Background: Based on various distinguished physical and chemical properties of gold
nanoparticles, they have far wide applications in several areas of industry and medicine, such as catalysis,
bio-sensor and drug delivery. Compared to a chemical method, biological synthesis is an
economical and less toxic process, thus it is a better alternative for nanoparticle synthesis. In this
study, an environmentally friendly method was chosen to produce AuNPs using Curcuma
Methods: Alkaline aqueous extract of C. xanthorrhiza rhizomes, which acts as a reducing and stabilizing
agent was used to produce AuNPs by bio-reduction of HAuCl4. The formation of AuNPs was
periodically monitored by UV-visible spectroscopy. The obtained AuNPs were characterized by Xray
diffraction, energy dispersive spectroscopy, scanning electron microscopy, transmission electron
microscopy, and Fourier transform infrared (FTIR) spectroscopy. Catalytic activity and toxicity of
the AuNPs were evaluated.
Results: The AuNPs obtained from this study mostly were spherical in shape with approximately 15
nm in size. The presence of functional groups derived from C. xanthorrhiza rhizome extract involved
in the gold bio-reduction process was confirmed by the spectrum of FTIR spectroscopy. The biosynthesized
AuNPs at the concentration of 0.5 μg/ml had catalytic activity in dye degradation of Congo
red. The results showed that this biogenic AuNPs did not cause any toxicity to zebrafish embryos and
all tested cell lines.
Conclusion: The biocompatible AuNPs with catalytic activity were successfully fabricated with C.
xanthorrhiza rhizome extract by simple eco-friendly and inexpensive method. This catalytic activity
of the obtained AuNPs is potentially useful for industrial applications as well as nanoscience and