Antibacterial Activity Of Essential Oils Research Articles

Comparative Analysis of Chemical Composition and Antibacterial Activity of Essential Oils from Five Varieties of Lavender Extracted via Supercritical Fluid Extraction

This study aimed to determine the chemical composition of five Lavender essential oils (LEOs) using the gas chromatography–mass spectroscopy technique and to assess their antibacterial activity against four marine Vibrio species, including Shewanella algae, Shewanella maridflavi, Vibrio harveyi, and Vibrio alginolyticus. Sensitivity tests were performed using the disk diffusion and serial dilution methods. The results showed that all five LEOs exhibited antibacterial activity against the four tested marine Vibrio species. The antibacterial activities of all five LEOs were above moderate sensitivity. The five LEOs from French blue, space blue, eye-catching, and true Lavender showed high sensitivity, particularly against Shewanella maridflavi. The compounds of LEOs from different varieties of Lavender were similar and mainly comprised linalool, linalyl acetate, eucalyptol, and isoborneol. Different varieties of LEOs possessed unique components besides common components, and the percentage of each one was different, which led to different fragrance loads. The major fragrances were lily of the valley, an aromatic compound fragrance, and an herbal fragrance. The antibacterial activity of LEO from eye-catching Lavender was better than that of others, which could provide a reference for its application in the prevention and control of marine Vibrio spp. and the development of antibacterial products.

Evaluation of the antibacterial activity of essential oils from oregano (Origanum vulgare) against Escherichia coli strains isolated from meat products.

The objective of this study was to analyze the antimicrobial and anti-stick capacity of essential oil extracted from oregano (Origanum vulgare) in relation to various strains of Escherichia coli (Ec 41, Ec 42, Ec 44, Ec 45) isolated from meat products. Techniques such as Determination of Minimum Inhibitory Concentration were used (MIC) and Minimum Bactericidal Concentration (CBM). Furthermore, the method was used disk diffusion method to examine the interaction between O. vulgare essential oil and synthetic antibiotics. Determination of the Inhibitory Concentration was also carried out Minimum Adhesion (CIMA). The results indicated that O. vulgare oil demonstrated antimicrobial activity against the E. coli strains tested, with values of MIC ranging between 256 μg/mL and 512 μg/mL, and MBC values ranging between 256 μg/mL and 1.024 μg/mL. Regarding associations, it was observed that O. vulgare had an antagonistic effect towards certain antibiotics, mainly ampicillin, showing greater interference from the essential oil. Furthermore, the oil was effective in inhibiting the adherence of E. coli bacterial strains, demonstrating a more significant antibiofilm agent than 0.12% chlorhexidine digluconate, a commonly used antibacterial. In short, O. vulgare essential oil exhibited antimicrobial potential against E. coli strains isolated from meat products, suggesting which, upon more detailed investigations, could be used both in isolation or in combination with synthetic antibiotics to combat infections caused by this pathogen.

Antioxidant and Antibacterial Activities of Chinese Native Thyme Essential Oils with Different Chemotypes.

Thyme essential oils (EOs) have antioxidant, antiviral, antifungal, antibacterial, anti-inflammatory, and immunological properties and are used in medicine, food, feed additives, and cosmetics. Here, we made use of a multidimensional analytical method to analyze the differences in the chemical components, chemotypes, and antioxidant and antibacterial activities of EOs from 24 Chinese native thymes. These Chinese native thymes comprised 10 species (Thymus quinquecostatus, T. mongolicus, T. inaequalis, T. mandschuricus, T. curtus, T. amurensis, T. roseus, T. proximu, T. marschallianus, and T. altaicus) and two varieties (T. quinquecostatus var. asiaticus and T. quinquecostatus var. przewalskii). Four primary chemotype groups were identified, namely carvacrol, thymol, geraniol, and α-terpineol. The maximum carvacrol, thymol, geraniol, and α-terpineol contents were 72.4, 58.6, 59.5, and 65.4%, respectively. The antioxidant capacities of the thymol and carvacrol chemotype EOs were found to be significantly superior to the other chemotypes using three antioxidant assays: DPPH, ABTS, and FRAP. Moreover, the thymol and carvacrol EO chemotypes could significantly inhibit the growths of the common food-borne pathogenic bacteria Staphylococcus aureus and Escherichia coli. A correlation analysis between the EO components and the bacteria showed that thymol significantly positively correlated with the bacteria. In summary, we analyzed the thyme EOs' antioxidant and antibacterial activities, which laid a foundation for their use in medicines, foods, feed additives, and cosmetics. The results will also be very useful for the selection of wild thymes for functional research on carvacrol-, thymol-, geraniol-, and α-terpineol-rich essential oil chemotypes and the product development of feed additives, cosmetics, etc.

Evaluation of Antibacterial and Antibiofilm Activity of Essential Oils Against Isolated Bacteria from Milk Samples

ABSTRACT: The consumption of food contaminated with bacteria or their toxins can result in foodborne infections or illnesses. This study investigated the antibacterial and antibiofilm activity of essential oils against bacteria isolated from milk samples collected in Pune, Maharashtra, India. Twenty-five raw milk samples were collected from local vendors and examined for the presence of biofilm-forming microorganisms. The isolated bacteria were identified and characterized using morphological and biochemical tests, revealing that 20% of the samples were contaminated with Acinetobacter spp. and 28% with E. coli. The antibacterial activity of the essential oils was evaluated using the disc diffusion method, and the minimum inhibitory concentration (MIC) was determined using 96-well plates. The minimum bactericidal concentration (MBC) was also assessed by inoculating assay mixtures from wells exhibiting no microbial growth onto sterile nutrient agar medium. Biofilm formation and disruption were evaluated using crystal violet assay and biofilm disruption assay, respectively. The results demonstrated that the Cinnamon Bark and Oregano essential oils exhibited significant antibacterial and antibiofilm activity at the lowest MIC value of 0.02-0.04 μg/ml against the isolated bacteria. The findings suggest that essential oils could be potential natural alternatives to conventional antibiotics for controlling bacterial contamination and biofilm formation in milk and dairy products. Further research is needed to explore the practical applications of essential oils in the dairy industry and to ensure their safety and efficacy as natural antimicrobial agents.

Evaluation of the antibacterial activity of some plant essential oils against Ralstonia solanacearum and the molecular diagnosis of the bacterium

Background Evaluation of the antibacterial activity of some essential oils for controlling potato bacterial wilt. Objective In vitro and planta trials, five essential oils, lemongrass, eucalyptus, thyme, ginger, and peppermint, were evaluated for their aptitude to impede the progress of Ralstonia solanacearum. Materials and methods Five essential oils were assessed for their activity to inhibit R. solanacearum growth using the disc diffusion method. Certain volumes of each tested plant essential oil were added on filter paper discs using tetrazolium chloride agar medium, which contained the tested bacterium to obtain the proposed concentrations used to evaluate the most efficient oil for controlling potato bacterial wilt. Serological and molecular identification was also conducted. Results and conclusion R. solanacearum was characterized using cultural characteristics on the selective medium South Africa, “which is the most effective in suppressing the growth of contaminating microorganisms, and the highest recovery rate of the tested bacterium,” immunofluorescence antibody staining tomato bioassay test and molecular identification via real-time PCR (Taq-man) assay. In-vitro studies showed that all tested plant essential oils (lemongrass, eucalyptus, thyme, ginger, and peppermint) significantly reduced R. solanacearum progress. Eucalyptus (Eucalyptus globulus) and peppermint (Mentha piperita) essential oils were the most efficient in suppressing R. solanacearum growth, where it showed the highest mean inhibition zone, followed by thyme oil (Thymus vulgaris), lemongrass oil (Comybogen citratus), and ginger oil (Zingiber officinale), respectively. Phenotypic variances in bacterial cell construction have been noticed via a transmission electron microscope. Eucalyptus oil led to cell wall lysis, cell laceration, bubble-like structures, and degraded cellular components in bacterial cells.

The potency of Cupressus sempervirens and Eucalyptus globulus Essential Oils Against Antibiotic-Resistant Escherichia coli and Mammaliicoccus sciuri from Diseased Animals in Tunisia.

This study aimed to investigate the antibacterial activity of essential oils from Cupressus sempervirens (CSEO) and Eucalyptus globulus (EGEO) against clinical isolates of colistin-resistant E. coli and methicillin-resistant M. sciuri recovered from diseased food-producing animals in Tunisia. The chemical compositions of both essential oils were analyzed using Gas chromatography-mass spectrometry (GC-MS). Antibacterial activity was determined through disk diffusion and microdilution assays, while the fractional inhibitory concentration index (FICI) was used to measure the synergistic effect of CSEO and colistin. The major constituents of CSEO were α-pinene (59.03%), δ-3 Carene (21.48%), D-limonene (5.62%) and α-thujene (3.08%), while EGEO contained eucalyptol (52.1%), α-pinene (26.51%), γ-terpinene (4.81%) and D-limonene (3.54%). The inhibition zone diameters (IZDs) against E. coli and M. sciuri ranged from 6 to 29mm for CSEO and 9.3 to 28.6mm for EGEO. Minimum inhibitory concentrations (MICs) showed a range of 4 to 512µg/mL for CSEO against M. sciuri and 2 to 426.66µg/mL for EGEO. For E. coli, MICs ranged from 170.66 to 512µg/mL for CSEO and 53.33 to 512µg/mL for EGEO. The checkerboard test demonstrated a synergistic effect between CSEO and colistin against two colistin-resistant E. coli isolates, with FICI 3- to 32-fold lower than the MICs of the individual compounds. This study highlights the potency of essential oils from CSEO and EGEO against antibiotic-resistant M. sciuri and E. coli strains from animals in Tunisia and provides evidence of the synergistic effect between CSEO and colistin against clinically relevant colistin-resistant E. coli isolates.

Chemical Composition and Antibacterial Activity of Plumeria alba L., Polianthes tuberosa L., and Cananga ordorata L. Flowers Essential Oils as Bioadditives in Transparent Solid Bath Soap

This study aimed to analyze the chemical components and antibacterial activity of essential oils from kamboja (Plumeria alba L.), sedap malam (Polianthes tuberosa L.), and kenanga (Cananga ordorata L.) flowers against Staphylococcus aureus ATTC 25923. Additionally, the study explored the application of these essential oils as bio additives in transparent solid bath soap. The research consisted of several stages: isolation and identification of chemical components of essential oils using the GC-MS Method, transparent solid bath soap formulation, antibacterial activity test of essential oils and transparent solid bath soaps against Staphylococcus aureus ATTC 25923, organoleptic test (color, aroma, transparency, solidity, and foam) and quality test of transparent solid bath soaps (pH, water content, foam stability, saponification number, and transparency). The essential oils extracted from kamboja, sedap malam, and kenanga flowers were found to contain 17, 20, and 20 compounds, respectively. Based on the result of GC-MS analysis showed that the predominant chemical components in each essential oil were 1,1’-oxydi-2-propanol (21.01%) for kamboja, benzyl ethanoate (24.52%) for sedap malam, and caryophyllene (43.77%) for kenanga. Transparent solid bath soaps with the highest antibacterial activity against S. aureus ATTC 25923 were obtained in the formula added with kamboja, sedap malam and kenanga flowers essential oils at 3.0%, 3.0%, and 3.0%, respectively, with respective inhibitory power of 14.48 mm (strong), 13.73 mm (strong) and 13.56 mm (strong) in diameter. Organoleptic tests revealed that each soap type exhibited characteristic of the respective flower. All soap types demonstrated good quality based on parameters such as pH, water content, foam stability, saponification number and transparency. Keywords: Cananga ordorata L., essential oil, Plumeria alba L., Polianthes tuberosa L., transparent solid bath soap

Antimicrobial Activity and Chemical Composition of Essential Oil Extracted from Hyoscyamus niger L. Inflorescence

This study aimed to analyze the chemical composition and evaluate the antibacterial activity of essential oils extracted from the H. niger inflorescence collected from Erzincan, Türkiye. The essential oils were extracted using hydrodistillation and analyzed by GC-MS, identifying 23 components, with major constituents being 10-heneicosene (35.72%), phytol (20.50%), and acetic acid, butyl ester (10.10%). The antibacterial activity was tested against six bacterial strains, including Staphylococcus aureus, Clostridium perfringens, Enterococcus faecalis, Bacillus cereus, Listeria monocytogenes, and Escherichia coli, using the disc diffusion method. The H. niger inflorescence essential oil exhibited moderate antibacterial activity, specifically against Clostridium perfringens, with a zone of inhibition of 11.7 ± 1.2 mm compared to the positive control imipenem (17.0±1.0 mm). The results suggest that H. niger inflorescence essential oil has potential as an antibacterial agent, highlighting the importance of exploring plant-derived compounds as alternatives to traditional antibiotics in combating multidrug-resistant bacteria.

Exploring the Antibacterial Properties and Chemical Profiles of Essential Oils from Syzygium aromaticum and Nigella sativa Against MDR Bacteria

For centuries, plants have been studied for their healing properties. Recently, the rise of antibiotic resistance in bacteria has prompted scientists to explore herbal remedies. Syzygium aromaticum, from the Myrtaceae family, has been utilized as a histological clearing agent. In contrast, Nigella sativa (black cumin), a member of the Ranunculaceae family, has long been utilized in traditional medicine dating back to ancient times. The current study investigates the chemical composition and antibacterial activity of essential oils from Syzygium aromaticum (clove) and Nigella sativa (black cumin) against multidrug-resistant (MDR) bacteria. Using the agar well diffusion method, Syzygium aromaticum exhibited significant antibacterial activity, particularly against Salmonella typhi (30.66 mm inhibition zone), while Nigella sativa was effective only against Staphylococcus aureus (19 mm). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values for Syzygium aromaticum ranged from 3.53 to 7.06 mg/mL, indicating stronger antibacterial properties than Nigella sativa (MIC: 12.7 mg/mL, MBC: 22.5 mg/mL). GC-MS analysis revealed that Syzygium aromaticum contained bioactive compounds like Diglycolic acid (76.59%) and Eugenol (2.06%), while Nigella sativa was dominated by Heptasiloxane (80.83%) and Thymoquinone (2.66%). These findings suggest that Syzygium aromaticum essential oil could serve as a potent natural antimicrobial agent against MDR pathogens.

The Composition, Antioxidant and Antibacterial Activity of Essential Oils from Five Species of the Magnoliaceae Family.

The leaves of Magnoliaceae family plants contain abundant essential oils (EOs), and these species can be used in many fields due to their high industrial, medicinal, and ornamental values. This study aims to identify the main compounds of the EOs from the leaves of five common Magnoliaceae species (Michelia maudiae, Michelia hedyosperma, Michelia macclurei, Manglietia lucida, Manglietia conifer) using hydrodistillation, GC-MS analysis, and in vitro tests. Additionally, the antioxidant and antibacterial activities of the EOs were also evaluated. The results show that 151 compounds were identified across five species, with sesquiterpenes being dominant. Some key compounds (such as β-caryophyllene, δ-amorphene, β-guaiene, globulol, and β-acorenol) were common among all the species, highlighting their crucial roles in plant physiology and resilience. Other compounds (like valeranone and nerolidol in M. maudiae and β-elemene in M. macclurei) were specific, indicating different functions. Among the five species, the essential oil of M. macclurei contains β-elemene and nerolidyl acetate, and it has the weakest antioxidant activity (IC50 value: 2918.61~21,341.98 μg/mL) but the strongest antibacterial activity (inhibition zone diameter: 8.55 ± 0.93~22.92 ± 0.46 mm; LC50 value: 0.02~0.78 mg/mL). Meanwhile, the EO of M. maudiae demonstrated the best antioxidant activity (the IC50 value was 1283.58~6258.32 μg/mL) and the second-best antibacterial activity (the inhibition zone diameter ranged from 7.61 ± 0.02 to 26.92 ± 0.46 mm, and the LC50 value was 0.03~2.28 mg/mL). Overall, the EO of M. maudiae had the best comprehensive performance. Therefore, the EOs of M. macclurei and M. maudiae showed different performances in biological activity categories, and they could be developed and used in different fields, with the possibility of discovering new applications. This brings inspiration to the potential commercial and industrial uses of sesquiterpenes in Magnoliaceae.

First Report on Salvia Sahendica Boiss & Buhs roots biocomponents characterization by GC-MS and HPLC and Antibacterial Potency

Treatment of bacterial infections with antibiotic resistance is complicated. For this reason, new therapeutic methods are needed to control bacterial infections. Therefore, it is necessary to discover new antibiotics from medicinal plants that can destroy drug-resistant bacteria. Essential oils (EO) of some medicinal plants have antimicrobial effects and can be used as antimicrobial agents in the treatment of infections and food industries. The aim of this study was to determine the EO composition and antimicrobial effects of EO and polyphenols profile of Salvia Sahendica roots for the first time. Chemical compounds and antibacterial activity of EOs against Staphylococcus aureus and Bacillus cereus as gram-positive and Escherichia coli and Pseudomonas aeruginosa as gram- negative bacteria were evaluated using microtiter broth dilution method. Studied organs of S. sahendica showed significant diversity in terms of type and percentage of essential oil and polyphenol compounds. Overall, 44, 46, 42, and 45 compounds were identified in the essential oil of leaves, flowers, stems, and roots of this plant, which constituted 99.6, 99.3, 98.2, and 99.4% of total oil composition, respectively. The current study collectively demonstrated inhibitory effects ranged from strong (S. aureus) to low inhibition (P. aeruginosa). According to the HPLC result, the amounts of coumaric acid, chlorogenic acid, and gallic acid compounds in the root are higher than in other plant parts, which indicate that the root can be a suitable source for the production of these valuable polyphenol compounds. Due to the results, it is possible to hope for the application of EO from S. sahendica as natural antibacterial in the pharmaceutical and food industries.

In vitro antibacterial activity of essential oils from Cymbopogon flexuosus and Cymbopogon winterianus

The objective of the study was to identify and quantify chemical compounds present in the essential oils of C. flexuosus and C. winterianus and evaluate their antibacterial action on Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. This is an in vitro experimental study using essential oils of Cymbopogon flexuosus and Cymbopogon winterianus. The gram-negative strains E. coli (ATCC 25922) and P. aeruginosa (ATCC 27853) and Staphylococcus aureus (ATCC 25923) were used as a Gram-positive strain for the analysis of the antibacterial properties of essential oil. Oil analyzes were carried out using gas chromatography coupled to mass spectrometry (GC/MS). The antibacterial activity of lemongrass (Cymbopogon flexuosus) and citronella (Cymbopogom winterianus) essential oils against bacteria of pathological relevance was confirmed, denoting the potential of using plant essential oils as antibacterial agents, an important alternative considering the emergence of antibiotic resistance.

Chemical composition and antibacterial activity of essential oils extracted from fresh and dried aerial parts of Rosmarinus officinalis L. Pistacia lentiscus L. and Thymus vulgaris L. from Algeria

ABSTRACT The aim of this study was to determine the chemical composition and antibacterial activity of essential oils (EOs) extracted from local plant by steam distillation from the aerial parts (fresh – dried) of rosemary (Rosmarinus officinalis L.), pistachio (Pistacia lentiscus L.) and thyme (Thymus vulgaris L.). Monoterpenes were identified by GC-MS as main compounds, namely 1,8-cineole (34.5–35 %), α-pinene (36.2–36.6 %) and thymol (42.2–42.1 %). Our results showed that EOs tested had antibacterial effects at different levels, with MICs ranging from 1.56 to 6.25 mg.mL−1. Fresh rosemary EO was synergistic against Pseudomonas aeruginosa ATCC 27,853 when combined with dried rosemary EO and fresh pistachio EO, with MICs half those of oils alone (from 6.25 to 3.12 mg.mL−1). In addition, antagonistic, additive and indifferent effects were recorded at 1 %, 3 % and 93 %, respectively. Our findings provide new data on antimicrobial potential of local plants and possibilities of their use as food preservatives.

Constituents and Antibacterial Activity of Essential Oil of Nyctanthes arbor-tristis Flower

Constituents and Antibacterial Activity of Essential Oil of Nyctanthes arbor-tristis Flower

Evaluation of anti-diabetic, anti-oxidant and anti-bacterial activities of essential oil collected from wildly growing Calotropis gigantea (Linn.) Aiton f. and its therapeutic applications: insights from chemical profiling, in-vitro and in-silico studies

Calotropis gigantea, often known as giant milkweed, the plant is widely known for producing herbal essential oils that are used as traditional and complementary medicine to cure various ailments. The aim of the present study was evaluation of anti-diabetic, anti-oxidant and anti-bacterial activities of essential oil collected from wildly growing Calotropis gigantea and its its therapeutic applications via chemical profiling, in-vitro and in-silico studies. After Calotropis gigantea (CEO) essential oil was extracted by hydro-distillation, its phytochemical, antioxidant, antibacterial, and anti-diabetic properties were assessed. Fingerprint analysis and GC-FID were used to create a chemical profile. Various tests for antioxidants, such as DPPH, nitric oxide radical, and iron chelating activity, were conducted. The disk diffusion approach was used for antibacterial efficacy against Gram-negative (G-) bacteria. The test of α-amylase inhibition was utilized to investigate anti-diabetic efficacy. In-silico analysis was also conducted to find out interaction of some components to α-amylase enzyme. Chemical profiling indicated the presence of phytol (24%), stearic acid (10%), and cyclohexyl ketone (6%), as predominant components. There was notable antioxidant activity ranged from 82 to 97% for various assays. IC50 values for various assays were iron chelating activity: 18.610, DPPH scavenging activity: 28.246, nitric oxide radical scavenging activity: 58.113. CEO showed a zone of inhibition value of 0.5 cm and significant antibacterial activity against Gram-negative (G-) bacteria. CEO blocked α-amylase in dose-dependent way. At a higher amount of 250 µl, CEO inhibition was 63% and mode of inhibition un-competitive. In-silico analysis validated the blocking of α-amylase and interaction of phytocomponents to α-amylase enzyme which were further validated by UV and fluorescent quenching techniques. It was determined that CEO may be extensively used in many different industries, including as food, herbal medicine, cosmetics.

Chemical composition and antibacterial activity of the leaf essential oil of Litsea mekongensis Lecomte growing wild in Lam Dong Province, Vietnam

Litsea mekongensis Lecomte is a native species that originated in Vietnam and Laos. To date, the volatile components and antibacterial activity of the essential oils derived from L. mekongensis leaves have not yet been reported. This study aims to investigate the chemical composition and antibacterial activity of L. mekongensis leaf essential oil. The chemical constituents were analyzed by gas chromatography-mass spectroscopy (GC-MS), and the antibacterial activity was evaluated using the agar well diffusion method. The GC-MS analysis showed that fifty-four volatile components were detected, of which sesquiterpene hydrocarbons accounted for almost 65% of the total, while the proportion of monoterpene hydrocarbons was 19.84%. Germacrene D (16.17%), γ-elemene (7.82%), β-phellandrene (6.76%), α-pinene (6.62%), and δ-cadinene (5.68%) were identified as major components. The essential oil exhibited strong antibacterial activity against Salmonella typhi, Staphylococcus aureus, and Escherichia coli. S. aureus was the most sensitive species, but no inhibitory activity against Pseudomonas aeruginosa was recorded. These findings revealed information on the chemical constituents of the essential oil prepared from L. mekongensis and its potential antibacterial activity against several pathogenic bacteria.

Laboratory Efficacy of Essential Oils Against Pectobacterium carotovorum Subsp. carotovorum and Pectobacterium atrosepticum Causing Soft Rot of Potato Tubers

AbstractThe antibacterial activity of essential oils (EOs) from Carum carvi, Cinnamomum zeylanicum, Cuminum cyminum, Eugenia caryophyllus, Foeniculum vulgare, Melaleuca alternifolia, Mentha × piperita, Origanum vulgare, Rosmarinus officinalis and Thymus vulgaris was tested against Pectobacterium carotovorum subsp. carotovorum (Pcc) and Pectobacterium atrosepticum (Pa), which cause soft rot of potato tubers. In disc diffusion, minimum inhibitory concentration and minimum bactericidal concentration (MBC) tests, cinnamon EO was found to be most effective against both bacteria. The inhibition zones ranged from 20.46 to 29.58 mm for a concentration of 100 μL/mL. The minimum inhibitory concentration was 0.5 μL/mL, and MBC was between 0.5 and 5 μL/mL. The higher sensitivity of bacteria was manifested in clove (Pcc and Pa), mint (Pcc), oregano (Pa) and thyme (Pa) EOs. Rosemary EO was the least effective. The results of the in vivo test were not entirely consistent with those of the in vitro tests. The most significant antibacterial effect was achieved with mint EO. The treatment of potato tuber discs with mint EO at a concentration of 3 μL/mL for Pcc and 3–10 μL/mL for Pa was 100% effective. The efficacy of the essential oils of caraway (5–10 μL/mL), thyme (10 μL/mL) and oregano (5 μL/mL) also ranged from 95.7 to 99.7%. Based on the results of the in vivo test, it may be recommended that mint EO and potentially caraway, oregano and thyme EOs be further tested for pickling potato tubers against bacteria of the genus Pectobacterium.

Chemical composition and antibacterial activity of essential oils from Daucus sahariensis Murb. roots and stems

Daucus genus (Apiaceae) comprises economically relevant plants distributed in temperate regions. These plants are used mainly as food but are also known for their biological properties. Here, the essential oils (EOs) obtained by hydro-distillation of roots and stems of D.sahariensis Murb. growing in Algerian Sahara were studied by GC-MS analysis. Fifty-two and fifty-five compounds were identified from the roots and stems, representing 95.1% and 93.8% of the whole EOs respectively. The main constituents of the EO from roots were myristicin (29.2%), (E)-anethole (14.2%), cis-chrysanthenyl acetate (8%) and estragol (7.5%). In the EO from stems, the main constituents were α-pinene (18.6%), myrcene (16.7%), limonene (13.7%) and myristicin (8%). The antibacterial activity of EOs was evaluated by disc diffusion method and tested against Gram-positive and Gram-negative bacteria. Results showed a mild activity against Bacillus subtilis and Klebsiella pneumoniae for both EOs, which can be potentially used as antibacterial in phytotherapy.

In Vitro Methods for Assessing the Antibacterial and Antibiofilm Properties of Essential Oils as Potential Root Canal Irrigants-A Simplified Description of the Technical Steps.

Essential oils have gained in significance due to their various biological activities, and there is a growing demand for them in many industries. The present article focuses on the technical steps for an in vitro evaluation of the antibacterial and antibiofilm activities of essential oils for potential use as root canal irrigant in dentistry. The bioactivities of the essential oil were investigated through in vitro assays. The gram-positive bacterium Enterococcus faecalis was used as a micro-organism model. The antibacterial activity of the essential oil was assessed using the microdilution method, and resazurin staining to determine the minimal inhibition concentrations (MICs) and the minimal bactericidal concentrations (MBCs). The antibiofilm effect was evaluated spectrophotometrically at 570 nm using the microplate cultivation technique and crystal violet staining. This article features a detailed in vitro protocol to facilitate the preparation of the essential oil samples, the bacterial suspension, and the methods used for assessment of the antibiofilm and antibacterial activities of the essential oil. The advantages of these approaches are presented in relation to the limits linked to the choice of the bacteria and the essential oil.

SESELI LIBANOTIS (L.) W.D.J. KOCH (APIACEAE): CHEMICAL COMPOSITION OF ESSENTIAL OILS, THEIR ANTIBACTERIAL AND CYTOTOXIC ACTIVITIES

Introduction. Infectious diseases and cancer remain among the leading causes of death worldwide. In this regard, the search for biologically active molecules from among synthetic and natural compounds for the purpose of creating medicines remains an urgent task of modern science. Plants that have impressive natural and biotechnological resource potential, taking into account modern advances in the field of ex situ, in situ and in vitro cultiva-tion, remain a promising source of native substances. One of the promising sources of biologically active substances is a perennial plant, the Seseli libanotis (L.) W.D.J. Koch, Apiaceae, growing in central, eastern Europe and Asia in dry pastures and forest edges. The main components of the genus Seseli L. are furo- and pyranocoumarins, essential oils and polyacetylene compounds, which exhibit antibacterial, antifungal, insecticidal, diuretic, antiviral, anti-inflammatory, and antitumor properties. The aim – study of the chemical composition, antibacterial and cytotoxic activities of S. libanotis roots essential oil. Material and methods. The roots were collected in places of natural growth in September 2022, during the fruiting period (Irkutsk region, Maloye Goloustnoye village). The voucher specimen is stored in the herbarium of the Institute of Ecological Ecology SB RAS (UUH 020438). Obtaining essential oils. Essential oils were obtained by hydrodistillation. The qualitative composition and quantitative content of essential oil compo-nents were studied by GC/MS. The study of the antibacterial activity of essential oils was carried out in vitro on test cultures of gram-positive and gram-negative bacteria (Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, Pseudomona saeruginosa, Salmonella enterica) using the disc diffusion method. Cell viability assay was performed on HeLa cell lines using trypan blue. Results. The composition and quantitative content of the components of essential oils of the roots of S. libanotis of the Baikal flora were studied for the first time. 28 components of predominantly monoterpene nature have been identified, the main ones being limonene (57,60%), α-pinene (6,88%), cis-β-ocimene (6,75%). Also found were fatty acids, polyacetylene-falcorinol and 7-isopen-tinyloxycoumarin. Essential oils of S libanotis have antibacterial activity against gram-positive bacteria Staphylococcus aureus, Streptococcus pyogenes and gram-negative bacteria Escherichia coli. Cultivation of Hela with S. libanotis essential oils resulted in decreased viability in the concentration range of 0.04–2.56 μL/mL for 72 hours. Conclusions. Essential oils of roots of S. libanotis, with high yield, containing falcarinol and coumarin, have antibacterial and cytotoxic activity.