In silico evaluation of Alstonia scholaris phytochemicals against periodontal pathogens

Objectives Porphyromonas gingivalis and Treponema denticola are red complex pathogens strongly associated with periodontal disease. P. gingivalis relies on the heme-binding receptor HmuY for heme acquisition, whereas T. denticola uses factor H-binding protein (FhbB) to evade immune responses. This study was aimed at evaluating the inhibitory potential of three phytocompounds (alstonine, echitamine chloride, and villalstonine) from Alstonia scholaris against these targets, which were compared with minocycline and chlorhexidine, via molecular docking. Methods Molecular docking was performed with validation by redocking and confirmation of receptor reliability (RMSD 1.821 Å for HmuY and 0.851 Å for FhbB). Chlorhexidine and minocycline were included as positive controls. Binding energies (ΔG), inhibition constants (Ki), and receptor–ligand interactions were analyzed. Results Echitamine chloride exhibited the strongest affinity for HmuY (ΔG −4.86 kcal/mol; Ki 274.96 μM), whereas alstonine bound most strongly to FhbB (ΔG −7.44 kcal/mol; Ki 3.53 μM). Villalstonine showed moderate affinity, whereas minocycline was the most potent overall. Key hydrogen bonds involved ARG178, TRP70, and TYR116. Conclusions A. scholaris phytochemicals, particularly echitamine chloride and alstonine, displayed promising but weaker inhibitory potential than standard antimicrobials. They therefore might serve as natural adjuncts in periodontal therapy, pending experimental validation.