts in the essential oil were γ-Eudesmol (6.98% of the total composition of the leaf’s essential oil), α-Humulene (6.22%), β-Selinene (4.5%), Eudesma-4(14),7(11)-diene (3.53%), α-trans-Bergamotene (3.27%), and Limonene (3.02%). This essential oil showed weak antimicrobial activities to most of the tested microbial strains in a concentration of 10%.

Stability of the antimicrobial activity of selected essential oils and nature identical compounds and their interaction with Tween 20 against reference bacterial strains of zootechnical interest

Essential oils (EOs) and nature identical compounds (NICs) express different antimicrobial activity (AAc) which can be affected by variability in composition, stability over time, and the carrier employed for their inclusion in feedstuff and products for animal treatments. The aim of the present study was to evaluate the stability over time of the AAc of 8 EOs and 5 NICs, alone and in combination with Tween 20, on four major bacterial livestock pathogens (E. coli, S. Typhimurium, S. aureus and MRSA). For this purpose, minimal inhibitory concentration (MIC) and checkerboard assay (CkA) tests were performed on EOs and NICs at batch first use (T0 – only MIC), and after 12 (T1) and 24 (T2) months. Several EOs showed initial MICs lower than 2% (v/v) and, except for clove bud and cinnamon EOs, reduced their efficacy over time. The best NICs’ AAc was showed at T1 by cinnamic aldehyde (against MRSA), carvacrol (against E. coli), and thymol (except against MRSA), while at T2 the MIC values decreased for most of the NICs. The CkA between EOs and Tween 20 showed different interactions (Fractional Inhibitory Concentration -FIC- index from 0.06 to 32.04) based on bacteria and time. No interactions were found between NICs and Tween 20 (FIC index from 1.0 to 3.0). The AAc of EOs and NICs changes over time. Therefore, the preservation interval of these additives is critical for the AAc of feedstuff and products intended for livestock animals. Moreover, the NICs seem more suitable for the association with Tween 20.

Essential oils of Lauraceae: antimicrobial activity and constituents of essential oil from two Machilus species from Vietnam

The chemical constituents and antimicrobial activity of the essential oils isolated from the leaves of Machilus cicatricosa S.K. Lee and Machilus bonii Lecomte from Vietnam were studied and reported. The techniques of gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC-MS) were used to characterize the chemical constituents of the essential oil while the microdilution assay was used to evaluate the antimicrobial activity. The main constituents of the leaf oil of M. cicatricosa were α-pinene (20.6%), bicyclogermacrene (15.2%), linalool (14.9%), and β-pinene (8.4%). On the other hand (E)-β-ocimene (26.3%), bicyclogermacrene (23.6%) and (E)-nerolidol (9.1%) were the major constituents of M. bonii leaf essential oil. The studied essential oils displayed antimicrobial activity against Enterococcus faecalis ATCC 29212, and Staphylococcus aureus ATCC 25923, with minimum inhibitory concentration (MIC) value of 64.0 μg/mL. In addition, essential oil from the leaf of M. bonii was the most active towards Bacillus cereus ATCC14579 with MIC value of 64.0 μg/mL, while M. cicatricosa showed stronger anti-candidal activity against Candida albicans ATCC 10231 with MIC value of 32.0 μg/mL. This is the first report on the chemical constituents and antimicrobial activity of the essential oils of M. cicatricosa and M. bonii.

Chemical Composition and Antimicrobial Activity of Essential Oils from Horse Chestnut Flowers

Essential oil of brown color was obtained by hydro-distillation from fresh flowers of horse chestnut. All major components of the corresponding oils were identified by gas chromatography-mass spectrometry. The microorganisms most sensitive to the studied essential oil of flowers were revealed: Staphylococcus aureus, Serratia marcescens, and Bacillus subtilis. Extensive documentation on the antimicrobial properties of essential oils and their constituents has been carried out by several workers. Although the mechanism of action of a few essential oil components has been elucidated in many pioneering works in the past, detailed knowledge of most of the compounds and their mechanism of action is still lacking. This knowledge is particularly important for the determination of the effect of essential oils on different microorganisms, how they work in combination with other antimicrobial compounds, and their interaction with food matrix components. Also, recent studies have demonstrated that nanoparticles (NPs) functionalized with essential oils have significant antimicrobial potential against multidrug-resistant pathogens due to an increase in chemical stability and solubility, decreased rapid evaporation and minimized degradation of active essential oil components.

Evaluation the Antimicrobial Activity of Essential Oils against Veterinary Pathogens, Multidrug-resistant Bacteria and Dermatophytes

Evaluation the Antimicrobial Activity of Essential Oils against Veterinary Pathogens, Multidrug-resistant Bacteria and Dermatophytes

Chemical composition, antimicrobial and larvicidal activities of essential oils of two Syzygium species from Vietnam.

The present study is the first to investigate the chemical composition, antimicrobial and larvicidal activities of the essential oils from the leaves of Syzygium attopeuense (Gagnep.) Merr. & L.M.Perry and Syzygium tonkinense (Gagnep.) Merr. & L.M.Perry collected in Vietnam. The essential oils were extracted by hydrodistillation and analyzed by GC and GC-MS. The study indicated the presence of a high percentage of sesquiterpenes in both investigated essential oils. The major components of S. attopeuense essential oil were bicyclogermacrene (24.26%), (E)-caryophyllene (11.72%), and (E)-β-ocimene (6.75%), whereas S. tonkinense essential oil was dominated by (E)-caryophyllene (80.80%). The antimicrobial activity of essential oils was evaluated by broth microdilution assay to determine the minimum inhibitory concentration (MIC) and median inhibitory concentration (IC50). Both essential oils exhibited remarkable inhibitory activity against all tested Gram-positive bacteria and yeast than Gram-negative bacteria. Among them, essential oils of S. attopeuense and S. tonkinense possessed the strongest activity against Enterococcus faecalis (MIC = 4.00 μg/mL; IC50 = 1.69 μg/mL) and Candida albicans (MIC = 16.00 μg/mL; IC50 = 8.67 μg/mL), respectively. Furthermore, the larvicidal activity of essential oils was tested using fourth-instar larvae of Aedes aegypti. Results from the larvicidal test revealed that both essential oils had an excellent inhibitory effect against A. aegypti larvae with LC50 values from 25.55 to 30.18 μg/mL and LC90 values from 33.00 to 39.01 μg/mL. Our findings demonstrate that the essential oil extracted from S. attopeuense and S. tonkinense are potential sources of natural antimicrobials and can act as inexpensive mosquito larvicidal agents.

Constituent Composition and Antimicrobial Activity of Essential Oil from Perovskia botschantzevii

Constituent Composition and Antimicrobial Activity of Essential Oil from Perovskia botschantzevii

Chemical Composition and Antibacterial activity of Essential Oils from Fruits of Vismia baccifera and Vismia macrophylla Collected at different Locations in Venezuelan Andes

Background: Genus Vismia (Hipericaceae/Clusiaceae) is distributed mainly in tropical and subtropical areas of Central America and South America although some species have been reported in Africa as well. Species of this genus have been used in traditional medicine to alleviate different ailments such as skin infections, to treat urinary tract disorders, as antirrheumatic, antipyretic, among others. Previous investigations have revealed that species from Vismia genus are composed mainly of terpenes, anthrones, lignans, flavonoids, anthraquinones, steroids and xanthones. The purpose of the investigation was to determine the chemical composition and antimicrobial activity of essential oils from the fruits of V. baccifera and V. macrophylla collected in Venezuelan Andes. Methods: Vimia species were collected at different locations in Mérida and Táchira state, Venezuela. Essential oils were obtained through Hidrodistilation and chemical compositon was performed by GC and GC/MS techniques. Antimicrobial analysis was carried out by disc diffusion assays. Results: GC and GC/MS analysis showed that these species are mainly composed of sesquiterpenes being α-curcumene, β-curcumene, germacrene D, γ-bisabolene and β-caryophyllene among the major components. Antimicrobial activity was also performed with species under investigation. Results showed a broad spectrum of activity since both species were able to inhibit not only Gram- positive (Stpahylococcus aureus, Enterococcus faecalis) and Gram-negative bacterial strains (Escherichia coli, Pseudomonas aeruginosa) but yeast (Candida albicans and Candida krusei) as well. Conclusions: According to the results observed in the investigation, Vismia species might be considered as an alternative to aid infectious diseases.

Antimicrobial activity of essential oils (Citrus bergamia Risso & Poiteau, Melaleuca alternifolia and Chenopodium botrys) on pathogen strains isolated in milk samples from mastitic sheep

The aim of this investigation was to study in vitro antibacterial activity of essential oils (EOs) (Citrus bergamia Risso & Poiteau, Melaleuca alternifolia and Chenopodium botrys) on pathogenic strains isolated in milk samples from mastitic sheep. The in vitro antibacterial activity showed that EOs induced higher bacterial inhibition against pathogens isolated in mastitic milk (Staphylococcus xylosus, Staphylococcus epidermidis, Streptococcus salivarius, Enterococcus faecium, Streptococcus agalactiae and Pseudomonas aeruginosa) than common antimicrobial agents used in veterinary medicine, with Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values significantly lower, excepted for P. Aeruginosa. The antibacterial activity of EOs has been attributed to the chemical composition of each phyto-complexes, constituted by monoterpenes, sesquiterpenes and their associated alcohols, identified by GC-MS analysis, with a synergic action in the bacterial cells. The results obtained confirmed in vitro antimicrobial activity of these EOs and their potential use in the treatment of sheep mastitis infection.

HOẠT TÍNH KHÁNG VI SINH VẬT CỦA TINH DẦU TỪ LÁ LOÀI TRÂM TRÁI TRẮNG (SYZYGIUM TSOONGII (MERR.) MERR. & PERRY), TRÂM BULLOCK (SYZYGIUM BULLOCKII (HANCE) MERR. & PERRY) VÀ TRÂM TÍCH LAN (SYZYGIUM ZEYLANICUM (L.) DC.) Ở HÀ TĨNH

Research on antimicrobial activity of essential oils from leaf of Syzygium tsoongii, Syzygium bullockii and Syzygium zeylanicum in Ha Tinh Province showed that essential oils from leaves of three species had antibacterial activity against three strains on the Gram (+): (Enterococus faecalis (ATCC 299212), Staphylococcus aureus (ATCC 25923), Bacillus cereus (ATCC 14579) and against Candida albicans (ATCC 10231). The essential oil from the leaves of Syzygium tsoongii and Syzygium zeylanicum had not antibacterial activity against Gram (-), while the essential oil from the leaves of Syzygium bullockii could be against 2 strains of Gram (-): Escherichia coli and Salmonella enterica strains.