Reducing power of Eucalyptus oleosa leaf extracts and green synthesis of gold nanoparticles using the extract

Assay of the antioxidant content and reducing power of the plant extracts is a crucial point in phytochemistry, the food industry, and nutrition. On the other hand, green synthesis of noble metal nanoparticles, such as gold by the aid of plant extract is dependent on the reducing power and antioxidant content of the extract. In this work, cyclic voltammetry was utilized as a facile technique for screening antioxidant properties and estimating the reducing power of the medicinal plant extracts. The effect of different extraction conditions on the reducing power of the aqueous extract was also determined through the cyclic voltammetry technique. The extract of Eucalyptus oleosa leaves obtained at optimum conditions of this study (with maximum reducing power based on cyclic voltammetry assay) was utilized for the green synthesis of gold nanoparticles. Furthermore, the kinetic of the synthesis reaction was investigated by the aid of ultraviolet-visible spectrophotometry based on surface Plasmon resonance for gold nanoparticles at 552 nm. Meanwhile, the synthesized gold nanoparticles were characterized by the transmission electron microscopy technique.