Green synthesis, characterization and cholinesterase inhibitory potential of gold nanoparticles

The green synthesis of gold nanoparticles (Au NPs) from their precursor was carried out using Delphinium uncinatum and Erythrophyleum guineense plants extracts. The Au NPs obtained were characterized by various instrumental techniques such as scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and UV/Visible (UV/VIS) spectrophotometer. The SEM study presented that E. guineense (GE) and D. uncinatum (GN) synthesized gold nanoparticles was below 100 and 300 nm, respectively. The micrographs also presented that E. guineense (GE) synthesized gold particles had irregular round shaped while the D. uncinatum (GN) synthesized nanoparticles had cylindrical shaped. The XRD spectra presented peaks at about 38.1°, 44.43°, 64.6° and 77.64° can be indexed to (111), (200), (220) and (311) orientation, respectively, which confirmed the presence of gold nanoparticles. It means that both E. guineense (GE) and D. uncinatum (GN) synthesized gold nanoparticles are highly crystalline. The UV/VIS analysis presented that both plant extracts significantly reduced the gold slat and as a result high quantity of gold nanoparticles were formed. The E. guanense gold NP and D. uncinatum gold NPs were investigated for their in-vitro cholinesterases inhibitory potentials in 62.5-1000 µg/mL concentrations range. The bioactivity results presented that the loading of the test samples in gold NPs enhanced their AChE and BChE inhibitory potentials.