Eucalyptus extract-based pharmaceutical products are widely used because of their medicinal properties and their rich content of secondary metabolites, mainly phenolic compounds. This study aimed to maximise the extraction yield of these compounds and reduce the extraction duration by using a pulsed electric field (PEF) level of 6 kV/cm. The pulse width (T), number of pulses (n), and solvent concentration [C] were analysed. Several ethanolic extracts were obtained from the leaves of Eucalyptus globulus, and the content of total phenols, total flavonoids, and condensed tannins was measured through spectrophotometry. The results, obtained immediately after PEF treatment, revealed that for optimal values of the analysed factors, the total phenol content doubled and the flavonoid content increased significantly. However, PEF pre-treatment had no effect on the tannin yield. Moreover, optimisation was performed using the design of experiments methodology for identifying optimal values of the analysed factors.

The objective of this work is firstly an ecobiological study, which aims to determine whether salinity is favorable for a good reproduction rate of cysts in the Artemia salina L., a species known for its use in aquaculture. Secondly, a short-term test of ammonium sulfate toxicity on its vitality is carried out as its environment is permanently subjected to sulphate-laden waste. The work consists of subjecting the species to different salinities in order to produce a good yield in cysts, which once recovered, hatching and breeding is maintained until individuals reach the adult stage. A toxicological study using toxicity test (CL50) is then conducted to study the resistance of these adults with various concentrations of ammonium sulphate. The results obtained from the ecobiological study show a mean similar to the natural environment (p > 0.05) with a favorable concentration for the reproduction of the species at a salinity of about 75 g dm⁻³. The toxicity test indicates a CL50 equal to 75 mg dm⁻³ after 24 hours. It is obvious that Artemia salina L. can be cultivated by controlling its reproduction by varying the salinity rate for its use during different seasons of the year, thus ammonium sulphate from waste is considered as a limiting factor.

Habitat characterisation for the threatened geophyte (Tulipa sylvestris L.) in the forest of Bouhriz (west Algeria)This work consists to evaluate the natural and ecological habitat of the threatened and rare species Tulipa sylvestris L., located in Bouhriz forest (Sidi Bel Abbes region). For this, four stations distributed in the South, South-East and North-East of the forest were chosen according to the presence of the geophytes, on which soil samples were analyzed and floristic surveys were carried out. Indeed, the Tulipa sylvestris was located in the southern part (station 3 only), soil results have shown that the species is associated with a sandy loam-sandy texture and a slightly alkaline pH, moderately rich in organic matter with a moderately calcareous soil. The floristic and statistical analysis by the correspondence factorial analysis (CFA) indicates an important richness of the order of 50 taxons subjected a strong therophytisation, an index of high perturbation, justifying thus the rarity and the vulnerability of Tulipa sylvestris L. due mainly to human activity and overgrazing associated with fires.Key words: Tulipa sylvestris L, Bouhriz forest, Algeria, anthropization. RésuméCe travail consiste à évaluer l’habitat naturel et écologique de Tulipa sylvestrisL. espèce menacée et rare, localisée dans la forêt de Bouhriz (région de Sidi Bel Abbes). Pour cela, quatre stations réparties dans la partie Sud, Sud-est et Nord-est de la forêt ont été choisies en fonction de la présence des géophytes, sur lesquels des prélèvements du sol étaient analysés et des relevés floristiques ont été effectués. En effet, Tulipa sylvestris L. est localisée dans la partie Sud (station 3 uniquement), les résultats pédologiques ont montré que l’espèce est liée à une texture limono-sableuse, peut humide et un pH légèrement alcalin, moyennement riche en matière organique avec un sol modérément calcaire. L’analyse floristique et statistique par l’analyse factorielle des correspondances (AFC) indiquent une importante richesse de l’ordre de 50 taxons soumis à une forte thérophytisation, un indice de perturbation élevé, justifiant ainsi la rareté et la vulnérabilité de Tulipa sylvestris L. dû essentiellement à l’action anthropique et au surpâturage associé aux incendies. Mots-clés: Tulipa sylvestris L., foret Bouhriz, Algérie, anthropisation.

The study of algal flora is an important component in determining the overall state of the marine ecosystem. It is still not well known, particularly in some parts of Mediterranean Western Algeria. This work seeks to update the checklist of Western Algeria algae to establish and enrich the floristic inventory of algae. Macroalgae were sampled at 13 stations along Algeria's west coast in the mediolittoral and upper infralittoral zones between 2019 and 2021 using a simple random method. The species description, accompanied by original photos taken from a representative living specimen, was used to make the determination, which was then interpreted in light of the most recent literature records. The results revealed that 80 marine macroalgae were discovered and identified. They are classified into three taxa: Phaeophyceae, Chlorophyceae, and Rhodophyceae. Almost half of the algae counted in this inventory belonged to the dominant Rhodophyte class. Furthermore, 15 new species have been discovered along the West Algerian coast. These findings could serve as a basis for future phycological and biogeographic studies of taxa in Algeria.