Antimicrobial Activity Of Essential Oils Research Articles

Chemical composition, antioxidant, and antimicrobial activities of P. roxburghii oleoresin essential oils extracted by steam distillation, superheated steam, and supercritical fluid CO2 extraction.

Pinus roxburghii is a rich source of high-quality oleoresin that is composed of resin acids and essential oil (EO). The present research work was planned to study and compare the yield, biological activities, and chemical profiling of P. roxburghii oleoresin EOs extracted through various green extraction methods. Steam distillation (SD), supercritical fluid extraction, and superheated SD (SHSD) at different temperatures (120, 140, and 160°C) were employed to extract EOs from P. roxburghii oleoresin. Antioxidant potential of EOs was determined by total antioxidant content/ferric-reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH)-free radical scavenging activity (DPPH-FRSA), hydrogen peroxide scavenging assays, and percentage inhibition in linoleic acid. Antimicrobial activity of EOs was determined by resazurin microtiter-plate, disc diffusion, and micro-dilution broth susceptibility assays. Gas chromatography-mass spectrometry was used to determine the chemical composition of EOs. It was observed that extraction methods significantly affected the yield, biological activities, and chemical composition of EOs. The maximum yield (19.92%) was found in EO extracted by SHSD at 160°C. EO extracted by SHSD at 120°C showed the highest DPPH-FRSA (63.33%±0.47%), linoleic acid oxidation inhibition (96.55%±1.71%), hydrogen peroxide scavenging activity (59.42%±0.32%), and total antioxidant contents/FRAP (134.49%±1.34mg/L of gallic acid equivalent). The antimicrobial activity results showed that superheated steam-extracted EO of 120°C revealed the highest antifungal and antibacterial activity. It is concluded that SHSD is an alternative and effective technique for the extraction of oleoresins EO that improves the EO yield and biological activities. Further research on optimization and experimental parameters for the extraction of P. roxburghii oleoresin EO by SHSD is required.

Virtual screening of antimicrobial plant extracts by machine-learning classification of chemical compounds in semantic space.

Plant extract is a mixture of diverse phytochemicals, and considered as an important resource for drug discovery. However, large-scale exploration of the bioactive extracts has been hindered by various obstacles until now. In this research, we have introduced and evaluated a new computational screening strategy that classifies bioactive compounds and plants in semantic space generated by word embedding algorithm. The classifier showed good performance in binary (presence/absence of bioactivity) classification for both compounds and plant genera. Furthermore, the strategy led to the discovery of antimicrobial activity of essential oils from Lindera triloba and Cinnamomum sieboldii against Staphylococcus aureus. The results of this study indicate that machine-learning classification in semantic space can be a highly efficient approach for exploring bioactive plant extracts.

Antimicrobial activity and constituents of the leaf essential oil of Syzygium petelotii Merr. & Perry and Syzygium syzygioides (Miq.) Merr. & Perry from Vietnam

Syzygium plants are known as sources of biologically active substances. The essential oils constituents and antimicrobial activity of Syzygium petelotii Merr. & Perry and Syzygium syzygioides (Miq.) Merr. & Perry from Vietnam are being reported. Essential oils were obtained by hydrodistillation of the leaves of S. petelotii and S. syzygioides collected from Pù Hoạt Nature Reserve, Vietnam. The constituents of the essential oils were determined by using gas chromatography (GC) and gas chromatography-mass (GC/MS) spectrometry methods. The antimicrobial activity was evaluated by microdilution broth susceptibility assay. The results indicate that γ-guaiene (24.1%), β-caryphyllene (9.3%), α-pinene (7.8%), and β-pinene (6.1%) were the major compounds of S. petelotii. The main constituents of S. syzygioides were caryophyllene oxide (14.8%), α-pinene (10.6%), β-pinene (6.6%) and spathulenol (6.4%). The essential oil of S. petelotii showed pronounced antimicrobial activity against Pseudomonas aeruginosa ATCC27853 and Enterococcus faecalis ATCC299212, with minimum inhibitory concentration (MIC) values of 16.0 μg/mL and 64.0 μg/mL, respectively. The essential oil of S. syzygioides only displayed activity towards Pseudomonas aeruginosa ATCC27853 with MIC value of 32.0 μg/mL. Both essential oils exhibited antimicrobial activity towards Bacillus cereus ATCC14579 (MIC value, 128.0 μg/mL), and anti-candidal action against Candida albicans ATCC10231 with MIC value of 64.0 μg/mL. The chemical compositions and antimicrobial activity of essential oils of S. petelotii and S. syzygioides are being reported for the first time.

Chemical profile and antibacterial activity of essential oil from ironwood (Eusideroxylon zwageri) sawdust

The current study describes for the first time the chemical compositions and antimicrobial activity of essential oils from ironwood sawdust (Eusideroxylon zwageri) obtained from Borneo Island. Fifteen terpene metabolites were identified by GC-MS of the ironwood sawdust essential oil extracted by steam distillation. (E)-β-Caryophyllene was the oil’s major compound (35.81 ± 0.25%), while its oxygenated derivative (caryophyllene oxide, 8.78 ± 0.08%) was the third biggest terpene. α-Copaene (13.05 ± 0.02%) was also observed in a significant amount together with other minor sesquiterpene hydrocarbons and oxygenated sesquiterpenes. The oil also exhibited antibacterial activities against Gram-positive Multi-Drug Resistant Staphylococcus aureus (MRSA) and Gram-negative Escherichia coli (strain ESBL) during a disc diffusion assay with inhibition zones of 6.13 ± 0.03 mm and 3.35 ± 0.05 mm, respectively.

The antimicrobial efficacy of native Australian essential oils in liquid and vapour phase against foodborne pathogens and spoilage microorganisms

Foodborne pathogens and spoilage microorganisms are a source of concern for public health and the food industry. Considering the problem of antimicrobial resistance in microbes, controlling these microorganisms using synthetic antimicrobials is challenging, thus, essential oils are a potential natural alternative. Previous studies have predominantly focussed on the antimicrobial activity of essential oils in the liquid phase. However, in this work we report on the in vitro antimicrobial activity of the liquid and vapour phases of essential oils from native Australian plants Tasmanian mountain pepper (Tasmannia lanceolata), lemon myrtle (Backhousia citriodora), as well as the common herb thyme (Thymus vulgaris) against 11 common food spoilage and pathogenic bacteria and fungi. Initial screening was conducted using the disc diffusion assay. The minimum inhibitory concentration (MIC) of the oils was determined using the broth microdilution assay. The vapour phase antimicrobial activity of the oils was assessed using an inverted petri plate assay and the vapour phase MIC (V-MIC) was quantified using a vapour diffusion assay. GC-MS was adopted to elucidate the compositional profile of the oil in liquid phase. Two extraction methods, namely solid-phase microextraction (HS-SPME) and gas tight syringe headspace sampling (HS) coupled with GC-MS were used for profiling the composition of the volatiles. The findings of this study confirmed the antimicrobial activity of the oils in both liquid and vapour phases, with lemon myrtle and thyme generally showing stronger antimicrobial activity than Tasmanian mountain pepper. The activity in liquid phase was generally higher than the volatiles. However, lemon myrtle and Tasmanian mountain pepper berry volatiles were more effective against Aspergillus niger and Saccharomyces cerevisiae, respectively, relative to the liquid phase highlighting their potential as vapour phase antifungals. In the liquid and gas phases, the major compounds in lemon myrtle were Z-citral (neral) and E-citral (geranial). Polygodial and thymol were the major compounds in Tasmanian mountain pepper and thyme in the liquid phase, respectively. However, the main compounds in their volatiles were p-cymene and γ-terpinene. In conclusion, our research indicates the essential oils' potent vapour phase activity, highlighting their potential application in gaseous diffusion-dependent food applications such as active antimicrobial food packaging.

Activity of plant essential oils against clinically and environmentally isolatedSalmonella entericaserotypes:in vitroassays and molecular docking

This research aimed to evaluate the antimicrobial activity of essential oils (EOs) against clinically and environmentally isolated Salmonella serotypes. Oregano, thyme, and grapefruit EO compounds were identified, and the antimicrobial activity was evaluated against the S. Saintpaul, Oranienburg, and Infantis serotypes. In addition, molecular docking was performed to explore the possible mechanisms between compounds of EOs with microbial enzymes. Thymol was the main compound identified in oregano (44.0%) and thyme (31%) EOs, while d-limonene was present in a greater proportion in grapefruit EO. Oregano EO had the highest antimicrobial activity, followed by thyme and grapefruit EOs. Oregano and thyme EOs illustrated a greater inhibitory capacity to all serotypes, particularly with the environmental S. Saintpaul. Oregano EO presented values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration of 0.1 μL/mL for all serotypes, while thyme and grapefruit EOs presented MIC values of 0.1 μL/mL for the clinical serotypes S. Infantis and S. Oranienburg, respectively. Molecular docking analysis showed the optimal binding free energies for thymol and carvacrol with glucokinase, ATP-dependent-6-fructokinase, outer membrane porin C, and topoisomerase IV. Our results indicate that these EOs can inhibit clinically and environmentally isolated Salmonella serotypes and can be used as alternatives for developing natural food preservatives.

Lindera Essential Oils from Vietnam: Antimicrobial Activity and Constituents of the Leaf of Lindera chunii Merr. (Lauraceae) Essential Oils and Chemotaxonomy

Lindera chunii Merr. is an important member of the Lauraceae family of plants which are known for their medicinal values. In this research article, the chemical constituents and antimicrobial activity of essential oils from the leaves of L. chunii grown in Vietnam were reported. The essential oil was obtained by hydrodistillation of the leaves of L. chunii while the constituents were determined by using gas chromatography (GC) and gas chromatography-mass (GC/MS) spectrometry methods. The antimicrobial activity was evaluated using a microdilution broth susceptibility assay. The constituents occurring in higher amounts in the leaf essential oil of L. chunii were mainly the monoterpene hydrocarbons comprising terpinolene (13.0%), α-pinene (8.0%), β-pinene (7.6%), camphene (7.3%), β-phellandrene (7.1%) and myrcene (5.0%). The leaf essential oil of L. chunii inhibited the growth of Enterococcus faecalis ATCC29212, Staphylococcus aureus ATCC25923 and Salmonella enterica ATCC13076, each with minimum inhibitory concentration (MIC) value of 64.0 μg/mL. The corresponding median lethal concentration (IC50) values were 19.45 μg/mL, 20.45 μg/mL and 18.78 μg/mL, respectively. The essential oil also displayed anti-candidal activity towards Candida albicans ATCC10231 with MIC value of 64.0 μg/mL, and IC50 value of 23.12 μg/mL. The antimicrobial activity of L. chunii essential oil was reported for the first time as a confirmation of the traditional uses of the plant in the treatment of microbial infections. Furthermore, the paper discusses the chemotaxonomy of Lindera oil samples.

Chemistry and Bioactivity of Croton Essential Oils: Literature Survey and Croton hirtus from Vietnam

Using essential oils to control vectors, intermediate hosts, and disease-causing microorganisms is a promising approach. The genus Croton in the family Euphorbiaceae is a large genus, with many species containing large amounts of essential oils, however, essential oil studies are limited in terms of the number of Croton species investigated. In this work, the aerial parts of C. hirtus growing wild in Vietnam were collected and analyzed by gas chromatography/mass spectrometry (GC/MS). A total of 141 compounds were identified in C. hirtus essential oil, in which sesquiterpenoids dominated, comprising 95.4%, including the main components β-caryophyllene (32.8%), germacrene D (11.6%), β-elemene (9.1%), α-humulene (8.5%), and caryophyllene oxide (5.0%). The essential oil of C. hirtus showed very strong biological activities against the larvae of four mosquito species with 24 h LC50 values in the range of 15.38-78.27 μg/mL, against Physella acuta adults with a 48 h LC50 value of 10.09 μg/mL, and against ATCC microorganisms with MIC values in the range of 8-16 μg/mL. In order to provide a comparison with previous works, a literature survey on the chemical composition, mosquito larvicidal, molluscicidal, antiparasitic, and antimicrobial activities of essential oils of Croton species was conducted. Seventy-two references (seventy articles and one book) out of a total of two hundred and forty-four references related to the chemical composition and bioactivity of essential oils of Croton species were used for this paper. The essential oils of some Croton species were characterized by their phenylpropanoid compounds. The experimental results of this research and the survey of the literature showed that Croton essential oils have the potential to be used to control mosquito-borne and mollusk-borne diseases, as well as microbial infections. Research on unstudied Croton species is needed to search for species with high essential oil contents and excellent biological activities.

Chemical Composition and Antimicrobial Activity of Essential Oil from Anaphalis virgata

Chemical Composition and Antimicrobial Activity of Essential Oil from Anaphalis virgata

Chemical Composition, in Vitro Antibacterial and Antifungal Activities of Different Parts Essential Oils of Neolitsea sericea var. aurata From Taiwan

This study examined the chemical composition and antimicrobial activities of essential oils isolated from the leaves, twigs, and fruits of Neolitsea sericea var. aurata from Taiwan. The major compounds responsible for antimicrobial activity were isolated and identified. The leaf, twig, and fruit essential oils were obtained through hydrodistillation in a Clevenger-type apparatus and were characterized through gas chromatography (GC) with flame ionization detection (GC/FID) and GC/mass spectrometry (GC/MS). The major compounds were ( E)-β-ocimene (49.3%) and sericenine (31.6%) in the leaf oil; ( E)-β-ocimene (73.7%), α-cadinol (6.8%), and α-muurolol (4.0%) in the twig oil; and ( E)-β-ocimene (84.7%) in the fruit oil. The twig oil exhibited the strongest antibacterial and antifungal activities. We isolated α-cadinol and α-muurolol, the main components of NTO4 fraction, and used them in antimicrobial tests; the two compounds exhibited excellent antimicrobial activities. The twig essential oil contains α-cadinol and α-muurolol and exhibited excellent antimicrobial activities against food-borne pathogens; thus, they are worthy of further research and development.

Chemical Compositions and Antimicrobial Activities of Essential Oils from the Leaves and Rhizomes of Meistera cristatissima from Vietnam

Chemical Compositions and Antimicrobial Activities of Essential Oils from the Leaves and Rhizomes of Meistera cristatissima from Vietnam

Phytochemical Composition and Antimicrobial Activity of Essential Oil from the Leaves of Artemisia vulgaris L.

Artemisia vulgaris is an enormously useful aromatic plant known for its insecticidal, antifungal, parasiticidal, and medicinal values. The main aim of this study is to investigate phytochemical contents and the potential antimicrobial activities of Artemisia vulgaris essential oil (AVEO) from the fresh leaves of A. vulgaris grown in Manipur. The AVEO isolated by hydro-distillation from A. vulgaris were analyzed by gas chromatography/mass spectrometry and solid-phase microextraction-GC/MS to describe their volatile chemical profile. There were 47 components identified in the AVEO by GC/MS, amounting to 97.66% of the total composition, while 97.35% were identified by SPME-GC/MS. The prominent compounds present in AVEO analyzed by direct injection and SPME methods are found to be eucalyptol (29.91% and 43.70%), sabinene (8.44% and 8.86%), endo-Borneol (8.24% and 4.76%), 2,7-Dimethyl-2,6-octadien-4-ol (6.76% and 4.24%), and 10-epi-γ-Eudesmol (6.50% and 3.09%). The consolidated component in the leaf volatiles comes to the terms of monoterpenes. The AVEO exhibits antimicrobial activities against fungal pathogens such as Sclerotium oryzae (ITCC 4107) and Fusarium oxysporum (MTCC 9913) and bacterial cultures such as Bacillus cereus (ATCC 13061) and Staphylococcus aureus (ATCC 25923). The percent inhibition of AVEO against the S. oryzae and F. oxysporum was found up to 50.3% and 33.13%, respectively. The MIC and MBC of the essential oil tested for B. cereus and S. aureus were found to be (0.3%, 0.63%) and (0.63%, 2.5%), respectively. Finally, the results revealed that the AVEO characterized by the hydro-distillation and SPME extraction yielded the same chemical profile and showed potent antimicrobial activities. Further research into A. vulgaris's antibacterial properties can be performed in order to use it as a source for natural antimicrobial medications.

Chemical Composition, Antioxidant and Antimicrobial Activities of Essential Oils Extracted from the Fresh and Dried Seeds of Lanxangia tsao-ko grown in Nghe An, Vietnam

Lanxangia tsao-ko has been used in traditional oriental medicine to treat malaria, abdominal pain, digestive disorders, and inflammation-related diseases. The aim of this study was to compare the volatile composition and evaluate the total phenolic content (TPC), antioxidant, and antimicrobial activities of L. tsao-ko fresh and dried seed essential oils (EOs) grown in Vietnam. The EOs of L. tsao-ko seeds were analyzed by gas chromatography-mass spectrometry. The results showed thatthe major constituents of the seed essential oils were 1,8-cineole, α-citral, tetracyclo[3.3.1.0.1(3,9)]decan-10-one, α-phellandrene, and β-citral. The TPC ranged from 1.47mg GAE/g EO in EOs of fresh seeds to 1.70 mg GAE/g EO in EOs of dried seeds. The EOs extracted from fresh and dried seeds could scavenge DPPH with IC50 values of 68.79 and 56.44 mg/mL, respectively. Moreover, the EOs were shown to be active against E. faecalis, S. aureus, cereus, E. coli, P. aeruginosa, S. .enterica, and C. albicans (with MIC = 32-128 µg/mL). The results generally indicated significant differences in chemical composition and bioactivities between EOs obtained from fresh and dried seeds. The findings of the study provide more information about the volatile profile and additional evidence of potential health-endorsing properties of L. tsao-ko EOs.

Synergistic Effect of Surfactants of Nocardia vaccinii IMV B-7405 and Essential Oils on Candida Genus Yeast

The increase in the number of resistant strains of Candida genus representatives, capable of forming biofilms on various surfaces, stimulates the search for new, alternative methods of combating them, one of which is the use of compounds of natural origin, such as essential oils. However, at the same time, their concentration should be minimal, which is due to the ability of essential oils to cause severe damage of the human’s central nervous system and aspiration pneumonia. This leads to the necessity of searching for new methods to reduce the concentration of essential oils and at the same time to preserve their properties, in particular, by their use in a mixture with other antimicrobial agents, which can be microbial surfactants. Previously, it was found that the degree of yeast biofilm destruction under the action of Nocardia vaccinii IMV B-7405 surfactants dependson the nature of the growth substrate and is the highest in the presence of preparations synthesized on purified glycerol. Aim. To study the synergism of antifungal activity and the role in the destruction of biofilms of a mixture of Nocardia vaccinii IMV B-7405 surfactants synthesized on glycerol of different quality and essential oils. Methods. N. vaccinii IMV B-7405 was grown in a medium containing purified glycerol or waste from biodiesel production at a concentration of 2% (v/v) as carbon sources. The surfactants were extracted from the supernatant of cultural liquid by a modified Folch mixture. The antimicrobial activity of essential oils, surfactants, and their mixtures was determined by the index of the minimum inhibitory concentration. To assess the synergistic effect of a mixture of surfactants with essential oils, the fractional inhibitory concentration index was used. The degree of biofilm destruction (%) was determined as the difference between the cell adhesion in untreated and treated with surfactants, essential oil, or their mixture wells of the polystyrene microplates. Results. It was found that the surfactants synthesized by N. vaccinii IMV B-7405 on both purified glycerol and waste from biodiesel production showed synergistic antifungal activity in mixtures with cinnamon and lemongrass essential oils. Thus, the minimum inhibitory concentrations against Candida albicans D-6, Candida utilis BVS-65, and Candida tropicalis RE-2 of a mixture of surfactants synthesized on purified glycerol with cinnamon and lemongrass essential oils were 1.8—7.5 and 3.7— 15 μg/mL, respectively, and were lower than in the case of using surfactants (30-60 μg/mL), cinnamon or lemongrass essential oil (156—312 μg/mL) alone. The use of a mixture of surfactants obtained on waste from biodiesel production and cinnamon or lemongrass essential oils made it possible to reduce the minimum inhibitory concentrations of the latter against studied yeast test cultures by 14—56 times. At the same time, the index of fractional inhibitory concentration did not exceed 0.5, which indicates the synergism of the antifungal activity of the mixture of these compounds. The destruction of Candida yeast biofilms under the action of surfactants synthesized on both purified glycerol and waste from biodiesel production in a mixture with cinnamon or lemongrass essential oils reached 60—67 and 67—77%, respectively, which is an average of 25—35% higher compared to the use of each monopreparation separately. Conclusions. The results presented in this paper confirm the previously obtained data that N. vaccinii IMV B-7405 surfactants, synthesized on both traditional substrates and toxic industrial wastes, have antimicrobial and antiadhesive synergistic action with essential oils, which allows us to consider them as potential components of the so-called «antifungal locks» in the fight against of Candida genus representatives.

Antimicrobial properties of some plant essential oils against two human pathogens

The antimicrobial activity of essential oils distilled from Tea tree () Rosemary (), Lavender (), Eucalyptus (), Clove (), , Geranium essential oils and mineral oils were screened against two pathogenic fungi, Candida albicans which causes scalp dandruff and Trichophyton rubrum that causes athlete's foot while for the testing, poison food method was used.The purpose of this brief review is to describe the properties of essential oils, principally as antifungal agents, against two most important fungal infections that are Dandruff and Athlete’s foot. The invitro studies of the tested essential oils revealed the positive inhibitory on the tested fungal pathogens. The results showed that the essential oil of almost three aromatic plants have the potential to be used for management of two pathogenic fungi, which causes scalp dandruff and that causes athlete's foot.Hence, the essential oils from medicinal plants used in this study hold great potential for the antifungal properties. However mineral oil showed less activity against the four fungi tested as compared to essential oils.

Chemical Composition and Antimicrobial Activity of Essential Oils

This Special Issue entitled "Chemical Composition and Antimicrobial Activity of Essential Oils" focuses on the chemical characterization of essential oils (EOs) through analytical techniques that are necessary for the identification and quantification of individual compounds [...].

Contribution To the Evaluation of The Antimicrobial Activity of Essential Oils Extracted from Mentha Pulegium and Laurus Nobilis

Contribution To the Evaluation of The Antimicrobial Activity of Essential Oils Extracted from Mentha Pulegium and Laurus Nobilis

Comparison of Conventional Extraction Techniques with Superheated Steam Distillation on Chemical Characterization and Biological Activities of Syzygium aromaticum L. Essential Oil

Syzygium aromaticum L. is an aromatic plant with a significant amount of essential oil (EO), which is used in food, medicine, for flavoring, and in the fragrance industry. The purpose of this study was to comparatively evaluate the chemical composition, yield, and antioxidant and antifungal activities of Syzygium aromaticum essential oils extracted by the conventional hydro-distillation, steam distillation, and the emerging superheated steam distillation methods. It was noticed that the extraction methods significantly influenced the yield, chemical composition, and antioxidant and antimicrobial activities of essential oils. The maximum yield was obtained using superheated steam distillation, followed by hydro-distillation and steam distillation. The antioxidant potential of EO extracts was evaluated following the scavenging of 2,2-dipenyl-1-picrylhydrazyl radicals, hydrogen peroxide scavenging activity and ferric reducing power assays. Results revealed that EO extracted superheated steam distillation exhibited the highest antioxidant activity. GC-MS analysis depicted eugenol (47.94–26.50%) and caryophyllene (20.24–9.25%) as the major compounds of Syzygium aromaticum EOs. The antimicrobial activity of EO extracts was evaluated, via the resazurin microtiter plate assay, microdilution broth assay, and disc diffusion methods, against normal and food pathogenic bacterial and fungal strains. After comparative evaluation, it was observed that superheated steam extracted EO exhibited the highest antimicrobial potential. Overall, methodical evaluation disclosed that superheated steam distillation is an effective method to extract EOs from plant sources, with greater yield and promising biological activities.

Chemical Compositions of Essential Oils and Antimicrobial Activities of Asteraceae: The Leaves of Blumea lacera (Burm. f.) DC., Tridax procumbens (L.) L., and Ageratum houstonianum Mill., from Vietnam

The paper reports the chemical compositions and antimicrobial activity of essential oils from Blumea lacera (Burm. f.) DC., Tridax procumbens (L.) L., and Ageratum houstonianum Mill., of Asteraceae family grown in Vietnam. The essential oils were isolated by hydrodisitllation and analysed by GC and GC/MS. The Minimum inhibitory concentration (MIC) and Median inhibitory concentration (IC50) values were measured by the microdilution broth susceptibility assay. The main compounds of B. lacera were germacrene D (25.5%), 2,5-dimethoxy-p-cymene (20.6%), β-caryophyllene (17.9%), thymol methyl ether (6.3%). T. procumbens afforded essential oil whose major constituent was β-pinene (13.4%), while germacrene D (21.3%), α-pinene (19.0%), and β-caryophyllene (8.9%) constitute the bulk of A. houstenianum essential oil. The leaf essential oils of A. houstenianum collected in August (MIC, 8.0 μg/mL) and B. lacera (MIC, 16.0 μg/mL) were the most active against Enterococcus faecalis ATCC 29212, with corresponding IC50 values of 4.00 μg/mL and 5.67 μg/mL, respectively. The essential oil of T. procumbens exhibited the most potent activity towards Staphylococcus aureus ATCC 25923 and Bacillus cereus ATCC 14579, with MIC value of 32.0 μg/mL and IC50 values of 12.45 μg/mL and 7.89 μg/mL, respectively. Also, both A. houstenianum essential oils collected in August and April displayed antibacterial action against Pseudomonas aeruginosa ATCC 27853 with MIC values of of 64.0 μg/mL (IC50, 21.45 μg/mL) and 32.0 μg/mL and (IC50, 15.22 μg/mL). Both B. lacera and T. procumbens showed anti-candidal property with MIC value of 16.0 μg/mL, as well as IC50 values of 5.69 μg/mL and 8.66 μg/mL, respectively.

Chemical composition, in vitro antioxidant and antimicrobial activities of essential oil extracted from the dried flower bud of Eugenia aromatica L.

Chemical composition, in vitro antioxidant and antimicrobial activities of essential oil extracted from the dried flower bud of Eugenia aromatica L.