Publications by authors named "Rumi Yamaoki"

2 Publications

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Electron spin resonance spectral analysis of irradiated royal jelly.

Food Chem 2014 Jan 9;143:479-83. Epub 2013 Aug 9.

Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan. Electronic address:

The analysis of unpaired electron components in royal jelly was carried out using electron spin resonance (ESR) with the aim to develop a detection method for irradiated royal jelly. The ESR spectrum of royal jelly had natural signals derived from transition metals, including Fe(3+) and Cu(2+), and a signal line near g=2.00. After irradiation, a new splitting asymmetric spectrum with overall spectrum width ca. 10mT at g=2.004 was observed. The intensities of the signals at g=2.004 increased in proportion to the absorbed dose in samples under different storage conditions: fresh frozen royal jelly and dried royal jelly powder at room temperature. The signal intensity of the fresh frozen sample was stable after irradiation. One year after 10kGy irradiation of dried powder, the signal intensity was sevenfold greater than before irradiation, although the intensity continued to steadily decrease with time. This stable radiation-induced radical component was derived from the poorly soluble constituent of royal jelly.
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http://dx.doi.org/10.1016/j.foodchem.2013.07.139DOI Listing
January 2014

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

J Nat Med 2009 Jan 1;63(1):28-31. Epub 2008 Aug 1.

Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka, 569-1094, Japan.

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.
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http://dx.doi.org/10.1007/s11418-008-0284-6DOI Listing
January 2009
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