A review on gold nanoparticles derived from plants and their antimicrobial applications

Gold nanoparticles (AuNPs) have attracted significant attention due to their broad range of applications in the health and environmental fields and the fact that gold is an inert metal with low physiological toxicity, making it a favorable candidate for biomedical use. In line with the growing interest in green nanotechnology, plant-based nanoparticle synthesis has emerged as a sustainable, low-cost, and environmentally friendly alternative to conventional methods. Among these, AuNPs synthesized using plant extracts have been extensively studied, particularly concerning their antimicrobial properties. In this sense, this study aimed to perform a bibliometric review of the antimicrobial potential of plant-based AuNPs focusing on articles published between 2014 and 2025. Searches were conducted at the Web of Science, PubMed, and Scopus databases, totaling 190 eligible studies. India is the leading country in terms of number of publications (36.84%), with leaves as the most employed plant part (42.6%). The reported AuNPs synthesized from various plant parts, including seeds, fruits, as well as leaves, exhibited significant antimicrobial activities. Although some AuNPs, such as those synthesized from seeds, were more effective against Gram-positive bacteria, others, such as those from fruits, showed greater activity against Gram-negative strains, and several leaf-based ones demonstrated broad-spectrum efficacy against both groups. These antimicrobial performance variations are primarily attributed to the presence of specific organic compounds like flavonoids, terpenoids, and phenolics unique to each plant species used in the synthesis process. Escherichia coli and Staphylococcus aureus were the most frequently tested bacterial strains, with main AuNPs effects comprising damage to their thiol and peptidoglycan cell walls. One hundred thirty three (Emmanuel et al. in Microb Pathog 113:295-302, 2017) articles expanded their evaluations to include fungi, protozoa and cytotoxic effects, with many reports encouraging results against antibiotic-resistant bacterial strains, reinforcing the potential of plant-based AuNPs as innovative antimicrobial therapy alternatives.