Green Synthesis of Silver Nanoparticles Mediated by Rosemary (Rosmarinus officinalis L. / Salvia rosmarinus) Extract: Chemical Insights, Characterization, Antimicrobial Efficacy, and Emerging Applications

Objective: This narrative review aims to consolidate existing literature on the green synthesis of silver nanoparticles (AgNPs) using rosemary (Rosmarinus officinalis L.), highlighting the relationships among synthesis variables, nanoparticle characteristics, antimicrobial performance, and identifying knowledge gaps in the field. Methods: : The review synthesizes findings from various studies focused on rosemary-mediated AgNP synthesis. It examines the influence of different synthesis parameters on nanoparticle formation, characterizes the resulting AgNPs, and assesses their antimicrobial efficacy against a range of pathogens, including multidrug-resistant strains. Results: The studies reviewed consistently report the production of spherical, crystalline AgNPs ranging from 10 to 60 nm in size, which demonstrate concentration-dependent antimicrobial activity against Gram-positive and Gram-negative bacteria, fungi, and biofilms. The mechanisms of action identified include membrane disruption, controlled release of Ag⁺ ions, and the generation of reactive oxygen species. Conclusions: This review underscores the potential of rosemary as a sustainable alternative for AgNP synthesis, while also addressing critical issues such as extract variability, long-term colloidal stability, and the need for comprehensive biocompatibility assessments. It emphasizes the importance of standardizing extract preparation and conducting further mechanistic studies to facilitate the clinical and industrial application of rosemary-mediated AgNPs.