Antibacterial and Antivirulence Activity of Lyophilized Plumbago auriculata Flower Extract Against Escherichia coli and Proteus mirabilis

Medicinal plants are recognized for their rich bioactive compounds, offering significant potential in the development of therapeutic alternatives to address current public health challenges. Plumbago auriculata is a traditionally used plant with the potential to treat various conditions. Therefore, this study evaluated the physicochemical properties and antibacterial and antivirulence potential of the lyophilized extract from Plumbago auriculata (ELPa). Physicochemical analysis revealed a highly porous morphology (pore diameter 5–10 µm), a yellowish-green color (Hue angle of 182.92), and a water activity (aw) of 0.5. Antibacterial assays established a minimum inhibitory concentration (MIC) of 64 mg/mL for clinical isolates of Escherichia coli (E. coli), Staphylococcus sciuri (S. sciuri), Staphylococcus aureus (S. aureus), Candida tropicalis (C. tropicalis), Streptococcus agalactiae (S. agalactiae), and Salmonella Dublin (S. Dublin) and 16 mg/mL for the E. coli CFT073 strain. Furthermore, ELPa demonstrated significant antivirulence properties; at a concentration of 8 mg/mL, the extract inhibited 55% of the swarming mobility and 58% of biofilm production in E. coli CFT073 after 24 and 48 h of exposure, respectively. The finding suggests that ELPa is a viable source of bioactive compounds with both antibacterial and antivirulence capabilities.