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In this study, we investigated the effects of gamma irradiation on the antioxidant activity and metabolite profiles of Euphorbia maculata calli (PC3012). Gamma irradiation at various doses (0, 0.05, 0.5, and 10 kGy) significantly enhanced the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS+) radical scavenging activities of the callus extracts of PC3012 in a dose-dependent manner. High-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography-quadrupole time-of-flight/mass spectrometry (UPLC-Q-TOF/MS) analyses revealed that irradiation increased the lysophospholipid content, although no new antioxidant compounds were formed. Furthermore, a PLS-DA analysis revealed evident metabolic differences between non-irradiated and irradiated samples, which were further verified by statistical validation. These findings suggest that gamma irradiation induces specific biochemical modifications that enhance the bioactive properties of PC3012 calli. This technology exhibits potential for utilization in the natural product and food sectors, particularly in the development of functional foods and nutraceuticals with improved health benefits. [ABSTRACT FROM AUTHOR]

A representative naturally occurring coumarin, 4-methylumbelliferone (5), was exposed to 50 kGy of gamma ray, resulting in four newly generated dihydrocoumarin products 1–4 induced by the gamma irradiation. The structures of these new products were elucidated by interpretation of spectroscopic data (NMR, MS, [α]D, and UV). The unusual bisdihydrocoumarin 4 exhibited improved tyrosinase inhibitory capacity toward mushroom tyrosinase with IC50 values of 19.8 ± 0.5 μM as compared to the original 4-methylumbelliferone (5). A kinetic analysis also exhibited that the potent metabolite 4 had non-competitive modes of action. Linkage of the hydroxymethyl group in the C-3 and C-4 positions on the lactone ring probably enhances the tyrosinase inhibitory effect of 4-methylumbelliferone (5). Thus, the novel coumarin analog 4 is an interesting new class of tyrosinase inhibitory candidates that requires further examination. [ABSTRACT FROM AUTHOR]

Many studies have been reported on the pharmacological effects and extraction methods of lavender essential oil, but little is known about a profiling analysis of terpenoids produced in lavender leaves by ionizing irradiation. Here, we performed the profiling analysis of volatile terpenoids produced by lavender (Lavandula angustifolia L.) leaves in response to gamma irradiation and the anticancer effects of terpenes induced by γ-irradiation. The analyses of volatile terpenoids revealed that lavender leaves biosynthesised 33 species of volatile terpenoids and their relative ratio were significantly changed after exposure to γ-ray. The relative ratio of monoterpene hydrocarbons such as limonene, p-cymene, and camphene (except for δ-3-carene, γ-terpinene, terpinolene, and allo-ocimene) was reduced to less than 60% at 1000 Gy, set to 100% at 0 Gy. On the contrary, the ratio of sesquiterpene hydrocarbons such as α-santalene, (E)-α-bergamotene, and γ-cadinene was up-regulated by more than 1.6-fold at 1000 Gy. Additionally, α-santalene, which was increased the most by γ-irradiation, significantly inhibited the proliferation of the human prostate cancer cell line (PC3) with an IC50 < 12.5 μg mL-1. Our findings indicate that the α-santalene is the most induced terpenoid after exposure to γ-ray in lavender leaves and that it has a pharmacological effect on reducing the cell viability in human prostate cancer cells. We suggest that non-destructive reconstitution of secondary metabolites in target plants (e.g., medicinal plants) can be achieved by using γ-irradiation as a tool. [ABSTRACT FROM AUTHOR]

Abstract: Pretreatment of poplar bark with a combination of sulfuric acid (3%, w/w, H2SO4) and gamma irradiation (0–1000kGy) was performed in an attempt to enhance enzymatic hydrolysis for bioethanol production. The yields of reducing sugar were slightly increased with an increasing irradiation dose, ranging from 35.4% to 51.5%, with a 56.1% reducing sugar yield observed after dilute acid pretreatment. These results clearly showed that soluble sugars were released faster and to a greater extent in dilute acid-pretreated poplar bark than in gamma irradiation-pretreated bark. When combined pretreatment was carried out, a drastic increase in reducing sugar yield (83.1%) was found compared with individual pretreatment, indicating the possibility of increasing the convertibility of poplar bark following combined pretreatment. These findings are likely associated with cellulose crystallinity, lignin modification, and removal of hemicelluloses. [Copyright &y& Elsevier]

Abstract: This review discusses the morphological changes and biological responses of plants irradiated with gamma rays. Seedlings exposed to relatively low doses of gamma rays (1–5Gy) developed normally, while the growth of plants irradiated with a high dose gamma ray (50Gy) was significantly inhibited. Based on TEM observations, chloroplasts were extremely sensitive to gamma irradiation compared to other cell organelles, particularly thylakoids being heavily swollen. In addition, some portions of the mitochondria and endoplasmic reticulum were structurally altered, for example, distortion and swelling. The cerium perhydroxide deposition, as a maker for H2O2 deposition, was typically manifest on the plasma membranes and cell walls of the tissues from both the control and irradiated plants. However, the intensities of cerium perhydroxide deposits (CPDs) were remarkably increased in the plasma membranes and cell walls of pumpkin tissues such as petiole, cotyledon, hypocotyl and especially leaf after gamma irradiation. These observations are in good agreement with the results of H2O2 content in all tissues. The immuno-localization analysis for peroxidase (POD) on the tissues from pumpkin plant showed the same pattern between the control and irradiated plants, but the density of gold particles as indication of POD localization was significantly increased on the cell corner middle lamellae of parenchyma cells, especially in the petiole after gamma irradiation. However, accumulation and localization of H2O2 and POD in vessels were not significantly different between both plants. The accumulation and localization of both H2O2 and POD were differentially affected by gamma irradiation depending on the different tissue types. The deposition of both H2O2 and POD in parenchyma cells appeared much higher than in vessels, suggesting that the former is more sensitive than the latter against gamma rays. [Copyright &y& Elsevier]

Abstract: Owing to homogeneous hollow tube shape and hydrophobicity of kapok fiber, the usages of this fiber are various such as fiberfill in pillows, quilts, non-woven fabric for oil spill cleanup and plastic green house. Even though kapok fiber is able to apply various industrial usages, it has a serious disadvantage which is the extreme sensitivity to spark or flame. Therefore, we try to make flame-resistant kapok fiber using gamma ray. The radiation caused loss of hydrophobic compounds in kapok fiber and no morphological change, especially fine hollow tube shape, was observed. The lignin contents were negligible changed after gamma irradiation. However, the building units of lignin polymer such as coniferyl alcohol, and sinapyl alcohol were significantly changed that is, functional group as a methoxyl group from lignin polymer was cleaved by gamma irradiation. Based on the results of removal of hydrophobic compounds and cleavage of methoxyl group from lignin polymer, kapok fiber can be converted into a flame-resistant fiber by gamma ray treatment. [Copyright &y& Elsevier]

Abstract: Extracts from centipedegrass (Eremochloa ophiuroides Munro) have been previously identified as having beneficial effects medically and cosmetically. In this study, the effects of gamma irradiation on pigment removal and biological activities of centipedegrass extracts to promote industrial application were investigated. The methanolic extracts were exposed to gamma irradiation at dose ranging from 2 to 20kGy. The major pigments of centipedegrass extracts, cyanidin-3-O-glucoside and cyanidin-3-O-(6″-malonyl-)glucoside, were found to be effectively removed by gamma irradiation above 10kGy. Although the reddish-orange color of the cyanidins was markedly decreased by gamma irradiation, the biological activities were relatively unaffected. The biological activities such as 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity, inhibition of tyrosinase activity, and inhibition of elastase activity in methanolic extracts were modulated from 50.5% to 70.2%, from 50.9% to 65.8% and from 65.6% to 94.0%, respectively. Surprisingly, the biological activities have the highest activities after 6–8kGy of gamma irradiation. These results indicate that despite pigment degradation, biological activities were maintained or increased by gamma irradiation. Based on these results, gamma irradiation may be a useful tool to remove the undesirable reddish-orange color present in centipedegrass without any loss of biological activities, thereby promoting its utility in industrial applications such as manufacturing of cosmetic products. [Copyright &y& Elsevier]

Abstract: PP1084 protein was exposed to gamma irradiation ranging from 5 to 500kGy. Native PAGE showed minor structural changes in PP1084 at 5kGy, and major structural changes at >15kGy. Size-exclusion chromatography (SEC) showed the formation of a new shoulder peak when the protein was irradiated with 15 and 30kGy, and a double peak appeared at 100kGy. The results of PAGE and SEC imply that PP1084 protein is degraded by gamma irradiation, with simultaneous oligomerization. PP1084 chaperone activity reached the highest level at 30kGy of gamma irradiation, and then, decreased in a dose-dependent manner with increasing gamma irradiation. However, the peroxidase activity significantly decreased following exposure to all intensities of gamma irradiation. The improvement of chaperone activity using gamma irradiation might be promoted by the oligomeric structures containing covalently cross-linked amino acids. Consequently, PP1084 modification using gamma irradiation could elevate chaperone activity by about 3–4 folds compared to the non-irradiated protein. [Copyright &y& Elsevier]

Abstract: The effect of gamma irradiation on the content of total phenolic compounds, especially quercetin (Q), in onion (Allium cepa L.) skin was investigated. Onion skin extracts contained two predominant flavonoid compounds, Q and quercetin-4′-glucoside (Q4′G). After 10kGy gamma irradiation, the yield of Q in the extracts increased significantly from 36.8 to 153.9μg/ml of the extract, and the Q4′G content decreased slightly from 165.0 to 134.1μg/ml. In addition, the total phenolic compound content also increased after irradiation at 10kGy, from 228.0μg/g of fresh weight to 346.6μg/g; negligible changes (237.1–256.7μg/g) occurred at doses of up to 5kGy. As we expected, radical-scavenging activity was enhanced remarkably (by 88.8%) in the 10kGy irradiated sample. A dose-dependent increase in the peak intensity of the electron paramagnetic resonance (EPR) spectra was observed in all irradiated samples, with a maximum increase at 10kGy. The intensity relative to that of the control was 0.15, and it increased to 1.10 in 10kGy irradiated samples. The optimum gamma irradiation dose, which is sufficient to break the chemical or physical bonds and release soluble phenols of low molecular weight in onion skin, is about 10kGy. [Copyright &y& Elsevier]

Abstract: The fruit of Schizandra chinensis Baillon is a well-known traditional medicinal plant in Korea, China and Japan. We examined the effects of gamma irradiation on decolourisation and biological activity of S. chinensis fruit extracts to facilitate industrial applications. Samples were exposed to gamma-ray irradiation from 0.5 to 10kGy. Irradiation of greater than 2kGy markedly reduced the major colourant in S. chinensis fruit extracts, cyanidin-3-O-xylosylrutinoside (Cya-3-O-xylrut), by 80–90%. Biological activities, such as radical-scavenging activity and elastase inhibition activity, were not affected by gamma irradiation, but we observed a 12.3% increase in tyrosinase inhibition activity. There were negligible changes in the amounts of the major lignans schizandrin, gomisin A and gomisin N, following irradiation. These results indicated that gamma irradiation can selectively remove undesirable colour in S. chinensis extracts without adverse changes in biological activity. [ABSTRACT FROM AUTHOR]

Abstract: Organic compost is a useful fertilizer for organic farming. However, it poses a microbiological hazard to the farm products because most of the composts are originated from excremental matters of domestic animals. In this study, the radiation treatment was performed to improve microbiological safety of organic compost and the effectiveness of gamma irradiation for inactivating Salmonella Typhimurium and Escherichia coli was investigated. The total aerobic and coliform bacteria in the 16 commercial composts were ranged from 105 to 107 CFU/ml and 0 to 103 CFU/ml, respectively. All coliform bacteria in the composts were eliminated by irradiation at a dose of 3kGy, while about 102 CFU/ml of the total aerobic bacteria were survived up to 10kGy. In the artificial inoculation test, the test organisms (inoculated at 107 CFU/g) were eliminated by irradiation at 3kGy. Approximate D 10 values of Salmonella Typhimurium and E. coli in the compost were 0.40 and 0.25kGy, respectively. In the cultivation test, the test organisms of the compost had transfer a lettuce leaves. The growth pattern of lettuce was not different between irradiated and non-irradiated composts. [Copyright &y& Elsevier]