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Background: Infectious diseases are responsible for millions of deaths a year worldwide. Antibiotics, which have saved so many lives and improved life expectancy, may become ineffective due to a worrying increase in bacterial resistance. Some of the appropriate actions that could be initiated to address this problem are to develop and search for new antimicrobial substances from medicinal plants, and combine antibiotics with antimicrobials agents isolated from a reservoir of bioactive natural products. Objectives: The purpose of this work was to study the chemical composition of the essential oil and hydrosol extract of Plumbago europaea, to evaluate their in-vitro antimicrobial activities and evaluate in-vitro combinatory antimicrobial effect of hydrosol extract with Gentamicin and Amphotericin B against a large panel of microorganisms in an effort to reduce their minimum effective dose and minimizing their side effects. Methods: The essential oil and hydrosol extract obtained from roots of Plumbago europaea were analyzed by GC/MS and tested for their antibacterial and antifungal activities against twelve different strains of microorganisms. The effectiveness, in-vitro, of the association between the hydrosol extract and both Gentamicin and Amphotericin B was also investigated using the checkerboard method. Results: The obtained results revealed that nine and four components, representing for 92.4 % and 97.4% of the total essential oil and hydrosol extract composition were identified, respectively and hydrosol extract was more active than the essential oil against all screened microorganisms, with interesting MIC values (19 μg/mL). An important effect of hydrosol extract was obtained in decreasing the MIC of Gentamicin and Amphotericin B in all tested combinations. Conclusion: The in-vitro combination of the hydrosol extract with Gentamicin and Amphotericin B led to substantial MIC reduction against all tested microorganisms. This combination can help to reduce the minimum effective dose of antimicrobial drugs used, which may help to decrease their side effects; and deliver these medicines with similar potency.

Background: Rhus pentaphylla Desf. (Anacardiaceae) widely grown in Algeria, is an underutilized plant and remains poorly studied. To investigate for the first time, the chemical composition profile of essential oil and hydrosol extract; besides Total Phenolic (TPC), Flavonoid (TFC) and Condensed Tannins Contents (CTC) of fruits, leaves and roots, the fatty acid composition was assessed. The radical scavenging activity of R. pentaphylla extracts was then evaluated. Methods: Essential oil and hydrosol extract were isolated respectively by hydrodistillation and liquidliquid- extraction from the aerial parts of R. pentaphylla. The antioxidant activity was evaluated using 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) radical and ferric reducing antioxidant power (FRAP). Chemical compositions of various extracts were investigated using Gas Chromatography (GC) and GC-Mass Spectrometry (GC-MS). Results: The results of GC and GC-MS analysis revealed 83 components in essential oil and 75 components in hydrosol extract representing respectively 96.9% and 92.5% of the total extract composition. The main constituents were hexadecanoic acid (31.5%) followed by spathulenol (14.9%) in the oil while the higher amount present in the hydrosol extract was of spathulenol (14.2%). Otherwise, 13 and 18 fatty acids were identified in roots and fruits respectively. The highest levels of TPC and CTC were found in roots extracts while the highest quantity of TFC has been recorded in the leaves extract. Besides, hydrosol extract was able to scavenge DPPH and FRAP free radicals more efficiently than essential oil. Conclusion: R. pentaphylla contains bioactive substances that could be used as a new promising source of antioxidant compounds in different applications.

International audience; Campylobacter is one of the major causes of bacterial gastroenteritis worldwide. Humans are infected by eating contaminated meat and antibacterial activity of essential oils could be one of the solutions to reduce the contamination of animals. Here, we studied the antibacterial activity of the Daucus carota essential oil and its active molecules against Campylobacter and other Gram-negative bacteria. Chemically synthesized molecules including (E)methylisoeugenol, elemicin and eugenol were also studied. The results showed that the entire oil and the (E)-methylisoeugenol which is the more active molecule had a bactericidal effect. 2 Same effects were observed using purified and chemically synthesized molecules. In addition, the intracellular potassium and intracellular ATP contents were affected in Campylobacter cells treated with Daucus carota essential oil and its active molecules. Inhibition of the membrane bound F O F 1-ATPase was also observed. Finally, an efflux mechanism of the Daucus carota essential oil active molecules was described for the first time in gamma proteobacteria and the specific antibacterial activity against Campylobacter jejuni was correlated with the lack of this efflux mechanism in this species.

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

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)-β-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