The potential of natural extracts for biogenic synthesis depends on the content of reducing substances.

The conditions of biosynthesis and possible mechanisms of nanoparticle formation with the participation of bacteria are presented. This review presents recently published research on the green synthesis of nanoparticles. The source of ecological technology for producing nanoparticles can be plants or microorganisms (yeast, algae, cyanobacteria, fungi, and bacteria). This is important given the drastically increased demand for nanomaterials in biomedical fields. They have proven useful not only as supplements preventing diseases caused by oxidative stress and food additives preventing oxidation but also as system components for the production of metallic nanoparticles by the so-called green synthesis. Natural extracts are the source of many antioxidant substances.