Molecules (May 2021)

Onion (<i>Allium cepa</i> L.)-Derived Nanoparticles Inhibited LPS-Induced Nitrate Production, However, Their Intracellular Incorporation by Endocytosis Was Not Involved in This Effect on RAW264 Cells

  • Masao Yamasaki,
  • Yumi Yamasaki,
  • Rina Furusho,
  • Hayaka Kimura,
  • Ichiro Kamei,
  • Hiroko Sonoda,
  • Masahiro Ikeda,
  • Tatsuya Oshima,
  • Kenjiro Ogawa,
  • Kazuo Nishiyama

DOI
https://doi.org/10.3390/molecules26092763
Journal volume & issue
Vol. 26, no. 9
p. 2763

Abstract

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The aim of this study was to evaluate the involvement of nanoparticles prepared from Allium cepa L. as anti-inflammatory agents. In the present study, we identified nanoparticles from Allium cepa L. using the ultracentrifugation exosome purification method. The nanoparticles were referred to as 17,000× g and 200,000× g precipitates, and they contained quercetins, proteins, lipids, and small-sized RNA. The nanoparticles inhibited nitric oxide production from lipopolysaccharide (LPS)-stimulated RAW264 cells without cytotoxic properties. Cellular incorporation was confirmed by laser microscopic observation after PKH26 staining. The inhibition of caveolae-dependent endocytosis and macropinocytosis significantly prevented the incorporation of the nanoparticles but had no effect on the inhibition of nitric oxide in RAW264 cells. Collectively, the identified nanoparticles were capable of inhibiting the LPS response via extracellular mechanisms. Taken together, the way of consuming Allium cepa L. without collapsing the nanoparticles is expected to provide an efficient anti-inflammatory effect.

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