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Chemical composition and antimicrobial properties of essential oils of three Australian Eucalyptus species

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Abstract

The chemical composition and antimicrobial properties of the essential oils of three common Australian Eucalyptus species, namely E. olida, E. staigeriana and E. dives were determined by gas chromatography/mass spectrometry and the agar disc diffusion method, respectively. A total of 24 compounds were identified from the essential oil of E. dives, with the dominant compounds being piperitone (40.5%), α-phellandrene (17.4%), p-cymene (8.5%) and terpin-4-ol (4.7%). For E. staigeriana, 29 compounds were identified with 1,8-cineole (34.8%), neral (10.8%), geranial (10.8%), α-phellandrene (8.8%) and methyl geranate (5.2%) being the dominant ones. In contrast, a single compound, (E)-methyl cinnamate, accounted for 99.4% of the essential oils of E. oilda, although 20 compounds were identified. The essential oils displayed a variable degree of antimicrobial activity with E. staigeriana oil showing the highest activity. In general, Gram-positive bacteria were found to be more sensitive to the essential oils than Gram-negative bacteria. Staphylococcus aureus was the most sensitive strain while Pseudomonas aeruginosa was the most resistant.

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... Previous studies performed with essential oils of green leaves of Eucalyptus sp. showed antimicrobial activity (GILLES et al., 2010;SELIM et al., 2014). ...
... In this study, the major constituents of EO dl ES were geranial (28.67%), neral (19.68%) and limonene (17.29%). GILLES et al. (2010) identified 29 compounds in oil extracted from fresh leaves of E. staigeriana, being the main components 1.8-cineole (34.8%), neral (10.8%), and geranial (10.8%). Similar results were found by MACEIL et al. (2010), who found out that the main compound extracted was limonene (28.82%), followed by citral (10.77%). ...
... EO dl ES showed in vitro antimicrobial activity only against gram-positive strains. Similar results were observed by GILLES et al. (2010) using S. aureus and E. faecalis strains, which reported high sensitivity for the essential oil of E. staigeriana. E. coli, P. aeruginosa and S. choleraesuis strains were no sensitive to EO dl ES. ...
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RESUMO: Nos últimos anos, compostos com propriedades biológicas produzidas por plantas têm recebido atenção como alternativa de controle de micro-organismos. Óleos essenciais extraídos de folhas verdes de Eucalyptus sp. têm demonstrado atividades antimicrobianas. No entanto, até o momento não há nenhum relato de atividade antimicrobiana de óleos essenciais extraídos de folhas secas de Eucalyptus staigeriana. O objetivo deste estudo foi determinar a composição química dos óleos essenciais obtidos de folhas secas de E. staigeriana e avaliar in vitro a sua atividade antimicrobiana e de antibiofilme contra gram-positivas e gram-negativas e também resistentes e multirresistentes de Enterococcus faecalis isolados de amostras de alimentos e clínicas. A caracterização de E. staigeriana foi realizada por CG-EM. Para este estudo foram utilizadas 26 cepas bacterianas, que incluíram 11 cepas referência e 15 cepas de E. faecalis resistentes a antibióticos. A atividade antimicrobiana de E. staigeriana contra gram-positivas e gram-negativas foi determinada utilizando o método de disco-difusão. Os valores da concentração inibitória mínima foram avaliados pela técnica de microdiluição. Os efeitos de antibiofilme foram avaliados pelo método de placa de microtitulação. Como resultado, 21 compostos foram identificados, sendo monoterpenos oxigenados (69,58%) a grande família química. E. staigeriana mostrou apenas atividade antimicrobiana contra cepas gram-positivas. Cepas de E. faecalis resistentes e multirresistentes mostraram a menor concentração inibitória mínima (3,12 para 6,25%) quando comparado com a cepa referência de E. faecalis. E. staigeriana apresentou a capacidade de inibir a formação de biofilme, mas pouca ou nenhuma capacidade de inibir o biofilme pré-formado. Este estudo demonstra que o óleo essencial obtido de folhas secas de E. staigeriana é uma alternativa promissora para controle importante de bactérias gram-positivas resistentes de origem alimentar e clínicas. PALAVRAS-CHAVE: atividade antimicrobiana; atividade anti-biofilme; óleos essenciais; folhas secas; cepas resistentes a antibió-ticos; Eucalyptus staigeriana. ABSTRACT: In recent years, compounds with biological properties produced by plants have received attention as an alternative to control microorganisms. Essential oils extracted from green leaves of Eucalyptus sp. have been demonstrated to have antimicrobial activities, but so far there are no reports of antimicrobial activity of essential oils extracted from dried leaves of Eucalyptus staigeriana. So, the objectives of this study were to determine the chemical composition of the essential oils obtained from dried leaves of E. staigeriana (EO dl ES) and to evaluate in vitro antimicrobial and antibiofilm activities of EO dl ES against gram-positive and gram-negative, resistance and multiresistant Enterococcus faecalis isolated from food and clinical samples. The characterization of EO dl ES was performed by gas chromatography-mass spectrometry (GC/ MS). For this study, 26 bacterial strains were used, which included 11 reference strains and 15 antibiotic resistant and multiresistant E. faecalis strains. Antimicrobial activities of EO dl ES against gram-positive and gram-negative were determined using the disc diffusion method. The minimum inhibitory concentration (MIC) value was evaluated by a microbroth dilution technique. The antibiofilm effects were assessed by microtiter plate method. As a result, 21 compounds were identified, being oxygenated monoterpenes (69.58%) the major chemical family. EO dl ES showed only antimicrobial activity against gram-positive strains. E. faecalis resistant and multiresistant strains show the lowest MIC (3.12 to 6.25%), when compared with reference E. faecalis strain. EO dl ES has the ability to inhibit the biofilm formation, but little or none ability to inhibit the preformed biofilm. This study demonstrates that EO dl ES is a promising alternative to control important foodborne and clinic gram-positive resistant bacteria.
... The MIC values were 14.2 µL/mL for S. aureus and 28.4 µL/mL for Escherichia coli, respectively. According to the results of the study by Fraternale et al. [66] the Angelica root EO showed antifungal activity against the plant pathogenic fungi Botrytis cinerea, Alternaria solani and some species of the Fusarium genus including Fusarium oxysporum and Fusarium verticillioides. The major compounds were a-pinene (21.3%), d-3-carene (16.5%), limonene (16.4%), and α-phellandrene (8.7%). ...
... Based on the studies by Gilles et al. also α-phellandrene and p-cymene could be regarded among the compounds exhibiting antimicrobial activity [66]. The authors investigated the chemical composition and antimicrobial properties of Eucalyptus dives leaves EO. ...
... The E. dives leaves EO was able to inhibit the growth of all the tested microbes. The dominant compounds identified were piperitone (40.5%), α-phellandrene (17.4%), p-cymene (8.5%) and terpin-4-ol (4.7%) [66]. ...
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Traditionally, arctic Finnish Angelica (Angelica archangelica L.), marsh Labrador tea (Rhododendron tomentosum, syn. Ledum palustre) and common tansy (Tanacetum vulgare) have been used as medicinal herbs in folklore medicine. However, these underutilised plants are a source of, e.g., oil-based compounds, which could benefit many modern applications implemented by the green chemistry extraction methods, as well. We extracted Angelica, marsh Labrador tea and common tansy by non-toxic and recyclable extraction methods, i.e., hydrodistillation and supercritical carbon dioxide (scCO2) extraction; characterised the essential oils (EOs) and scCO2 extracts by combination of gas chromatography and mass spectrometry (GC-MS), and in addition, analysed the antimicrobial properties. As expected for Angelica root and common tansy inflorescence, the scCO2 extraction method produced less amount of volatile compounds compared to hydrodistillation. On the other hand, more coumarins, alkanes, fatty alcohols and fatty acids were obtained. Additionally, sesquiterpenoids palustrol and ledol were predominant compounds in both marsh Labrador tea EO and scCO2 extract. According to our results, however, all the EOs and scCO2 extracts showed broad spectrum of antimicrobial activities against the selected microbes, but the effects were extract-specific. The strongest and broadest antimicrobial activities were performed by marsh Labrador tea scCO2 extract, which showed extremely strong effect on Staphylococcusaureus subsp. aureus and strong effect on Candida albicans.
... Pseudomona aeruginosa (Gram negative) was the most resistant strain with an inhibition zone of 9.1 ± 0.3 when 10 µl of the essential oil was added (Gilles et al. 2010). Donsi and colleagues research has focused on the effect of encapsulating two essential oils, a mixture of terpenes from Melaleuca alternifolia (commonly known as Narrow-leaved Tea-tree, which have been used for medical purposes since the colonization of Australia at the end of the 18 th century), and D-limonene into nanoemulsion to enhance their antimicrobial activity and improve the delivery system and have published 2 reports on this topic. ...
... Although the comparison of results concerning the antimicrobial activity of natural herbs and spices is challenging due to the differences in methods, bacterial strains, antimicrobial concentrations and contact time (Burt 2004), it has been proved that the amount of essential oil needed to effectively inactivate microorganisms in vitro is much lower than the quantity required to achieve the same results in a food system (Burt 2004, Devlieghere et al. 2004, Gutierrez et al. 2008). In addition, gram positive strains have shown to be more susceptible to the antimicrobial effect of essential oils than gram negatives (Tassou and Nychas 1995, Mendoza-Yepes et al. 1997, Lambert et al. 2001, Gilles et al. 2010. Burt (2004) conducted an extensive review on essential oils and their antibacterial properties with various food systems and concluded the following ranking of essential oils from higher bactericidal effect to lower: oregano/ clove/ coriander/ cinnamon> thyme> mint> rosemary> mustard> clinatro/ sage. ...
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Nanoemulsions have been shown to be effective delivery vehicles for natural antimicrobials that are poorly soluble in water. In this study the antimicrobial activity of carvacrol (5-isopropyl-2-methylphenol) nanoemulsions against a bioluminescent Escherichia coli O157:H7 was investigated using light emission as an indicator of cell viability. Different emulsifiers (Ultralec Lecithin and Tween 20), oils (Palm stearin and Coconut oil) and various carvacrol concentrations (0, 1, 2 and 2.5%) were evaluated. Bioluminescence was monitored in situ using a Hamamatsu (photo multiplier tube) sensor module integrated with a Programmable Logic Controller interfaced with a PC for data acquisition. Bioluminescence decreased rapidly with the addition of emulsions containing increasing concentrations of carvacrol (250ppm-1000ppm). However when cells were assayed for viability, plate counts showed there was not a correlation of bioluminescence to cell inactivation. Bioluminescence was able to recover after the removal of carvacrol from the surrounding media. The same bioluminescent pattern was also observed with sub-lethal doses of the oxidative uncoupler 2,4-dinitrophenol and the supplementary addition of the luciferase reaction substrate recovered the light emission in presence of carvacrol.
... galapageium could be tested in vitro on the samples taken from the birds' feathers. P. galapageium also contains eucalyptol (Cimadom et al., 2016, Martina et al. submitted), which has skin soothing properties (Gilles et al., 2010). If parasites cause itchy skin irritations, a soothing effect of P. galapageium could elicit the behaviour of preening with leaves. ...
... revealed that this plant not only contains insect repellent or insecticidal compounds but also compounds with antimicrobial properties (α -Pinene, Nerolidol, Eucalyptol, Terpinene, Guiaol;Chan et al., 2016;Choudhary et al., 2007;Gilles et al., 2010;Iacobellis et al., 2005;Maciel et al., 2010;Nissen et al., 2010). In addition, the closely related tree species, Psidium guajava, has antifungal and antibacterial properties(Morais-Braga et al., 2017;Padrón-Márquez et al., 2012; ...
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Birds host a wide range of ectoparasites and have developed behavioural strategies to combat them, such as preening, dust bathing and water bathing. In addition, a wide range of avian taxa anoint their feathers with insects or plants that have pharmaceutical properties, though most observations on anointing are anecdotal. Darwin's finches preen with leaves of an endemic tree (Psidium galapageium) and a previous laboratory study has shown that this plant has compounds that repel both mosquitoes and the invasive parasitic fly Philornis downsi, whose larvae suck blood from nestlings and incubating females and cause high nestling mortality. In the current study, we tested the hypothesis that preening with P. galapageium leaves serves to repel these parasites with an indirect approach. Mosquitoes and P. downsi affect their hosts mainly during the bird breeding season and P. downsi only affects breeding females, but not adult males. To test our hypothesis, we gathered quantitative data on leaf‐preening behaviour in Darwin's finches during their breeding and non‐breeding season and also investigated the influence of time of day and humidity, as humid conditions facilitate the release of volatile organic compounds. Contrary to our predictions, anointing occurred significantly more often during the non‐breeding season when mosquito and P. downsi numbers are lower. Four Darwin's finch species anointed their feathers habitually, and during the non‐breeding season, 56% of all preening events were with leaves. We found no effect of sex, but preening with leaves occurred predominately in the morning when leaves were wet. Our study is the first to provide quantitative data on anointing behaviour in birds and the high percentage of preening with leaves in the non‐breeding season suggests that the behaviour has an adaptive value. However, further studies are needed to test whether it reduces the negative impact of parasites other than mosquitoes and P. downsi.
... This variability could be due to differences in phytochemical compositions among Eucalyptus species (Yangui et al., 2017). In this context, various studies have proved that Eucalyptus essential oils including E. citriodora, E. globulus, E. staigeriana and E. camaldulensis possess powerful antimicrobial effect against a wide range of pathogenic microbes (Cimanga et al., 2002;Gilles et al., 2010;Rocha Caldas et al., 2015;Yangui et al., 2017). The efficacy of Eucalyptus extracts against B. mediterranea could be attributed to their phenolic substances, which are among the most antifungal active substances present in plants. ...
... (2000) in which a series of hydrolysable tannins and related compounds showed significant potencies against filamentous fungi including Aspergilus, Penicillium and Rhizopus. Moreover, tannins have been reported to be effective against wood-damaging insects in various studies (Civelek et al., 2008;Santana et al;2010;Kirker et al., 2013). ...
Article
Phenolic compounds have become of great importance giving their efficacy against pests including pathogens. This study aimed at evaluating the phenolic composition, the antifungal and repellent activities of three Eucalyptus species: Eucalyptus microtheca F.Muell., Eucalyptus loxophleba Benth. and Eucalyptus gillii Maiden collected from the arboreta of Hajeb Layoun (Kairouan, Tunisia). These species revealed significant variability in total phenolic, flavonoid and condensed tannin contents. The evaluation of their effect against Biscogniauxia mediterranea (De Not.) Kuntze showed considerable antifungal activity especially for Eucalyptus loxophleba which inhibited 93% of the mycelial growth at a concentration of 30 mg/ml. Similarly, the assessment of the repellent activity revealed that Eucalyptus loxophleba was the most effective species against Tribolium castaneum Herbst (RC50= 0.24mg/100μl). Both activities were correlated to condensed tannin contents which proved their role as natural insect repellents and biofongicides. Thus, this study explains that Eucalyptus extracts could have an interest in the control of pests and offer safe alternatives to chemical pesticides.
... Consequently, the discovery of new, innovative, and environmentally friendly strategies has become a vital trend to control fungal pathogens [5,12,13]. Applying different essential oils and medicinal plant extracts might be a sustainable environmental and economical solution for controlling phytopathogens due to their having little or no toxicity to humans and the environment [14]. In this context, the search for innovative, safer, and available alternatives that are derived naturally must be developed in order to decrease the postharvest fruit losses. ...
... Consequently, the discovery of new, innovative, and environmentally friendly strategie has become a vital trend to control fungal pathogens [5,12,13]. Applying different essentia oils and medicinal plant extracts might be a sustainable environmental and economica solution for controlling phytopathogens due to their having little or no toxicity to human and the environment [14]. In this context, the search for innovative, safer, and availabl alternatives that are derived naturally must be developed in order to decrease th postharvest fruit losses. ...
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Recently, there have been urgent economic and scientific demands to decrease the use of chemical fungicides during the treatment of phytopathogens, due to their human health and environmental impacts. This study explored the biocontrol efficacy of novel and eco-friendly preen (uropygial) oil and endophytic Bacillus safensis in managing postharvest Botrytis grey mold in strawberry fruit. The preen oil (25 μL/mL) showed high antifungal activity against B. cinerea Str5 in terms of the reduction in the fungal radial growth (41.3%) and the fungal colony-forming units (28.6%) compared to the control. A new strain of Bacillus safensis B3 had a good potential to produce chitinase enzymes (3.69 ± 0.31 U/mL), hydrolytic lipase (10.65 ± 0.51 U/mL), and protease enzymes (13.28 ± 0.65 U/mL), which are responsible for the hydrolysis of the B. cinerea Str5 cell wall and, consequently, restrict fungal growth. The in vivo experiment on strawberry fruit showed that preen (uropygial) oil reduced the disease severity by 87.25%, while the endophytic bacteria B. safensis B3 reduced it by 86.52%. This study reports the efficiency of individually applied bioagents in the control of phytopathogenic fungi for the first time and, consequently, encourages their application as a new and innovative strategy for prospective agricultural technology and food safety.
... These trees of the genus Eucalyptus belong to the Myrtaceae family and were named by the French botanist Charles Louis L'Héritier de Brutelle in 1788 [1]. This plant is native to Australia and Tasmania and was reclassified by Hill and Johnson in 1995 based on morphology and molecular characteristics [2][3][4][5][6][7]. The natural distribution of Eucalyptus is mainly limited to the southern hemisphere [8]. ...
... Units of some species can reach 400-500 years of age [8]. This tall evergreen tree ( Figure 1) has been successfully introduced into many countries around the world, where it is currently one of the most widely planted trees [3,[9][10][11][12][13]. Eucalyptus species are grown in the tropics and subtropics, including Asia, America, Europe and Africa. ...
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Eucalyptus plants have attracted the attention of researchers and environmentalists worldwide because they are a rapidly growing source of wood and a source of oil used for multiple purposes. The main and the most important oil component is 1,8-cineole (eucalyptol: 60%–85%). This review summarizes the literature reported to date involving the use of 1,8-cineole for the treatment of disorders. Additionally, we describe our efforts in the use of eucalyptol as a solvent for the synthesis of O,S,N-heterocycles. Solvents used in chemistry are a fundamental element of the environmental performance of processes in corporate and academic laboratories. Their influence on costs, safety and health cannot be neglected. Green solvents such as bio-based systems hold considerable additional promise to reduce the environmental impact of organic chemistry. The first section outlines the process leading to our discovery of an unprecedented solvent and its validation in the first coupling reactions. This section continues with the description of its properties and characteristics and its reuse as reported in the various studies conducted. The second section highlights the use of eucalyptol in a series of coupling reactions (i.e., Suzuki–Miyaura, Sonogashira–Hagihara, Buchwald–Hartwig, Migita–Kosugi–Stille, Hiyama and cyanation) that form O,S,N-heterocycles. We describe the optimization process applied to reach the ideal conditions. We also show that eucalyptol can be a good alternative to build heterocycles that contain oxygen, sulfur and nitrogen. These studies allowed us to demonstrate the viability and potential that bio solvents can have in synthesis laboratories.
... Research has focused on essential oils from medicinal plant as natural sources of antimicrobial and antioxidant compounds. Due to their bioactive constituents, these plants can act as stabilisers, increasing the shelf-life of foods and beverages (Gilles et al., 2010). Endophytic fungi co-exist with their host plants, without causing any diseases. ...
Article
Endophytic fungi constitute an important source of structurally diverse and pharmacologically active secondary metabolites. Most medicinal plants possess antimicrobial activity and host a number of endophytic fungi used in defense mechanisms against attack by pathogens. The aim of this study was to determine biodiversity of endophytic fungi isolated from black seeds, using morphological and molecular-based tools. Each isolate was, thereafter, subjected to stress tolerance through varying conditions of pH (2,3 and 12), salinity (3%,8% and 10%) and temperature (2 °C,25 °C,37 °C and 50 °C). Four hundred and ninety-two (n=492) black seeds were used to isolate fungal strains on potato dextrose agar. A combination of microscopic examination and PCR amplification of Internal Transcribed Spacer (ITS 1 and ITS 4) regions were used to identify fungal isolates. One hundred (n=100) endophytic fungi were successfully isolated with a 20% isolation rate. Under salt-stress conditions, most isolates managed to grow at 3% concentration, representing 88% fungal growth, with a maximum of 75–80.5 mm growth diameter. Fifty-eight percent (58%) of the fungi survived at pH 2, 16% survived at 37 °C, while there was no survival at a temperature higher than 50 °C. All the fungi belonged to the Ascomycota phylum, classified under Dothideomycetes (46%), Eurotiomycetes (39%) and Sordariomycetes (11%). The predominant genera identified were Penicillium (35%), Alternaria (26%) and Cladosporium (17%). The findings revealed that medicinal plants, including Nigella sativa, are a source of untapped novel endophytic fungi, with abundant therapeutic and agricultural applications.
... Eucalyptus (E. globulus) is a fast-growing evergreen tree having a wide range of properties such as anti-microbial, anti-fungal, and insecticidal effects (Echeverri-Molina and Santolamazza-Carbone 2010; Gilles et al. 2010). Lemons (C. ...
Article
Adult mosquitoes are the main transmitter for vector-borne diseases, including malaria, dengue fever, and encephalitis. In such diseases, vector control is more accessible and logical than treatment. The use of mosquito repellent is one prevention strategy, especially in endemic areas, to minimize contact with mosquitoes. Essential oils (EO)s based repellents receive more attention as an alternative to chemicals, e.g., N, N-diethyl-meta-toluamide (DEET); they are suspected of causing toxicity. In this research, ingredients of nine medicinally important EOs, including clove, dill, eucalyptus, lemon, myrtle, orange, peppermint, tarragon, and zingiber, were identified using GC-MS analysis. Their repellent activities at a concentration of 0.5% (v/v) were investigated using the Klun & Debboun method against the primary malaria vector, i.e., Anopheles stephensi. The observed protection times for the EOs were in the range of 1-63 min. The highest protection time (63 min) was achieved by applying Clove EO (Syzygium aromaticum). It is noted that eugenol's repellent activity as the major component of clove EO had no significant difference with the total EO. Due to the low price and naturality, the use of EO is preferred over eugenol. In conclusion, Clove EO could be introduced as an excellent candidate for the preparation of green nano/formulation with the repellent effect.
... The sort of microscopic organisms moreover has an impact on the effectiveness of the unstable oil and oleoresins. Gram-negative bacteria were, by and large, less vulnerable than Gram-positive (Gilles et al., 2010). ...
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Tuberculosis (TB) is a contagious infectious disease caused by Mycobacterium tuberculosis. 10 million people suffer from TB Every year. Although TB is a preventable and treatable disease, 1.5 million people die every year due to TB. Alternative treatments continue to be pursued, and treatment with the latest TB drugs that are continuously being encouraged. Black cumin (Nigella sativa) seed contains essential oils with active compounds such as thymohydroquinone, Oleoresins, flavonoids, alkaloids, saponins, tannins, and terpenoids that act as antibacterial drugs. This study aims to determine the sensitivity of N. sativa seed extract in inhibiting the growth of M. tuberculosis strain H37RV and MDR-TB (Multidrug Resistance-TB). This research using Microscopic-Observation and Drug-Susceptibility Assay (MODS) method. Extraction of N. sativa was carried out by the maceration method using 70% methanol as a solvent. The results showed that the M. tuberculosis strain H37RV and MDR-TB were sensitive to N. sativa extract at concentrations of 5 and 10% but resistant to N. sativa extract at concentrations of 1 and 3%.Abstrak: Tuberkulosis (TB) adalah penyakit menular yang disebabkan oleh Bakteri Mycobacterium tuberculosis. Penyakit ini menimbulkan dampak kematian yang cukup mengkhawatirkan. Penyakit tersebut dapat dicegah dan diobati. Salah satu sumber pengobatannya menggunakan biji jintan hitam (Nigella sativa) yang mengandung minyak atsiri dengan senyawa aktif seperti timohidrokuinon, oleoresin, flavonoid, alkaloid, saponin, tanin, dan terpenoid yang berfungsi sebagai obat antibakteri. Penelitian ini bertujuan untuk mengetahui sensitivitas ekstrak biji N. sativa dalam menghambat pertumbuhan M. tuberculosis strain H37RV and MDR-TB (Multidrug-Resistance-TB). Penelitian ini menggunakan metode Microscopic-Observation and Drug-Susceptibility Assay (MODS). Ekstraksi N. sativa dilakukan dengan metode maserasi menggunakan pelarut metanol 70%. Hasil yang diperoleh menunjukkan bahwa bakteri M. tuberculosis strain H37RV dan TB-MDR, kedua strain tsb sensitif terhadap ekstrak N. sativa konsentrasi 5 dan 10%, tetapi resisten terhadap ekstrak N. sativa konsentrasi 1 dan 3%.
... The essential oil of Cinnamomum camphora Ness and Eberm var. linaloolifera Fujita, commonly known as 'ho-sho', is cited in the literature as having antimicrobial, antioxidant, and insecticidal activities (Liu et al., 2006;Cansian et al., 2010;Gilles et al., 2010;Wang et al., 2011;Tomazoni et al., 2017). ...
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This study evaluated the insecticidal effect of Cinnamomum camphora var. linaloolifera essential oil and its major compound, linalool, on Trialeurodes vaporariorum. Essential oil treatments were applied at 0.5, 1.0, 1.5, and 2.0% v/v on eggs, nymphs, and adult individuals and linalool equivalent concentrations on nymphs of T. vaporariorum. The negative controls water and Tween-80® (0.5% v/v) and a positive control (spiromesifen 0.05% v/v for eggs and nymphs; pymetrozine 0.04% m/v for adults) were also used. The essential oil of C. camphora at 2.0% v/v caused egg mortality of 49.7%; same concentration caused the highest nymph mortality (88.5%). For adults, the essential oil at 2.0% v/v caused the highest mortality (40.0%) after 48 h, not changing from 48 to 72 h. The essential oil and linalool performed similarly relative to the nymphs, whose mortalities have not differed statistically, with exception of the concentrations of 0.5 and 1.0% v/v. Regarding the chemical control, the concentration of 2.0% v/v has had similar mortality for nymphs; for eggs and adults, the essential oil caused lower mortality (49.4 and 40.0%) than the synthetic pesticide (65.0 and 72.0%). The essential oil of C. camphora may be a potential control alternative for T. vaporariorum, especially regarding the Integrated Pest Management (IPM) practices.
... The word Eucalyptus originates from the prefix "Eu," which implies "true," and "calyptus," which implies "to cover," and corresponds to the lower bud made up of united calyx and corolla parts that seal the flower until it blooms ( Kantvilas, 1996 ). Eucalyptus oil is ethnomedicinally important and popular essential oil (EO) with diverse therapeutic activities such as analgesic ( Silva et al., 2003 ), antimicrobial ( Gilles et al., 2010 ), anti-oxidant ( Mishra et al., 2010 ), antibacterial ( Bachir and Benali, 2012 ), antiviral ( Elaissi et al., 2012 ), sedative ( Teixeira et al., 2008 ), CNS stimulant ( Kovar et al., 1987 ), pulmonary decongestant ( Burrow et al., 1983 ), antispasmodic ( Coelho-de-Souza et al., 2005 ), etc. Due to its therapeutic potential, Eucalyptus essential oil (EEO) has found its application in the treatment of various ailments such as bronchitis ( Lu et al., 2004 ), sinusitis ( Kehrl et al., 2004 ), asthma ( Juergens et al., 2003 ), Chronic obstructive pulmonary disease (COPD) ( Worth et al., 2009 ), pain ( Jun, Yang Suk et al., 2013 ), infections ( Schnitzler et al., 2001 ;Yadav and Chandra, 2017 ), wounds ( Velmurugan et al., 2014 ), cancer ( Takasaki et al., 2000 ), malaria ( Nathan, 2007 ) and last but not the least COVID-19 ( Panikar et al., 2021 ). Moreover, it is widely used in perfumery, cosmetics, food, beverages, aromatherapy, phytotherapy, and soap industries. ...
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Background: The interest in the use of Eucalyptus genus members, in parallel with preclinical studies has been steadily growing over the last few decades in the field of pharmaceuticals, agriculture, cosmetics, food, etc. Eucalyptol (1,8-cineole or cineole), the main terpenoid constituent in Eucalyptus species, has been studied in both preclinical and clinical settings for its various pharmacologic activities. Investigations into the pharmacological activities of the genus Eucalyptus revealed that it manifests astounding potential in the treatment and management of respiratory disorders, COVID-19, pain, oral health, infectious diseases, cancer, etc. Purpose: This review congregates and discusses the hitherto scattered data on Eucalyptus species morphology, chemical composition, some of its profusely investigated multifaceted therapeutic applications with insights into their molecular mechanisms, and clinical studies. The current understanding of the molecular mechanisms arising from cell lines, animal models, and clinical trials are emphasized. Lattermost, this review sheds light on various reported Eucalyptus-based formulations and relevant patents. Overall, this review aims to summarize and bridge the lacunae in the current research and offer a plethora of opportunities for the researchers engaged in the validation of the traditional claims and development in Eucalyptus utilization for safe and effective treatment of various diseases Method: The systematic and comprehensive review was carried out by adhering to the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statements. PubMed, Scopus, ScienceDirect, Google Scholar, and Google patents databases were used to explore literature published till April 2021 by using relevant keywords. Results: The systematic search retrieved 306 papers that were potentially relevant and after the selection procedure, 103 studies were included in this review and discussed. The evidence reviewed herein suggested that several Eucalyptus species possess anti-inflammatory, anti-microbial, anti-viral, anti-oxidant, anti-nociceptive, anti-cancer, anti-diabetic, etc., activities. Conclusion: Preclinical and clinical studies have shown that the Eucalyptus plant and its chemical constituents have enormous potential for disease prevention and treatment. Eucalyptus, an ancient and underutilized ally with its diverse therapeutic applications can give rise to a paradigm shift in the treatment regime of several diseases in this era of modern science.
... linaloolifera Fujita, whose common name is 'ho-sho', is one of these species. Several studies described the antimicrobial, antioxidant, and insecticidal activity of its leaf essential oil (20)(21)(22)(23)(24). ...
Article
This work aimed to evaluate the insecticidal activity of the leaf essential oil of C. camphora and its major compound, linalool, on A. gemmatalis by ingestion. The individuals were evaluated in 24, 48, 72, and 96 h of exposure to the following concentrations of essential oil and linalool: 0.1, 0.5, 1.0, 1.5, and 2.0% v/v. The biometric parameters of the surviving pupae were also evaluated. The results indicated that C. camphora leaf essential oil was effective in controlling A. gemmatalis, with 96% mortality after 24 h of exposure (2.0% v/v). Linalool was more effective, causing higher mortality percentages in the same exposure time. Higher exposure times increased the mortality percentages at smaller concentrations. There was no evidence of residual or lasting toxic effects of both the essential oil and linalool on the surviving pupae since the biometric parameters of the pupae have not differed from the negative controls.
... Eucalyptus oil has great biological properties (such as antimalarial, anti-allergenic, antiseptic, and anti-asthmatic ones), making it suitable to be used in pharmaceuticals. It has also been used in cleaning, cosmetic and food products [116], and nanotechnology [117]. Figure 5. Schematic mechanism of synthesis MNPs from Eucalyptus. ...
Article
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Nanotechnology is a promising tool that has opened the doors of improvement to the quality of human’s lives through its potential in numerous technological aspects. Green chemistry of nanoscale materials (1–100 nm) is as an effective and sustainable strategy to manufacture homogeneous nanoparticles (NPs) with unique properties, thus making the synthesis of green NPs, especially metal nanoparticles (MNPs), the scientist’s core theme. Researchers have tested different organisms to manufacture MNPs and the results of experiments confirmed that plants tend to be the ideal candidate amongst all entities and are suitable to synthesize a wide variety of MNPs. Natural and cultivated Eucalyptus forests are among woody plants used for landscape beautification and as forest products. The present review has been written to reflect the efficacious role of Eucalyptus in the synthesis of MNPs. To better understand this, the route of extracting MNPs from plants, in general, and Eucalyptus, in particular, are discussed. Furthermore, the crucial factors influencing the process of MNP synthesis from Eucalyptus as well as their characterization and recent applications are highlighted. Information gathered in this review is useful to build a basis for new prospective research ideas on how to exploit this woody species in the production of MNPs. Nevertheless, there is a necessity to feed the scientific field with further investigations on wider applications of Eucalyptus-derived MNPs.
... They are characterised by strong odour and obtained from medicinal and aromatic plants part such as flowers, leaves, seeds, bark, fruits and roots (Burt, 2004). EOs have been reported to possess antifungal, antibacterial, antiviral, antioxidant, analgesic and anti-inflammatory activities (Gao et al., 2011;Gilles et al., 2010;Kordali et al., 2005;Mourey & Canillac, 2002;Prakash et al., 2011). There is an dire need for newer antimicrobial compounds, and EOs are less studied. ...
... According to previous studies, the presence of some constituents (e.g., carvacrol) and oxygenated carvacrol derivatives (e.g., carvacrol methyl ether and thymol methyl ether) and terpenes (e.g., γ-terpinene, eucalyptol, p-cymene, and α-pinene) might improve the antimicrobial activity of EOs. 18,19 Furthermore, the findings of another study, the physicochemical features of NEOs (e.g., surface charge, particle size, shape, and homogeneity) are key factors in determining the rheological properties of nano-colloidal systems, the release of the core material within droplet walls, and the cellular absorption of droplets by microorganisms. 20 To exert antimicrobial effects, emulsion particles should attach onto the cell membrane and efficiently penetrate through the cell wall layer. ...
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Background: Several occurrences of infections and intoxications have been globally announced as a result of the Escherichia coli contamination of foodstuffs. In addition, the emergence of antibiotic resistance in different geneses of bacteria is becoming a major concern for public/medical health authorities and researchers. Objective: Accordingly, this study determined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the essential oil (EO) nanoemulsion (NEO) of Zataria multiflora Boiss against E. coli. Finally, different sub-MIC concentrations of the NEO of zataria EO on the growth rate and the gene expression of stx1A and stx2A were investigated as well. Materials and Methods: Oil in water NEO was formed by the phase inversion technique. The mean diameter of droplets and the zeta potential of NEO were determined, and then the MIC and MBC of EO and NEO were estimated using the broth microdilution method. Eventually, the growth rate and expressions of the stx1A and stx2A genes of E. coli were evaluated after exposure to various sub-MICs. Results: Based on the results, carvacrol was the main constituent of the EO, and NEO droplets had an average size of 61.5 nm and a zeta potential of -27 mV. Further, the MIC values of EO and NEO were 0.45 ± 0.17 and 0.25 ± 0.10 mg/mL, and their MBCs were found 0.55 ± 0.20 and 0.30 ± 0.05 mg/mL, respectively. Furthermore, NEO expressed a stronger inhibitory effect against E. coli growth compared to pure EO. At 75% MIC of EO, the transcriptional rate of stx1A and stx2A decreased 2.24 and 2.66 times at the end of the 72-hour period compared with the control, respectively. After 72 hours, treatment with 75% MIC of NEO resulted in the down-regulation of stx1A and stx2A as 4.75 and 4.80 fold, respectively. Conclusion: The greater activity of the NEO of Z. multiflora Boiss. in comparison with pure EO for slowing down the growth of E. coli and Shiga toxin production shows its potential as a novel ‘green’ food-grade preservative.
... Besides, some EOs also display anti-bacterial effects and are used in the food industry and food packaging in recent years (Table 1) (Wen et al. 2016). EOs from Australian Eucalyptus (containing piperitone, αphellandrene, p-cymene) could interact with the cell membrane of gram-negative and gram-positive bacteria (Gilles et al. 2010). Carvacrol and geraniol from herb oils have been shown to inhibit S. aureus and some gramnegative bacteria via interacting with their cell membrane, respectively (Miranda-novales and Solo 2012). ...
Article
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Food-borne viruses and contaminants, as an important global food safety problem, are caused by chemical, microbiological, zoonotic, and other risk factors that represent a health hazard. Natural bioactive substances, originating from plants, animals, or microorganisms, might offer the possibility of preventing and controlling food-borne diseases. In this contribution, the common bioactive substances such as polyphenols, essential oils, proteins, and polysaccharides which are effective in the prevention and treatment of food-borne viruses and contaminants are discussed. Meanwhile, the preventive effects of natural bioactive substances and the possible mechanisms involved in food protection are discussed and detailed. The application and potential effects of natural bioactive substances in the adjuvant treatment for food-borne diseases is also described. Graphical abstract
... [31][32][33][34][35][36] Piperitone is a dominant component of essential oils obtained from a family of Eucalyptus dives, Mentha, and Cymbopogon and has a structure similar to hydrogenated carvone in terms of substituents, methyl and isopropyl groups on the cyclohexene ring, whereas the substituted positions are different. [1][2][3][4]37,38 Piperitone is also obtained by chemical and biological oxidation of limonene and p-menthene. 39,40 Both these α,β-unsaturated carbonyl compounds are used in flavor, fragrance, and medicinal industries. ...
Article
A series of biobased conjugated dienes with exo-methylene and a 6-membered ring was prepared from naturally abundant terpenoids bearing an α,β-unsaturated carbonyl group, such as verbenone, piperitone, or carvone, and cationically polymerized to form novel biobased cycloolefin polymers with characteristic structures originating from natural products. The obtained exo-methylene-conjugated dienes showed high cationic polymerizability comparable to that of vinyl ethers despite the absence of electron-donating heteroatoms. The polymerization proceeded via regioselective 1,4-conjugated addition by initiating systems effective for living cationic polymerization of vinyl ethers, resulting in well-defined polymers with controlled molecular weights and substituted cyclohexenyl rings in the main chain. These polymers showed high glass transition temperatures (Tg) ranging from 110 to 160 °C depending on the substituents. The hydrogenation of the main-chain cyclohexenyl ring resulted in novel biobased cycloolefin polymers with good thermal stability. The reactivity of the exo-methylene-conjugated diene monomers was evaluated by living cationic copolymerizations with a series of vinyl ethers with different reactivities, i.e., isopropyl, isobutyl, and 2-chloroethyl vinyl ether. In particular, the dienes possessing a methyl group at the 4-position, which can generate a conjugated tertiary cation, were more reactive than a representative vinyl ether with an isobutyl substituent. The sequence distribution of the copolymers varied from statistically random to tapered block structures depending on the monomer reactivities. Block copolymerizations of the dienes and vinyl ethers using the same initiating system for sequential monomer addition resulted in well-defined block copolymers bearing high (>100 °C) and low (∼0 °C) Tg segments, of which microphase separation was confirmed by atomic force microscopy of the thin film.
... In addition, higher inhibition was detected against Pseudomonas aeruginosa which is a major nosocomial pathogen that has the respiratory tract as one of its preferential niches (Riou et al., 2010). Different result was obtained by Gilles et al. (2010) for the P. aeruginosa as it was the most resistant to the essential oils tested. Boulekbache--Makhlouf et al. (2013) have founded a weak antibacterial activity of E. globulus fruit extract against B. subtilis which is similar to that of tannic acid with inhibition zones of 5.33 ± 1.15 mm and 5.5 ± 0.5 mm, respectively. ...
Article
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The aromatic medicinal plant Eucalyptus and its essential oils have been used since antiquity in folk medicine. The interest in this genus has increased remarkably over the last decade mostly because of their various biological activities. This study aimed to determine the chemical composition of essential oils of thirteen Eucalyptus species leaves and their antioxidant and antibacterial activities. Obtained results showed that E. maidenii had the highest essential oil yield (6.16 ± 1.55 %). Chemical composition (by GC/MS) was highly affected by the species factor (P < 0.001), with the abundance of the major compound 1,8-cineole (82.64 % in E. microcarpa) in most Eucalyptus species. Essential oils exhibited a moderate antioxidant activity, but an interesting bacteriostatic effect against all tested bacteria. Eucalyptus camaldulensis had the strongest bioactivities despite its major compound was spathulenol with efficacy concentration of 50 % EC 50 = 2.96 ± 0.11 mg/mL for the reducing power assay and presented an important inhibition zone (25.33 ± 2.84) and lowest minimum inhibitory concentration (MIC = 0.93 mg/mL) against Serratia marcescens bacteria. This result demonstrated that biological activities could be explained by the synergistic effect between major and minor compounds.
... The EO of Origanum vulgare was mainly composed of carvacrol (78.01%), p-cymene (7.82%), γ-terpinene (4.31%) and thymol (4%). These chemical compositions are consistent with the literature (Gilles et al. 2010;Amrouni et al. 2014;Habbadi et al. 2017). ...
Article
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Macroalgae live in tight association with bacterial communities, which impact most aspects of their biology. Clean, ideally axenic, algal starting material is required to control and study these interactions. Antibiotics are routinely used to generate clean tissue; however, bacterial resistance to antibiotics is increasingly widespread and sometimes related to the emergence of potentially pathogenic, multi-resistant strains. In this study, we explore the suitability of two alternative treatments for use with algal cultures: essential oils (EOs; thyme, oregano and eucalyptus) and povidone-iodine. The impact of these treatments on bacterial communities was assessed by bacterial cell counts, inhibition diameter experiments and 16S-metabarcoding. Our data show that thyme and oregano essential oils (50% solution in DMSO, 15 h incubation) efficiently reduced the bacterial load of algae without introducing compositional biases, but they did not eliminate all bacteria. Povidone-iodine (2% and 5% solution in artificial seawater, 10 min incubation) both reduced and changed the alga-associated bacterial community, similar to the antibiotic treatment. The proposed EO- and povidone-iodine protocols are thus promising alternatives when only a reduction of bacterial abundance is necessary and where the phenomena of antibiotic resistance are likely to arise.
... Furthermore, essential oils may contain sulfur and nitrogen substances of coumarins. The percentage shares of individual components vary and depend on many factors, i.e., plant ontogenesis, geographical region, growing and harvest conditions, storage method and preparation for further processing (Gonçalves et al. 2003;Silva et al. 2003;Dob et al. 2005;Bakkali et al. 2008;Gilles et al. 2010;Stefanakis et al. 2013). ...
Article
Novelty statement: That is probably the first study to date of trees and shrubs differing in age and growing on post-industrial soil contaminated with calcium (Ca) and selected toxic metals/metalloids. The obtained results show that an alkaline reaction (less than 9) of soil and an unusually high Ca concentration may help the studied tree species to adapt/survive in unfavorable habitat conditions (high concentration of toxic elements). The efficiency of phytoextraction of toxic elements was so high that, especially for forest animals (roe-deer) that consume, e.g., willow shoots, it could pose a serious threat to health and life, both for them and potentially for humans.
... The use of eucalyptus oils, mostly obtained from the leaves, is grouped as medicinal, industrial, aromatic and flavoring, depending on their chemical composition (Li, Madden, & Potts, 1996;Ogunwande, Olawore, Adeleke, & Ekundayo, 2005;Sartorelli, Marquioreto, Amaral-Baroli, Lima, & Moreno, 2007). Numbers of reports are available all around the world which shows the antibacterial (Bachheti, Joshi, & Singh, 2011;Gilles, Zhao, An, & Agboola, 2010) and antioxidant (Bachheti, 2015;Barra, Coroneo, Dessi, Cabras, & Angioni, 2010;Marzoug et al., 2011), antiseptic agent (Song, Wang, & Liu, 2009) of Eucalyptus Leaves. Essential oils of E. globulusare constituted mainly by the monoterpenes 1, 8-cineole (eucalyptol, 60%), α-pinene (30%) and D-limonene (5%) and the sesquiterpene aromadendrene (Ammon, Barton, Clarke, & Tjandra, 1985). ...
Article
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Eucalyptus globulus trees are available abundantly in the highland part of Ethiopia and traditionally used for the treatment of various ailments including influenza, common cold, warts, febrile illness, and headache. In view of its traditional uses, an attempt was made to explore the chemical profile and antibacterial studies of the leaves of Eucalyptus globulus from two district area. The chemical composition of essential oil obtained by steam distillation extraction from the leaves of Eucalyptus globulus was analyzed by GC-MS. The extraction yields of essential oils of the leaves of E. globulus collected from Haramaya Campus, and Entoto Park were 0.23% and 0.24%, respectively. Twenty-one compounds, constituting about 99.20% of the total oil, were identified from the Haramaya University Campus, whereas eighteen compounds, constituting about 98.03% of the total oil, were identified from Entoto Park. The main constituents identified in both areas were 1, 8-cineole (68.25-72.10%), cis-sabinol (12.10-14.31%), Limonene (2.35-2.96%), α-pinene (2.15-2.50%) and α-terpineol (1.62-2.13. The antimicrobial activity of the oil was evaluated against four microorganisms using paper disk diffusion methods. Essential oils extract of Eucalyptus globulus leaves from Haramaya Campus showed comparatively less antibacterial activity than Entoto Park.
... Furthermore, essential oils may contain sulfur and nitrogen substances of coumarins. The percentage shares of individual components vary and depend on many factors, i.e., plant ontogenesis, geographical region, growing and harvest conditions, storage method and preparation for further processing (Gonçalves et al. 2003;Silva et al. 2003;Dob et al. 2005;Bakkali et al. 2008;Gilles et al. 2010;Stefanakis et al. 2013). ...
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Key message Studied organic molecules in Pinus sylvestris L. seem to have acted as a safety net for metal transport, chelation and sequestration, allowing adaptation and growth under highly polluted conditions. Abstract Pinus sylvestris L. is known for its ability to survive in areas of highly elevated metal pollution, such as flotation tailings. The aim of the study was to estimate the content of selected organic molecules (including aliphatic low molecular weight organic acids (ALMWOAs), phenolic compounds and terpenes) and the physiological mechanisms underlying differences in metal/metalloid tolerance of P. sylvestris growing in unpolluted (soil) and polluted (flotation tailings) areas. The dominant ALMWOAs in rhizosphere soil extracts were citric acid followed by malic and oxalic acids, whereas in flotation tailings malic and oxalic acids. In roots and needles, the content of ALMOWAs was significantly higher in P. sylvestris L. tissue from flotation tailings in comparison to soil. Phenolic compounds were detected only in roots and needles, with a generally higher content of nearly all detected compounds from flotation tailings. The composition of roots did not contain all the compounds detected in needles. The profile of needles additionally contained four hydroxybenzoic, protocatechuic and salicylic acids. In pine needles, 24 volatile terpenes were identified in total. The content of these compounds in pine needles from the polluted area was markedly different from the unpolluted area. The dominant volatile monoterpenes in P. sylvestris L. needles from the unpolluted area was three carene, while in pine needles from the polluted area monoterpenes α-pinene was dominant.
... The antioxidant ability of this herbal medicine is due to the presence of polyphenol, oenothein B, gallic acid, ellagic acid, flavonoids, and hydrolyzable tannin dimer in its extract. Eucalyptus extract also contains kaempferol-3-O-β-D-glucuronides and quercetin [250][251][252][253]. The presence of flavonoids also enhances the chances of having antioxidant ability in the extracts and essential oil of eucalyptus. ...
Article
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Recently, increasing public concern about hygiene has been driving many studies to investigate antimicrobial and antiviral agents. However, the use of any antimicrobial agents must be limited due to their possible toxic or harmful effects. In recent years, due to previous antibiotics’ lesser side effects, the use of herbal materials instead of synthetic or chemical drugs is increasing. Herbal materials are found in medicines. Herbs can be used in the form of plant extracts or as their active components. Furthermore, most of the world’s populations used herbal materials due to their strong antimicrobial properties and primary healthcare benefits. For example, herbs are an excellent material to replace nanosilver as an antibiotic and antiviral agent. The use of nanosilver involves an ROS-mediated mechanism that might lead to oxidative stress-related cancer, cytotoxicity, and heart diseases. Oxidative stress further leads to increased ROS production and also delays the cellular processes involved in wound healing. Therefore, existing antibiotic drugs can be replaced with biomaterials such as herbal medicine with high antimicrobial, antiviral, and antioxidant activity. This review paper highlights the antibacterial, antiviral, and radical scavenger (antioxidant) properties of herbal materials. Antimicrobial activity, radical scavenger ability, the potential for antimicrobial, antiviral, and anticancer agents, and efficacy in eliminating bacteria and viruses and scavenging free radicals in herbal materials are discussed in this review. The presented herbal antimicrobial agents in this review include clove, portulaca, tribulus, eryngium, cinnamon, turmeric, ginger, thyme, pennyroyal, mint, fennel, chamomile, burdock, eucalyptus, primrose, lemon balm, mallow, and garlic, which are all summarized.
... The antibacterial activity may be the result of the presence of α-pinene, α-terpineol and linalool, compounds that are known to possess antibacterial activity [47]. Although present in low concentrations, those constituents could have imparted a significant effect on the antibacterial activities of the oils via a synergistic effect [48]. Escherichia coli 0 ± 00 0 ± 00 0 ± 00 0 ± 00 0 ± 00 0 ± 00 0 ± 00 0 ± 00 0 0 ...
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The aim of this work was to study the chemical composition of the essential oil extracted from ginger rhizomes (Zingiber officinale Roscoe) and cardamom seeds (Elettaria cardamomum (L.) Maton). Using gas chromatography coupled with mass spectrometry (GC/MS), a total of 43 compounds were identified in ginger essential oil and 17 compounds in cardamom. The most abundant components, respectively, were zingiberene (22.18%) and 1.8-cinéol (43.47%). Essential oils, metha-nol, ethanol and chloroform extracts for both plants were tested against nine bacteria and yeast. The highest sensitivity was noticed against Staphylococcus aureus with a 25 mm inhibition zone. The an-tioxidant potency of both oils and extracts were measured using DPPH (1,1-diphenyl-2-picryl hy-drazyl) free radical scavenging and the ferric reducing power (FRP) method; the ethanolic extract of cardamom fruits exhibited the best results for both tests, with an IC 50 = 0.423 ± 0.015 mg/mL and 95.03 ± 0.076 FRP mg AAE/g.
... [2] So, antifungal and antibacterial effects of essential oils on different microorganisms have been reported in several studies. [3][4][5][6][7] Otherwise known as the islands to perfumes, the Comoros archipelago possesses a variety of aromatic and medicinal herbs that most of whom grow in wild. So little studies existed for their chemical characterization and description of their biological properties. ...
Article
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This study aims to determine the chemical composition, antioxidant and antimicrobial activity of Essential oil from roots of Vetiveria zizanioides. Essential oil was obtained by hydrodistillation with a yield of 1%. Chemical analysis was done by GC and GC-MS and showed 40 compounds representing 99, 98% of the essential oil. The major components Khusimol (25.60%), Bicyclo-vetivenol (11.47%), α-Vetivone (7.76%), epi-α-Cadinol (5.97%), Nootaktone (5.28%), Khusinol acetate (3.75%), Nootkatol (3.53%), 1, 10-epi-cubenol (3.06%) and Khusinol (3.02%) constituted 69,44% of oil. Antioxidant activity was evaluated in vitro using DPPH radical scavenging and results showed dose-dependent antioxidant activity. Essential oil showed an antibacterial activity, against Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Micrococcus luteus, more important at a concentration of 1/5000 (v/v). However, for fungicidal activity results was low, with inhibition concentration of 1/500 (v/v) against Aspergillus niger and Penicillium expensum, and 1/2000 (v/v) against Penicillium digitatum. These results suggest a possible
... Eucalyptus extracts can exhibit toxicity against a wide range of microbes, including bacteria, fungi, and soil-borne pathogens (Dhakad et al., 2018;Sabo and Knezevic, 2019). Such antimicrobial effects can be attributed to the presence of terpenoid and phenolic compounds, which have antimicrobial activities in pure form (Gilles et al., 2010). These antimicrobial reagents can be released into the surrounding environment when Eucalyptus residuals are improperly handled, and a vast ecotoxicological risk is raised in real-world scenarios. ...
Article
Eucalyptus is widely planted in China for wood industries, and there are increasing concerns about its ecotoxicity in the environment. This study explored the in-vitro toxicity of Eucalyptus extracts by assessing the impacts of water-soluble and dimethylsulfoxide (DMSO)-soluble fractions via a whole-cell bioreporter, Acinetobacter baylyi ADPWH_recA. Compounds identified in Eucalyptus extracts included one tannin, two phenolic acids, four terpenoids, four glycosides, and five flavonoids. The leaf extracts contained more biological-active components than barks and roots. Genotoxicity induced by Eucalyptus extracts was mainly associated with water extracts (e.g., flavonoids, phenolic acids) instead of DMSO extracts. The significant cytotoxicity was explained by programmed cell death (PCD), suggested by the results of propidium iodide (PI) and 2′,7′-dichlorofluorescein-diacetate (DCFH-DA) assays. Generally, water-soluble fractions contributed more toxicities than DMSO-soluble fractions, particularly at high concentrations. A robust linear regression was built between the compromised toxicity and PCD index (Compromised toxicity = −2.192 × PCD index + 2.219; R² = 0.8886), suggesting a PCD-dependent compromised toxicity which was greatly underestimated. Our results implied non-neglectable ecotoxicological risks of Eucalyptus extracts, hinting at the possible magnified ecological impacts of its large-scale plantation and the potential adverse outcomes to the surrounding ecosystems.
... Different EOs had been reported for their antimicrobial activities as EO of thyme (Tohidpour et al. 2010;Hazzit et al. 2009;Rota et al. 2008;Braga et al. 2008;Khadir et al. 2016), basil (Hussain et al. 2008;Bozin et al. 2006), eucalyptus (Gilles et al. 2010), pistachio (Koutsoudaki et al. 2005) (Taran et al. 2010), savory (Oke et al. 2009;Cavar et al. 2008;Vagionas et al. 2007;Skocibusic et al. 2006), oregano (Carneiro De Barros et al. 2009;Winward et al. 2008;Bendahou et al. 2008), black cumin (Ramadan 2007;Piras et al. 2013), coriander (Lo Cantore et al. 2004), peppermint (Gulluce et al. 2007), sumac (Fazeli et al. 2007), clove, cinnamon (Oussalah et al. 2007;Oussalah et al. 2006), guarana (Majhenic et al. 2007), fennel (Lai and Roy 2004), orange, geranium, juniper, rosemary (Schelz et al. 2006), cumin, laurel, marjoram, sage (Ozcan et al. 2006;Kelen and Tepe 2008;Tepe et al. 2005), pepper, turmeric, ginger, and pine (Sacchetti et al. 2005). 16 Delivery Systems of Plant-Derived Antimicrobials 402 ...
Chapter
Pteridophytes constitute the primitive vascular plant group, which are found scattered all over the world. There are 580 taxa of Nepalese pteridophytes, which are most diverse and adapted in different climatic zones forming an attractive component of the vegetation showing different ecological habits such as epiphytic, lithophytic, terrestrial, tree ferns, hanging club mosses, climbers, and hydrophytic. Human beings have been using pteridophytes because of their several useful properties, including food and medicine. Some important bioactive compounds have been identified from the Nepalese pteridophytes and the chemical compounds isolated have shown antimicrobial properties, which has revealed that pteridophytes play a potential role in Nepalese pharmacopoeia and drug discovery. Finally, the challenges and opportunities of pteridophyte research are discussed.
... In order to determine the biological activity of two bacterial strains, Vibrio Harveyi and Vibrio alginolyticus were used in different conditions. The results showed that the maximum biological activity of the aqueous extract of Eucalyptus camaldulensis leaves in both species of vibrio has shown at low temperatures, so that with increasing temperature, this activity gradually decreases, but it can be noted that the increase The temperature, breaking some of the chemical bonds and destroying some of the extracted compounds, reduce the amount of biological activity and antibacterial effects of the aqueous extract (Giles et al., 2009) [6] . The salinity of the Vibrio harveyi bacteria used in this study is noteworthy that this species is able to create more virulent in saline (Kannapiran et al., 2009; Selven and Philip, 2013) [9] . ...
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Litopenaeus vannamei shrimps are one of the important aqueous proteins resources that has successfully cultured from 1990. Some bacterial diseases like vibriosis among penaeus shrimps have affected shrimp industry. Vibrio harveyi (PTCC1755) and vibrio algynolyticus (MK641453.1) bacteria cause vibriosis in Peaeus shrimps. But over use of antibiotics led to the emergence of drug resistant strains of bacteria and nature cause to find and replace natural therapeutic sources like eucalyptus camaldulensis leafs. In this study we determined antibacterial activity of aqueous extract of eucalyptus camaldulensis against vibrio harveyi (PTCC1755) and vibrio algynolyticus (MK641453.1) bacteria tested in different salinity and temperature Results showed that the most antibacterial activity of eucalyptus camaldulensis for both vibrio harveyi (PTCC1755) and vibrio algynolyticus (MK641453.1) was Respectively in 78 ppt at 35 ºC and 60ppt at 35 ºC. According to the results, it can be concluded that the aqueous extract of eucalyptus camaldulensis can have an inhibitory effect on vibriosis with Vibrio harveyi (PTCC1755) and Vibrio algynolyticus (MK641453.1) bacteria.
... The sort of microscopic organisms moreover has an impact on the effectiveness of the unstable oil and oleoresins. Gram-negative bacteria were, by and large, less vulnerable than Gram-positive (Gilles et al., 2010). ...
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Tuberculosis (TB) is a contagious infectious disease caused by Mycobacterium tuberculosis. 10 million people suffer from TB Every year. Although TB is a preventable and treatable disease, 1.5 million people die every year due to TB. Alternative treatments continue to be pursued, and treatment with the latest TB drugs that are continuously being encouraged. Black cumin (Nigella sativa) seed contains essential oils with active compounds such as thymohydroquinone, Oleoresins, flavonoids, alkaloids, saponins, tannins, and terpenoids that act as antibacterial drugs. This study aims to determine the sensitivity of N. sativa seed extract in inhibiting the growth of M. tuberculosis strain H37RV and MDR-TB (Multidrug Resistance-TB). This research using Microscopic-Observation and Drug-Susceptibility Assay (MODS) method. Extraction of N. sativa was carried out by the maceration method using 70% methanol as a solvent. The results showed that the M. tuberculosis strain H37RV and MDR-TB were sensitive to N. sativa extract at concentrations of 5 and 10% but resistant to N. sativa extract at concentrations of 1 and 3%. Abstrak: Tuberkulosis (TB) adalah penyakit menular yang disebabkan oleh Bakteri Mycobacterium tuberculosis. Penyakit ini menimbulkan dampak kematian yang cukup mengkhawatirkan. Penyakit tersebut dapat dicegah dan diobati. Salah satu sumber pengobatannya menggunakan biji jintan hitam (Nigella sativa) yang mengandung minyak atsiri dengan senyawa aktif seperti timohidrokuinon, oleoresin, flavonoid, alkaloid, saponin, tanin, dan terpenoid yang berfungsi sebagai obat antibakteri. Penelitian ini bertujuan untuk mengetahui sensitivitas ekstrak biji N. sativa dalam menghambat pertumbuhan M. tuberculosis strain H37RV and MDR-TB (Multidrug-Resistance-TB). Penelitian ini menggunakan metode Microscopic-Observation and Drug-Susceptibility Assay (MODS). Ekstraksi N. sativa dilakukan dengan metode maserasi menggunakan pelarut metanol 70%. Hasil yang diperoleh menunjukkan bahwa bakteri M. tuberculosis strain H37RV dan TB-MDR, kedua strain tsb sensitif terhadap Mashuri Masri, Cut Muthiadin, Masita, Tri Cahyanto, Lianah Lianah, Rusny, & Siska Tridesianti : Black Cumin (Nigella sativa) Against Mycobacterium tuberculosis Strain H37RV And MDR-TB
... [8] Eucalyptus genus, indigenous to Australia, comprises over 900 species and subspecies of aromatic trees and shrubs and represents one of the significant members of this family. [9,10] Owing to their fast growth and easy adaptability, numerous Eucalyptus species have been successfully introduced and widespread all over the world, particularly in subtropical and warm temperate regions, including Tunisia. [11] They are considered as the most extensively planted pulpwood species. ...
Article
In recent years, there has been a growing interest in the screening of natural active ingredients from Eucalyptus essential oils because of their evident importance in practical utility and their undeniable therapeutic properties. Based on this, the aim of the present study was to investigate the chemical profile of the essential oils of the trunk bark of Eucalyptus torquata Luehm. (ETEO), and E. salmonophloia F. Muell. (ESEO), growing in Tunisia. The in vitro cytotoxic properties of the extracted EOs were also evaluated against two human cancer cell lines: breast carcinoma cell lines MDA‐MB‐231 and colorectal cancer cell lines SW620. The analysis by gas chromatography coupled with mass spectrometry (GC/MS) led to the identification of 32 compounds from the ETEO, with the dominant constituents being the monoterpenes trans‐myrtanol (73.4 %) and myrtenol (4.7 %), and the apocarotene (E)‐β‐ionone (3.9 %). In the case of ESEO, 29 compounds were identified with trans‐myrtanol (25.0 %), decanoic acid (22.1 %), nonanoic acid (9.8 %), γ‐elemene (6.5 %), γ‐maaliene (5.5 %), and α‐terpineol (5.3 %) as the main components. The cytotoxicity of EOs against the two chosen cell lines was tested using Crystal Violet Staining (CVS) assay and 5‐fluorouracil as a reference drug. The two EOs exhibited a significant dose‐dependent inhibition against the viability of the used cell lines. Their inhibitory effects were particularly observed towards SW620 colon carcinoma cells with IC50 values of 26.71±1.22 and 22.21±0.85 μg/mL, respectively, indicating that both oils were more cytotoxic for SW620 cells compared to MDA‐MB‐231 one.
... Different EOs had been reported for their antimicrobial activities as EO of thyme (Tohidpour et al. 2010;Hazzit et al. 2009;Rota et al. 2008;Braga et al. 2008;Khadir et al. 2016), basil (Hussain et al. 2008;Bozin et al. 2006), eucalyptus (Gilles et al. 2010), pistachio (Koutsoudaki et al. 2005) (Taran et al. 2010), savory (Oke et al. 2009;Cavar et al. 2008;Vagionas et al. 2007;Skocibusic et al. 2006), oregano (Carneiro De Barros et al. 2009;Winward et al. 2008;Bendahou et al. 2008), black cumin (Ramadan 2007;Piras et al. 2013), coriander (Lo Cantore et al. 2004), peppermint (Gulluce et al. 2007), sumac (Fazeli et al. 2007), clove, cinnamon (Oussalah et al. 2007;Oussalah et al. 2006), guarana (Majhenic et al. 2007), fennel (Lai and Roy 2004), orange, geranium, juniper, rosemary (Schelz et al. 2006), cumin, laurel, marjoram, sage (Ozcan et al. 2006;Kelen and Tepe 2008;Tepe et al. 2005), pepper, turmeric, ginger, and pine (Sacchetti et al. 2005). 16 Delivery Systems of Plant-Derived Antimicrobials 402 ...
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According to WHO and FAO, the current global problem in public health/environmental which is of high economic impact is the lack of effectiveness/resistance to "antimicrobials” by many pathogens (e.g., Staphylococcus spp., Mycobacterium spp., Klebsiella spp., Pseudomonas spp., Helicobacter spp., Listeria spp., Salmonella spp., Acinetobacter spp., Aspergillus spp., Candida spp.) that cause disease in humans (e.g., septicemia, nosocomial, respiratory, STD) and food-producing animals (e.g., cattle, goats, poultry), which could be related to food security. Nonetheless, since 1990s, new antimicrobials (new chemical libraries or structures/scaffolds) have not been found in the pharmaceutical industry, but their “new agents” (commercially available drugs) were redesigned from earlier times and prospecting for new discoveries was no longer relevant. In that sense, the WHO has mentioned/emphasized the need to research/develop new antimicrobials since the available therapeutic options are limited, due to the low investment in development and research of new drugs, as well as the few incentives to search/isolate/synthesize new molecules that allow to combat/control/reduce the problem of resistance. Among this search for therapeutic options, the WHO itself has recommended the inclusion of traditional and complementary medicine as a potential/promising alternative that, if it does not completely solve the problem of resistance, at least temporarily contributes to the solution as a new treatment. Thus, nature has provided from some plants certain constituents (isolated/in mixture) with a high biological potential against particular pathogenic microorganisms that cause human/animal diseases. In this chapter, specific cases of molecules/essential oils/extracts of certain medicinal plants from some Latin American countries (Bolivia, Brazil, Colombia, Mexico, and Peru) that have been effective against disease-causing pathogens in humans and/or animals are described.
... Results showed that the essential oils of C. nepeta, L. luisieri and T. mastichina have high antimicrobial activity, representing a non-toxic alternative to inhibit the fungal growth of Cladosporium, Penicillium and Aspergillus strains, while Bacillus strain is sensitive to R. officinalis EO and resistant to New Des 10% and Igran 500 FW 10%, v/v biocides. The bibliography refers that essential oils rich in terpenoids, namely oxygenated monoterpenes and phenolic compounds, showed antimicrobial activity, suggesting that these components may be responsible for the antimicrobial activity of essential oils, either because they present themselves as major compounds or when they are minority compounds, they present an important role due to the synergistic effects [96][97][98]. Some studies carried out with essential oils and their major components showed synergistic interactions between the compounds of the EOs, potentiating their antimicrobial effect [79,84,85,97,99]. ...
Article
Microbial biodeterioration is a growing problem in cultural heritage (CH). Many biocides used to control CH biodeterioration have toxic effects and risks of contamination for health and the environment. Essential oils (EOs) due to their antimicrobial potential and low toxicity represent a sustainable and safe alternative in the control of microbial growth in heritage assets. Nevertheless, EOs volatility is one of the main challenges for its use in bio-mitigation adapted to cultural heritage. The encapsulation of EOs may have an alternative strategy for the use of EOs as green biocides that promote a controlled release of EO. In this study, seven EOs of flavouring herbs were screened to evaluate their antimicrobial potential against filamentous fungi, yeast or bacteria strains, previously isolated from colonized artworks. Free EOs, namely L. luisieri and C. nepeta EOs, showed a large antimicrobial spectrum, with high activity for A. niger, Cladosporium spp., Penicillium spp., Rhodotorula sp. and Arthrobacter sp. strains. EO of T. vulgaris shows similar antifungal activity when encapsulated by co-precipitation with β-cyclodextrin, for an encapsulation efficiency higher than 50%. The results suggest the potential use of EO in the safeguard of cultural assets, as eco-friendly, biodegradable and non-toxic biocides, as a green and useful approach when compared to traditional biocides.
... It is a cyclic ether and monoterpenoid, it controls airway mucus hypersecretion and asthma via anti-inflammatory cytokine inhibition. It is abundant in many Eucalyptus species (Myrtaceae) [135]. It has low toxicity (LD 50 for rats 2.5 g/kg) [116]. ...
Article
Background: Many publications discussed the potential role of medicinal plants in the management of COVID-19. However, clinical studies of the efficacy and safety of specified phytochemical(s) are limited. Objectives: To explore the pharmacological profile of specified compounds against COVID-19 Method: Systematic literature search of academic databases to explore specified phytochemicals for the management of COVID-19 using appropriate search terms. Rayyan software was used to organize 786 citations of which. 236 articles were included in this review. Results: Initially 70 compounds were identified to have a potential role in the management of COVID-19. In this review, 18 compounds were selected for further search Conclusion: In vitro anti-SARS-CoV-2activity has been demonstrated for a variety of natural compounds. However, preclinical research for most phytochemicals is scarce, and only a few compounds have been evaluated in clinical trials against COVID-19. A comprehensive pharmacological profile of these phytochemicals is urgently needed.
... It is a cyclic ether and monoterpenoid, it controls airway mucus hypersecretion and asthma via anti-inflammatory cytokine inhibition. It is abundant in many Eucalyptus species (Myrtaceae) [135]. It has low toxicity (LD 50 for rats 2.5 g/kg) [116]. ...
Article
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Background: Many publications discussed the potential role of medicinal plants in the management of COVID-19. However, clinical studies of the efficacy and safety of specified phytochemical(s) are limited. Objectives: To explore the pharmacological profile of specified compounds against COVID-19 Method: Systematic literature search of academic databases to explore specified phytochemicals for the management of COVID-19 using appropriate search terms. Rayyan software was used to organize 786 citations of which. 236 articles were included in this review. Results: Initially 70 compounds were identified to have a potential role in the management of COVID-19. In this review, 18 compounds were selected for further search Conclusion: In vitro anti-SARS-CoV-2activity has been demonstrated for a variety of natural compounds. However, preclinical research for most phytochemicals is scarce, and only a few compounds have been evaluated in clinical trials against COVID-19. A comprehensive pharmacological profile of these phytochemicals is urgently needed
... The RGEO exhibited a moderate MIC for S. mutans and S. pyogenes and showed low activity against the rest of the analyzed bacteria. Overall, RGEO showed low efficiency in inhibiting the Gram-negative strains compared to Gram-positive strains, following previous studies [6,27,49,61,62]. These differences in susceptibility could be associated with different rates of penetration of EO constituents into the cell wall and cell membrane structures. ...
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The research aimed to investigate the chemical composition and antioxidant and antibac-terial potential of the essential oil (EO) isolated from the aerial parts (flowers, leaves, and stems) of Ruta graveolens L., growing in western Romania. Ruta graveolens L. essential oil (RGEO) was isolated by steam distillation (0.29% v/w), and the content was assessed by gas chromatography-mass spec-trometry (GC-MS). Findings revealed that 2-Undecanone (76.19%) and 2-Nonanone (7.83%) followed by 2-Undecanol (1.85%) and 2-Tridecanone (1.42%) are the main detected compounds of the oil. The RGEO exerted broad-spectrum antibacterial and antifungal effects, S. pyogenes, S. aureus, and S. mutans being the most susceptible tested strains. The antioxidant activity of RGEO was assessed by peroxide and thiobarbituric acid value, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), and β-carotene/linoleic acid bleaching testing. The results indicated moderate radical scavenging and relative antioxidative activity in DPPH and β-carotene bleaching tests. However, between the 8th and 16th days of the incubation period, the inhibition of primary oxidation compounds induced by the RGEO was significantly stronger (p < 0.001) than butylated hydroxyanisole (BHA). Molecular docking analysis highlighted that a potential antimicrobial mechanism of the RGEO could be exerted through the inhibition of D-Alanine-d-alanine ligase (DDl) by several RGEO components. Docking analysis also revealed that a high number RGEO components could exert a potential in vitro protein-targeted antioxidant effect through xanthine oxidase and lipoxygenase inhibition. Consequently, RGEO could be a new natural source of antiseptics and antioxidants, representing an option for the use of synthetic additives in the food and pharmaceutical industry. Citation: Jianu, C.; Goleț, I.; Stoin, D.; Cocan, I.; Bujancă, G.; Mișcă, C.; Mioc, M.; Mioc, A.; Șoica, C.; Lukinich-Gruia, A.T.; et al.
... In addition to antimicrobial and antioxidant effects, some natural compounds have beneficial effects on human health (Sutherland et al., 2009). Essential oils, plant extracts, bacteriophages, peptides, bacteriocins, and probiotic bacteria are examples of natural preservatives used to improve food quality (Aziz & Karboune, 2018;Gao et al., 2015;Gilles et al., 2010;Pandini et al., 2017). ...
Article
The objectives of present study were to evaluate the potential of Lactobacillus reuteri or Lactobacillus casei combined with black pepper extract (BPE) and ethylenediamine tetraacetic acid (EDTA) for controlling the growth of E. coli O157:H7 and improving the chemical, microbiological and sensory quality of ground beef stored at 10 °C for 12 days. The in vitro results indicated that the combination of L. casei with BPE and EDTA had the most potent antibacterial effect against E. coli and resulted in 2.7 log CFU/ml reduction. In ground beef, the combination of L. reuteri or L. casei with BPE and EDTA decreased E. coli and aerobic mesophilic bacteria counts up to 1 and 1.6 log CFU/g, respectively. Meanwhile, this combination significantly reduced the lipid oxidation rate (up to 60%) and improved odor and overall acceptability scores of ground beef. It was concluded that the combination of L. casei with BPE and EDTA could be used in ground beef to control microbial proliferation, retard lipid oxidation, and improve sensory quality.
... Therefore, mixing of lemongrass oil with other essential oils for potential synergistic effects needs further investigations. The phytotoxicity of eucalyptus essential oil mainly refers to the monoterpene 1,8-cineol, causing oxidative stress followed by membrane disruption and electrolyte leakage [131,146,204]. It inhibits mitosis by inhibiting G1 phase and several enzymes as p38, resulting in further metabolic interceptions, for example, in photosynthesis and energy metabolism [148], which lead to cellular damage and death of the target plant [205]. ...
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Concerning human and environmental health, safe alternatives to synthetic pesticides are urgently needed. Many of the currently used synthetic pesticides are not authorized for application in organic agriculture. In addition, the developed resistances of various pests against classical pesticides necessitate the urgent demand for efficient and safe products with novel modes of action. Botanical pesticides are assumed to be effective against various crop pests, and they are easily biodegradable and available in high quantities and at a reasonable cost. Many of them may act by diverse yet unexplored mechanisms of action. It is therefore surprising that only few plant species have been developed for commercial usage as biopesticides. This article reviews the status of botanical pesticides, especially in Europe and Mediterranean countries, deepening their active principles and mechanisms of action. Moreover, some constraints and challenges in the development of novel biopesticides are highlighted.
... Different EOs had been reported for their antimicrobial activities as EO of thyme (Tohidpour et al. 2010;Hazzit et al. 2009;Rota et al. 2008;Braga et al. 2008;Khadir et al. 2016), basil (Hussain et al. 2008;Bozin et al. 2006), eucalyptus (Gilles et al. 2010), pistachio (Koutsoudaki et al. 2005) (Taran et al. 2010), savory (Oke et al. 2009;Cavar et al. 2008;Vagionas et al. 2007;Skocibusic et al. 2006), oregano (Carneiro De Barros et al. 2009;Winward et al. 2008;Bendahou et al. 2008), black cumin (Ramadan 2007;Piras et al. 2013), coriander (Lo Cantore et al. 2004), peppermint (Gulluce et al. 2007), sumac (Fazeli et al. 2007), clove, cinnamon (Oussalah et al. 2007;Oussalah et al. 2006), guarana (Majhenic et al. 2007), fennel (Lai and Roy 2004), orange, geranium, juniper, rosemary (Schelz et al. 2006), cumin, laurel, marjoram, sage (Ozcan et al. 2006;Kelen and Tepe 2008;Tepe et al. 2005), pepper, turmeric, ginger, and pine (Sacchetti et al. 2005). 16 Delivery Systems of Plant-Derived Antimicrobials 402 ...
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The Brazilian Amazon is the largest biome in the country and encompasses about 40% of the forest remnants of the humid tropic. The use of homemade medicines from medicinal plants has been practiced since the dawn of human civilization. In prehistoric age, man sought to alleviate his pain or treat his illnesses through the action of bioactive compounds present in plants, although in an intuitive way based on random discoveries. Such secondary metabolites of medicinal plants have proven to have antimicrobial activity due to the action of their bioactive compounds. The extraction of bioactive compounds is an especially important step, not only for the separation of compounds, but also during the analysis of solid materials. There are several conventional and unconventional techniques for the extraction of bioactive compounds from plant matrices, those that use a solvent. Nanotechnology emerges as a potential technology to enhance the action of bioactive compounds present in plant matrices, as it can maintain its characteristics and stability, making these compounds used in several areas. As many of the biologically active compounds have insolubility and hydrophobicity, nanoencapsulation facilitates the delivery of these poorly bioavailable compounds when applied to functional products and drugs, which increases their absorption into cellular structures through properties of favorable particles of shape, size, and surface. Nanotechnology has proved to be a great tool to potentiate the action of such bioactive compounds.
Article
Several species of the genus Eucalyptus are used in many traditional medicine systems for the treatment of respiratory tract infections, colds, flu, sore throats, and bronchitis. The genus Eucalyptus (Myrtaceae) is a well‐known natural source of bioactive phloroglucinols. These polyphenolic compounds bear an aromatic phenyl ring with three hydroxy groups (1,3,5‐trihydroxybenzene) which have been exhibiting a variety of biological activities such as antimicrobial, anticancer, anti‐allergic, anti‐inflammatory, and antioxidant activities. This review summarizes the literature published from 1997 until the end of 2021 and addresses the structure diversity of phloroglucinols isolated from Eucalyptus species and their biological activities. Phloroglucinol‐terpene adducts are the main class of compounds that have been reported in this genus.
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Medicinal traditional plants are a source of inspiration for the discovery of new bioactive substances. Plant infusions, extracts, and essential oils are known for their diverse biological activity since they are rich in secondary metabolites. The Mediterranean area in general and Lebanon in particular is known for its plant diversity due to its climate and geographical location. This chapter will provide an overview of Lebanese plants with antimicrobial activity. Many of these plants are known for their culinary and traditional medicinal uses for the treatment of different ailments. The main plant families discussed here include Amaryllidaceae, Anacardiaceae, Apiaceae, Asteraceae, Berberidaceae, Cannabaceae, Cistaceae, Lamiaceae, Myrtaceae, Pinaceae, Portulacaceae, Ranunculaceae, Rutaceae, Rosaceae, and others.
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Understanding immunity in wildlife populations is important from both One Health and conservation perspectives. The constitutive innate immune system is the first line of defence against pathogens, and comparisons among taxa can test the impact of evolution and life history on immune function. We investigated serum bacterial killing ability (BKA) of five marsupial species that employ varying life history strategies, demonstrated to influence immunity in other vertebrates. The brushtail possum and eastern grey kangaroo had the greatest BKA, while ringtail possums and koalas had the least. These differences were independent of social structure, captivity status and phylogeny, but were associated with diet and body size. Sex and disease status had no effect on BKA in koalas, however potential for differences between wild and captive koalas warrants further investigation. The current study has provided a foundation for future investigations into how adaptive and innate immunity interact in marsupials from an eco-evolutionary perspective.
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The antibacterial activity and mechanism of plant essential oils against the specific spoilage organism of aquatic products in vitro were studied. All four selected essential oils performe antibacterial activities against five targeted bacterial strains (Escherichia coli, Shewanella putrefaciens, Pseudomonas aeruginosa, Vibrio parahaemolyticus, and Staphylococcus aureus), while eucalyptus essential oil (EEO) displayed the highest inhibitory effect in five strains. The minimum inhibitory concentrations (MIC) of EEO against five bacteria was in the range of 0.63–2.00 µl/ml. Scanning electron microscopy and transmission electron microscopy displayed noticeable damages of bacterial morphology and ultrastructure on two model bacteria. The increments of electric conductivity and the optical density at 260 nm and the decrease of intracellular ATP content, suggesting that the permeability of bacterial membrane increased while cell integrity and cell physiological function were damaged when treated with EEO at MIC. Therefore, the great potential of EEO in seafood preservation has been shown, which provides new insight for further researches. Essential oils extracted from natural plants are considered to be served as alternative sources of antibacterial components. In our study, eucalyptus essential oil (EEO) showed excellent antibacterial ability by affecting cell physiological function, which was possibly resulted from a loss of cell homeostasis. Therefore, it has a great potential in the utilization of EEO in seafood preservation.
Chapter
The use of essential oils as antimicrobial agents is widely applied in medical field, pharmaceutical industry, and food preservation. However, essential oils are hydrophobic, volatile, and unstable; in addition, they undergo degradation by environmental factors, such as light, oxygen, and heat, which represent obstacles for their wide utility. Green industry via incorporating these natural substances in pharmaceutical vehicles is one of the most commonly used technologies to impart exclusive features for the essential oils. Desirably, assortment of lipid and non-lipid-based delivery systems have been employed aiming to improve their stability and antimicrobial activity, provide sustained release pattern, and boost their bioavailability. This chapter offers an overview of various delivery systems that have been utilized to encapsulate some antimicrobial essential oils exploitable in the pharmaceutical field in recent literature. The versatility of nature of the proposed vehicles and harnessed natural and synthetic polymers, as well as advancement in fabrication techniques, are highlighted. Specifically, the stability and fulfillment of antimicrobial effectiveness of encapsulated essential oils are greatly emphasized.
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The chemical composition of essential oils (EOs) can vary from one plant to another of the same species and can be affected by several factors including the environment of growth. The research was carried out on the EOs of Eucalyptus camaldulensis leaves grown in three separate greenhouses differentiated by their low-density polyethylene (LDPE) covering material. This study aimed to compare the impact of the type of the greenhouse cover film on the internal microclimate, light intensity, and chemical composition of E. camaldulensis EOs. Eucalyptus species was initially cultivated from the seeds and the EOs were extracted from the leaves of 14 weeks aged trees. The extraction was performed by hydrodistillation using a Clevenger-type apparatus. Qualitative and quantitative analyses of the extracted EOs were performed using gas chromatography coupled with mass spectrometry (GC-MS) and gas chromatography coupled with a flame ionization detector (GC-FID). The analyzed samples were rich in terpenes with a total of 66 identified compounds. The oxygenated monoterpenes pinocarvone and D-carvone were only identified in the essential oils from multilayered greenhouses. cis-1-Methyl-4-(1-methylethyl-)-2-cyclohexen-1-ol was absent in eucalyptus EOs from the three-layer greenhouse, unlike the others that had it. Different compound contents were detected in the extracted essential oils, according to their greenhouse cover conditions. 1,8-Cineol was the compound present in a higher amount as expected, with the highest value of c.a 164.78 mg/gdw from the leaves of E. camaldulensis cultivated in the ordinary greenhouse. Contents of 51.55 mg/gdw and 42.11 mg/gdw were obtained from E. camaldulensis cultivated in the three-layers and monolayer greenhouses, respectively. In contrast, the EOs of E. camaldulensis grown under the monolayer greenhouse presented the highest content of some aromadendranes family compounds. This study shows that the greenhouse cover-film should be chosen thoughtfully because it plays a major function regarding its effect on the chemical composition of the EOs of E. camaldulensis cultivated in greenhouse environments.
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This investigation intended at fabricating gelatin active packaging films based on nano‐sized droplets of coconut oil emulsified by Pickering emulsion (PE) using chitosan/Arabic gum (CH/AG) nanoparticles (NPs) as a stabilizer and in the presence of titanium dioxide NP (TiO2 NPs) as an extra antimicrobial agent. The developed films were characterized by attenuated total reflectance–Fourier transmittance infrared, X‐ray diffraction, and scanning electron microscope. The antimicrobial, antioxidant, water vapor sorption isotherm, and mechanical properties of the prepared films were assessed. The (CH/AG) NPs weight ratios (1:1, 1:2, and 2:1) impact on particle size (PS), zeta potential, wettability, morphology, and in vitro cumulative release was investigated. The (CH/AG) NPs (1:2) exhibits the small PS (246.4 nm). (CH/AG) NPs and PE exhibit spherical and oval morphologies. The CH/AG (1:2) exhibits the higher water contact angle (85.7o). At the oil volume fraction (α) = 1.0, nearly 81% of the entrapped oil released from the NPs. Gelatin films enriched with P at α = 1.0 exhibits two‐fold increasing scavenging activity % (35.69 ± 0.56) compared with control film (14.8 ± 0.25). The films have a considerable antibacterial and antifungal activity for all test microorganism. However, control sample did not show antimicrobial activity against Bacillus cereus and Candida albicans.
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In the ancient time Eucalyptus globulus used for the various purpose. It is a tall and an evergreen tree that can grow up to the height of 70m and its diameter is about 4 to7ft. which was first found on the island of Tasmania in 1792 which associate to the Myrtaceae family which is commonly called as Tasmanian Blue Gum, southern blue gum or blue gum are the different names of eucalyptus globulus grow in the various parts of India. The particular species of Eucalyptus globulus have been used for various purposes. It had been found that eucalyptus is a rich source of phytochemical constituent and also possesses medicinal use. The different part of the eucalyptus is very nutritionally and highly valuable therapeutically property because of the presence of some specific chemical composition as its essential oil contain esters, carboxylic acids, aldehyde etc. phytochemical analysis of this tree has revealed that their leaf oil contain 1.8 cineole, cryptophone etc., essential oil had been extracted from its buds. The aim of this review paper is compiling all the information about eucalyptus such as anti-inflammatory, analgesic, anti-nociceptive antimicrobial, anti-fungal, anti-viral and anti-oxidant agent of the nature.
Article
The purpose of the present research was to fabricate ethylcellulose (ECL)/polycaprolactone (PCL)/gelatin (GEL) electrospun nanofibers containing Zataria multiflora essential oil (ZEO) and zinc oxide nanoparticle (ZnO) to provide an appropriate substrate for food packaging. The ECL/PCL/GEL was incorporated with ZEO and ZnO at the concentrations of 10, 20, 30 and 50 wt% and 3 wt%, respectively. The results of ECL/PCL/GEL/ZEO/ZnO nanofiber exhibited uniform morphology with a mean diameter ranging from 361.85 ± 18.7 to 467.33 ± 14.50 nm and enhanced thermal stability. The ECL/PCL/GEL/ZEO/ZnO nanofiber had the highest mechanical parameters, such as young's modulus (437.49 ± 18), tensile strength (7.88 ± 0.7), and elongation at break (5.02 ± 0.6) and water contact angle (61.13 ± 0.5), compared with the other nanofibers. The cell viability during 48 and 72 h was obtained to be about more than 80% for all the nanofibers. Additionally, the ECL/PCL/GEL incorporated with 50% ZEO and 3% ZnO displayed the highest antioxidant activity (34.61 ± 1.98%) and antifungal properties against Penicillium notatum and Aspergillus niger. In general, the ECL/PCL/GEL with the weight ratio of 20:70:10 nanofiber incorporated with 30% ZEO and 3% ZnO was obtained to have appropriate mechanical, antioxidant, and antimicrobial properties and thermal stability.
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Adams, R. P. 2007. Identification of essential oil components by gas chromatography/ mass spectrometry, 4th Edition. Allured Publ., Carol Stream, IL Is out of print, but you can obtain a free pdf of it at www.juniperus.org
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During screening of twenty six essential oils against Botrytis cinerea, the essential oils of the ten plants viz. Chenopodium ambrosioides, Eucalyptus citriodora, Eupatorium cannabinum, Lawsonia inermis, Ocimum canum, O. gratissimum, O. sanctum, Prunus persica, Zingiber cassumunar and Z. officinale were found to exhibit absolute fungitoxic activity (100% growth inhibition). The essential oils of O. sanctum, P. persica and Z. officinale were selected for further investigation because these oils showed lower Minimum Inhibitory Concentration (MIC) as compared to the other fungitoxic oils. The selected oils were subsequently standardized through physico-chemical and fungitoxic properties. The MIC values of O. sanctum, P. persica and Z. officinale were found to be 200, 100 and 100ppm (mg/l) respectively. The oils showed fungistatic nature at their respective MIC. The oils were thermostable, and exhibited a wide range of fungitoxicity against 15 other post-harvest fungal pathogens. The oils had the potency to withstand high inoculum density. The antifungal potency of oils was found to be greater in comparison to some prevalent synthetic fungicides. Practical applicability of the essential oils was observed in control of grey mould of grapes caused by B. cinerea during storage. The O. sanctum- and P. persica-oil-treated grapes showed enhancement of storage life up to 5 and 4days respectively. The storage life of Z. officinale-oil-treated grapes was found to be enhanced up to 6days. The oils did not exhibit any phytotoxic effect on the fruit peel. Therefore, the oils could be recommended as a potential source of ecofriendly botanical fungicide, after long term and wide ranging trials.
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The present study describes the phytochemical profile and antimicrobial activity of Satureja subspicata Vis. essential oils, collected in Dalmatia (Croatia). Three samples of essential oils were obtained from the aerial parts of the plant by hydrodistillation and analyzed by GC–MS. From the 24 compounds representing 97.47% of the oils, carvacrol (16.76%), α-pinene (13.58), p-cymene (10.76%), γ-terpinene (9.54%) and thymol methyl ether (8.83%) appear as the main components. The oils also contained smaller percentages of myrcene, linalool, β-caryophyllene, limonene, geranyl acetate, 1-Octen-3-ol, nerol, thymol and borneol. Furthermore, antimicrobial activity of the oil was evaluated using agar diffusion and broth microdilution methods. The antimicrobial test results showed that the oils had a great potential antimicrobial activity against all 13 bacteria and 9 fungal strains. Gram-positive bacteria are more sensitive to the investigated oil, with a range of 0.09 to 6.25 μl/ml than Gram-negative bacteria in the range which is significantly higher from 1.56 to 25.00 μl/ml. Results presented here may suggest that the essential oil of S. subspicata possesses antimicrobial properties, and is therefore a potential source of antimicrobial ingredients for the food and pharmaceutical industry.
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The composition and variability of the essential oils of several populations of Thymus caespititius from Portugal were investigated by GC, GC-mass spectrometry and 13C NMR. All samples from NW Portugal were characterized by their high α-terpineol content, while the main components in the oil sample from Pico island (Azores archipelago) were carvacrol and thymol. The analytical data of individual samples from NW Portugal showed no chemical polymorphism in this area. The different areas of distribution (NW Portugal and Azores) that show great climatic and soil variation conditions may be the origin of the α-terpineol-type oil from NW Portugal and the carvacrol/thymol-type oil from the Azores. 13C NMR spectra of the essential oil, previously fractionated by column chromatography, led to the identification of trans-dihydroagarofuran, a new oxygenated sesquiterpene for the genus Thymus and a characteristic compound of T.caespitiuius.
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Diffusion and dilution methods have been employed to study the antimicrobial activity of medicinal plants. A number of modifications have been made in the technique in order to obtain better results. Since some factors (culture medium composition, microorganisms tested, extractive method, pH, solubility of the sample in the culture medium, etc.) can change results, it is difficult using these methods to standardize a procedure for the study of antimicrobial plants. Bioautography is another method for studying antimicrobial activity. With it, previously chromatographed principles are diffused to the agar. The results can also change according to the method employed. All the various techniques are reviewed here and, in order to unify the different criteria and parameters, standard methods to study the antimicrobial activity of medicinal plants are proposed.
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The beneficial health effects of extracts from many types of plants that are used as seasoning agents in foods and beverages have been claimed for centuries. The purpose of this study was to examine the effectiveness of selected herb and spice essential oils for control of growth and survival of microorganisms. Inhibition of growth was tested by the paper disc agar diffusion method. Antibiotic susceptibility discs were used as control. Minimum lethal concentration (MLC) was determined by the tube dilution method. Essential oils from anise, angelica, basil, carrot, celery, cardamom, coriander, dill weed, fennel, oregano, parsley, and rosemary were evaluated. Inhibition ranged from complete with oregano to no inhibition with carrot oil for each of the test strains that included: Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O:157:H7, Yersinia enterocolitica, Pseudomonas aeruginosa, Lactobacillus plantarum, Aspergillus niger, Geotrichum, and Rhodotorula. Oregano essential oil showed the greatest inhibition (zone, > or = 70 to 80 mm) (MLC, approximately 8 ppm). Coriander and basil were also highly inhibitory (MLC, approximately 25 to 50 ppm) to E. coli O:157:H7 and to the other bacteria and fungi tested. Anise oil was not particularly inhibitory to bacteria (inhibition zone, approximately 25 mm); however, anise oil was highly inhibitory to molds. Because some of the herbal and spice essential oils are highly inhibitory to selected pathogenic and spoilage microorganisms, they may provide alternatives and supplements to conventional antimicrobial additives in foods.
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The antimicrobial activity of three Salvia species, i.e. S. santolinifolia, S. hydrangea and S. mirzayanii, essential oils were investigated. The essential oils were obtained from the aerial parts of plants and analyzed by GC-MS. The main constituents of aforementioned species were alpha-pinene (72.4%), beta-pinene (6.6%) and limonene (5.3%); beta-caryophyllene (25.1%), 1,8-cineol (15.2%) and caryophyllene oxide (11.5%); alpha-terpinenyl acetate (22.6%), 1,8-cineol (21.2%) and linalool (8.9%), respectively. Bioassays exhibited that the property of the oil of S. myrzayanii was superior to others. The antimicrobial activity of essential oil from Salvia species may well be due to the presence of synergy between six tested compounds (linalool, 1,8-cineol, alpha-pinene, beta-pinene, beta-caryophyllene and limonene) and other constituents of the oils with various degrees of antimicrobial activity. Among these, linalool and 1,8-cineol had the highest antimicrobial activity.
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Unlabelled: The objective of the present study was that of verifying a possible synergistic antibacterial effect between Pelargonium graveolens [Lis-Balchin, M., Deans, S.G., Hart, S., 1996. Bioactive Geranium oils from different commercial sources. J. Essential Oil Res. 8, 281-290.] essential oil (and its main components) and Norfloxacin antibiotic. As a first step growth inhibition by some types of essential oils was assessed in five microbial species. The antimicrobial effects of P. graveolens oil, as well as those of its components, were evaluated by means of the agar dilution method (ADM) against Bacillus cereus ATCC 11778, Bacillus subtilis ATCC 6633, Escherichia coli ATCC 35218, Staphylococcus aureus ATCC 6538 and S. aureus ATCC 29213. The results obtained highlighted the occurrence of a pronounced synergism between P. graveolens essential oil and Norfloxacin against three of the five bacterial species under study with a FIC index in the 0.37-0.50 range. Such antibacterial effects were also shown to increase, although to a lesser extent, when Norfloxacin was given with the main components of P. graveolens essential oil. Significance and impact of the study: The combination of Norfloxacin with either P. graveolens essential oil, or with some of the main components of this latter, in the treatment of infections caused by some bacterial species is likely to reduce the minimum effective dose of Norfloxacin thus minimizing the side effects of the antibiotic.
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A total of 39 essential oils were tested for antifungal activities as volatile compounds against five phytopathogenic fungi at a dose of 1 per plate. Five essential oils showed inhibitory activities against mycelial growth of at least one phytopathogenic fungus. Origanum vulgare essential oil inhibited mycelial growth of all of the five fungi tested. Both Cuminum cyminum and Eucalyptus citriodora oils displayed in vitro antifungal activities against four phytopathogenic fungi except for Colletotrichum gloeosporioides. The essential oil of Thymus vulgaris suppressed the mycelial growth of C. gloeosporioides, Fusarium oxysporum and Rhizoctonia solani and that of Cymbopogon citratus was active to only F. oxysporum. The chemical compositions of the five active essential oils were determined by gas chromatography-mass spectrometry. This study suggests that both E. citriodora and C. cyminum oils have a potential as antifungal preservatives for the control of storage diseases of various crops.
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Nine plant essential oils (EOs) were studied for their anti-bacterial effect on spores and vegetative cells ofClostridium botulinum62A andBacillus cereusT. Cedar oil at the concentration of 300 ppm was the most active againstB. cereusT andC. botulinumspores and vegetative cells. Spores were generally less resistant than vegetative cells, except for the essential oils of eucalyptus and camomile (300 ppm), which demonstrated a significant activity againstB. cereusT andC. botulinumvegetative cells. In general, spores ofBacillus were more sensitive to these essential oils thanClostridiumspores. ForB. cereusT, EO of rosemary (≥170 ppm), eucalyptus (≥450 ppm), orange (≥300 ppm), savage carrots (≥400 ppm) and artemisia (≥500 ppm) were partially sporicidal; whereas, EO of camomile and grapefruit (≥300 ppm) were sporostatic. In the case ofC. botulinum62A, eucalyptus, camomile, savage carrots, vervain, grapefruit and orange oils were sporostatic at the tested concentrations. However, EO of cedar (≥300 ppm) was partially sporicidal. These EOs inhibited specifically one or more stage(s) of the spore cycle depending on the EO and its concentration. Eucalyptus, orange, artemisia and cedar oils (300 ppm) and grapefruit, savage carrots and vervain (400 ppm) inhibited the growth ofC. botulinum62A spores by blocking their germination inL-alanine. The inhibition of spore germination ofC. botulinum62A by EOs (at ≥300 ppm) was by inhibition of commitment-to-germinate of spores. However, the outgrowth was not sensitive to cedar, eucalyptus, vervain and savage carrots oils at the concentration of 400 ppm.
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Pet. Ether (65°-69°C) extracts of Eucalyptus olida L. Johnson et K. Hill leaves and stems from 3-5 year old trees in a trial planting generally contained very high levels (>91% of oil yield) of methyl cinnamate (MC). Some trees had low (0%) or variable levels (0-21%) of MC, highlighting the need to explore selection of proven clones for plantation-scale production of MC. Leaf age and time of harvesting affected MC levels and yields, and also oil yields, which peaked in younger leaves in mid summer. In general, higher MC yields were more closely related to high yields of oil in the foliage rather than high levels of MC in the oil.
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The seasonal variation in essential oil yield and composition from naturalized Thymus vulgaris L. in Central Otago, New Zealand, is reported. Essential oil yield (l/ha), from replicated, pilot-scale distillations, was influenced by both the field production of herb and the essential oil content of the herb. The oil yield peaked at 22.8 l/ha in December, after flowering had finished. Essential oil composition also varied significantly during the 13-month sampling period. Levels of the phenolic components, thymol and carvacrol, peaked at a total of 37% after flowering in summer (December and January). p-Cymene was an important component of Central Otago thyme oils and ranged from 40% to 50% in winter and early spring (May to October), declining to 21% in January. To maximize yields and phenol content of the oil, naturalized thyme in Central Otago should be harvested after flowering has finished in December.
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The fungitoxicity of crude extracts and essential oils of Achillea millefolium, Cymbopogon citratus, Eucalyptus citriodora and Ageratum conyzoides on the fungus Didymella bryoniae was verified in vitro by means of germination of spores and mycelial growth. In addition, some observations were made using scanning electron microscopy (SEM) to detect possible alterations on the hyphae of Didymella bryoniae. The results revealed that crude extracts of E. citriodora and A. conyzoides were more effective in inhibiting the mycelial growth of D. bryoniae whereas in the germination of spores A. conyzoides and A. millefolium were responsible for most of the inhibition, namely, 52 and 46%, respectively. The essential oils of C. citratus, A. conyzoides and E. citriodora provided 100% inhibition of the mycelial growth and germination of spores of D. bryoniae. SEM observations revealed alterations in the growth pattern of hyphae of D. bryoniae when the essential oil of A. millefolium was present.
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The bacteriostatic and bactericidal activities of six components of conifer essential oils (α and β pinene, R- and S-limonene, 1,8 cineole, borneol) were tested on Listeria monocytogenes serovars 4b and 1/2c. α Pinene was the most active component with an average minimal inhibitory concentration (MIC) of 0.019% against L. monocytogenes 4b. Conversely, the concentration of 1,8 cineole required to achieve the same effect on this serovar was 0.375%, although this concentration was directly bactericidal. The bacteriostatic and bactericidal activities differed more between different components than between different serovars. Given that these products are highly active against L. monocytogenes, they might be used to kill this species or to prevent its growth.
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Technological application of essential oils, as natural sanitizing agents, to reduce food pathogens in the post-harvest processing of foods requires the establishment of the optimal conditions. The present work evaluated the parameters of antimicrobial activity of the essential oils of eucalyptus (Eucalyptus globules), tea tree (Melaleuca alternifolia), rosemary (Rosmarinus officinalis), mint (Mentha piperita), rosa moschata (Rosa moschata), clove (Syzygium aromaticum), lemon (Citrus limonum), oregano (Origanum vulgare), pine (Pinus silvestrys) and sweet basil (Ocimum basilicum) on survival and growth of different strains of E. coli O157:H7. The strains of E. coli exhibited similar susceptibilities to the action of the essential oils assayed. The essential oil with the lowest MIC and MBC (Minimum Inhibitory and Bactericidal Concentration, respectively) was clove (0.25 ml/100 ml and 0.3 ml/100 ml, respectively) and the results demonstrated that clove exerted a significant bactericidal and bacteriostatic action.
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The inhibitory effect of 60 different essential oils was evaluated on a Pseudomonas putida strain of meat origin, associated with meat spoilage. Essential oils were tested at concentrations from 0.003 to 0.8% (wt/vol) to determine minimum inhibitory and maximal tolerated concentrations (MIC and MTC, respectively) using an agar medium culture. Of the 60 samples tested, Corydothymus capitatus essential oil was the most active showing a MIC of 0.025% and a MTC of 0.06%. Seven essential oils (Cinnamomum cassia, Origanum compactum, Origanum heracleoticum, Satureja hortensis, Satureja montana, Thymus vulgaris carvacroliferum, Thymus vulgaris thymoliferum) have shown a strong antimicrobial activity against P. putida with a MIC of 0.05% and a MTC ranging from 0.013% to 0.025%. Ten other oils (Cinnamomum verum (leaf and bark), Eugenia caryophyllus, Cymbopogon martinii var. motia, Cymbopogon nardus, Melaleuca linariifolia, Origanum majorana, Pimenta dioica, Thymus satureoides, Thymus serpyllum) showed a high antimicrobial activity showing a MIC ranging from 0.1% to 0.4%, while the remaining were less active showing a MIC⩾0.8%.
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The aim of the study was to evaluate the potential of essential of from local plant in controlling some major seed-borne fungi of sorghum grow in Burkina Faso. Essential oils from Cymbopogon citratus (Lemongrass) Eucalyptus camaldulensis , (Eucalyptus) and crude oil from Azadirachta indica (Neem) were tested in vitro for inhibitory activity against Colletotrichum graminicola , Phoma sorghina and Fusarium moniliforme . Plant extracts were also tested on naturally infected sorghum seeds for controlling the fungi above mentioned. Essential oil from C. citratus significantly inhibited the in vitro radial growth of C. graminicola (76.2% inhibition), compared to the fungicide Dithane M-45. The mycelial growth of P. sorghina and F. moniliforme was slightly affected by this oil at the concentrations used. The extent of inhibition of the fungal growth was dependent on the concentration of essential oil used. Neem crude oil and Eucalyptus essential oil presented low inhibitory activity against test fungi. Concentrations of Eucalyptus essential oil were not harmful to sorghum seedling growth, while neem crude oil was highly phytotoxic. Essential oil of lemongrass at the concentration of 6% was effective in controlling seed-borne infection and seed-to-seedling transmission of C. graminicola and P. sorghina without affecting seedling development. Lemongrass has the potential to be used as sorghum seed treatment for controlling C. graminicola , P. sorghina and F. moniliforme .
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The flowering aerial parts of Mentha pulegium L. (Labiatae) has been traditionally used for its antiseptic properties for treatment of infectious diseases. In order to validate its antiseptic properties with respect to traditional uses, we have screened the antimicrobial activity of flowering aerial parts of Mentha pulegium L. essential oil against different microorganisms. This oil was obtained using hydrodistillation method and analyzed by GC and GC/MS. The antimicrobial activity was achieved using disc diffusion method and microbroth dilution assay. Analysis of the essential oil revealed the presence of piperitone (38.0%), piperitenone (33.0%), alpha-terpineol (4.7%), and pulegone (2.3%) as the major components. The results showed a significant activity against microorganisms especially Gram-positive bacteria with inhibition zones and minimal inhibitory concentration values in the range of 8-21 mm and 0.25-4 microl/ml, respectively, whereas the least susceptible were Gram-negative bacteria especially Escherichia coli. This investigation showed that the oil of Mentha pulegium L. has a potent antimicrobial activity and the Iranian Mentha pulegium L. oil belongs to piperitone/piperitenone type. Further research is required to evaluate the practical values of therapeutic applications.
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Essential oils from dill (Anethum graveolens L.), coriander (seeds of Coriandrum sativum L.), cilantro (leaves of immature C. sativum L.) and eucalyptus (Eucalyptus dives) were separated into heterogeneous mixtures of components by fractional distillation and were analyzed by gas chromatography-mass spectroscopy. Minimum inhibitory concentrations against gram-positive bacteria, gram-negative bacteria and Saccharomyces cerevisiae were determined for the crude oils and their fractions. Essential oil of cilantro was particularly effective against Listeria monocytogenes, likely due to the presence of long chain (C6-C10) alcohols and aldehydes. The strength and spectrum of inhibition for the fractions often exceeded those determined in the crude oils. Mixing of fractions resulted in additive, synergistic or antagonistic effects against individual test microorganisms.
Article
The volatile oil extracted from the leaves of Eucalyptus citriodora showed a wide spectrum of antifungal activity.
Article
The volatile metabolites of Salvia fruticosa plants, growing wild in 15 localities scattered across Greece, were analyzed by means of GC and GC-MS. The essential oil content ranged from 0.69 to 4.68%, and the results of the analyses showed a noticeable variation in the amounts of the five main components [1,8-cineole, alpha-thujone, beta-thujone, camphor, and (E)-caryophyllene]. The antifungal activities of the essential oils from two localities, belonging in two different groups of cluster and principal component analysis, and their main components (1,8-cineole and camphor) were evaluated in vitro against five phytopathogenic fungi. Both oils were slightly effective against Fusarium oxysporum f. sp. dianthi and Fusarium proliferatum, whereas against Rhizoctonia solani, Sclerotinia sclerotiorum, and Fusarium solani f. sp. cucurbitae the oils exhibited high antifungal activities.
Article
We investigated the antimicrobial activities of eucalyptus leaf extracts to find effective antibacterial agents. The antimicrobial activities of leaf extracts from 26 species of eucalyptus were measured. Extracts of Eucalyptus globulus, E. maculata and E. viminalis significantly inhibited the growth of six Gram-positive bacteria (Staphylococcus aureus, MRSA, Bacillus cereus, Enterococcus faecalis, Alicyclobacillus acidoterrestris, Propionibacterium acnes), and of a fungus (Trichophyton mentagrophytes), but they did not show strong antibacterial activity against Gram-negative bacteria (Escherichia coli, Pseudomonas putida). 2',6'-dihydroxy-3'-methyl-4'-methoxy-dihydrochalcone, eucalyptin and 8-desmethyl-eucalyptin, isolated from E. maculata extracts, exhibited potent antimicrobial activities against seven micro-organisms with minimum inhibitory concentrations (MIC) ranging from 1.0 to 31 mg l(-1). The eucalyptus extracts and three compounds from E. maculata were found to be effective against micro-organisms that cause food poisoning, acne and athlete's foot. This study shows potential uses of extracts from E. globulus, E. maculata and E. viminalis, and antimicrobial compounds isolated from E. maculata.
Article
In vitro studies have demonstrated antibacterial activity of essential oils (EOs) against Listeria monocytogenes, Salmonella typhimurium, Escherichia coli O157:H7, Shigella dysenteria, Bacillus cereus and Staphylococcus aureus at levels between 0.2 and 10 microl ml(-1). Gram-negative organisms are slightly less susceptible than gram-positive bacteria. A number of EO components has been identified as effective antibacterials, e.g. carvacrol, thymol, eugenol, perillaldehyde, cinnamaldehyde and cinnamic acid, having minimum inhibitory concentrations (MICs) of 0.05-5 microl ml(-1) in vitro. A higher concentration is needed to achieve the same effect in foods. Studies with fresh meat, meat products, fish, milk, dairy products, vegetables, fruit and cooked rice have shown that the concentration needed to achieve a significant antibacterial effect is around 0.5-20 microl g(-1) in foods and about 0.1-10 microl ml(-1) in solutions for washing fruit and vegetables. EOs comprise a large number of components and it is likely that their mode of action involves several targets in the bacterial cell. The hydrophobicity of EOs enables them to partition in the lipids of the cell membrane and mitochondria, rendering them permeable and leading to leakage of cell contents. Physical conditions that improve the action of EOs are low pH, low temperature and low oxygen levels. Synergism has been observed between carvacrol and its precursor p-cymene and between cinnamaldehyde and eugenol. Synergy between EO components and mild preservation methods has also been observed. Some EO components are legally registered flavourings in the EU and the USA. Undesirable organoleptic effects can be limited by careful selection of EOs according to the type of food.
Article
The leaf-essential oil from Eucalyptus robusta and E. saligna, the latter in two phenologic stages, were analysed by gas chromatography coupled to mass spectrometry (GC-MS). The major constituent in E. robusta oil was the monoterpene alpha-pinene (73.0% of the total amount). The oil composition of the E. saligna was dependent of the phenologic stage. In the vegetative phase, the major constituents were p-cymene (54.2%) and gamma-terpinene (43.8%), while during the blossoming alpha-pinene became the major constituent followed by p-cymene (22.5%). Additionally, the antimicrobial activity for all three oils was evaluated against Staphylococcus aureus, Escherichia coli and Candida albicans. The E. robusta oil presented the highest growth inhibition for all the microorganisms tested.
Relative activity of essential oils from plants against Penicillium digitatum causing post-harvest fruit rot of Kinnow mandarin
  • H J S Dhaliwal
  • T S Thind
  • M Chander
Dhaliwal, H. J. S., Thind, T. S., & Chander, M. (2004). Relative activity of essential oils from plants against Penicillium digitatum causing post-harvest fruit rot of Kinnow mandarin. Plant Disease Research, 19, 140-143.
Field guide to Eucalypts Northern Australia Melbourne: Bloomings Books Essential oils: Their antibacterial properties and potential applications in foods – A review
  • M I H Brooker
  • D A Kleinig
Brooker, M. I. H., & Kleinig, D. A. (2004). Field guide to Eucalypts (2nd ed.). Northern Australia (Vol. 3). Melbourne: Bloomings Books. Burt, S. (2004). Essential oils: Their antibacterial properties and potential applications in foods – A review. International Journal of Food Microbiology, 94, 223–253.
Naturally occurring compounds
  • D E Conner
Conner, D. E. (1993). Naturally occurring compounds. In P. Davidson & A. L. Branen (Eds.), Antimicrobials in foods (pp. 441-468). New York: Marcel Dekker Inc.