Exploring Anti-Biofilm Mechanisms of Spilanthes paniculata Essential Oil Against Oral Pathogens: An In Vitro and In Silico Study.

Spilanthes paniculata (toothache plant) belongs to the Asteraceae plant family and has been traditionally used in dentistry for treating several oral ailments, including gingivitis, periodontitis, odontalgia, and xerostomia. This present study investigated the in vitro antibacterial-antibiofilm activities of S. paniculata essential oils (EOs) from leaves and flowers against Staphylococcus aureus, Streptococcus mutans, and Escherichia coli using agar well diffusion and biofilm assays. Further, quantitative phytochemical analyses of EOs were carried out using GC-MS analysis, where Spathulenol, Germacrene D, and (E)-caryophyllene were found to be leading preliminary phytochemical constituents. Molecular docking investigated the binding efficacy against biofilm-associated target enzymes, sortase A of S. aureus and S. mutans, and PgaB of E. coli, taking tetracycline as a standard. Physicochemical and pharmacokinetic profiles were also predicted. The in vitro studies suggested the flower EOs exhibited stronger antibacterial-antibiofilm potency than the leaf EOs, with the leading inhibition zone (ZI) (27.66 mm) and MIC (≥ 125 µg/mL) values against S. aureus. Docking results indicated that (E)-caryophyllene comparatively showed high binding affinities with SrtA (-5.91 and -6.03 kcal/mol) along with PgaB (-6.2 kcal/mol). Overall, scientific validation of the traditional claim of S. paniculata and flower EOs could be used as a natural oral therapy against biofilm-related infections.