No abstract

Findings of this study indicate that essential oils extracted from aromatic plants can be used in treatment of intractable oral infections, especially caused by biofilm of multidrug-resistant E. faecalis.

If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. AbstractPurpose -To evaluate the effect of natural rosemary oil as non toxic inhibitor on the corrosion of steel in H 3 PO 4 media at various temperatures. Design/methodology/approach -The oil was hydro-distilled. The oil was used as inhibitor in various corrosion tests. Gravimetric and electrochemical techniques were used to characterise the corrosion mechanism. Findings -Chromatographic analysis by GC showed that the oil was rich in 1,8-cineole. The oil was a good inhibitor. But, its efficiency decreased with temperature.Research limitations/implications -The inhibition efficiency increased with the concentration of the natural oil to attain 73 per cent at 10 g/l. Good agreement between the various methods explored was observed. Polarisation measurements showed that rosemary oil acted essentially as a cathodic inhibitor. Practical implications -The efficiency of the oil increased with the concentration but decreased with the rise of temperature in the 298-348 K range. The natural oil could thus be used in chemical cleaning and pickling processes. Originality/value -The originality of this work is the finding of a safe and cheap inhibitor from natural plants.

Platelet hyperactivity plays an important role in arterial thrombosis and atherosclerosis. The present study was undertaken to investigate the effects of different extracts of Urtica dioica leaves on platelet aggregation. Rat platelets were prepared and incubated in vitro with different concentrations of the tested extracts and aggregation was induced by different agonists including thrombin (0.5 U/mL), ADP (10 microm), epinephrine (100 microm) and collagen (5 mg/mL). The crude aqueous extract inhibited thrombin-induced platelet aggregation in a dose-dependent manner. At 1 mg/mL, the percent inhibition was 17.1 +/- 4.2%. Soxhlet extraction of the plant leaves with different successive solvents showed that the ethyl acetate extract exhibited the most antiaggregant effect with an inhibition of 76.8 +/- 6.1% at 1 mg/mL. Flavonoids isolated from the plant leaves, produced a strong inhibitory effect on thrombin-induced platelet aggregation with an IC(50) of 0.25 +/- 0.05 and 0.40 +/- 0.04 mg/mL for genins and heterosidic flavonoids, respectively. Flavonoids also markedly inhibited platelet aggregation induced by ADP, collagen and epinephrine. It is concluded that Urtica dioica has an antiplatelet action in which flavonoids are mainly implicated. These results support the traditional use of Urtica dioica in the treatment and/or prevention of cardiovascular disease.

The chemical composition of the essential oils isolated from the aerial parts of Micromeria inodora (Desf.) Benth. collected in 24 Algerian localities was investigated from the first time using GC-FID, GC/MS and C-NMR. Altogether, 83 components which accounted for 94.7% of the total oil composition were identified. The main compounds were trans-sesquisabinene hydrate (1; 20.9%), α-terpinyl acetate (2; 19.8%), globulol (3; 4.9%), caryophyllene oxide (4; 4.3%), β-bisabolol (5; 2.9%) and trans-7-epi-sesquisabinene hydrate (6; 2.6%). Comparison with the literature highlighted the originality of the Algerian M. inodora oil and indicated that 1 might be used as taxonomical marker. The study of the chemical variability allowed the discrimination of two main clusters confirming that there is a relation between the essential-oil compositions and the soil nature of the harvest locations. Biological activity of M. inodora essential oil was assessed against fourteen species of microorganisms involved in nosocomial infections using paper disc diffusion and dilution agar assays. The in vitro study demonstrated a good activity against Gram-positive strains such as Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, and Enterococcus faecalis, and moderate activity against Candida albicans. These results might be useful for the future commercial valorization of M. inodora essential oil as a promising source of natural products with potential against various nosocomial community and toxinic infections.

A B S T R A C TObjective: To study the antimicrobial activity of actinomycetes isolated from sabkha of Kenadsa and identification of the isolate interesting. Methods: Eighteen strains were isolated, using four culture media from sebkha of Kenadsa (Bechar, Southwestern Algeria). Screening of antimicrobial activity consisted of two steps: in primary screening, antibacterial activity was determined by using the agar plug method against test strains; in secondary screening, better isolate which showed a good activity in the first screening was selected to extract antimicrobial substances. The antimicrobial activities of extracts were evaluated by using Kirby-Bauer disc diffusion method. Partial characterization of antimicrobial products was performed on the basis of chemical revelations, UV-vis spectrometry and infrared spectroscopy. The identification of isolate interesting was performed through morphological, chemical, biochemical and physiological characteristics. Results: All isolates showed antimicrobial activity against at least one microorganism test. One isolate, LAM143cG3, was selected for its broad spectrum and high antimicrobial activity. The isolate LAM143cG3 was identified as Spirillospora sp. The comparison between the species of this genus (Spirillospora rubra and Spirillospora albida) and our isolate indicated the existence of several physiological and biochemical differences which led us to suppose that this was a new member of this genus. Primary characterization of antimicrobial substances produced by the isolate LAM143cG3 indicated the presence of amines and phenols. The UV-vis spectrum suggested a nonpolyenic nature of substances secreted by our isolate, while infrared confirmed the presence of amine groups. Conclusions: The result of the present study revealed that sebkha of Kenadsa was rich in rare actinomycetes, that secreted interesting antimicrobial substance.

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-β-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-β-farnesene have a more selective antitrypanosomal activity.

Actinobacteria are one of the most important phyla of microorganisms that produce a wide variety of bioactive secondary metabolites, 1,2 including many clinically used antibiotics and anticancer drugs. 3,4 A contemporary strategy for obtaining new bioactive compounds is based on the isolation of rare actinomycetes from neglected environments, 5 which should contain gene clusters for biosynthetizing novel secondary metabolites. 6 One of the pharmaceutically and biotechnologically important rare actinomycetes that attracts natural products researchers is the genus Nocardiopsis. 7,8 Species of this genus are aerobic, Gram-positive, non-acid-fast, and their aerial mycelia bear long chains of spores. 9,10 Nocardiopsis species were mainly recovered from salty habitats. The members of this genus produce an array of bioactive compounds that may aid their survival under these conditions. 11 In recent years many new natural products, belonging to different classes of molecules, including polyketides and peptides, 12,13,14 were isolated from Nocardiopsis species. 15,16 These classes display cytotoxic, 17 antimicrobial, 18 and immunomodulatory activities. 19 Recently, three new angucyclines, nocardiopsistins A-C, with anti-Methicillin-Resistant Staphylococcus aureus (MRSA) activity were isolated from a marine sponge-derived Nocardiopsis sp. HB-J378, 20 and a new cytotoxic cyclic peptide was obtained from the marine sponge-associated Nocardiopsis sp. UR67. 14 According to the World Health Organization (WHO, 2018), «Cancer is the second leading cause of death globally, and is responsible for an estimated 9.6 million deaths in 2018 », hence it is necessary to continue the discovery of new classes of molecules with cytotoxic activity, which may be further developed as anticancer drugs. 14 In fact, cytotoxicity-guided fractionation of the crude extract of the marine obligate actinomycetes, Salinispora tropica, led to the isolation of salinosporamide A, which entered phase I human clinical trials for the treatment of multiple myeloma. 21 In the course of screening for new bioactive metabolites from our collection of actinobacteria, which had been isolated from different areas of Algeria, Nocardiopsis CG3