Molecular Docking and In Vitro Evaluation of Violacein-Alginate Beads for Targeted Inhibition of Staphylococcus...

Violacein, produced by Chromobacterium violaceum, exhibits significant antibacterial, antiviral, antifungal, and antioxidant properties. However, its poor aqueous solubility substantially limits its bioavailability. To overcome this constraint, violacein was encapsulated in sodium alginate beads, and its antibiofilm efficacy against Staphylococcus aureus was evaluated. Violacein-loaded alginate beads (VIABs) were synthesized and characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, and ultraviolet-visible spectrophotometry. Molecular docking analysis was further conducted to examine the interactions between violacein and the icaADBC proteins (UniProt accession: Q9RQP9, Q9RQP8, Q9RQP7, andQ9RQP6 ), which play a critical role in polysaccharide intercellular adhesin production during biofilm formation. The crude violacein extract displayed antibacterial activity, generating an inhibition zone of 12.3 ± 0.5 mm against S. aureus. The average particle sizes of dry alginate beads and violacein-loaded alginate beads were 0.97 ± 0.16 and 0.66 ± 0.11 mm, respectively. VIABs (20-5 mg/mL) significantly suppressed S. aureus biofilm formation by 77.4, 67.4, and 46.8%. Molecular docking analysis demonstrated strong binding affinities between violacein and the target proteins. Furthermore, violacein adhered to Lipinski's Rule of Five, suggesting favorable pharmacokinetic properties. These findings highlight the potential of VIABs as a promising therapeutic and food preservative agent due to their potent antibiofilm activity.