Sonochemical activation of hematoporphyrin: An ESR study

N. Yumita, R. Nishigaki, K. Umemura, P. D. Morse, H. M. Swartz, C. A. Cain, S. I. Umemura

研究成果: Article査読

72 被引用数 (Scopus)


The production of 2,2,6,6-tetramethyl-4-piperidone-N-oxyl by reaction of 2,2,6,6-tetramethyl-4-piperidone (TMPone) with ultrasonically generated active species in oxygenated solutions of hematoporphyrin (Hp) was studied by electron spin resonance spectroscopy. The nitroxide production rate in air- saturated TMPone solutions in phosphate-buffered saline of pH 9.0 was significantly higher in the presence of Hp than in its absence. The enhancement of nitroxide production by Hp was significantly inhibited in the presence of sodium azide or histidine in the solution. The production rate with Hp was doubled by substitution of deuterium oxide, while the rate without Hp increased only modestly. These results suggest that a substantial amount of active oxygen can be generated by ultrasound in aqueous solutions of Hp. Since the production rate was not reduced by mannitol and no nitroxide was produced in nitrogen-saturated solutions, it appears that hydroxyl radicals do not account for a major portion of the active oxygen species which reacted with TMPone to yield a nitroxide.

ジャーナルRadiation Research
出版ステータスPublished - 1994

ASJC Scopus subject areas

  • 放射線
  • 生物理学
  • 放射線学、核医学およびイメージング


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