In silico analysis of Barleria cuspidata compounds against Streptococcus mutans biofilm-associated proteins

Dental caries is a prevalent chronic infection caused by tooth-adherent cariogenic bacteria, mainly Streptococcus mutans, which demineralize tooth structure and lead to plaque formation. The present study evaluated the potential of Barleria cuspidata leaf extract (BCLE) to combat tooth decay by investigating its effects on S. mutans, a major contributor to dental caries, using both in vitro and in silico approaches. BCLE strongly inhibited the growth of S. mutans, showing a zone of inhibition of 17.4 mm at 150 µ g/mL, with a minimum inhibitory concentration (MIC) of 1 mg/mL. At twice the MIC (2 mg/mL), it exhibited bactericidal effects, prevented acid production, reduced cell surface hydrophobicity, and inhibited biofilm formation. Thirty-six major compounds revealed from Gas chromatography-mass spectrometry results of BCLE were subjected to molecular docking with the receptors, dextranase, N-terminal, and central regions comprising the third A-repeat through the first P-repeat (A3VP1) of antigen I/II, glucan binding protein C, deoxycytidylate deaminase, and dextran glucosidase that coordinates with the demineralization of tooth structure and plaque formation. Out of thirty-six compounds docked, the top fourteen showed no violations for the drug-likeness feature except monoethylhexylphthalate, pentadecanoic acid, and 3-hydroxy carbofuran phenol. Among them, Octadecanedioic acid represented the highest inhibition with deoxycytidylate deaminase (SmdCD) (PDB ID: 5C2O), and the complex, further analyzed for molecular dynamic simulation for 100ns, was found to be stable from 60-100ns with strong ionic and hydrogen bond interactions. Thus, the study suggested that the anti-cariogenic effect of BCLE would be beneficial in exploring the co-existence of plant extract and inventing novel herbal medicines to enhance caries protection.

The online version contains supplementary material available at 10.1007/s40203-025-00529-9.