Artemisia Ketone Research Articles

IN VITRO CULTURE AND STUDING THE CHEMICAL COMPOSITION OF THE ESSENTIAL OILS EXTRACTED FROM THREE SAMPLES OF ERIOCEPHALUS AFRICANUS L. PLANT IN EGYPT

The present study aimed to establish new protocol for propagation via tissue culture techniques to observe the effect of plant growth regulators especially cytokinins, gibberellic acid and auxins with different concentrations on in vitro growth of Eriocephalus africanus L. for improving the potentiality of regeneration and secondary metabolites production and identification of the main active constituents of volatile oil by GC/MS. The results showed that, the best sterilization treatment was the shoot tip explants rinsed in a solution of clorox at 15% for 15 min was gave the highest values for survival percentage and plant strength 100% and 4.58, respectively also B5 medium at full strength gave the best results in the both growth measurements. BAP at 2.00 mg/l recorded the highest values in survival percentage (93.33%), shootlet number/cluster (16.50) and shootlet strength (4.50), respectively. Using the high level from GA3 (4.00 mg/l) in medium was more effective in the elongation of shootlets. In rooting stage B5 medium supplemented with 0.50 mg/l IBA and 0.15% active charcoal was more effective for increasing root number/explant to 8.67 and root length to 5.78 cm. The chemical analysis for the volatile oils extracted from three samples (field, in vivo and in vitro) of Eriocephalus africanus L. by using GC/MS confirmed that, the total number of the constituents identified ranged from 30-34 compounds representing 79.67-99.41% of the total oil contents. Artemisia ketone (17.10-30.62%), bicyclogermacrene (4.14-15.56%), globulol (2.17-8.30%), allo-aromadendrene epoxide (0.51-9.00%), caryophyllene oxide (2.85-6.76%) and α-pinene (3.10-4.25%) were the main compounds.

Effects of Different Methods of Isolation on Volatile Composition of Artemisia annua L.

In order to determine influence of extraction method on volatile oil composition of Artemisia annua L., steam distillation, hydrodistillation, organic solvent extraction, and headspace sampling have been applied. The relative abundance of volatile compounds from the odorous aerial parts of A. annua, obtained by different extraction techniques, was analyzed by GC-MS. Exactly fifty constituents were identified. The leaf and flower essential oil yield ranged from 0.9 to 2.3% (v/w). Oxygenated monoterpenes were predominant in all samples ranged from 42.6% for steam-distilled fraction of petroleum ether extract to 70.6% for headspace of plant material. Essential oils isolated by steam distillation and hydrodistillation indicate that A. annua belongs to artemisia ketone chemotype with its relative content of 30.2% and 28.3%, respectively. The principal constituent in headspace sample of plant material was also artemisia ketone (46.4%), while headspace of petroleum ether extract had camphene (25.6%) as the major compound. The results prove the combined approaches to be powerful for the analysis of complex herbal samples.

Supercritical anti-solvent fractionation for improving antioxidant and anti-inflammatory activities of an Achillea millefolium L. extract

Achillea millefolium L. is a plant widely used in traditional medicine. Nowadays, there is a growing concern about the study of its bioactive properties in order to develop food and nutraceutical formulations. Supercritical anti-solvent fractionation (SAF) of an A. millefollium extract was carried out to improve its antioxidant and anti-inflammatory activities. A selective precipitation of phenolic compounds was achieved in the precipitation vessel fractions, which presented an antioxidant activity twice than original extract, especially when fractionation was carried out at 10 MPa. The main phenolic components identified in this fraction were luteolin-7-O-glucoside, 3,5-dicaffeoylquinic acid, 6-hidroxyluteolin-7-O-glucoside and apigenin-7-O-glucoside. However, separator fractions presented higher anti-inflammatory activity than precipitation vessel ones, particularly at 15 MPa. This fact could be related to separator fractions enrichment in anti-inflammatory compounds, mainly camphor, artemisia ketone and borneol.Therefore, SAF produced a concentration of antioxidant and anti-inflammatory compounds that could be used as high-added valued ingredients.

Essential oil composition of Pentzia incana (Asteraceae), an important natural pasture plant in the Karoo region of South Africa

Pentzia incana is one of the most important of all natural pasture plants in the dry interior (Karoo) region of South Africa. This highly aromatic shrub is thought to be responsible for the distinctive flavour of Karoo lamb (a registered geographical indication), yet the essential oil is here characterised for the first time. Leafy twigs are traditionally chewed for relief of stomach ache. Essential oil is associated with numerous small, multicellu- lar glands. Gas chromatography and gas chromatography/mass spectrometry analysis of 17 essential oil samples from five populations showed considerable variation in both yield (0.12% to 0.88% dry weight) and composition. Of interest was the presence of one major biosynthetic group comprising yomogi alcohol (to 38.9%), artemisia alcohol (to 26.1%), artemisia ketone (to 35.0%) and artemisyl acetate (to 9.4%). High levels of fragranol (26.9%) and fragranyl acetate (27.1%) were observed only in a single specimen. Other main compounds were 1,8-cineole (to 16.7%), santolina alcohol (to 11.3%), camphor (to 47.9%), linalyl acetate (to 17.4%) and bicyclogermacrene (to 11.8%). Six of the 10 major compounds were isolated and their identities confirmed by nuclear magnetic resonance. The volatile compounds may possibly be linked to the medicinal use of P. incana, as well as the flavour profile of Karoo lamb.

Chemical Polymorphism of Essential Oils of Artemisia vulgaris Growing Wild in Lithuania.

Compositional variability of mugwort (Artemisia vulgaris L.) essential oils has been investigated in the study. Plant material (over ground parts at full flowering stage) was collected from forty-four wild populations in Lithuania. The oils from aerial parts were obtained by hydrodistillation and analyzed by GC(FID) and GC/MS. In total, up to 111 components were determined in the oils. As the major constituents were found: sabinene, 1,8-cineole, artemisia ketone, both thujone isomers, camphor, cis-chrysanthenyl acetate, davanone and davanone B. The compositional data were subjected to statistical analysis. The application of PCA (Principal Component Analysis) and AHC (Agglomerative Hierarchical Clustering) allowed grouping the oils into six clusters. AHC permitted to distinguish an artemisia ketone chemotype, which, to the best of our knowledge, is very scarce. Additionally, two rare cis-chrysanthenyl acetate and sabinene oil types were determined for the plants growing in Lithuania. Besides, davanone was found for the first time as a principal component in mugwort oils. The performed study revealed significant chemical polymorphism of essential oils in mugwort plants native to Lithuania; it has expanded our chemotaxonomic knowledge both of A.vulgaris species and Artemisia genus.

The Genus Artemisia: a 2012-2017 Literature Review on Chemical Composition, Antimicrobial, Insecticidal and Antioxidant Activities of Essential Oils.

Essential oils of aromatic and medicinal plants generally have a diverse range of activities because they possess several active constituents that work through several modes of action. The genus Artemisia includes the largest genus of family Asteraceae has several medicinal uses in human and plant diseases aliments. Extensive investigations on essential oil composition, antimicrobial, insecticidal and antioxidant studies have been conducted for various species of this genus. In this review, we have compiled data of recent literature (2012–2017) on essential oil composition, antimicrobial, insecticidal and antioxidant activities of different species of the genus Artemisia. Regarding the antimicrobial and insecticidal properties we have only described here efficacy of essential oils against plant pathogens and insect pests. The literature revealed that 1, 8-cineole, beta-pinene, thujone, artemisia ketone, camphor, caryophyllene, camphene and germacrene D are the major components in most of the essential oils of this plant species. Oils from different species of genus Artemisia exhibited strong antimicrobial activity against plant pathogens and insecticidal activity against insect pests. However, only few species have been explored for antioxidant activity.

Liquid and Vapor-Phase Activity of Artemisia annua Essential Oil against Pathogenic Malassezia spp.

Artemisia annua essential oil has given us many encouraging results for its numerous antimicrobial properties. In this study, the essential oil, both in liquid and in vapor phases, was tested against various Malassezia species closely related to many skin disorders in humans and animals. Malassezia treatment and eradication are mainly based on old azole drugs, which are characterized by poor compliance, unpredictable clinical efficacy, emerging resistance, and several side effects. Monoterpenes (ca. 88%) represent the most abundant group of compounds in the essential oil, mainly the oxygenated derivatives (ca. 74%) with camphor (25.2%), 1,8-cineole (20%), and artemisia ketone (12.5%). In vapor phase, monoterpenes represent more than 98% of the constituents, α-pinene being the main constituent (22.8%), followed by 1,8-cineole (22.1%) and camphene (12.9%). Essential oil of A.annua, both in vapor phase and liquid, showed strong antimicrobial activity towards almost the tested twenty strains of Malassezia analyzed. The minimum fungicidal concentrations from most of the strains tested were from 0.78 µL/mL to 1.56 µL/mL, and only three strains of Malassezia sympodialis required a higher concentration of 3.125 µL/mL. Overall, the minimal inhibitor concentrations obtained by vapor diffusion assay were lower than those obtained by the liquid method. The average values of minimal inhibitor concentrations obtained by the two methods at 72 h are 1.3 - 8.0 times higher in liquid compared to those in the vapor phase.

Chemical Composition of Essentials Oils of Artemisia frigida Willd. (Asteraceae) Grown in the North and Central Asia

The compositions of essential oils found in Artemisia frigida Willd. growing within the Republic of Buryatia (Russia), Mongolia, and China are analyzed in this work. We identified 152 compounds in the essential oils of A. frigida, including acyclic, aromatic, mono-, sesqui- and diterpene compounds. The dominant compounds found in plants from the Republic of Buryatia were mostly monoterpenes, including 1,8-cineol, camphor, borneol and terpinen-4-ol. The samples from the Chita region of Russia and from Mongolia, which was drier than the Republic of Buryatia, contained a similar composition of major compounds as well as sesquiterpenes (e.g. caryophyllene, germacrene D) in addition to the above-mentioned monoterpenes. The samples from Qinghai Province, China, contained α-bisabolone oxide A, B, camphor, and 1,8-cineol as dominant compounds. There were some irregular monoterpenes (e.g., yomogi alcohol, artemisia ketone, artemisia alcohol, and lavandulol) in the Chinese samples. Eastern A. frigida populations were characterized by a high proportion of sesquiterpene compounds, while high-elevation mountain plants contain high concentrations of spathulenol and germacrene D.

Chemical composition and anticancer activity of Elsholtzia ciliata essential oils and extracts prepared by different methods

Abstract E. ciliata (Lamiaceae) is very interesting and promising herb mainly for chemical composition and pharmacological activities. The aim of this study was to determine chemical composition of the essential oils of fresh, frozen and dried herbal materials of E. ciliata and compare different extraction methods This is the first study on composition of E. ciliata volatile compounds from fresh, frozen and dried herbal samples. The samples were prepared by hydrodistillation (HD), extraction with polar solvent-ethanol (ESE) and dynamic headspace solid-phase micro extraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC–MS) method. A total of 48 compounds were identified by GC–MS. Dehydroelsholtzia ketone, elsholtzia ketone, sesquiterpenes β-bourbonene, caryophyllene, α-caryophyllene, germacrene D and α-farnesene were identified and found to be predominant compounds in SPME composition of the fresh, frozen and dried herbal samples. The major amounts of ketones (dehydroelsholtzia and elsholtzia) were determined in dried herbal samples where they made up 24.94% ( p 0.05 ) and 71.34% ( p 0.05 ) of the SPME composition. Artemisia ketone was determined only in fresh herb. No previous report exists regarding this ketone in E. ciliata fresh, frozen and dried herbal materials or essential oil. There were 26 components identified in the essential oil obtained by HD. The main compounds of this essential oil were dehydroelsholtzia ketone (78.28%) and elsholtzia ketone (14.58%). Essential oil showed antiproliferative activity on three tested cancer cell lines (human glioblastoma (U87), pancreatic cancer (Panc-1) and triple negative breast cancer (MDA-MB231)) in vitro . EC 50 (half maximal effective concentration) values of essential oil against those cells were in the range of 0.017–0.021%. The viability of human normal fibroblasts exposed to the same concentrations of the essential oil was statistically significantly higher compared to the viability of cancer cells ( p 0.05 ). The extracts did not show any effect on U87 cells, and only slightly decreased MDA-MB231 cell viability (up to 76.4%) at the highest concentration of 10 mg/mL. The impact that different extraction methods have on the yield of the essential oil from the tested herbal materials requires a further research. It would enable production of pharmaceutical forms enriched by these essential oils, which are notable for their anticancer activity.

Chemical composition and allelopathic, antibacterial, antifungal and in vitro acetylcholinesterase inhibitory activities of yarrow (Achillea millefolium L.) native to India

The present study was conducted to evaluate the variability in the essential oil yield and chemical composition of Achillea millefolium L. (whole aerial-parts, leaves and inflorescence) grown in the subtropical region of north India during annual growth. The allelopathic, antibacterial, antifungal, and antiacetylcholinesterase activities of the oil were also examined. The essential oil yield varied due to harvesting stages and plant-parts processed (0.10–0.70%). The oils obtained from different stages and plant-parts were analysed using GC-FID and GC–MS. Altogether thirty-nine constituents, forming 93.0–97.8% of the total oil composition were identified. Major constituents of the oils were germacrene D (1.1–46.6%), sabinene (4.0–38.9%), borneol (4.7–24.9%), camphor (0.6–17.6%), α-pinene (0.8–11.7%), artemisia ketone (3.1–12.9%), chamazulene (0.8–9.6%), γ-cadinene (0.3–8.2%), and camphene (0.2–5.7%). Cluster analysis grouped overall compositions into six main groups based on their dominant components. It was observed that season of harvesting and plant-parts affect the essential oil yield and chemical composition of A. millefolium. The chemical composition of the examined essential oil was different from those described from other geographical origins. Moreover, this oil displayed a significant allelopathic activity.

Chemical Composition, Antimicrobial Activity, and Mode of Action of Essential Oils against Paenibacillus larvae, Etiological Agent of American Foulbrood on Apis mellifera.

This study aimed to characterize the chemical composition of Aloysia polystachia, Acantholippia seriphioides, Schinus molle, Solidago chilensis, Lippia turbinata, Minthostachys mollis, Buddleja globosa, and Baccharis latifolia essential oils (EOs), and to evaluate their antibacterial activities and their capacity to provoke membrane disruption in Paenibacillus larvae, the bacteria that causes the American Foulbrood (AFB) disease on honey bee larvae. The relationship between the composition of the EOs and these activities on P.larvae was also analyzed. Monoterpenes were the most abundant compounds in all EOs. All EOs showed antimicrobial activity against P.larvae and disrupted the cell wall and cytoplasmic membrane of P.larvae provoking the leakage of cytoplasmic constituents (with the exception of B.latifolia EO). While, the EOs' antimicrobial activity was correlated most strongly to the content of pulegone, carvone, (Z)-β-ocimene, δ-cadinene, camphene, terpinen-4-ol, elemol, β-pinene, β-elemene, γ-cadinene, α-terpineol, and bornyl acetate; the volatiles that better explained the membrane disruption were carvone, limonene, cis-carvone oxide, pentadecane, trans-carvyl acetate, trans-carvone oxide, trans-limonene oxide, artemisia ketone, trans-carveol, thymol, and γ-terpinene (positively correlated) and biciclogermacrene, δ-2-carene, verbenol, α-pinene, and α-thujene (negatively correlated). The studied EOs are proposed as natural alternative means of control for the AFB disease.

Chemical Components and Molecular Microcapsules of Folium Artemisia argyi Essential Oil with β-Cyclodextrin Derivatives

Chemical components of natural spice, folium Artemisia argyi essential oil (FAAEO) was analyzed by Gas chromatography (GC) and Gas chromatography/Mass spectrometry (GC-MS). Forty-five compounds were identified, representing 98.9% of total oil. The major components were eucalyptol (16.2%), β-pinene (14.3%), camphor (14.0%), artemisia ketone (13.9%), and α-pinene (11.1%). The thermodynamic parameters (ΔG, ΔH, and ΔS) and formation constants (Ká) of inclusion reactions of FAAEO with β-cyclodextrin (β-CD), heptakis (2,6-di-methyl)-β-CD (DM-β-CD) and mono [2-O(2-hydroxy-propyl)]-β-CD (HP-β-CD) were determined. The results showed that the capability of forming microcapsules was β-CD> DM-β-CD> HP-β-CD and the stoichiometry of FAAEO with β-CD derivatives in the molecular microcapsules was 1:1 (molar ratio). The processes of forming microcapsules were exothermic and enthalpy-driven ones accompanied with negative entropic contribution and ΔG293K were -15.9, -14.2, -13.7 kJ/mol, and Ka at 293 K were 674.9, 343.4, 278.3 L/mol, respectively.

Vapour and Liquid-Phase Artemisia annua Essential Oil Activities against Several Clinical Strains of Candida.

Candida spp. are often the cause of infection in immune-compromised individuals. They are characterized by a strong resistance to antimicrobial drugs and disinfectants. The activity of Artemisia annua essential oil against Candida spp. was determined by vapour contact and microdilution assay. The oil was characterized by the presence of oxygenated monoterpenes (more than 75 % of the constituents), mainly represented by the irregular monoterpene artemisia ketone (ca. 22 %), and the widespread monoterpenes 1,8 cineole (ca. 19 %) and camphor (ca. 17 %). Other representative constituents were artemisia alcohol (5.9 %), α-pinene (5.7 %), and pinocarvone (3.0 %). Thujone, a typical toxic constituent of the Artemisia species, was not detected. The results are reported as minimum inhibitory concentration, minimum fungicidal concentration, and diameter of inhibition zone obtained by the vapour diffusion assay. We tested 10 clinical Candida strains, coming from both clinical samples and international collections. The results show that the antifungal activity of A.annua is influenced by the type of method adopted. The inhibitory action of the essential oil was, in fact, higher in the vapour than in the liquid phase. Our results show an average minimum inhibitory concentration in the liquid phase of 11.88 µL/mL, while in the vapour phase, the growth of all Candida strains tested at a concentration of 2.13 µL/cm(3) was inhibited. A strain of Candida glabrata was found to be less susceptible to the liquid medium than the vapour assay (50 µL/mL vs. 0.64 µL/cm(3), respectively). Candida albicans and Candida dubliniensis were the most susceptible to the vapour test, while Candida parapsilosis was the most resistant.

Introduction of Artemisia Species into the Egyptian Cultivation

The seeds of three different Artemisia spp. were imported from Germany in order to en-hance the Egyptian cultivation with new medicinal plants. A field experiment was conducted on three species of Artemisia to evaluate their behavior under Egyptian environmental condition using organic farming system. Growth parameters and essential oil content were evaluated. Artemisia annua produced the highest values of fresh and dry weights, plant height, and number of branches per plant and content of artemisinin. Maximum yield of essential oil was achieved with Artemisia annua while the minimum one was obtained from Artemisia dracunculoides. The essential oils were analyzed by GC-MS. The main compound was found to be artemisia ketone and followed by 1, 8-cineole , camphor and germacrene in the oil of Artemisia annua, while the major compound in the essential oil of A. dracunculoides was found to be sabinene, followed by methyl-eugenol. Trans-isoelemicin,methyl-chavicol (estragole), trans-β-ocimene, linalool and methyl-eugenol were the main compounds in the essential oil of Artemisia dracunculus. Artemisinin was detected only in Artemisia annua and ranged from 3.18 to 61.53 kg/fed (feddan = 4200 m2).

Anti-inflammatory activity of the essential oils of Cymbopogon validus (Stapf) Stapf ex Burtt Davy from Eastern Cape, South Africa.

To evaluate the essential oil composition and the anti-inflammatory activity of Cymbopogon validus (C.validus) leaves and flowers. A total of 300g of fresh or dry (leaves and flowers) of C.validus were cut into small pieces and subjected to hydro-distillation method for approximately 5h using the Clevenger apparatus. The extracted essential oils were then used for testing the anti-inflammatory activity. The anti-inflammatory activity was evaluated by using egg albumin-induced paw edema. The extracted oils had the following yields 2.2% for fresh leaves, 2.0% for dry leaves and 2.4% v/w for dry flowers. GC-MS results revealed that the oils contained artemisia ketone (37.5%), linalool (3.2%-29.6%), northujane (4.4%-16.8%), verbenone (13.5%), naphthalene (1.7%-9.6%), δ-cadinene (0.5%-8.1%), hedycaryol (5.4%-7.6%) and α-eudesmol (6.5%-6.7%) as the major constituents. C.validus essential oils showed significant (P<0.05) anti-inflammatory effects from the first 30min after albumin injection compared to aspirin which had a later onset of effect. The findings of this study show that the essential oil extracted from C.validus fresh or dry leaves and flowers have anti-inflammatory properties; that might be associated with the major components and the minor components found in the essential oils.

Variability in the Essential Oils from Aerial Parts of Artemisia vulgaris L. Grown in Uttarakhand (India)

The present study aims to determine the variability in the chemical composition of the essential oils from the aerial parts of Artemisia vulgaris L. grown in different locations of Uttarakhand Himalaya. The essential oils were obtained through hydro-distillation and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). In the oils from two locations (Jhanjhar and Kaditalla), α-thujone was found as the major constituent, ranging from 14.40–21.66 % followed by artemisia ketone (6.77–8.64 %), trans-caryophyllene (6.22–6.94 %) and 1,8-cineole (4.75–5.13 %); however in Chakrata region, artemisia ketone (29.38 %) was determined as a principal constituent followed by p-cymene (7.60 %) and yomogi alcohol (5.48 %), while α-thujone found to be only 3.10 %. Essential oils from all the locations were dominated by oxygenated monoterpenoids (52.04–59.24 %), whereas oxygenated sesquiterpenoids found to be 23.08–24.05 % in Jhanjhar and Kaditalla locations and only 2.44 % in the oil from Chakrata.

T-shaped trichome-specific expression of monoterpene synthase ADH2 using promoter-β-GUS fusion in transgenic Artemisia annua L.

Artemisinin, a sesquiterpene lactone isolated from Artemisia annua L. (sweet wormwood), is extensively used in the treatment of malaria. In order to better understand the metabolism of terpenes in A. annua and the influence of terpene synthases on artemisinin yield, the expression pattern of a monoterpene alcohol dehydrogenase (ADH2) has been studied using transgenic plants expressing promoter-β-glucuronidase (GUS) fusion. ADH2 played a major role in monoterpenoid biosynthesis including carveol, borneol, and artemisia ketone through in vitro biochemical analysis. In this study, the ADH2 promoter was cloned by the genome walking method. A number of putative cis-acting elements were predicted in promoter region, suggesting that the ADH2 is driven by a complex regulation mechanism. ADH2 gene was highly expressed in old leaves, whereas the artemisinin biosynthetic genes were mainly expressed in bud and young leaves. The expression of ADH2 gene increased quickly during leaf development, revealed by qRT-PCR. GUS expression analysis in different tissues of transgenic A. annua demonstrates that ADH2 expression is exclusively located to T-shaped trichome, not glandular secretory trichome.

Composition and antibacterial activity of the essential oil of Artemisia nilagirica var. septentrionalis from India

Essential oil composition of the aerial parts of Artemisia nilagirica (Clarke) Pamp. var. septentrionalis Pamp. was analyzed by GC-FID and GC-MS methods. Altogether forty-one constituents were identified, accounting for 95.9% of total composition. The essential oil was characterized by monoterpenoids (76.6%) represented by artemisia ketone (62.6%), artemisia alcohol (3.7%), perillene (3.1%), bornyl acetate (1.4%), along with sesquiterpenoids (16.1%) viz. β-caryophyllene (3.5%), α-muurolol (3.5%), δ-cadinene (2.1%) and germacrene D (1.8%). Essential oil was tested against nine pathogenic bacterial strains viz. Staphylococcus aureus (MTCC 96), Staphylococcus aureus (MTCC 2940), Streptococcus mutans, Staphylococcus epidermidis, Bacillus subtilis, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhimurium. Based on zone of inhibition and MIC/MBC results, it is concluded that the essential oil of A. nilagirica var. septentrionalis exhibited good antibacterial activity against Staphylococcus aureus (MTCC-2940), Staphylococcus aureus (MTCC-96) and Bacillus subtilis, and moderate activity against Escherichia coli, Staphylococcus epidermidis, Salmonella typhimurium, and Streptococcus mutans.

Chemical Composition and Antipathogenic Activity of Artemisia annua Essential Oil from Romania.

The essential oil extracted by hydrodistillation from Romanian Artemisia annua aerial parts was characterized by GC/MS analysis, which allowed the identification of 94.64% of the total oil composition. The main components were camphor (17.74%), α-pinene (9.66%), germacrene D (7.55%), 1,8-cineole (7.24%), trans-β-caryophyllene (7.02%), and artemisia ketone (6.26%). The antimicrobial activity of this essential oil was evaluated by determining the following parameters: minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), minimal fungicidal concentration (MFC), and minimal biofilm eradication concentration (MBEC). Moreover, the soluble virulence factors were quantified with different biochemical substrates incorporated in the culture media. The reference and resistant, clinical strains proved to be susceptible to the A. annua oil, with MICs ranging from 0.51 to 16.33 mg/ml. The tested essential oil also showed good antibiofilm activity, inhibiting both the initial stage of the microbial cell adhesion to the inert substratum and the preformed mature biofilm. When used at subinhibitory concentrations, the essential oil proved to inhibit the phenotypic expression of five soluble virulence factors (hemolysins, gelatinase, DNase, lipases, and lecithinases). Briefly, the present results showed that the A. annua essential oil contained antimicrobial compounds with selective activity on Gram-positive and Gram-negative bacterial strains as well as on yeast strains and which also interfere with the expression of cell-associated and soluble virulence factors.

Antibacterial activity of Tuscan Artemisia annua essential oil and its major components against some foodborne pathogens

Recently, the attention of researchers regarding Artemisia annua has been focused on the antimicrobial activity of the essential oil. This oil, rich in mono- and sesquiterpenes, has a strong activity against some Gram-negative and Gram-positive bacteria.The aim of our study is to further contribute to the knowledge of the antibacterial activity of an Artemisia annua essential oil collected in Tuscany and its three most represented compounds (artemisia ketone, 1,8-cineole and camphor).The essential oil obtained by hydrodistillation gave a yield of 0.37% (w/w fresh plant material). The composition of the essential oil extracted from flowering aerial parts was determined by gas chromatography (GC/FID and GC/MS).The essential oil and compounds were tested for activity against Escherichia coli O157, Salmonella Enteritidis, Salmonella Typhi, Yersinia enterocolitica and Listeria monocytogenes, all of which have great significance in foodborne infections.The antibacterial activity was tested using disk diffusion method and broth microdilution assay. The microorganisms tested were all sensitive to the A. annua essential oil in toto and to all its components, which often have lower activity than oil in toto.