This study aimed to investigate the phytochemical constituents, antimicrobial activity, and antioxidant effects of successive extracts of Ziziphora capitata L. aerial parts. UPLC-QTOF-MS/MS identified 79 phytoconstituents, including phenolic acids, alkaloids, flavonoids, and anthocyanins, as major phytoconstituents. Additionally, primary phytochemical investigations revealed the presence of terpenoids, steroids, flavonoids, alkaloids, tannins, and saponins in various plant fractions. The MICs of successive extracts were tested against a range of microorganisms, including gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, Streptococcus mutants, Enterococcus faecalis, Methicillin-Resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis), gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhimurium, and Enterobacter cloacae), fungi (Aspergillus niger and Penicillium aurantiogriseum), and yeast (Candida albicans and Candida tropicalis), using the disk diffusion technique. The ethyl acetate and 95% ethanol extracts exhibited significant antibacterial activity against the tested microorganisms; however, the hexane fraction affected only P. aeruginosa. The effects of the CHCl3 and H2O fractions varied in their activities against most of the bacteria examined. Additionally, the AcOEt and 95% EtOH extracts exhibited significant antioxidant activity with IC50 = 18.6 ± 0.97 and 30.4 ± 1.86 µg/mL, respectively, compared to that of ascorbic acid (IC50 = 10.6 ± 0.8 µg/mL, reference drug). Antibacterial and antioxidant activities can be attributed to phytoconstituents, which were identified using UPLC-QTOF-MS/MS. Furthermore, docking simulations of the top ten phytochemicals of the 70% methanolic extract were carried out inside the active site of S. aureus DNA gyrase (PDB: 2XCT) and dihydropteroate synthase (DHPS) from S. pneumoniae (PDB: 2VEG) as bacterial targets and these compounds exhibited good binding modes with different types of interactions.
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