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This work is part of the valuation of essential oil of Mentha Rotundifolia harvested in the mountains of El Hamdania, in the Atlas Blideen (northern Algeria). The essential oil of Mentha rotundifolia extracted by hydro distillation have been analysed by means of Gas Chromatography GC-FID and GC-FID coupled to a Mass Spectrometer GC-MS in combination with retention indices. 34 constituents were identified accounting for 92 % of the essential oil. The main components were piperitenone oxide (30.37%) and piperitone oxide (23.78%). The antimicrobial activity evaluated on seven microbial strains revealed sensitivity for the majority of the bacteria except pseudomonas aeruginosa. The antioxidant activity was determined according to the ability of the tested samples to scavenge the free radicals 2,2-diphenyl-1-picrylhydrazyl (DPPH*). The essential oil were slightly active 21.8% comparing with Quercetin (98.2%) of these oils can be attributed to the absence of some phenolic components, which may play an important role. The inhibitory effect of this essential oil on the development of bacteria and more particularly its effect on staphylococcus aureus sees glimpses of applications in the pharmaceutical industry as a natural antibiotic, and for other applications in the food and cosmetic industries., Arabian Journal of Medicinal and Aromatic Plants, Vol 7, No 3 (2021)

L’étude analytique des huiles essentielles d’Artemisia herba-alba poussant en Algérie a mis en évidence une différence remarquable dans la composition chimique et les rendements d’extraction selon les régions (position géographique) et les techniques d’extraction utilisées. L’analyse des huiles essentielles par CG et par CG-SM nous a permis d’identifier 164 constituants, représentant 65,2 à 98,3 % de la composition totale pour l’hydrodistillation et 61,4 à 95,6 % pour la micro-onde. Les composés cétoniques : tels que l’α- thujone, la β-thujone, le camphre, la chrysanthénone et la davanone en constituent la majeure partie. Cette étude nous a permis de confirmer la diversité des chémotypes dont l’existence serait étroitement liée à des variations de patrimoines génétiques. Par rapport à HD,MD permet d’obtenir de l’huile en très peu de temps, avec des qualités comparables et des économies d’énergie substantielles. L’étude de l’activité antimicrobienne des huiles essentielles sur 14 souches a montré un très bon pouvoir inhibiteur (concentration minimale inhibitrice ne dépassant pas 10 mg/ml) pour tous les échantillons. La faible activité antioxydante de ces huiles pourrait être attribuée à l’absence de certains composants phénoliques.

The composition of the essential oils of six individual plants of Artemisia herba-alba Asso, growing wild in six different locations from southern Algeria, were investigated by capillary gas chromatography (GC) and GC/mass spectrometry (GC/MS) in combination with retention indices. Accounting for 76.3–97.2% of the oils, 132 constituents were identified, predominantly α-thujone (trace–47.1%), camphor (5.6–30.0%), chrysanthenone (trace–13.5%), β-thujone (trace–9.2%), 1,8-cineole (4.1–11.4%), cis-jasmone (0.8–12.1%) and davanone (trace–34.0.%). Regarding the α- and β-thujone toxicity and the extensive use of A. herba-alba as an aromatic and medicinal plant in folk medicine, we report here, with previous investigations, the thujone content of forty individual plants of A. herba-alba growing wild in sixteen different locations from the high table-lands, steppes and Sahara desert of Algeria. The available data indicate a high degree of variability in the percentage of the two constituents. Large amounts were pr...

Four caffeoylquinic acid (CQA) derivatives, 5-O-caffeoylquinic acid (1), 3,5-di-O-caffeoylquinic acid (3), 4,5-di-O-caffeoylquinic acid (4), and 3,4,5-tri-O-caffeoylquinic acid (5), have been isolated from Artemisia herba-alba growing wild in Algeria, using the on-line HPLCDADDPPH radical-scavenging detection technique as guidance. In the course of the purification work, the non-frequent (E)-2-(β-D-glucopyranosyloxy)-4-methoxycinnamic acid (2) has also been isolated. The CQAs showed fair-to-good antioxidant activities determined by the DPPH. scavenging assay. The structures of the five isolated compounds were determined by spectroscopic methods. The on-line HPLCDADDPPH technique allowed for a rapid pinpointing of antioxidants in the studied plant, accomplishing the facile guided isolation of the target molecules. Algerian A. herba-alba could be an interesting source of natural antioxidants that deserve further work.

Isolation of the essential oil from Artemisia herba-alba collected in the North Sahara desert has been conducted by hydrodistillation (HD) and a microwave distillation process (MD). The chemical composition of the two oils was investigated by GC and GC/MS. In total, 94 constituents were identified. The main components were camphor (49.3 and 48.1% in HD and MD oils, respectively), 1,8-cineole (13.4–12.4%), borneol (7.3–7.1%), pinocarvone (5.6–5.5%), camphene (4.9–4.5%) and chrysanthenone (3.2–3.3%). In comparison with HD, MD allows one to obtain an oil in a very short time, with similar yields, comparable qualities and a substantial savings of energy.

Polymers are often used as palliatives against fretting damage, particularly in quasi-static assemblies subjected to vibration. Velocity accommodation mechanisms and surface damage vary with the material chosen and the application. Transparent materials (polycarbonate and polymethylmethacrylate) were chosen and rubbed against steel counterfaces. Videos were taken through the back of the polymers. Cracks and particle detachment were observed. Cracks propagated until the fretting amplitude was taken up by the elastic deformation of the cracked substrate, at which time wear stopped since surface slip was zero. Particle detachment led to third-body formation which protected the substrate. Oxides were sometimes formed and the rate of progress of the oxide coating was determined. The conditions which led to the formation or not of oxides with the same material combination and under identical running conditions were not identified. However, in all cases oxide patches were initiated at the contact periphery and gradually spread over the entire contact. Results obtained elsewhere on the behaviour of polymers lubricated with solvents of close solubility were confirmed.

The fretting wear behaviours of metal-polymer contacts are analysed in the cases of small amplitude reciprocating movements. Polymers are polycarbonate (PC) or plexiglass (PMMA). This paper discusses the formation of the third bodies from the polymer and the possible occurrence of metallic debris. The contact behaviour is described as a “race” between the quick formation of polymeric debris that can protect the metallic counterface and the appearance of metallic debris. The accommodation of the displacement in the polymer is a consequence of a cracking process and of the formation of rolls. The friction coefficient is the mixture of combined located mechanisms that change during the test.