Selected antimicrobial essential oils to eradicate multi-drug resistant bacterial biofilms involved in human nosocomial infections.

Biofilms are the primary source of contamination linked to nosocomial infections by promoting bacterial resistance to antimicrobial agents, including disinfectants. Using essential oils, this study aims to inhibit and eradicate the biofilm of enterobacteria and staphylococci responsible for nosocomial infections at Guelma Hospital, northeastern Algeria. Thymbra capitata, Thymus pallescens and Artemesia herba-alba essential oils were evaluated against clinical strains of Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus. The antimicrobial activity of the essential oils under consideration was assessed using an agar disc diffusion assay and the determination of minimum inhibitory concentrations (MICs). In addition, the crystal violet method and scanning electron microscopy (SEM) evaluated biofilm inhibition and eradication by those antimicrobial agents. The results indicate that T. pallescens essential oil was the most effective antimicrobial agent against pathogenic bacteria, with large zones of inhibition (up to 50 mm against S. aureus), low MICs (0.16 to 0.63 mg/mL), and powerful biofilm eradication up to 0.16 mg/mL in both 24 h and 60-min exposure times. Thus, Algerian thyme and oregano could be used in various ways to combat the biofilm that causes nosocomial infection in local hospitals.

Evaluation of the antioxidant and anti-inflammatory activity of the Anacyclus valentinus L. essential oil and its oxygenated fraction.

AIM AND OBJECTIVE: Synthetic antioxidants and anti-inflammatories are widely used by the food and pharmaceutical industries. Like any synthetic product, these are toxic and represent a significant health risk. The objective of this study was to determine the chemical composition of Anacyclus valentinus essential oil and its oxygenated fraction, as well as their in-vitro antioxidant and anti-inflammatory properties. MATERIALS AND METHODS: The essential oil was hydrodistilled using a Clevenger-type device and the oxygenated fraction was obtained by column chromatography using diethyl ether. The essential oil and its oxygenated fraction were analysed by GC and GC/MS. The antioxidant activities were performed using three different methods Radical scavenging activity (DPPH), ß-carotene bleaching test, and the Ferric-Reducing Antioxidant Power (FRAP), using BHT as a positive control. The activity of anti-inflammatory of essential oil and its oxygenated fraction was assessed by the protein denaturation method using the diclofenac sodium as a positive control. RESULTS: The essential oil of Anacyclus valentinus was represented mainly by oxygenated sesquiterpene compounds (37.7%), hydrocarbon sesquiterpenes (14.7%), oxygenated monoterpenes (18.4%) and non-terpenic compounds (15.6%). The oxygenated fraction was composed mainly of oxygenated sesquiterpenes (40.6%), oxygenated monoterpenes (38.5%), and non-terpene compounds (19.4%). Essential oil and hydrosol extract showed antioxidant activity. The most potent activity was observed by the oxygenated fraction in the DPPH (IC50 = 8.2 mL/L) and ß-carotene bleaching (IC50 = 5.6 mL/L) tests. While the essential oil of A. valentinus showed very good anti-inflammatory activity with an IC50 of 0.3 g/L higher than that of diclofenac (IC50= 0.53 g/L). CONCLUSION: The results showed that the essential oil and the oxygenated fraction of A. valentinus are rich in sesquiterpene compounds and possess interesting antioxidant and anti-inflammatory properties. However, other studies are necessary to be able to offer these extracts to the pharmaceutical and food industries.

First Phytochemical Profiling and In-Vitro Antiprotozoal Activity of Essential Oil and Extract of Plagiochila porelloides.

Volatiles metabolites from the liverwort Plagiochila porelloides harvested in Corsica were investigated by chromatographic and spectroscopic methods. In addition to already reported constituents, three new compounds were isolated by preparative chromatography and their structures were elucidated by mass spectrometry (MS) and NMR experiments. Hence, an atypic aliphatic compound, named 1,2-dihydro-4,5-dehydronerolidol and two isomers, (E) and (Z), possessing an unusual humbertiane skeleton (called p-menth-1-en-3-[2-methylbut-1-enyl]-8-ol) are newly reported and fully characterized in this work. The in vitro antiprotozoal activity of essential oil and extract of P. porelloides against Trypanosoma brucei brucei and Leishmania mexicana mexicana and cytotoxicity were determined. Essential oil and Et2O extract showed a moderate activity against T. brucei with IC50 values: 2.03 and 5.18 µg/mL, respectively. It is noteworthy that only the essential oil showed a high selectivity (SI = 11.7). Diethyl oxide extract exhibited moderate anticancer (cancerous macrophage-like murine cells) activity and also cytotoxicity (human normal fibroblast) with IC50 values: 1.25 and 2.96 µg/mL, respectively.

Efficacy of endemic Algerian essential oils against single and mixed biofilms of Candida albicans and Candida glabrata.

OBJECTIVES: This study investigated the in vitro effect of Origanum glandulosum, Ammoides verticillata, and Saccocalyx satureioides essential oils against planktonic cells and biofilms formed by single and mixed species of Candida albicans and Candida glabrata oral isolates. The effect of the essential oils in combination with amphotericin B on planktonic cells was also studied. DESIGN: The antifungal susceptibility of planktonic cells was evaluated by disc diffusion and broth microdilution methods. Resazurin assay and scanning electron microscopy (SEM) were employed to determine the antibiofilm activity. The combinatory effect was evaluated by the checkerboard method. Essential oils were characterized by gas chromatography-mass spectrometry (GC-MS). RESULTS: The minimal inhibitory concentrations (MICs) and the minimum fungicidal concentrations (MFCs) of the studied essential oils were ranged between 250 and 2000 µg/mL. Biofilms were inhibited and eradicated by the essential oils at sub-inhibitory concentrations of 500 and 1000 µg/mL, respectively. SEM studies revealed a reduction in the preformed biofilm as a result of Origanum glandulosum essential oil treatment for single and mixed biofilms. Synergistic activity was found when Origanum glandulosum essential oil was combined with amphotericin B against Candida albicans. GC-MS analysis revealed that thymol was the major compound in Origanum glandulosum (38.36 %) and Ammoides verticillata (48.99 %) essential oils, while Saccocalyx satureioides essential oil was dominated by borneol (27.36 %). CONCLUSIONS: The studied essential oils showed significant antifungal and antibiofilm activities, which support their effectiveness as promising candidates for the management of oral Candida infections.

A combined in vitro-in silico approach for the discovery of novel endogenous enzymatic and ctDNA sequence of bioactive molecules from aerial and root parts of Centaurea sulphurea as antioxidant's agents.

The excess free radicals not neutralized by the antioxidant defenses damage the essential macromolecules of our cells, causing abnormalities in the expression of genes and membrane receptors, cell proliferation or death, immune disorders, mutagenesis, deposits of proteins or lipofuschin in tissues. The first objective of this study was to elucidate the composition of the essential oil of the aerial and root part of Centaurea sulphurea during beginning of the vegetative cycle (March), beginning of the flowering stage (April) and full bloom (May/June) using GC/FID and GC/MS. The second aim was to describe the antioxidant activity using three methods (2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric-reducing antioxidant power (FRAP), ß-carotene bleaching assay) and bioinformatical study of ctDNA sequence and three endogenous enzymes inhibition. The essential oils obtained from the root during the full bloom period consisted mainly of caryophyllene oxide, aplotaxene and (Z)-phytol. While, the aerial parts were dominated by caryophyllene oxide, verridiflorol and humulene epoxide II. The results showed that essential oil presented an excellent antioxidant activity with IC50 values of 2.06 g/L and 1.29 g/L, for aerial and root parts, compared to butylated hydroxyltoluene (BHT) and Ethylenediaminetetraacetic acid (EDTA) controls and the nicotinamide adenine dinucleotide phosphate (NADPH) co-crystallized inhibitor. The results of the molecular docking revealed that (Z)-phytol (Ligand 39) has an affinity to interact with ctDNA sequence, and three targets Endogenous enzymes. The molecular dynamics study was conducted for the best inhibitors (Z)-phytol. A few key residues were identified at the binding site of receptors. The in-silico assessment of the ADME properties and BOILED-Egg plot reveals that compound (Z)-phytol (L39) is permeable to the blood brain barrier and have high lipophilicity and high coefficient of skin permeability in the intestines with good bioavailability. The ADMET analysis also showed that this oxygenated diterpene is safer to replace the synthetic drugs with side effects. Further testing is needed to assess its effectiveness in reducing oxidative stress for use in the pharmaceutical industry.Communicated by Ramaswamy H. Sarma.

Guaianolide Derivatives from the Invasive Xanthium spinosum L.: Evaluation of Their Allelopathic Potential.

Ziniolide, xantholide B (11α-dihydroziniolide), and 11ß-dihydroziniolide, three sesquiterpene lactones with 12,8-guaianolide skeletons, were identified as volatile metabolites from the roots of Xanthium spinosum L., an invasive plant harvested in Corsica. Essential oil, as well as hydrosol and hexane extracts, showed the presence of guaianolide analogues. The study highlights an analytical strategy involving column chromatography, GC-FID, GC-MS, NMR (1D and 2D), and the hemi-synthesis approach, to identify compounds with incomplete or even missing spectral data from the literature. Among them, we reported the 1H- and 13C-NMR data of 11ß-dihydroziniolide, which was observed as a natural product for the first time. As secondary metabolites were frequently involved in the dynamic of the dispersion of weed species, the allelopathic effects of X. spinosum root's volatile metabolites were assessed on seed germination and seedling growth (leek and radish). Essential oil, as well as hydrosol- and microwave-assisted extracts inhibited germination and seedling growth; root metabolite phytotoxicity was demonstrated. Nevertheless, the phytotoxicity of root metabolites was demonstrated with a more marked selectivity to the benefit of the monocotyledonous species compared to the dicotyledonous species. Ziniolide derivatives seem to be strongly involved in allelopathic interactions and could be the key to understanding the invasive mechanisms of weed.

Smart IM-MS and NMR study of natural diastereomers: the study case of the essential oil from Senecio transiens.

Unambiguous identification of the components of a natural mixture remains a challenging and meticulous issue. Usually, different analytical techniques and laborious separation protocols are employed; nevertheless, in some cases, delicate and equivocal problems are hardly addressed by traditional methods. In this context, an original methodology for the analysis of natural samples consisting of recent mass spectrometry methods based on ion mobility (MS-IM) is proposed. As an example, a polar fraction obtained by the essential oil prepared from Senecio transiens, an endemic plant harvested on the Corsica Island, was selected for this study to show how IM-MS-based methods easily provide very useful insights suggesting the presence of two diastereomers. To unambiguously confirm this hypothesis and verify reliability of the IM-MS results, the purified compounds were further analysed by means of nuclear magnetic resonance (NMR) methodologies, allowing the structural elucidation and the identification of two new natural compounds, diastereomers of 4-acetoxy-5,9-dimethyl-3-(2-methylpropenyl)-2-oxabicyclo[4.4.0] dec-9-ene, reported here for the first time.

Chemical composition/pharmacophore modelling- based, virtual screening, molecular docking and dynamic simulation studies for the discovery of novel superoxide dismutase (SODs) of bioactive molecules from aerial parts of Inula Montana as antioxydant's agents.

The accumulation of free radicals in the body develops chronic and degenerative diseases such as cancer, autoimmune diseases, rheumatoid arthritis, cardiovascular and neurodegenerative diseases. The first aim of this work was to study the chemical composition of Inula Montana essential oil using GC-FID and GC/MS analysis and the antioxidant activities using radical scavenging (DPPH) and the Ferric -Reducing Antioxidant Power (FRAP) tests. The second aim was to describe the assess the antioxidant activity and computational study of Superoxide Dismutase (SODs) and ctDNA inhibition. Sixty-nine compounds were identified in the essential oil of the aerial part of Inula montana. Shyobunol and α-Cadinol were the major compounds in the essential oil. The antioxidant power of the essential oil showed an important antioxidant effect compared to ascorbic acid and the methionine co-crystallized inhibitor. The results of the docking simulation revealed that E, E-Farnesyl acetate has an affinity to interact with binding models and the antioxidant activities of the ctDNA sequence and Superoxide Dismutase target. The penetration through the Blood-Brain Barrier came out to be best for E, E-Farnesyl acetate and E-Nerolidolacetate and was significantly higher than the control molecule and Lref. Finally, the application of ADMET filters gives us positive information on the compound E, E-Farnesyl acetate, which appears as a new inhibitor potentially more active towards ctDNA and SODs target. The active compounds, E,E-Farnesyl acetate can be used as templates for further development of more potent antioxidative agents.Communicated by Ramaswamy H. Sarma.

Statistical analysis/theoretical investigations of novel vascular endothelial growth factor of Davanoide from Scolymus grandifloras Desf as potent anti-angiogenic drug properties.

Many pro-angiogenic factors acting directly or indirectly on the proliferation and differentiation of endothelial cells have been highlighted, in particular: VEGF ('Vascular Endothelial Growth Factor'), FGF ('Fibroblast Growth Factor'), PDGF ('Platelet-Derived Growth Factor'), VEGF exerts its pro-angiogenic activity by binding to the surface of receptors with tyrosine kinase activity (VEGFR). The first objective of this study was to elucidate the composition of the essential oil of the roots of Scolymus grandifloras Desf. The second aim was to describe the intra-species variation in essential oil composition in natural populations of 21 oil samples from different Algerian locations using statistical analysis and bioinformatical study of VEGFR inhibition. The essential oil isolated from the root parts, was a really source of Davanoide compounds. The results of the docking simulation revealed that davanone (Ligand 13) has an affinity to interact with cDNA, VEGF and its receptors. The ADMET properties and BOILED-Egg plot validate the compound 13 pass the brain barrier and have high absorption in the intestines with good bioavailability. The findings of this study contribute to the pharmacological knowledge and the therapeutic efficacy of davanone and can initiate the development of new anti-angiogenic drugs. Results showed that essential oil of Scolymus grandiflorus presented a large level of percentage of davanone, davanol D1 and 2-hydroxy davanone. These components may be a new source of nontoxic anticancer agents. However, an additional in vitro and/or in vivo experimental study should make it possible to verify the theoretical results obtained in silico.Communicated by Ramaswamy H. Sarma.

Chemical composition variability and vascular endothelial growth factor receptors inhibitory activity of Inulaviscosa essential oils from Algeria.

Angiogenes is therefore appears to be a complex phenomenon, finely regulated by various activators (pro-angiogenic factors) and inhibitors (anti-angiogenic factors). Among the pro-angiogenic factors, VEGF (Vascular Endothelial Growth Factor) seems to be one of the main players in tumor angiogenesis. It exerts its pro-angiogenic activity by attaching to the surface of receptors with tyrosine kinase activity (VEGFR). The aim of this research was the bioinformatical study of VEGFR inhibition by essential oils of the Inula viscosa.Analyses of essential oils obtained by hydrodistillation from the aerial parts of the plant were performed using GC and GC/MS analysis. We used molecular modeling approaches as molecular mechanics to theoretical investigation VEGF receptors by natural inhibitors.Nineteen compounds were identified, constituting 90.1-98.8% of the total essential oils. The main components of the plants were (E)-nerolidol (15.5-20.2 %), caryophyllene oxide (10.6-18.1%), (E)-Z-farnesyl acetone (13.2-25.1%) and (E)-ß-farnesene (1.5-5.6%). Essential oil samples were clustered into two groups according to their chemical compositions. The molecular dynamics study was conducted for the best inhibitors. A few key residues were identified at the binding site of VEGFR. The Pharmacokinetics was justified by means of lipophilicity and high coefficient of skin permeability. The in silico evaluation of ADME revealed that L19 has high absorption. The essential oil of I. viscosa presents a significant variability. This study revealed that (E)-Z-Farnesylacetone is a functional inhibitor of VEGF activities and subsequently can be the best inhibitors candidate to be scrutinized in vivo and in vitro.Communicated by Ramaswamy H. Sarma.

Chemical Variability and Antioxidant Activities of the Essential Oils of the Aerial Parts of Ammoides verticillata and the Roots of Carthamus caeruleus and their Synergistic Effect in Combination.

AIM AND OBJECTIVE: Oxidative stress is implicated in the development and progression of many diseases. Some of the appropriate actions that could taken to resolve the problem of these diseases are search for new antioxidant substances isolated from plants. The aims of this study were to research the intraspecies variations of A. verticillata and C. caeruleus essential oils from 8 locations using statistical analysis, the in vitro antioxidant properties of collective essential oils and in combinations. MATERIALS AND METHODS: The essential oils were analyzed by GC and GC-MS. The intraspecies variations of the essential oil compositions were discussed using principal component analysis (PCA) and cluster analysis (CA). The antioxidant properties were evaluated DPPH-radical scavenging activity and ß-carotene bleaching test. RESULTS: The main components of Ammoides verticillata collective essential oil (Coll EO) were thymol (30.5%), carvacrol (23.2%), p-cymene (13.1%), limonene (12.5%) and terpinene-4-ol (12.3%). While roots of Carthamus caeruleus essential oil were dominated by carline oxide (86.2%). The chemical variability allowed the discrimination of two main Groups for both Coll EOs. A direct correlation between the altitudes, climate and the chemical compositions was evidenced. Ammoides verticulata and Carthamus caeruleus Coll Eos showed good antioxidant activity. In binary mixture, the interaction between both Coll Eos and between oils rich of thymol and/or carvacrol with carlina oxide produced the best synergistic effects compared to individual essential oils and the synthetic antioxidant (BHT). CONCLUSION: Ammoides verticillata and Carthamus caeruleus essential oil blends can be used as a natural food preservative and alternative to chemical antioxidants.

Anti-Inflammatory, Antimicrobial and Insecticidal Properties of Daucus Gracilis Steinh Flowers Essential Oil.

BACKGROUND: Daucus gracilis Steinh belongs to the Apiaceae family. The flowers of this plant have been used by the population of western Algeria for the treatment of mouth ulcers. However, very few studies exist concerning the biological properties of essential oil of Daucus gracilis Steinh flowers. OBJECTIVES: The purpose of this work was to study the chemical composition of the essential oil of Daucus gracilis flowers and to evaluate their antimicrobial, insecticidal and anti-inflammatory properties. METHODS: The distilled essential oil was analyzed by GC and GC-MS. The antimicrobial activity of the essential oil was evaluated using two methods i) diffusion method, and ii) micro dilution technique. The insecticidal activity of essential oil was evaluated against adults of Tribolium confusum by fumigant test. The in vitro assessment of the anti-inflammatory property of essential oil was assessed by the protein denaturation method. RESULTS: Daucus gracilis flowers essential oil mainly represented oxygenated monoterpenes such as geranyl acetate (18.3%), lavandulyl acetate (15.2%), lavandulyl isobutyrate (13.6%) and citronellyl isobutyrate (6.8%). According to the results of antimicrobial activity, the essential oil of flowers presented prominent inhibitory action against Aspergillus flavus (0.06 µg/mL), followed by Staphylococcus aureus, Escherichia faecalis, Bacillus cereus and Candida albicans with MIC values of 0.125 µg/mL. The Daucus gracilis essential oil flowers proved to be very biocidal toward adults of Tribolium confusum; mortality of 100% of the population was noted with a dose of 2 µl/L air after 24 hours of exposure. Furthermore, the oil has shown a very good inhibition of protein denaturation comparable to Diclofenac at a concentration of 30 µL/mL. CONCLUSION: Daucus gracilis essential oil can be used as a pharmacological tools for inflammatory, antimicrobial and insecticidal properties.

Caution: Chemical Instability of Natural Biomolecules During Routine Analysis.

Natural products (NPs) constitute a significant source of active biomolecules widely used in medicine, pharmacology and cosmetics. However, NPs structural characterization has the drawback of their chemical instability during the extraction steps and their likely transformation during the analytical protocol. In particular, tamariscol and conocephalenol are two compounds largely used in the cosmetic industry for their odorant properties. Thus, in the present study, we focused on the evolution of these two metabolites (extracted from Frullania tamarisci and Conocephalum conicum, respectively), as followed by NMR. Interestingly, we found that, once dissolved in deuterated chloroform, these two tertiary alcohols are both subjected to transformation processes, leading to degradation compounds with altered structures. Accordingly, these detected degradation compounds have been fully characterized by NMR and the experimental findings were supported by computational chemistry data.

Direct Identification of α-Bisabolol Enantiomers in an Essential Oil Using a Combined Ion Mobility-Mass Spectrometry/Quantum Chemistry Approach.

Enantiomer-specific identification of chiral molecules in natural extracts is a challenging task, as many routine analytical techniques fail to provide selectivity in multicomponent mixtures. Here we describe an alternative approach, based on the combination of ion mobility-mass spectrometry (IM-MS) and quantum chemistry (QM), for the direct enantiomers differentiation in crude essential oils. The identification of α-bisabolol enantiomers contained in the raw essential oil (EO) from the Corsican Xanthium italicum fruits is reported as a proof-of-concept. Accordingly, IM-MS experiments performed in Ag+-doped methanol revealed the presence of both (+)- and (-)-α-bisabolol in the EO, while molecular simulations provided the structures of the two α-bisabolol enantiomer silver(I) adducts.

Chemical Composition and Combinatory Antifungal Activities of Ammoides verticillata, Allium sativum and Curcuma longa Essential Oils Against Four Fungi Responsible for Tomato Diseases.

BACKGROUND: Tomato is considered a model plant in genetics and is one of the most economically important crops of all those that exist in the world. Several species of fungi are reported on tomato fruit, causing damage both during cultivation and after harvest. Some of the appropriate actions that could be initiated to resolve the problem are to develop and search for new antimicrobial substances isolated from the bioactive natural products, such as essential oils. AIMS AND OBJECTIVE: The aim of this work was to determine the chemical composition of essential oils of Ammoides verticillata, Allium sativum and Curcuma longa, to evaluate their in-vitro antifungal activities and in-vivo antifungal effect of essential oils to prevent the diseases caused by tomato. MATERIALS AND METHODS: The essential oils obtained from aerial parts of plants were analyzed by GC/MS and tested for their antifungal activities against Penicillium expansum, Fusarium solani, Rhizopus stolonifer and Alternaria alternata using the radial growth technique method. The effectiveness in-vivo of the association between Allium sativum and Curcuma longa essential oils was also investigated on tomatoes inoculated by fungi. RESULTS: The essential oil from A. verticilata was mainly composed of phenolic compounds (54.4%), the A. sativum oil was mainly composed of sulfur compounds (91.5%) and C. longa oil was dominated by oxygenated monoterpenes (82.0%). The obtained results in-vitro antifungal revealed that individual essential oils of A. verticillata and A. sativum were more active than the essential oil of C. longa against all screened microorganisms. An important antifungal effect of A. sativum and C. longa essential oils blend was obtained against P. expansum (100%), F. solani (95.2%), R. stolonifer (95.1%) and A. alternata (48.5%). Furthermore, A. sativum and C. longa essential oils blends have demonstrated promising in-vivo antifungal activity to control infection of tomato against P. expansum and R. stolonifer. CONCLUSION: A. sativum and C. longa essential oil blends can be used as a natural food preservative and alternative to chemical fungicides to protect stored tomato against many phytopathogens.

Ammoides verticillata Essential Oil as Biocontrol Agent of Selected Fungi and Pest of Olive Tree.

BACKGROUND: Ammoides verticillata Briq is an aromatic and medicinal herb that has been widely used in folk medicine for treatment of several types of pathologies such as respiratory problems, colds, fever, headache, gastric disorders and renal infections. OBJECTIVE: Essential oils have been subjected of numerous works for their antimicrobial and insecticidal properties which have been valued by hundreds of publications and patents. The main objective of this work was to evaluate the chemical composition, and the in vitro and in vivo antifungal, and insecticidal properties of essential oil of Ammoides verticillata. METHODS: In this work, the air-dried aerial parts of Ammoides verticillata were hydrodistilled in a Clevenger-type apparatus. The essential oil isolated was analyzed using gas chromatography (GC) and mass spectrometry (GC/MS). The in vitro antifungal activity of the essential oil was investigated against four plant fungi using radial growth technique. The effect of the essential oil on disease development of olive caused by Penicillium crustosum and Aspergillus niger in the in vivo conditions. The fumigation test of the essential oil was evaluated against L3 stages, pupas and adults of Bactrocera oleae known as the olive fly. RESULTS: The essential oil of A. verticillata was characterized mainly by carvacrol (44.3%), limonene (19.3%) and p-cymene (19.2%). The result of in vitro antifungal activity of essential oil showed an interesting antifungal inhibition against Alternaria alternata and Fusarium solani strains with percentage inhibition of 89%. Furthermore, oil of A. verticillata has demonstrated promising in vivo antifungal activity to control infections of olives caused by Aspergillus niger and Penicillium crustosum. In addition, the essential oil exhibited fumigation toxicity against Bactrocera oleae with mortality percentage of 100% at 2 µL/L air. CONCLUSION: The results showed that essential oil of A. verticillata has interesting biological activities, which suggests that oil have the potential to be used as biocide to protect olives of pathogenic fungi and pests.

Essential Oil of Algerian Eryngium campestre: Chemical Variability and Evaluation of Biological Activities.

The chemical composition of essential oils extracted from aerial parts of Eryngium campestre collected in 37 localities from Western Algeria was characterized using GC-FID and GC/MS analyses. Altogether, 52 components, which accounted for 70.1 to 86.8% of the total composition oils were identified. The main compounds were Germacrene D (0.4-53.4%), Campestrolide (1.6-35.3%), Germacrene B (0.2-21.5%), Myrcene (0.1-8.4%), α-Cadinol (0.2-7.6%), Spathulenol (0.1-7.6%), Eudesma-4(15)-7-dien-1-ß-ol (0.1-7.6%) and τ-Cadinol (0.3-5.5%). The chemical compositions of essential oils obtained from separate organs and during the complete vegetative cycle of the plant were also studied. With the uncommon 17-membered ring lactone named Campestrolide as the main component, Algerian E. campestre essential oils exhibited a remarkable chemical composition. A study of the chemical variability using statistical analysis allowed the discrimination of two main clusters according to the geographical position of samples. The study contributes to the better understanding of the relationship between the plant and its environment. Moreover, the antimicrobial activity of the essential oil was assessed against twelve strains bacteria and two yeasts involved in foodborne and nosocomial infections using paper disc diffusion and dilution agar assays. The in vitro study demonstrated a strong activity against Gram-positive strains such as S. aureus, B. cereus, and E. faecalis. The cytotoxicity and antiparasitic activities (on Lmm and Tbb) of the collective essential oil and one sample rich in campestrolide, as well as some enriched fractions or fractions containing other terpenic compounds, were also analyzed. Campestrolide seems to be one compound responsible for the cytotoxic and antileishmanial effect, while myrcene or/and trans-ß-farnesene have a more selective antitrypanosomal activity.

Structural Elucidation and Cytotoxicity of a New 17-Membered Ring Lactone from Algerian Eryngium campestre.

The chemical composition of a hexanic extract of Eryngium campestre, obtained from its aerial parts, was investigated by GC-FID, GC/MS, HRMS, NMR and VCD analyses. The main compounds were germacrene D (23.6%), eudesma-4(15)-7-dien-1-ß-ol (8.2%) and falcarindiol (9.4%), which are associated with a new uncommon and naturally found 17-membered ring lactone. This 17-membered ring features conjugated acetylenic bonds, named campestrolide (23.0%). The crude extract showed moderate antitrypanosomal (Trypanosoma brucei brucei), antileishmanial (Leishmania mexicana mexicana) and anticancer (cancerous macrophage-like murine cells) activities, and also displayed cytotoxicity, (human normal fibroblasts) in similar concentration ranges (IC50 = 3.0, 3.9, 4.0 and 4.4 µg/mL respectively). Likewise, campestrolide displayed low activity on all tested cells (IC50: 12.5⁻19.5 µM) except on Trypanosoma, on which it was very active and moderately selective (IC50 = 2.2 µM. SI= 8.9). In conclusion, the new compound that has been described, displaying a singular structure, possesses interesting antitrypanosomal activity that should be further investigated and improved.

Essential oils from Algerian species of Mentha as new bio-control agents against phytopathogen strains.

Chemical composition and antifungal activity of essential oils of Algerian Mentha species were studied. Chemical compositions of different Mentha species oils (Mentha rotundifolia, M. spicata, M. pulegium, and M. piperita) were investigated by capillary GC and GC/MS, and their antifungal activities were evaluated by means of paper disc diffusion method and minimum inhibitory concentration (MIC) assays. In total, 98 components from all Mentha species were identified. All oils were rich in monoterpene-oxygenated components. In addition, we reported fumigant antifungal activity of Algerian Mentha essential oils against four fungi: Botrytis cinerea, Penicillium expansum, Monilinia laxa, and M. fructigena. All oils demonstrated very good inhibition especially against B. cinerea, M. laxa, and M. fructigena. Both Monilinia fungi were extremely sensitive to all Algerian Mentha oils, which suggests that Mentha essential oils have the potential to be used as bio-pesticides to protect fruit trees, such as apple and pear trees, and provides an alternative to chemical pesticides.

Chemical Composition and Biological Investigations of Eryngium triquetrum Essential Oil from Algeria.

The chemical composition, antibacterial and antioxidant activities of the essential oil obtained from Eryngium triquetrum from Algeria were studied. The chemical composition of sample oils from 25 locations was investigated using GC-FID and GC/MS. Twenty-four components representing always more than 87% were identified in essential oils from total aerial parts of plants, stems, flowers and roots. Falcarinol is highly dominant in the essential oil from the roots (95.5%). The relative abundance of falcarinol in the aerial parts correlates with the phenological stages of the plant. Aerial parts of E. triquetrum produce an essential oil dominated by falcarinol during the early flowering stage, and then there is a decrease in falcarinol and rebalancing of octanal during the flowering stage. To our knowledge, the present study is the first report of the chemical composition of E. triquetrum essential oil. Evaluation of the antibacterial activity by means of the paper disc diffusion method and minimum inhibitory concentration assays, showed a moderate efficiency of E. triquetrum essential oil. Using the DPPH method, the interesting antioxidant activity of E. triquetrum essential oil was established. These activities could be attributed to the dominance of falcarinol. The outcome of our literature search on the occurrence of falcarinol in essential oils suggests that E. triquetrum from Algeria could be considered as a possible source of natural falcarinol.