Comparison of the characteristics of gold nanoparticles synthesized using aqueous plant extracts and natural plant essential oils of Eucalyptus globulus and Rosmarinus officinalis

Abstract

In this work we successfully utilized 1% (m/v) aqueous leaf extracts and 1% (v/v) natural essential oils originating from Eucalyptus globulus and Rosmarinus officinalis as bioreducing and capping agents for gold nanoparticles (AuNPs) synthesis. UV/Vis absorption spectra revealed that AuNPs were well-dispersed and spherical when synthesized with E. globulus aqueous leaf extract, but also with R. officinalis aqueous leaf extract and its essential oil. Only AuNPs fabricated by utilizing E. globulus essential oil exhibited various shapes and a partial aggregation. TEM analysis showed that the average sizes of AuNPs produced with the aid of E. globulus aqueous leaf extract and its essential oil were 12.8 ± 6.3 nm and 42.2 ± 42.0 nm, while in the case of R. officinalis, resultant AuNPs reached 8.66 ± 2.03 nm and 60.7 ± 60.6 nm in diameter, respectively. By EDS, Au, O, and C were detected in all tested nanofluids. Functional groups of organic compounds occurring in the investigated aqueous plant extracts and essential oils were identified by ATR-FTIR, and they were established as quite similar among the analyzed plant extracts, but also among the essential oils. Finally, GC-MS analysis were implemented to determine the key constituents of the E. globulus and R. officinalis aqueous extracts and their essential oils. Keywords: Gold nanostructures, Nanotechnology, Green synthesis, Bioreduction