Chemical Profiling by High‐Performance Liquid Chromatography With Diode Array Detection and Gas Chromatography‐Mass Spectrometry Analysis and Antimicrobial Potential of <i>Achillea santolina</i> Plant Extracts against Extended‐Spectrum Beta‐Lactamase

The study examines the chemical composition and antimicrobial properties of petroleum ether and hydro-methanolic extracts of Achillea santolina from Algeria. Chemical profiling was performed using high-performance liquid chromatography with diode array detection for the hydro-methanolic extract and gas chromatography-mass spectrometry for the petroleum ether extract. Antibacterial and antifungal activities were evaluated using the disc diffusion method and broth dilution technique. Epicatechin (24.54 mg/g extract), and camphor (19.18%) were identified as main compounds in the hydro-methanolic and petroleum ether extracts, respectively. Both extracts showed significant antibacterial effects against extended-spectrum beta-lactamase-producing Escherichia coli strains, with inhibition diameters ranging from 10 to 13 mm, and minimum inhibitory concentration (MIC) values between 0.78 and 3.5 mg/mL. Anti-fungal activity was also notable, particularly against Candida albicans, with an inhibition diameter of 14 mm, and MIC values between 0.39 and 1.56 mg/mL. The hydro-methanolic extract showed up to 90% of growth inhibition against Aspergillus niger. These findings suggest that A. santolina could serve as a promising source of antimicrobial compounds to combat resistant pathogens.