Original Article
Green synthesis of gold nanoparticles using chlorogenic acid and their enhanced performance for inflammation

https://doi.org/10.1016/j.nano.2015.05.002Get rights and content

Abstract

Here we developed a novel green synthesis method for gold nanoparticles (CGA-AuNPs) using chlorogenic acid (CGA) as reductants without the use of other chemicals and validated the anti-inflammatory efficacy of CGA-AuNPs in vitro and in vivo. The resulting CGA-AuNPs appeared predominantly spherical in shape with an average diameter of 22.25 ± 4.78 nm. The crystalline nature of the CGA-AuNPs was confirmed by high-resolution X-ray diffraction and by selected-area electron diffraction analyses. High-resolution liquid chromatography/electrospray ionization mass spectrometry revealed that the caffeic acid moiety of CGA forms quinone structure through a two-electron oxidation causing the reduction of Au3 + to Au0. When compared to CGA, CGA-AuNPs exhibited enhanced anti-inflammatory effects on NF-κB-mediated inflammatory network, as well as cell adhesion. Collectively, green synthesis of CGA-AuNPs using bioactive reductants and mechanistic studies based on mass spectrometry may open up new directions in nanomedicine and CGA-AuNPs can be an anti-inflammatory nanomedicine for future applications.

From the Clinical Editor

Gold nanoparticles (Au NPs) have been shown to be very useful in many applications due to their easy functionalization capability. In this article, the authors demonstrated a novel method for the synthesis of gold nanoparticles using chlorogenic acid (CGA) as reductants. In-vitro experiments also confirmed biological activity of the resultant gold nanoparticles. Further in-vivo studies are awaited.

Graphical Abstract

  • •

    The caffeic acid moiety of CGA mediates the formation of CGA-AuNPs without chemical reductants through a two-electron oxidation during the reduction of Au3 + to AuNPs.

  • •

    CGA-AuNPs exhibit enhanced anti-inflammatory activity in vitro and in vivo through NF-κB down-regulation compared to CGA.

  1. Download : Download high-res image (101KB)
  2. Download : Download full-size image

Section snippets

Reagents and cells

Raw 264.7 cells, widely used murine macrophages, were obtained from the Korean Cell Line Bank (KCLB) and grown in Dulbecco’s Modified Eagle’s Medium (DMEM, Gibco BRL) supplemented with 10% fetal bovine serum (FBS; Gibco BRL) and penicillin (100 U/mL)/streptomycin (100 μg/mL) (Gibco BRL). Lipopolysaccharide (LPS), CGA, Griess reagent, caffeic acid, (−)-quinic acid, and hydrochloroauric acid trihydrate (HAuCl4 · 3H2O) were purchased from Sigma–Aldrich (St. Louis, MO, USA). All other reagents were of

UV-Visible, FT-IR Spectra and HR-XRD analysis of CGA-AuNPs

CGA (1) is composed of two natural compounds, caffeic acid (2) and (−)-quinic acid (3), linked through an ester bond (Figure 1, A). When CGA was used as a reductant, the CGA-AuNPs turned pink in color and exhibited a characteristic surface plasmon resonance band with maximum absorbance at 545 nm (Figure 1, B, line ii), whereas no color change was observed in the solution without the reductant (Figure 1, B, line i). The FT-IR spectrum of CGA standard was described in our previous report.17 As

Discussion

CGA has been reported in various functions such as anti-oxidant, anti-aging, and anti-diabetic.11, 12 For instance, it slows the release of glucose into the blood, helping counter the accumulation of body fat caused by excess blood glucose and reduce the risk of diabetes. Recently, the anti-inflammatory effect of CGA has been reported in LPS-inflamed murine macrophage cells, mouse retinal inflammation model, carbon tetrachloride (CCl4)-induced liver fibrosis model, and LPS-inflamed

References (30)

  • A.J. Mieszawska et al.

    Multifunctional gold nanoparticles for diagnosis and therapy of disease

    Mol Pharm

    (2013)
  • V. Biju

    Chemical modifications and bioconjugate reactions of nanomaterials for sensing, imaging, drug delivery and therapy

    Chem Soc Rev

    (2014)
  • M.C. Daniel et al.

    Gold nanoparticles: assembly, supremolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology

    Chem Rev

    (2004)
  • R.A. Sperling et al.

    Biological applications of gold nanoparticles

    Chem Soc Rev

    (2008)
  • Y. Park et al.

    Polysaccharides and phytochemicals: a natural reservoir for the green synthesis of gold and silver nanoparticles

    IET Nanobiotechnol

    (2011)

    • Cited by (0)

    Financial support: This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Korean Government, the Ministry of Education (2012R1A1A2042224) and the Ministry of Science, ICT & Future Planning (2013R1A1A1059709 and 2010-18282).

    1

    These authors contributed equally to this work.

    View full text
    Copyright © 2015 Elsevier Inc. All rights reserved.