Detection of organic free radicals in irradiated Foeniculi fructus by electron spin resonance spectroscopy

  • Rumi Yamaoki
  • Toshiaki Tsujino
  • Shojiro Kimura
  • Yoshiki Mino
  • Masatoshi Ohta
Original Paper


Foeniculi fructus were irradiated with an electron beam and organic free radicals were detected by electron spin resonance (ESR) spectroscopy for the purpose of identifying radio-disinfected and sterilized herbal drugs. An ESR single-line spectrum near g = 2.005 was observed in the sample before irradiation. After irradiation, the intensity of the signal near g = 2.005 increased. In addition, two subsignals derived from cellulose radicals were observed approximately 3 mT to either side of the main signal, at g = 2.023 and g = 1.987. The intensity of the subsignal at g = 2.023 was proportional to the absorbed dose of radiation. The decrease in intensity of the signals was considerable 2 weeks after irradiation, and continued to decrease steadily thereafter. Among the signals, the fading of the subsignal at g = 2.023 was relatively small. The intensity of the subsignal at g = 2.023 was detectable for over 1 year in the sample that had been irradiated to the level of disinfection and sterilization. Therefore, organic free radicals in irradiated Foeniculi fructus can be measured rapidly and with high sensitivity by ESR spectroscopy. The stable signal at g = 2.023 is a promising indicator of the detection of irradiated herbal drugs.


Foeniculi fructus Radiation irradiation Electron spin resonance Organic free radical Identification 


  1. 1.
    Ando S, Taniyama T, Fukuda Y, Kitagawa N, Mirin Y (1999) Study on the application of electron beam sterilization to powdered crude drugs. Nat Med 53:283–290Google Scholar
  2. 2.
    Joint FAO/IAEA/WHO Expert Committee (1981) Wholesomeness of Irradiated Food, technical report series 659. WHO, GenevaGoogle Scholar
  3. 3.
    Joint FAO/IAEA programme (2008) Food and environmental protection, food irradiation clearance database. IAEA, ViennaGoogle Scholar
  4. 4.
    EN 1787 (1996) Foodstuffs—detection of irradiated food containing cellulose, method by ESR spectroscopy. European Committee for Standardization, BrusselsGoogle Scholar
  5. 5.
    EN 13708 (2001) Foodstuffs—detection of irradiated food containing crystalline sugar by ESR spectroscopy. European Committee for Standardization, BrusselsGoogle Scholar
  6. 6.
    Yamaoki R, Kimura S, Ohtsu N, Chikuta Y, Aoki K, Mino Y, Ohta M (2008) Effectiveness of electron beam microbial decontamination and change of essential oil components in fennel. Radioisotopes 57:367–373CrossRefGoogle Scholar
  7. 7.
    Dismukes GC, McGuire A, Blankenship R, Sauer K (1978) Electron spin polarization in photosynthesis and the mechanism of electron transfer in photosystem I. Experimental observations. Biophys J 21:239–256PubMedCrossRefGoogle Scholar
  8. 8.
    Calucci L, Pinzino C, Zandomeneghi M, Capocchi A, Ghiringhelli S, Saviozzi F, Tozzi S, Galleschi L (2003) Effects of γ-irradiation on the free radical and antioxidant contents in nine aromatic herbs and spices. J Agric Food Chem 51:927–934PubMedCrossRefGoogle Scholar
  9. 9.
    Uchiyama S, Kawamura Y, Saito Y (1990) Identification of γ-irradiated spices by electron spin resonance (ESR) spectrometry. J food Hyg Soc Japan 31(6):499–507Google Scholar
  10. 10.
    Raffi JJ, Agnel JPL (1989) Electron spin resonance identification of irradiated fruits. Radiat Phys Chem 34:891–894Google Scholar
  11. 11.
    Korkmaz M, Polat M (2001) Radical kinetics and characterization of the free radicals gamma irradiated red pepper. Radiat Phys Chem 62:411–421CrossRefGoogle Scholar
  12. 12.
    Yamaoki R, Sasaki T, Ishii R, Okabe H, Kimura S, Nosaka K, Nishimoto S (2005) Sterilization of black pepper by electron beam irradiation and identification of organic free radicals in irradiated sample by electron spin resonance. Radioisotopes 54:365–373Google Scholar
  13. 13.
    Yamaoki R, Kimura S, Aoki K, Nishimoto S (2007) Detection of electron beam Irradiated crude drugs by electron spin resonance (ESR). Radioisotopes 56:163–172Google Scholar
  14. 14.
    Raffi J, Yordanov ND, Chabane S, Douifi L, Gancheva V, Ivanova S (2000) Identification of irradiation treatment of aromatic herbs, spices and fruits by electron paramagnetic resonance and thermoluminescence. Spectrochim Acta [A] 56:409–416CrossRefGoogle Scholar

Copyright information

© The Japanese Society of Pharmacognosy and Springer 2008

Authors and Affiliations

  • Rumi Yamaoki
    • 1
  • Toshiaki Tsujino
    • 1
  • Shojiro Kimura
    • 1
  • Yoshiki Mino
    • 1
  • Masatoshi Ohta
    • 2
  1. 1.Osaka University of Pharmaceutical SciencesTakatsukiJapan
  2. 2.Faculty of EngineeringNiigata UniversityNiigataJapan

Personalised recommendations