Chitosan microparticles with Yucca baccata Torr. extract: antibacterial and antibiofilm activity against Salmonella Typhimurium

The increasing prevalence of antibiotic-resistant Salmonella Typhimurium poses a serious public health challenge, prompting the exploration of alternative antimicrobial strategies. This study evaluated the antibacterial and antibiofilm activities of chitosan microparticles containing Yucca baccata butanolic extract (MPCY) against S. Typhimurium in vitro. The extract (YBE), rich in steroidal saponins (25.04%), was efficiently encapsulated in microparticles (84.54% immobilization efficiency). Antibacterial activity revealed a minimum inhibitory concentration (MIC) of 60 mg/mL for YBE, while MPCY exhibited a MIC of 200 mg/mL. Both treatments significantly inhibited biofilm formation at sub-MIC levels, with YBE (60 mg/mL) and MPCY (200 mg/mL) reducing biofilm biomass by 58.97% and 52.44%, respectively. However, motility inhibition remained below 6% across all treatments. In silico docking suggested that asparagoside C, the predominant saponin in YBE, may interfere with the BcsA subunit of cellulose synthase, potentially impairing biofilm synthesis by disrupting c-di-GMP signaling. Toxicity assays using Artemia salina indicated no cytotoxicity for MPCY up to 400 mg/mL, in contrast to YBE, which showed a lethal concentration 50 (LC₅₀) of 0.24 mg/mL. These findings support the potential of MPCY as a safe and effective antimicrobial system, with promising applications in food safety and pharmaceutical development. Further in vivo studies are warranted to confirm its efficacy and biosafety.