[en] The feasibility of sterilizing traditional Chinese medicines (TCMs) by γ-irradiation has been systematically evaluated by the biological, toxicological and physicochemical tests on irradiated hundreds of TCMs. Those TCMs investigated in general show no significant biological or toxicological changes after irradiation, yet physicochemical changes are detectable in some irradiated TCMs, and water in TCMs enhances the effects. Those results obtained from radiolysis of some major effective components of TCMs in aqueous or ethanolic solutions reveal that the site selection of radiolytically generated radicals follows the example of simple compounds with same function groups. Wholesomeness and chemical clearance present a bright future to sterilizing TCMs by γ irradiation, however, some important measures and steps should be adopted: (1) The producers must strictly execute manufacturing procedure to reduce microbiological contamination thus lower the applied dose for sterilization which is recommended to be controlled under 5, 7 or 10 kGy for dry herb, 7 kGy for herbal medicine and 5 kGy for some special herbal medicine; (2) Herb to be sterilized by γ-irradiation should exist in possible dry state; (3) Powder TCMs is recommended to mix with honey forming bolus, which can minimize the decomposition of herb

[en] Pulse radiolysis of epicatechin in aqueous solution has been done to investigate the reactions of epicatechin derived phenoxy radical (EpO^.) at neutral pH. EpO^. was generated by N₃^. reacting toward EpOH, the rate constant was measured to be 3x10⁸ dm³ mol^-1 s^-1. The bimolecular termination of EpO^. is rather slow (2κ<2x10⁶ dm³ mol^-1 s^-1) and results in products exhibiting strong visible absorption around 450 nm. No reactions have been observed for EpO^. with O₂ and O₂^.- in the time scale of pulse radiolysis (0.01 s), suggesting the bimolecular rate constants are less than 10⁴ and 5x10⁶ dm³ mol^-1 s^-1, respectively

[en] In this paper, pork fat peroxidation by γ-irradiation and the possible effects of oxygen, UV-irradiation and storage after the γ-irradiation have been investigated. It has been found that the level of peroxides in irradiated pork increases linearly with the increasing absorbed dose. The chemical yield of peroxides formed in the irradiated fat is about 4.2 and independent on the sample temperature or absorbed dose rate, but dependent on storage time of sample before γ-irradiation. The irradiated pork exhibits some unusual features as following: 1) the peroxide content in irradiated pork is higher than that in unirradiated one; 2) the peroxide content in irradiated pork increases gradually on storage and is essentially constant in unirradiated one, which is very useful for the detection of irradiated pork; 3) the further peroxidation in irradiated pork is much more susceptible to UV radiation than that in unirradiated pork

[en] OH-radical-induced dechlorination of pentachlorophenol (PCP) has been studies pulse and γ-radiolytically. OH radicals react with PCP by both electron transfer (53%) and addition followed by very rapid HCl-elimination to form phenoxyl radicals. The phenoxyl radicals decay to form products (e.g. chloranil) that unstable in alkaline aqueous solution and release some more Cl^-, therefore G(Cl^-) is high. Primary HPLC-MS analysis reveals that some quinones among the final products, whose toxicity remains unclear. Ozone can also oxidize PCP very rapidly, and this oxidation may destroy the benzene ring of PCP

[en] Radiolysis of rutin was performed in aerated ethanolic solution. Two major radiolytic products (RP1, RP2) were isolated by HPLC, and their possible structures were deduced from their UV, IR and MS spectra, and elementary analysis as well. The G-values of RP1 and RP2 increase with increasing rutin concentration, and in all cases both of them equal the G-value of rutin consumption. The addition of rutin leads to the decrease of G(H₂O₂) but has little effect on G(CH₃CHO). Therefore the formation of RP1 and RP2 was proposed to be from further addition of HO%s· ₂ to the phenolic radical (generated from H-abstraction by HO%s· ₂) followed by fragmentation

[en] The mechanism and kinetics of glycyrrhizic acid monoamonium (GAM) reacting with hydroxyl radical generated by γ-ray irradiated N₂O-saturated aqueous solutions were studied. The radiolytic products were separated with HPLC and the molecular structures were determined by UV, IR, MS and elementary analysis methods. The major product was formed by the attack of hydroxyl radical to the C-C double bond of GAM. The others resulted from the release of one and two glucuronic acid molecules in GAM respectively. The rate constant of GAM reacting with the hydroxyl radical was measured using a competition method by pulse radiolysis technique to be of 3.0x10⁹ dm³ mol^-1 s^-1. The transient species generated by pulse radiolysis of GAM aqueous solution saturated with N₂O at pH 10 exhibited an absorption maximum at about 325 nm with extinction coefficient 260 dm³ mol^-1 cm^-1. The rate constant of second-order decay of transient species was 5.8 x 10⁸ dm³ mol^-1 s^-1. The transient species was formed by the attack of hydroxyl radical to the C-C double bond of GAM. The G values of GAM and its radiolytic products of 4.0x10^-4 mol dm^-3 aqueous solution saturated with N₂O at absorbed dose of 500 Gy are: G(-GAM) = 2.4, G(RP1) 2.2, G(RP2) = 0.3, G(RP3) = 0.1

No abstract available

[en] Studies in China on the detection method of irradiated food, mechanism of DNA damage induced by peroxidation, radiolysis of natural products and herbs are reviewed on the update open literature, and some progress on applications of radiation technology is summarized. (author)

[en] Short communication. 4 refs, 1 fig

[en] The effect of dose rate on the radiation chemical yield of hydroxy terephthalate (HOTA) in the radiolysis of aerated terephthalate (TA) aqueous solution has been investigated, and the generation of ·OH by copper ion catalyzed Fenton reaction has been evaluated with the help of TA. No significant difference in the G(HOTA) was observed at dose rate ranging from 8.2 x 10^-3 to 1.6 Gy s^-1. The presence of Cu²⁺ at concentration less than 1/10 of [TA] lowers the G(HOTA) to 0.53, however G(HOTA) does not change with [Cu²⁺] added. As indicated by the formation of HOTA, the '·OH' generated by the Fenton-type reaction catalyzed by copper ion is different from that generated radiolytic, the former is rather localized and therefore difficult to be scavenged by TA