Quality Control of Gamma Irradiated Dwarf Mallow (Malva neglecta Wallr.) Based on Color, Organic Acids, Total Phenolics and Antioxidant Parameters.

This study addresses the effects of gamma irradiation (1, 5 and 8 kGy) on color, organic acids, total phenolics, total flavonoids, and antioxidant activity of dwarf mallow (Malva neglecta Wallr.). Organic acids were analyzed by ultra fast liquid chromatography (UFLC) coupled to a photodiode array (PDA) detector. Total phenolics and flavonoids were measured by the Folin-Ciocalteu and aluminium chloride colorimetric methods, respectively. The antioxidant activity was evaluated based on the DPPH(•) scavenging activity, reducing power, ß-carotene bleaching inhibition and thiobarbituric acid reactive substances (TBARS) formation inhibition. Analyses were performed in the non-irradiated and irradiated plant material, as well as in decoctions obtained from the same samples. The total amounts of organic acids and phenolics recorded in decocted extracts were always higher than those found in the plant material or hydromethanolic extracts, respectively. The DPPH(•) scavenging activity and reducing power were also higher in decocted extracts. The assayed irradiation doses affected differently the organic acids profile. The levels of total phenolics and flavonoids were lower in the hydromethanolic extracts prepared from samples irradiated at 1 kGy (dose that induced color changes) and in decocted extracts prepared from those irradiated at 8 kGy. The last samples also showed a lower antioxidant activity. In turn, irradiation at 5 kGy favored the amounts of total phenolics and flavonoids. Overall, this study contributes to the understanding of the effects of irradiation in indicators of dwarf mallow quality, and highlighted the decoctions for its antioxidant properties.

Elimination of Listeria monocytogenes from vacuum-packed dry-cured ham by E-beam radiation.

The inactivation kinetics for Listeria monocytogenes Scott A (CIP 103575, serotype 4b) and Listeria innocua (NTC 11288) after E-beam radiation were studied in vacuum-packed ready-to-eat dry-cured ham to optimize the sanitation treatment of this product. A treatment of 1.12 kGy was calculated to reach the food safety objective according to the U.S. Department of Agriculture criterion. No irradiation treatment is necessary to meet the European Union microbiological criterion for this bacterium. No changes (at doses < or =4 kGy) in the 2-thiobarbituric acid reactive substances values and texture were observed. Dry-cured hams treated with 1 and 2 kGy had negligible sensory modifications (appearance, odor, and flavor). However, the application of 3 and 4 kGy resulted in an increase in the intensity of off-odors and off-flavors. Despite these effects, all irradiated vacuum-packed dry-cured hams treated at < or =4 kGy were deemed acceptable for trading.

Electron beam irradiation improves shelf lives of Korean ginseng (Panax ginseng C.A. Meyer) and red ginseng.

Effect of electron beam irradiation on microbial growth and qualities of vacuum-packaged Korean ginseng and red ginseng during storage was investigated. Korean ginseng and red ginseng were treated at irradiation doses of 0, 2, 8, and 16 kGy. After treatment, samples were individually vacuum-packaged and stored at 20 degrees C. Microbial growth results of the irradiated samples presented that populations of total bacteria, yeast and mold, and total coliforms were decreased by 2 to 3 log CFU/g. The pH values of the samples were not significantly different among treatments. Thiobarbituric acid-reactive substance values of the samples increased during storage. Electron beam treatment caused negligible changes in Hunter's color L, a, and b values among the samples. Sensory evaluations like color and odor of the samples exhibited that there were no significant changes among the samples. During storage, content of saponin, a leading compound in ginseng, was not affected by irradiation. These results suggest that electron beam treatment should be useful in extending shelf lives of Korean ginseng and red ginseng.

Melatonin prevents inflammation and oxidative stress caused by abdominopelvic and total body irradiation of rat small intestine

We investigated the day-night differences in intestinal oxidative-injury and the inflammatory response following total body (TB) or abdominopelvic (AP) irradiation, and the influence of melatonin administration on tissue injury induced by radiation. Rats (male Wistar, weighing 220-280 g) in the irradiated groups were exposed to a dose of 8 Gy to the TB or AP region in the morning (resting period - 1 h after light onset) or evening (activity span - 13 h after light onset). Vehicle or melatonin was administered immediately before, immediately after and 24 h after irradiation (10, 2.0 and 10 mg/kg, ip, respectively) to the irradiated rats. AP (P < 0.05) and TB (P < 0.05) irradiation applied in the morning caused a significant increase in thiobarbituric acid reactive substance (TBARS) levels. Melatonin treatment in the morning (P < 0.05) or evening (P < 0.05) decreased TBARS levels after TB irradiation. After AP irradiation, melatonin treatment only in the morning caused a significant decrease in TBARS levels (P < 0.05). Although we have confirmed the development of inflammation after radiotherapy by histological findings, neither AP nor TB irradiation caused any marked changes in myeloperoxidase activity in the morning or evening. Our results indicate that oxidative damage is more prominent in rats receiving TB and AP irradiation in the morning and melatonin appears to have beneficial effects on oxidative damage irrespective of the time of administration. Increased neutrophil accumulation indicates that melatonin administration exerts a protective effect on AP irradiation-induced tissue oxidative injury, especially in the morning.

Melatonin prevents inflammation and oxidative stress caused by abdominopelvic and total body irradiation of rat small intestine.

We investigated the day-night differences in intestinal oxidative-injury and the inflammatory response following total body (TB) or abdominopelvic (AP) irradiation, and the influence of melatonin administration on tissue injury induced by radiation. Rats (male Wistar, weighing 220-280 g) in the irradiated groups were exposed to a dose of 8 Gy to the TB or AP region in the morning (resting period - 1 h after light onset) or evening (activity span - 13 h after light onset). Vehicle or melatonin was administered immediately before, immediately after and 24 h after irradiation (10, 2.0 and 10 mg/kg, ip, respectively) to the irradiated rats. AP (P < 0.05) and TB (P < 0.05) irradiation applied in the morning caused a significant increase in thiobarbituric acid reactive substance (TBARS) levels. Melatonin treatment in the morning (P < 0.05) or evening (P < 0.05) decreased TBARS levels after TB irradiation. After AP irradiation, melatonin treatment only in the morning caused a significant decrease in TBARS levels (P < 0.05). Although we have confirmed the development of inflammation after radiotherapy by histological findings, neither AP nor TB irradiation caused any marked changes in myeloperoxidase activity in the morning or evening. Our results indicate that oxidative damage is more prominent in rats receiving TB and AP irradiation in the morning and melatonin appears to have beneficial effects on oxidative damage irrespective of the time of administration. Increased neutrophil accumulation indicates that melatonin administration exerts a protective effect on AP irradiation-induced tissue oxidative injury, especially in the morning.

Plasma level of lipid peroxidation, total sulphydryl groups and nitric oxide levels in cancer patients irradiated on different anatomic fields: a case-control study.

AIM: The aim of this study was to evaluate the effect of radiotherapy on lipid peroxidation, total sulfhydryl groups (RSH) and nitric oxide (NO radical) levels in plasma of cancer patients treated on different anatomic sites, and to compare the results with control subjects. METHODS: 89 patients with various malignancies and 33 healthy control subjects were recruited for the study. Cancer patients were grouped according to the irradiation portals (head and neck, thoracic, breast, abdominal and pelvic). Two blood samples before and after the completion of the fifth week of radiotherapy were collected from each patient. RESULTS: Plasma levels of malondialdehyde (MDA) and NO radical of cancer patients before irradiation were found higher than those in control subjects. After irradiation, a marked lipid peroxidation increase was demonstrated as well as the significant decrease of plasma RSH level. CONCLUSION: The alterations of the parameters indicate enhanced oxidant stress and point to the necessity of antioxidant prophylaxis upon application of radiotherapy.

Inhibitory effect of local ischaemic preconditioning in total body irradiated rats.

The aim of this study was to explore the relationship between local ischaemic preconditioning and the effectiveness of fractionated radiotherapy. The rat serum, bone marrow, and small intestine were examined for oxidative changes induced by total body irradiation with gamma rays with applied local ischaemic preconditioning immediately before irradiation. Serum concentrations of TBA-RS examined 12 hours after the last irradiation did not reveal any differences among the groups of animals analyzed. Twenty-four hours after the last dose of irradiation, the serum concentrations of TBA-RS varied in particular groups (P<0.0001). The concentration of triglycerides in the serum of local preconditioned ischaemia and irradiated animals showed a reversed shape similar to the TBA-RS fluctuation (P<0.003). The level of uric acid in the serum of animals treated only with radiation is slightly higher than the level of this acid in the serum of the local preconditioned ischaemia radiation group (P<0.58). The number of bone marrow polychromatic erythrocytes did not appear to differ substantially in both irradiated groups. At the first 12 hours after irradiation, the frequency of micronucleated polychromatic erythrocytes is significantly different in the bone marrow of both groups either in combination with ischaemic preconditioned radiation or with radiation alone (P<0.0002). In irradiated animals without ischaemic preconditioning, on the 3rd day after irradiation the number of crypts increased and in the next days decreased achieving the level of the control group on the 7th day. Irradiated rats with local ischaemic preconditioning did not reveal an increase in the number of crypts. The difference was statistically significant (P<0.05). These data indicate that the local ischaemic preconditioning modifies the radiation peroxidising effects through inhibition of free radical-dependent lipid peroxidation and, probably, other unrecognized mechanisms.

Adequate intakes of vitamin E and protein prevent increases of oxidative damage to DNA, lipids, and protein induced by total body irradiation in mice.

We examined the influence of the level of dietary protein or vitamin E (VE) on oxidative damage to DNA, lipids, and protein in the liver after total body irradiation (TBI) with X-rays at 1 or 4 Gy. Levels of 8-hydroxydeoxyguanosine, thiobarbituric acid-reactive substances, and protein carbonyls in the liver did not differ among the groups that did not receive TBI. However, oxidative damage to lipids and protein was increased by TBI only in the 1% protein group. DNA damage, lipid peroxidation, or protein oxidation in the liver was increased by TBI in a dose-dependent manner, and the damage was consistently higher in the 1% than in the 20% protein group. In the 1% protein group, a greater decrease in relative spleen weight by TBI was also observed. Concentrations of antioxidants (vitamins C and E and glutathione) in the liver were lower and the concentration of nonheme iron in the liver was higher in the 1% than in the 20% protein group. Mice fed a 1% protein diet became susceptible to TBI-induced oxidative damage, and decreases in antioxidant levels and an increase in iron level were involved in the mechanism of this susceptibility. These results suggest that dietary VE and protein can prevent oxidative damage to DNA, lipid, and protein in mice subjected to TBI. Consumption of a VE-free diet significantly increased 8-hydroxydeoxyguanosine levels in DNA from mice fed the 1% protein diet with TBI, but such changes were not detected in DNA from mice fed the 20% protein diet.

A comparison of the kinetics of low-density lipoprotein oxidation induced by copper or by gamma-rays: influence of radiation dose-rate and copper concentration.

The oxidation of low-density lipoproteins is the first step in the complex process leading to atherosclerosis. The aim of our study was to compare the kinetics of low density lipoprotein oxidation induced by copper ions or by oxygen free radicals generated by 60Co gamma-rays. The effects of copper concentration and irradiation dose-rate on LDL peroxidation kinetics were also studied. The oxidation of LDL was followed by the measurement of conjugated diene, hydroperoxides, and thiobarbituric acid reactive substance formation as well as alpha-tocopherol disappearance. In the case of gamma irradiation, the lag-phase before the onset of lipid peroxidation was inversely correlated to the radiation dose-rate. The radiation chemical rates (nu) increased with increasing dose-rate. Copper-induced LDL peroxidation followed two kinetic patterns: a slow kinetic for copper concentrations between 5-20 microM, and a fast kinetic for a copper concentration of 40 microM. The concentration-dependent oxidation kinetics suggest the existence of a saturable copper binding site on apo-B. When compared with gamma-rays, copper ions act as drastic and powerful oxidants only at higher concentrations (> or = 40 microM).

5-aminolevulinic acid induced lipid peroxidation after light exposure on human colon carcinoma cells and effects of alpha-tocopherol treatment.

This work relates to studies on modes of phototoxicity by protoporphyrin (PpIX) after incubation of 5-aminolevulinic acid (5-ALA) on cultured cells. Lipid peroxidation in the 5-ALA incubated primary adenocarcinoma cells from the rectosigmoid colon (WiDr cells) was determined by measurement of protein-associated thiobarbituric acid reactive substances (TBARS). TBARS were increased 2-fold in cells treated with 2 mM 5-ALA for 3.5 h in serum enriched medium. After illumination of 5-ALA incubated cells, TBARS were formed in a light dose dependent manner. TBARS analysis were compared with high-performance liquid chromatography (HPLC) analysis of malondialdehyde, and results indicate that 90% of the thiobarbituric reactive substances were due to malondialdehyde. Pretreating WiDr cells with alpha-tocopherol for 48 h inhibits the cytotoxic effect of 5-ALA and increases 5-fold the light dose needed to kill 50% of the cells. Pretreatment with alpha-tocopherol shows a considerable decrease (about 80%) on TBARS formation after illumination. The cellular content of alpha-tocopherol was determined by HPLC and found to be 15.3 pmol/10(6) cells.

Pantothenol protects rats against some deleterious effects of gamma radiation.

Rats were exposed to gamma radiation from a 60Co source, receiving 0.25 Gy at weekly intervals. During 2 d before each irradiation, the animals received daily intragastric doses of 26 mg pantothenol or 15 mg beta-carotene per kg body weight. One hour after the third irradiation session, the animals were killed and their livers were analyzed. In animals not supplied with pantothenol, the irradiation resulted in a significant decrease of total liver lipids and a 50% decrease in phospholipids. Liver cholesterol was decreased by about 20%. Irradiation produced lipid peroxidation as expressed by doubling of the amounts of conjugated dienes and ketone dienes and of thiobarbituric acid reactive compounds. The amount of CoA in liver was decreased by 24% and that of reduced glutathione by 40%. The NAD+/NADH ratio was increased by 60% and the activity of NADP-dependent malate dehydrogenase (decarboxylating) was decreased by 26%. The amount of pantothenic acid and its derivatives (expressed as pantolactone-generating compounds) in blood decreased by about 80%. In rats to which pantothenol was administered, the content of pantothenic acid in blood was tripled compared to nonirradiated (control) rats, and all the biochemical parameters measured in liver were the same as in nonirradiated animals.