Comparative analysis of specialized metabolites and antioxidant capacity in vitro of different natural populations of Globularia spp.

Total phenolic, flavonoid, condensed tannin and iridoid content, as well as antioxidant capacity in vitro, were determined spectrophotometrically in methanolic extracts of different plant parts of the Mediterranean medicinal plant Globularia alypum L. and three widespread European species of the same genus: G. cordifolia L., G. meridionalis (Podp.) O. Schwarz and G. punctata Lapeyr. In order to consider possible environmental influences on the production of specialized metabolites, each species, except G. alypum, was collected from three different natural populations. Great variations in the amounts of specialized metabolites were observed among different plant parts and species. For example, total phenolic content ranged from 10.13 (G. punctata, flowers) to 44.90 (G. cordifolia, flower stems) mg gallic acid equivalent g–1 dry weight. Moreover, great differences, attributed to location-specific environmental factors, were observed among different populations of the same species. For example, a strong positive correlation was observed among mean monthly temperatures and total phenolic contents in the leaves of studied Globularia spp. (r = 0.75, p = 0.019). However, despite these differences, all species were rich in bioactive substances when compared to G. alypum, especially in their aerial parts. A very good positive correlation was observed between total phenolic content and DPPH radical scavenging capacity (r = 0.86, p < 0.001)/ABTS radical scavenging capacity (r = 0.83, p < 0.001). The results obtained show that G. cordifolia, G. meridionalis and G. punctata are rich in bioactive substances, providing support for their pharmaceutical utilization. Further investigations are needed to verify the possibility of their medicinal use

CONTRIBUTION A L’ÉTUDE D'UNE PLANTE MÉDICINALE ET AROMATIQUE MYRTUS COMMUNIS L.

This work of thesis was financed by the Algerian Ministry of the Higher Education and the Scientific Researchunder the program PROFAS «B». The aim of this study is the valorization of PMA in Algeria, through out the chemical composition of essential oils and the evaluation of their biological properties. For this, we used various chromatographic and spectroscopic techniques, including an analytical method based on 13C NMR spectroscopy, developed in the University of Corsica. Thus, we have illustrated the method developed at the University of Corsica. This application carried out the chemical composition of essential oils isolated from Myrtus communis L. We have made explicit the analysis method based on the 13C NMR developed in the laboratory and highlighted the importance of complementarity of spectroscopic and chromatographic technic of analysis. This methodology has been applied on the study of the chemical variability of Myrtus communis L. For that,we performed a sampling in two steps. In a first step, we analysed 27 samples of myrtle essential oil from North-Eastern Algeria. The chemical composition was homogeneous, dominated by the association of α-pinene/1,8-cineole and characterized by the lack of myrtenyle acetate. In a second step, we analysed 55 samples of essential oil obtained from aerial parts of M. communis growing wild in Algeria in order to have a global view of Algerian myrtle. Despite the fact that the composition of these samples, are largely dominated by α-pinene and 1,8-cineole, the statistical analysis suggested the existence of two groups, which could be differentiated by their content of α-pinene, 1,8-cineole, limonene and linalool. According our results there is no correlation between pedoclimatic factors and the chemical composition of Algerian myrtle oil, which is close to that reported for oils from Corsican Sardinia, and Tunisia. Conversely, it differs from oils described in Morocco, Spain, and Portugal which are characterized by the presence of myrtenyle acetate. In a comprativeview, we were also interested in an endemic species growing wild in Sahara Central M. nivellei. Thus, we describe a detailed analysis of M. nivellei leaf essential oil. 1,8-cineole and limonene were by far the major components. We have remarked the presence of two molecules which were absent from the commercial libraries and those built at the laboratory. The structure elucidation of new compounds was achieved by the collaboration of the University of Corsica, identified as 1-hydroxy-1-(3- methylbutoxy)-2-acetoxy-3,5,5-trimethyl-3-cyclopentene and 1-hydroxy-1-(3-methyl-2-butenoxy)-2- acetoxy-3,5,5-trimethyl-3-cyclopentene. These new compounds have been found in all investigated samples (9) isolated from two stations in Southern Algeria, and could be considered as markers of M. nivellei. Finally, we evaluated the biological potential of Algerian myrtle essential oil (M. communis and M. nivellei), through out the antifungal test, the anti-inflammatory activity as well as the cytotoxicity in macrophages and keratinocytes cells. For each species, the oils revealed significant antifungal activity against Cryptococcus neoformans and dermatophyte strains Microsporum canis FF1, Trichophyton rubrum CECT 2794and Epidermophyton floccosum FF9.Both oils were also able to inhibit significantly the production of NO, without affecting cell viability, in concentrations up to 0.64 µL/mL. Furthermore, evaluation of cell viability showed no cytotoxicity in HaCaT keratinocytes at concentrations up to 1.25 μL/mL. These findings information to the pharmacological activity of essential oil reinforcing the use of these two species in traditional medicine reported in ethnobotanical surveys, thus justifying further «in vivo» assays to confirm the effectiveness of the «in vitro» results.Ce travail de thèse, financé par une bourse du Ministère algérien de l’Enseignement Supérieur et de la Recherche Scientifique dans le cadre du «PROFAS B», a pour objectif la valorisation des PMA en Algérie, par la caractérisation de diverses plantes poussant à l’état spontané à travers la composition chimique des huiles essentielles et l’évaluation de leurs propriétés biologiques. Pour cela, différentes techniques chromatographiques et spectroscopiques ont été mises œuvre, incluant la RMN 13C suivant une méthode mise au point et développée par l’Université de Corse. Ainsi, nous avons illustré la méthode d’analyse développée à l’Université de Corse. Cette application a concerné l’étude de la composition chimique de l’huile essentielle de Myrtus communis L., qui a permis d’expliciter la méthode d’analyse basée sur la RMN du 13C et démontrer l’importance de la complémentarité des techniques d’analyse. Nous avons poursuivi notre étude, par l’application de cette méthodologie dans l’étude de la variabilité chimique du myrte d’Algérie, nous avons réalisé un échantillonnage en deux temps. Dans un premier temps, nous avons montré que la composition chimique de l’huile essentielle du myrte du Nord-Est algérien, avec l’analyse de 27 échantillons est homogène, dominée par l’association α- pinène/1,8-cinéole et caractérisée par l’absence d’acétate de myrtényle. Ensuite, nous avons analysé 55 échantillons d’huile essentielle préparés avec du matériel végétal récolté dans tout le pays, afin d’avoir une vision globale du myrte d’Algérie. Bien que les compositions de ces échantillons soient largement dominées par l’α-pinène et le 1,8-cinéole, l’analyse statistique a permis de distinguer deux groupes sur la base des teneurs en α-pinène, 1,8-cinéole, linalol et acétate de linalyle. Cette variabilité est indépendante des conditions pédoclimatiques et la composition chimique de l’huile essentielle de myrte d’Algérie est proche de celle décrite en Corse, en Tunisie et en Sardaigne mais très différente de celle décrite au Maroc, Portugal et Espagne, caractérisée par la présence d’acétate de myrtényle. Nous nous sommes aussi intéressés à une espèce endémique au Sahara Central M.nivellei, dans un but comparatif avec l’huile essentielle de M. communis. Pour cela, nous avons décrit l’analyse détaillée d’un échantillon d’huile essentielle extraite à partir des parties aériennes. La composition chimique est dominée par le 1,8-cinéole et le limonène. Nous avons également remarqué la présence de deux molécules absentes des bibliothèques commerciales et celles construites au laboratoire. Dans le cadre de la collaboration scientifique avec l’équipe de Chimie et Biomasse, Université de Corse, l’élucidation structurale, réalisée en collaboration avec l'Université de Corse, a permis d’identifier deux composés nouveaux le 1-hydroxy-1-(3-méthylbutoxy)-2-acétoxy-3,5,5-triméthyl-3-cyclopentène et le 1-hydroxy- 1-(3-méthyl-2-butenoxy)-2-acétoxy-3,5,5-triméthyl-3-cyclopentène. Ces deux molécules sont présentes dans tous les échantillons étudiés (9) provenant de deux stations du Sud algérien et pourraient être considérées comme des marqueurs de l’espèce M. nivellei. Enfin, afin de confirmer les utilisations traditionnelles du myrte, le potentiel biologique des huiles essentielles de M. communis et M. nivellei a été évalué par des tests antifongiques, anti- inflammatoires et par la mesure de la cytotoxicité vis-à-vis de deux lignées cellulaires (macrophages et kératinocytes). Pour chacune des espèces, une meilleure sensibilité a été observée pour Cryptococcus neoformans suivi partrois dermatophytes Microsporum canis FF1, Trichophyton rubrum CECT 2794 et Epidermophyton floccosum FF9. De plus, nous avons constaté une inhibition significative de la production de NO par les macrophages. L’absence de cytotoxicité a été observée aussi bien pour l’huile essentielle de M. communis que celle de M.nivellei, vis-à-vis des macrophages (concentrations inférieures ou égales à 0,64 μL/mL) et des kératinocytes HaCaT (concentrations inférieures ou égales à 1,25 μL/mL). Ces informations relatives à l’activité pharmacologique, valident l’utilisation de ces deux espèces en médecine traditionnelle reporté dans des enquêtes ethnobotaniques, et doivent être complétées par des essais «in vivo» pour confirmer l’efficacité des tests «in vitro»

Hot Ductility of a Microalloyed Steel in the Intermediate Temperature Range

In this study hot ductility has been determined from tensile tests for two states of a microalloyed steel : after casting and after rolling processes. Hot deformations were carried out at speeds varying from 10-4s-1 to 10-2s-1 and temperatures from 750°C to 1100°C. Two heat treatments were chosen before hot deformation. A ferrite precipitation is observed at austenitic grain boundaries in the intercritical temperature range, causing intergranular embrittlement. Ductility trough is deeper in the as-cast samples due to the growth of large grain size. Also, precipitation makes the hot ductility curve wider and deeper around 900°C. The results show a decrease in hot ductility. Minimum values of hot ductility are determined for (ITC) treatment at 900°C and for (DTC) treatment at 800°C. For this second treatment another decrease in hot ductility was observed at 900°C. We can explain hot ductility losses by the presence of precipitates in the austenitic region and the presence of the two-phase structure in the intercritical region

Ethnopharmacognosy of Echinops spinosus L. in North Africa: A Mini Review

Background: The genus Echinops (Asteraceae family, Echinopeae class) consists of ca. 120 species and is native to Africa, the Middle East, Europe, and Asia. In Algeria, this genus is represented by the very common species Echinops spinosus L. also known as "tesskra," which is used as a diuretic, hypoglycemic, for stomachic effects, liver disorders, and post-partum care.Objective: The aim of this presentation is to provide an overview of the ethnopharmacognosy studies conducted on E. spinosus in North Africa. Data on ethnomedicinal uses, chemical constituents, and pharmacological activity were systematically compiled.Methods: Several popular search databases, including PubMed, ScienceDirect, Scopus, Web of Science, and Stanford libraries were scrutinised to extract relevant information. The research focused only on English-written papers published between 1980 and 2017.Results: Echinops spinosus L. is traditionally used in North Africa, and it was found that the most ethnomedicinal use reports were from Morocco and Algeria. Promising results have been reported regarding its phytochemistry and pharmacological activity. Forty-three compounds were isolated from different parts of this species. No studies have been conducted to highlight the toxicity and clinical safety of this species.Conclusion: This review highlights the therapeutic potential of E. spinosus used in traditional medicine. Furthermore, clinical trials on standardized preparations are necessary to explore the full safety and efficacy of E. spinosus in North Africa

Influence of Sulphur and Phophorus on the Hot Deformation of Fe-Cr 13% High Purity Steel

A series of Fe-Cr13%-C high purity steels containing increasing volume fractions of Sulphur (30, 60 and 100ppm) and Phosphorus (30, 60 and 100ppm) were prepared in order to study their hot deformation properties by tensile tests at various strain rates (10-1s-1 to 10-4s-1) and at temperatures from 700°C to 1100°C. It is observed that the hot ductility is lowered at 1000°C with the addition of sulphur. However, this decrease is relatively small (about 30% for l00ppm of sulphur) and quite similar for all additions of sulphur. When phosphorus is added, the embrittlement is along the whole deformed specimen. The usual criteria of ductility by parameter Z do not seem to be sufficient to describe this embrittlement

Swellings due to alkali-silica reaction and delayed ettringite formation: Characterisation of expansion isotropy and effect of moisture conditions

International audienceThis paper investigates the effect of different conditions on the development of concrete expansions due to alkali-silica reaction (ASR), delayed ettringite formation (DEF) and their combination. The presence of products of the two reactions has been observed during structure diagnosis. The aim of this research is to study the two reactions in concretes with close mix designs but with various types of aggregate and moisture conditions. Measurements performed in the three directions of stress-free specimens showed that DEF expansions could be considered as isotropic for stress-free material. DEF expansions were largely influenced by the storage conditions (immersed in water or in sealed conditions). The volume of storage water modified the kinetics. Under sealed conditions, no expansions were measured for mortar containing non-reactive aggregate, while small positive strains were obtained for mortar containing reactive aggregate. In all cases, new water supply caused fast, large expansions. The different effects of alkali leaching and moisture conditions on DEF and ASR expansions are discussed. (C) 2011 Elsevier Ltd. All rights reserved

Effects of restraint on expansion due to delayed ettringite formation

International audienceDelayed ettringite formation (DEF) is a chemical reaction that causes expansion in civil engineering structures. The safety level of such damaged structures has to be reassessed. To do this, the mechanical conditions acting on DEF expansions have to be analysed and, in particular, the variation of strength with expansion and the effect of restraint on the DEF expansion. This paper highlights several points: DEF expansion is isotropic in stress-free conditions, compressive stresses decrease DEF expansion in the direction subjected to restraint and lead to cracks parallel to the restraint, and expansion measured in the stress-free direction of restrained specimens is not modified. Thus restraint causes a decrease of the volumetric expansion and DEF expansion under restraint is anisotropic. Moreover, the paper examines the correlation between DEF expansion and concrete damage, providing data that can be used for the quantification of the effect of stresses on DEF induced expansion