The two main methods for creating nanoparticles are physical and chemical, both of which are frequently expensive and potentially harmful to the environment. Many academics attentions have recently been focused on the assessment of green chemistry or biological methods for producing metal nanoparticles from plant extracts. This study discusses the literature on the environmentally friendly creation of nanoparticles using several metals (such as gold, silver, zinc, titanium, and palladium) and plant extracts. Reduction, stabilization, nucleation, aggregation, and capping are all components of the generalized mechanism of nanoparticle synthesis. Characterizations, monitoring the development factors such as temperature, pH, and reaction time during biosynthesis can help to resolve the significant challenges frequently encountered in preserving particles structure, size, and yield. Researchers must first investigate the real mechanism underlying the plant-assisted synthesis of a metal nanoparticle and its impact on other nanoparticles to build a widely accepted strategy. The creation of alternative, sustainable, safe, less hazardous, and environmentally friendly methods is made easier thanks to the green synthesis of NPs. Thus, green nanotechnology using plant extract opens up new possibilities for the synthesis of novel nanoparticles with the desirable characteristics required for developing biosensors, biomedicine, cosmetics and nano-biotechnology, and in electrochemical, catalytic, antibacterial, electronics, sensing and other applications.

Index Terms - Nanoparticle, plant extract, sustainable application, biosynthesis, green chemistry.