Green synthesis of gold nanoparticles from fruit extract of Terminalia arjuna, for the enhanced seed germination activity of Gloriosa superba

K Gopinath,A Arumugam,V Karthika,S Gowri

doi:10.1007/s40097-014-0115-0

Abstract

This study reveals the synthesis of spherical gold nanoparticles (Au NPs) using aqueous fruit extract of Terminalia arjuna, which contains tannin, terpenoid, saponins, flavonoids, glycosides and polyphenolic compounds. The synthesized Au NPs were characterized by UV–visible spectroscopy (UV–vis), Fourier transform infrared (FTIR), X-ray diffraction (XRD), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential (ZP) analyses. UV–visible spectra of the fruit extract containing Au NPs showed a surface plasmon resonance peak at 523 nm. FTIR analysis was performed to analyze the biomolecules responsible for the reduction of Au NPs. FTIR analysis clearly showed that Au NPs were capped with plant compounds. The EDX analysis was used to identify the elemental composition of the synthesized Au NPs. The high crystallinity of Au NPs with a face-centered cubic phase is evident to XRD patterns. AFM and TEM observations revealed that synthesized Au NPs were spherical shape with the range 20–50 nm. DLS measurement revealed that Au NPs were obtained in the average size of 25 nm and it is found to be stable at 21.9 mV through ZP analysis. The synthesized Au NPs were investigated for its antibacterial activity. By contrast, Au NPs did not show any antibacterial activity against Gram-positive and Gram-negative bacteria. The Au NPs were treated with two different concentrations (500 and 1,000 μM) of Gloriosa superba seeds. Au NPs exposure at 1,000 μM concentration has most significant effect on seed germination rate and vegetative growth of G. superba. This is the first report on Au NPs as a biocompatibility material to enhance the seed yield of this endangered medicinal plant.

Highlights

IntroductionAu NPs can be synthesized by physical and chemical methods such as physical vapor deposition [12], chemical vapor deposition [13], Microwave irradiation [14], UV irradiation [15], sol–gel technique [16], aerosol technology [17], sono-chemical method [18] and photochemical reduction [19]
This study reveals the synthesis of spherical gold nanoparticles (Au NPs) using aqueous fruit extract of Terminalia arjuna, which contains tannin, terpenoid, saponins, flavonoids, glycosides and polyphenolic compounds
The synthesized Au NPs were characterized by UV–visible spectroscopy (UV–vis), Fourier transform infrared (FTIR), X-ray diffraction (XRD), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential (ZP) analyses

Summary

Introduction

Au NPs can be synthesized by physical and chemical methods such as physical vapor deposition [12], chemical vapor deposition [13], Microwave irradiation [14], UV irradiation [15], sol–gel technique [16], aerosol technology [17], sono-chemical method [18] and photochemical reduction [19]. Most of these techniques are expensive, hazardous and employed by toxic chemicals. Plant extracts have been reported to show high efficacy in Au NPs synthesis such as Anacardium occidentale [20], Centella asiatica [21], Chenopodium album [22], Coleus amboinicus [23], Crocus sativus [24], Euphorbia hirta [8], 115 Page 2 of 11

Methods

Results

Conclusion