Antimicrobial, Anti-inflammatory and Cytotoxicity Evaluation of a Novel Formulated Nano-Colloidal Mouthwash: An in vitro Study

Background

Adjunctive mouthwashes are widely used in periodontal care to control plaque and gingival inflammation. Conventional agents such as chlorhexidine are effective but associated with adverse effects including tooth staining, altered taste, and mucosal irritation. Herbal and nanoparticle-based formulations are being explored as safer alternatives with dual antimicrobial and anti-inflammatory properties.

Aim

To formulate a nano-colloidal mouthwash incorporating clove (Syzygium aromaticum) extract, stevia (Stevia rebaudiana) extract, and green-synthesized Silver Nanoparticles (AgNPs), and to evaluate its antimicrobial, anti-inflammatory, and cytocompatibility profiles against common oral pathogens.

Materials and Methods

Clove and stevia extracts were prepared by Soxhlet and hot-water extraction, respectively. AgNPs were synthesized using a green reduction method with plant extracts as reducing agents. Characterization was performed using Field-Emission Scanning Electron Microscopy (FE-SEM) and Energy-Dispersive X-ray spectroscopy (EDAX). Antimicrobial activity against Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, and Candida albicans was assessed using the agar well diffusion method. Anti-inflammatory activity was evaluated by protein denaturation and membrane stabilization assays. Cytocompatibility was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay on human gingival fibroblasts.

Results

FE-SEM revealed spherical AgNPs with an average size of 20-40 nm, and EDAX confirmed elemental silver peaks. The nano-colloidal mouthwash produced inhibition zones ranging from 12 mm (Candida albicans) to 18 mm (E. faecalis). Protein denaturation was inhibited by >60%, and membrane stabilization was comparable to standard anti-inflammatory agents. MTT assay showed 79.8% cell viability at working concentration, confirming acceptable cytocompatibility.

Conclusion

The formulated nano-colloidal mouthwash combining clove, stevia, and AgNPs exhibits potent antimicrobial and anti-inflammatory activity with good biocompatibility. It holds promise as a natural and biocompatible alternative to conventional mouthwashes. Further in vivo and clinical studies are recommended to validate safety and efficacy in periodontal therapy.