Scientific Reports (Apr 2019)

Decomposition and oxidation of methionine and tryptophan following irradiation with a nonequilibrium plasma jet and applications for killing cancer cells

  • Giichiro Uchida,
  • Yusuke Mino,
  • Tensho Suzuki,
  • Jun-ichiro Ikeda,
  • Takashi Suzuki,
  • Kosuke Takenaka,
  • Yuichi Setsuhara

DOI
https://doi.org/10.1038/s41598-019-42959-4
Journal volume & issue
Vol. 9, no. 1
pp. 1 – 17

Abstract

Read online

Abstract We present evidence for the decomposition and oxidation of amino acids in aqueous solution following irradiation with a nonequilibrium plasma jet. Of 15 amino acids tested in cell culture medium, plasma irradiation induced a marked chemical change in methionine and tryptophan due to the effective production of reactive oxygen species by plasma-water interaction. We also report that plasma-treated methionine and tryptophan aqueous solutions can kill cancer cells, greatly decreasing the viability of human endometrial carcinoma (HEC-1) cancer cells due to the presence of decomposition or oxidation products generated from the amino acid. Plasma-treated methionine and tryptophan aqueous solutions also induced an anti-cancer effect on cancer-initiating cells.