en <p style="text-align:justify"><span style="font-size:11pt"><strong><span style="font-size:10.0pt">Background:</span></strong><span style="font-size:10.0pt"> Teeth are vital structures prone to issues such as caries and plaque formation, often caused by <em>Streptococcus mutans (</em></span><span style="font-size:10.0pt">S. <em>mutans)</em></span><span style="font-size:10.0pt">. This issue can be mitigated using natural ingredients like mangosteen fruit (<em>Garcinia mangostana</em> <em>L</em>.), especially its peel, is known for its medicinal benefits. However, its extract may take time to show effects, so it is being combined with nanosilver for improved drug distribution. To observe the antibacterial and antibiofilm potential of Mangosteen Peel Extract (MPE) in nanosilver form as a preventive agent in dentistry. </span></span></p> <p style="text-align:justify"><span style="font-size:11pt"><strong><span style="font-size:10.0pt">Methods:</span></strong><span style="font-size:10.0pt"> The extraction was succeeded by a phytochemical assay and biosynthesis of MPE into Mangosteen Peel Extract Nanosilver (MPNs). </span><span style="font-size:10.0pt">Particle Size Analysis (PSA) and Transmission Electron Microscopy (TEM) were used to study this procedure. Disc diffusion tests were used to evaluate the antibacterial properties, and the Minimum Inhibition Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were also determined. Furthermore, the antibiofilm activity against S. <em>mutans</em> was investigated. </span></span></p> <p style="text-align:justify"><span style="font-size:11pt"><strong><span style="font-size:10.0pt">Results:</span></strong><span style="font-size:10.0pt"> the phytochemical contents in MPE were flavonoids, tannins, saponins, phenols, alkaloids, triterpenoids, and terpenoids. Particle size of MPNs was 126.1 <em>nm</em> and the Polydispersity Index (PDI) was 0.419. The highest antibacterial concentration as inhibition zone against <em>S. mutans</em> was 16.37&plusmn;0.38 <em>mm</em> and 119.37&plusmn;2.16% inhibitory activity, at the highest concentration (100%) p&lt;0.05. The percentage of biofilm inhibition against <em>S. mutans</em> was 27.64-105.94% which was concentration dependent. </span></span></p> <p style="text-align:justify"><span style="font-size:11pt"><strong><span style="font-size:10.0pt">Conclusion:</span></strong><span style="font-size:10.0pt"> MPNs has potential as an antibacterial and antibiofilm agent that can be used as a preventive agent in medicine.</span></span></p> Antibacterial agents, Garcinia mangostana, Nanoparticle drug delivery system, Phytochemicals, Streptococcus mutans 277 285 https://www.ajmb.org/En/Article.aspx?id=70628 https://www.ajmb.org/PDF/En/FullText/70628.pdf VinnaKurniawati Sugiaman 92416RosalinaIntan Saputri Faculty of Dentistry, Maranatha Christian University, Bandung 40164, West Java, Indonesia92417JeffreyJeffrey Faculty of Dentistry, Universitas Jenderal Achmad Yani, Cimahi 40531, West Java, Indonesia92418WahyuWidowatiFaculty of Medicine, Maranatha Christian University, Bandung 40164, West Java, Indonesia92419MariskaElisabethBiomolecular and Biomedical Research Center, Aretha Medika Utama, Bandung 40163, West Java, Indonesia92420ViniAyuni Biomolecular and Biomedical Research Center, Aretha Medika Utama, Bandung 40163, West Java, Indonesia92421DhanarSeptyawan Hadiprasetyo Faculty of Pharmacy, Universitas Jenderal Achmad Yani, Cimahi 40531, West Java, Indonesia92422