Phytochemical Screening and In Vitro Antimicrobial Activity of an Aqueous Extract of Ephedra Alata from Southwestern Algeria

Abstract

Ephedra alata is a medicinal plant native to arid regions of North Africa and is widely used in traditional medicine. This study characterized its phytochemical profile and evaluated the in vitro antimicrobial activity of an aqueous extract prepared from aerial parts collected in the Béchar region of southwestern Algeria. Dried plant material (30 g) was extracted with 300 mL of distilled water at 90°C, and qualitative phytochemical screening was performed across ether, methanolic, and aqueous preparations. Antibacterial activity was assessed against Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 10876, Escherichia coli ATCC 8739, and Pseudomonas aeruginosa ATCC 27853 using direct-contact, disk-diffusion, and agar-well diffusion assays. Antifungal activity was evaluated against Fusarium oxysporum f. sp. albedinis, Rhizopus stolonifer, and Candida albicans ATCC 10231. The aqueous extraction yield was 12.36%. Screening detected several secondary-metabolite classes across the plant preparations, including phenolic compounds, flavonoids, tannins, terpenoids, saponins, free quinones, fatty acids, reducing compounds, and steroidal/triterpenoid glycosides. The direct-contact assay yielded inhibitory concentrations of 0.75 g/mL for B. cereus and P. aeruginosa and 1.0 g/mL for S. aureus and E. coli. Diffusion assays produced inhibition zones of 6–19 mm, depending on the organism, concentration, and assay. Radial growth was inhibited by 80.88% for F. oxysporum f. sp. albedinis and 32.22% for R. stolonifer, whereas no detectable inhibition was observed against C. albicans. These findings indicate organism- and assay-dependent antimicrobial activity of the crude aqueous extract and support further standardized susceptibility testing and chemical characterization.