Phytochemical-Mediated Synthesis of Silver Nanoparticles from Piper betle and Psidium guajava: A Sustainable Approach to Oral Care

Abstract This study presents the development and characterization of a novel oral care formulation incorporating silver nanoparticles (AgNPs) synthesized using guava and betel leaf extracts. Oral infections caused by pathogenic microorganisms remain a significant global health challenge, necessitating innovative approaches that transcend conventional treatment modalities. The acetone extract (70:30) of betel and guava leaves was prepared and subjected to phytochemical analysis, revealing the presence of bioactive compounds including alkaloids, polyphenols, tannins, flavonoids, and saponins. GC-MS analysis identified 24 distinct compounds, with 2-pentanone,4-hydroxy-4-methyl- (37.26%), 1H-cyclopropa[a]naphthalene derivatives (19.26%), and phenolic compounds (8.27%) being predominant. The extract demonstrated significant antimicrobial activity against oral pathogens, with minimum inhibitory concentration (MIC) values of 500 µg/ml for Streptococcus spp. and 250 µg/ml for Candida albicans (NCIM 3628), outperforming conventional antimicrobials Streptomycin and Fluconazole (both 1000 µg/ml). Green synthesis of AgNPs was accomplished using the plant extracts as reducing and stabilizing agents, confirmed through visual colour change and FTIR spectroscopy. The FTIR spectrum revealed characteristic functional groups including hydroxyl (3438 cm⁻¹), carbonyl (1692 cm⁻¹), and aromatic compounds (1615 cm⁻¹, 1513 cm⁻¹), validating successful nanoparticle formation. The formulated gel exhibited optimal physical properties with a pH of 7.2, excellent homogeneity, spreadability, and stability. This innovative formulation represents a sustainable, eco-friendly, and economically viable alternative to conventional oral care products, effectively addressing the challenges of antimicrobial resistance while leveraging traditional ethnopharmacological knowledge through modern nanotechnological approaches.