Background: Natural products possess interesting biological activities, which attracted several researchers to their elucidation to provide knowledge that will lead to the advancement medicine. Chenopodaceae is an important plant family in the world; it contains a number of phytochemicals and has been used to treat a wide range of human diseases. The aim of this work was to carry out qualitative analyses of secondary metabolites and an antimicrobial investigation on the crude extracts from Atriplex halimus (Chenopodaceae) growing in Algerian Sahara. Methods: In this laboratory investigation during 2021-2022, phytochemical screening based on staining and precipitation tests was carried out using some solvents of different polarities. The antibacterial essay was carried out by the disc diffusion method on solid medium, using seven bacterial strains chosen for their high pathogenicity. Result: The secondary metabolites detected in the various extracts were essentially flavonoids, tannins, saponins and terpenoids. The antibacterial investigation made it possible to know that the aqueous extract from Atriplex halimus showed a significant inhibition against all bacteria tested. Diethyl ether and chloroform exracts had only one activity against Enterococcus faecalis and Listeria monocytogenes, respectively, whereas the methanolic extract exhibited the highest inhibition of Pseudomonas aeruginosa.

Background: This study is part of the contribution to the development of the medicinal plant Ephedra alata from the region of Bechar, Algeria. This work aimed to measure yields, total phenols, total flavonoids, antioxidant capacity and antibacterial evaluation. Methods: In this laboratory investigation during March 2023 to December 2023, the samples were macerated; total phenolic and flavonoids contents were analyzed using a colorimetric method, while antioxidant capacity was assessed through DPPH. The antibacterial essay was carried out by the disc diffusion method on a solid medium using Muller Hinton. Result: Phytochemical screening confirms the presence of alkaloids, flavonoids, free quinones, reducing sugars, saponins, sterols, tannins and terpenes. Methanol extract represents the highest yield (4.41%), followed by butanol extract (3.3%), ethyl acetate extract (1.25%) and dichloromethane extract (0.69%). The dosage carried out revealed the content of plyphenols and flavonoids in the methanol extract was (175.73±0.25 μg EAG/mg DE) and (35.2±0.17 μg QE/mg DE), respectively. The evaluation of the antioxidant effect of the crude extracts by free radical scavenging DPPH gave the IC50 values of the extracts methanol, butanol, ethyl acetate and dichloromethane (0.170, 0.244, 0.324 and 2.23 mg/mL), respectively. The investigation into antibacterial activity revealed that the methanol extract significantly inhibited all tested bacteria, while the dichloromethane extract showed the lowest inhibition of Escherichia coli.

This study explored the chemical composition and antimicrobial properties of Eucalyptus globulus essential oil. The oil was extracted by hydrodistillation, yielding a 0.23% concentration. Gas chromatography (GC) analysis revealed three primary constituents: 1,8-cineole (commonly known as eucalyptol) at 81.55%, D-limonene at 5.409%, and alpha-pinene at 4.107%, collectively comprising 91.067% of the oil. Additionally, two minor constituents, making up 1.196% and 1.017% of the oil composition, were detected but remain unidentified. The antimicrobial potential of the oil was assessed against two bacterial strains, highlighting its bioactive properties. Results indicated that Eucalyptus globulus essential oil exhibited strong inhibitory effects against Staphylococcus aureus, a Gram-positive bacterium known to cause various infections. It also showed moderate activity against Escherichia coli, a Gram-negative bacterium commonly found in the intestines but also associated with foodborne illness. These findings underscore the potential of Eucalyptus globulus oil as a natural antimicrobial agent, particularly for targeting Gram-positive bacteria like Staphylococcus aureus. The presence of 1,8-cineole as the predominant component is likely responsible for the oil's notable antimicrobial efficacy, suggesting possible applications in medicinal and preservation contexts.