Enhanced Antibacterial Activity of Artemisia absinthium Extract Containing Artemisinin and Polyphenols Loaded into Mesoporous Silica Calcium- and Cerium-Doped Nanoparticles

Background: Artemisia absinthium (A. absinthium) is a perennial plant valued for its antibacterial, antioxidant, and anti-inflammatory properties, exhibiting broader therapeutic potential. Given the need to deliver low doses of A. absinthium extract, mesoporous silica nanoparticles have attracted considerable attention as promising nanocarriers due to their distinctive physical and chemical properties. Methods: Physicochemical characterization of the materials was performed and biological assays were conducted to investigate the ROS, antibacterial and antioxidant activity of A. absinthium extract encapsulated within cerium- and calcium-doped mesoporous silica nanoparticles (MNSiCaCe) against both aerobic and anaerobic bacteria. Results: FTIR, SEM, and BET analysis confirmed successful synthesis of the MNSiCaCe. Phytochemical profiling of Artemisia absinthium extract using HPLC revealed the presence of artemisinin and a rich composition of phenolic and flavonoid constituents, with a total phenolic content of 182 ± 3.6 mg GAE/100 g dry plant material and a total flavonoid content of 42.5 ± 0.6 mg QE/100 g. Quantitative drug loading profiling demonstrated that while plain MNSi nanocarriers achieved a loading capacity of 16.96%, the MNSiCaCe enhanced this threshold to 43.11%. The in vitro controlled-release kinetics exhibited a highly prolonged and slow-release profile of the MNSiCaCe. The materials demonstrated excellent hemocompatibility and high mitochondrial activity with human periodontal ligament cells (hPDLCs). Elevated ROS generation was observed under conditions where antibacterial activity was most pronounced. While the artemisinin-doped nanoparticles showed notable antibacterial effects, the complete Artemisia absinthium-loaded nanoparticles achieved a significantly greater reduction in bacterial viability probably due to the synergistic interaction between artemisinin and the extract’s rich polyphenol profile. Conclusions: These findings highlight MNSiCaCe as a promising and safe nanocarrier system for drug delivery, with strong antibacterial potential, offering valuable applications in antibacterial therapies.