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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The effectiveness of electron beam (EB) disinfection and sterilization technology when applied to turmeric powder (Curcuma longa Linne) was investigated. The bacteria in turmeric powder were sensitive to EB irradiation. From an initial turmeric aerobic bacterial count of 10 7 colony-forming units per gram (cfu/g), a microbial contamination level of below 1.0 3 10 3 cfu/g was obtained atan absorbed dose of more than 7 kGy EB irradiation. EB irradiation at 10 kGy gave a contamination level of less than 10 cfu/g after 1 year of storage at room temperature. At the irradiation level necessary for decontamination of turmeric powder, the amount of dilute ethanol-soluble extract from the sample was 9% greater than the level from a non-irradiated turmeric powder. HPLC analysis of an irradiated sample indicated that EB radiolysis of curcuminoids was less than the level detectable by instrumental analysis. Practical applicationsRadiosterilization has been recognized as an effective method for controlling microorganisms and for extending the shelf life of food. In particular, EB irradiation is economically advantageous over gamma irradiation because of the higher EB dose rate. This study evaluates the use of 4.8 MeV EB radiation for the decontamination of turmeric powder for food additive and pharmaceutical uses. This method is found to be effective for sterilization and avoiding degradation of the yellow pigment components.

Perillae Herba, Sennae Folium, Cinnamomi Cortex, Phellodendri Cortex, Ginseng Radix, Glycyrrhizae Radix, Paeoniae Radix, and Zingiberis Rhizoma were irradiated with electron beam (5 MeV) and organic radicals were detected by ESR measurement, before and after irradiation (10 kGy). A single line spectrum was detected at around g=2.005 in non-irradiated crude drugs, and radical concentrations were high in the leaf varieties of crude drugs. After irradiation, the signal intensity around g=2.005 increased, and a new subsignal was detected as a 3 mT shoulder of this signal. Broad, asymmetrically divided signals were also detected in irradiated root varieties of crude drugs. The free radical localized on the organic components of irradiated crude drugs tended to decrease with the water content. After irradiation, signal intensity reduced and reached a steady state after about 1 to 2 months. However, specificity of the ESR signal shape appearing after irradiation continued to be detectable for 6 months in leaf varieties and for a year in bark and root varieties of crude drugs. Consequently, it was concluded that ESR could be applied as an initial screening procedure to detect irradiated crude drugs.