• Journal of Life Science
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• v.20 no.12
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• pp.1777-1783
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• 2010

Plants generate reactive oxygen species (ROS) as a by-product of normal aerobic metabolism or when exposed to a variety of stress conditions, which can cause widespread damage to biological macromolecules. To protect themselves from oxidative stress, plant cells are equipped with a wide range of antioxidant proteins. However, the detailed reaction mechanisms of these are still unknown. Peroxiredoxins (Prxs) are ubiquitous thiol-containing antioxidants that reduce hydrogen peroxide with an N-terminal cysteine. The active-site cysteine of peroxiredoxins is selectively oxidized to cysteine sulfinic acid during catalysis, which leads to inactivation of peroxidase activity. This oxidation was thought to be irreversible. Recently identified small protein sulphiredoxin (Srx1), which is conserved in higher eukaryotes, reduces cysteine.sulphinic acid in yeast peroxiredoxin. Srx1 is highly induced by $H_2O_2$-treatment and the deletion of its gene causes decreased yeast tolerance to $H_2O_2$, which suggest its involvement in the metabolism of oxidants. Moreover, Srx1 is required for heat shock and oxidative stress induced functional, as well as conformational switch of yeast cytosolic peroxiredoxins. This change enhances protein stability and peroxidase activity, indicating that Srx1 plays a crucial role in peroxiredoxin stability and its regulation mechanism. Thus, the understanding of the molecular basis of Srx1 and its regulation is critical for revealing the mechanism of peroxiredoxin action. We postulate here that Srx1 is involved in dealing with oxidative stress via controlling peroxiredoxin recycling in Arabidopsis. This review article thus will be describing the functions of Prxs and Srx in Arabidopsis thaliana. There will be a special focus on the possible role of Srx1 in interacting with and reducing hyperoxidized Cys-sulphenic acid of Prxs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.8
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• pp.1337-1343
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• 2003

Diabetes mellitus has been known to be a state of increased oxidative stress. Free radical formation and lipid peroxidation are accelerated in this metabolic disorder. Buchu (Allium tuberosum Rottler) contains lots of antioxidative nutrients such as chlorophyll, vitamin C, $\beta$-carotene, phenolic compounds and sulfur compounds. To investigate the protective effects of buchu, 10% lyophilized buchu diet was fed to streptozotocin (STZ)-induced diabetic rats for 14 weeks and lipid peroxidation, protein oxidation, contents of reactive oxygen species, activities of antioxidative enzymes and contents of accumulated lipofuscin were measured as indicators of oxidative stress. Hepatic MDA and carbonyl contents tended to decrease in 10% buchu diet group compared with control group. Dietary buchu significantly suppressed lipid and protein oxidation in the skin of rats (p<0.05). Contents of hepatic hydroxyl radicals, which exert the highest toxicity among the reactive oxygen species, were significantly decreased in rats fed 10% buchu diet (P<0.05). Activities of antioxidative enzyme, such as superoxide dismutase, catalase, and glutathione peroxidase, tended to increase in liver and skin of rats fed 10% buchu diet, while hepatic catalase activity was significantly increased in buchu group compared with control group. Buchu supplementation significantly inhibited the accumulation of lipofuscin, an end-product of lipid peroxidation reactions induced by reactive oxygen radicals, in eye tissues compared with control diet (p<0.001). In conclusion, buchu supplementation diminished the oxidative stress, so dietary buchu could help to attenuate diabetes complications.

• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.66-71
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• 2008

Phosphorus transfer from agricultural soils to surface waters is an important environmental issue. Fly ash and phospho-gypsum which are industrial by-product were investigated as a means of reducing dissolved phosphorus in arable soil. To determine the optimum mixing ratio of fly ash(FA) and phospho-gypsum(PG) for reducing dissolved reactive P(DRP) in soil, various mixture ratio of FA and PG were mixed with two soil. The DRP content and pH in soils were analysed after 3 weeks incubation under flooding condition. Although DRP content in soils was significantly decreased by FA-PG mixture compared with control, there were no significant difference among the FA and PG mixture ratio of 75:25, 50:50, and 25:75. The mixture of 75% FA and 25% PG was selected for field test. A field experiment was carried out to evaluate the reducing DRP content in paddy soil to which 0(NPK), 20(FG 20), 40(FG 40), and 60(FG 60) Mg $ha^{-1}$ of the mixture were applied. The DRP content was reduced by 31% at the application rate of 60 Mg $ha^{-1}$. In contrast to deceasing DRP, Ca-P content increased significantly with the mixture application rate. After rice harvesting, available $SiO_2$, P, and exchangeable Ca content in soil increased significantly with application rate due to high content of Si, P, and Ca in the mixture. Mixtures of fly ash and gypsum should reduce P loss from paddy soil and increase soil fertility.

• Journal of Energy Engineering
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• v.6 no.1
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• pp.77-86
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• 1997

In this study, numerical computations were performed to scrutinize the effect of the size of coal particles on reactive flow fields and concentration distribution of product gases for five cases with four different particle sizes (40 $\mu\textrm{m}$, 60 $\mu\textrm{m}$, 100 $\mu\textrm{m}$, 120 $\mu\textrm{m}$, 140 $\mu\textrm{m}$) in an axisymmetric cylindrical coal gasifier in which Alaska Usibelli subbituminous coals were gasified. Predictions showed that coal particle size affected the concentration distribution of product gases. When coals of 100 $\mu\textrm{m}$ were gasified, the maximum average concentrations of major products, H$_2$and CO, were predicted at the exit of the gasifier. The average mole fractions of CO and H, were shown to be 0.62, and 0.16 (dry basis, inert free), respectively. The cold gas efficiency of 83% was also predicted for the same particle size of 100 $\mu\textrm{m}$.

• Food Science of Animal Resources
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• v.38 no.3
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• pp.593-605
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• 2018

The present study was undertaken to assess the efficacy of sapota powder (SP) as natural preservatives and its better utilization in food processing with the incorporation of various levels of SP (2, 4, and 6%) by replacing lean meat. Based on the sensory attributes, pork patties with 4% incorporation of SP was found optimum and selected for further storage studies with control under aerobic and modified atmosphere packaging at refrigeration temperature ($4{\pm}1^{\circ}C$) for 42 days for assessing its antioxidant and antimicrobial efficiency. During entire storage period, indicators of lipid oxidative parameters such as thiobarbituric acid reactive substances (TBARS), free fatty acids (FFA) and peroxide value (PV) followed an increasing trend for control as well as treated products; however, treated product showed a significantly (p<0.05) lower value than control. A significantly lower (p<0.05) microbial count in treated patties than control was noted during entire storage. The sensory attributes are better retained in treated product as compared to control and even on $42^{nd}$ day, overall acceptability of treated patties was found to fall in moderately acceptable category (5.95 in aerobic packets and 5.91 in modified atmosphere packets). Therefore SP has potential to enhance antioxidant and antimicrobial properties of pork patties during storage.

• Korean Journal of Medicinal Crop Science
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• v.17 no.1
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• pp.1-7
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• 2009

Several parts of Lythrum salicaria were used for this study. Scavenging activities on radicals, inhibitory activity on linoleic acid peroxidation and total phenol contents of extracts from root, flower, and aerial part were evaluated. Flower and root selected from in vitro assay were subjected to in vivo assay on $CCL_4$-induced liver injury rat model for two weeks. Carbon tetrachloride intoxication on rats produced large amounts of hepatic lipid peroxidation product, thiobarbituric acid reactive substance (TBARS) compared with normal rats. Treatment with root extract of L. salicaria (LSR) showed effective inhibitory activity on lipid peroxidation product. Administration with LSR extract significantly alleviated $CCL_4$-induced increase in GPT activity which were more effective than silymarin. The results of this study suggest that root and flower of L. salicaria have antioxidant and liver protecting activities, and root part is the most effective candidate to develop a new functional material.

• Preventive Nutrition and Food Science
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• v.21 no.3
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• pp.221-226
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• 2016

A new type of doenjang was manufactured by mixing soaked soybean, koji (Rhizopus oryzae), cheonggukjang (Bacillus amyloliquefaciens MJ1-4 and B. amyloliquefaciens EMD17), and Pichia farinosa SY80 as a yeast, salt, and water, followed by fermentation with koji that was made by fermenting whole wheat with R. oryzae. The mixed culture doenjang was designed to have a more palatable flavor and stronger biological activities than the conventional product. The extract of mixed culture doenjang showed higher antioxidant activity than the commercial doenjang as evaluated by the ferric reducing antioxidant power assay although it was not significantly different from the commercial product in 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activities. Further, the mixed culture doenjang reduced intracellular reactive oxygen species levels and protected cells from glutamate-induced cytotoxicity more efficiently in human hippocampal HT22 neuroblastoma cells than the commercial doenjang. In conclusion, a newly-developed mixed culture doenjang had a strong antioxidant activity in vitro and cultured cell model systems, exhibited a potential to prevent oxidative stress-associated disorders although animal and clinical studies are needed to confirm its in vivo efficacy.

• Archives of Pharmacal Research
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• v.27 no.2
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• pp.177-183
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• 2004

In order to develop new anti-photoaging agents, we examined the antioxidative activity and the inhibition effect of matrix metalloproteinase-1 (MMP-1) on the extracts of a marine product, Zostera marina L., which is known for its potent activity. Three compounds (compounds 1, 2, and 3) were isolated from an ethyl acetate (EtOAc) soluble fraction of the product; they were identified as apigenin-7 -O-$\beta$-D-glucoside (1), chrysoeriol (2), and luteolin (3). These compounds were found to scavenge radicals and reactive oxygen species (ROS) and were measured to have $SC_{50}$/ values of 0.18 mM, 0.68 mM, and 0.01 mM against the 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical and 0.04 mM, 0.03 mM, and 0.01 mM against the superoxide radical in the xanthine/xanthine oxidase system, respectively. Compound 3 suppressed the expression of MMP-1 by up to 44％ at 4.0 $\mu$M and inhibited the production of interleukin 6 (IL-6), which is known as a cytokine that induces MMP-1 expression. From these results, compound 3 and the other compounds were determined to have antioxidative activity and to inhibit MMP-1 expression. Thus, the three compounds are expected to be useful for preventing the photoaging of skin.

• Food Science of Animal Resources
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• v.41 no.5
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• pp.826-839
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• 2021

A 60-d feeding trial was conducted to evaluate the effects of diets supplemented with two concentrations (0% and 0.3%) of black raspberry (Rubus coreanus Miquel) fruit by-product (RCFB) on the physicochemical characteristics, oxidative stability, antioxidant capacity, antioxidant enzyme activity, and fatty acid profile of M. longissimus dorsi (LL) porcine muscle from Berkshire finishing pigs meat. Results revealed that regardless of the sex, diets supplemented with 0.3% RCFB reduced (p<0.05) the thiobarbituric acid reactive substances (TBARS) expressed as malonaldehyde (MDA) content effectively. A higher antioxidant capacity [2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity] was found (p<0.05) in response to feeding supplemented with 0.3% RCBF for male or female pigs. Moreover, 0.3% RCFB dietary feed increased (p<0.05) the glutathione peroxidase enzyme activities (GPX1) in blood plasma for male or female pigs. However, no influences were observed (p>0.05) on meat color, WHC, shear force, and fatty acid contents while fed diet supplemented with 0% or 0.3% RCFB for male or female pigs. Overall, this study suggests that a diet supplemented with 0.3% RCFB may beneficially affect owing to better oxidative stability, higher antioxidant capacity, and antioxidant enzyme activity (blood plasma) in pigs which could be a promising natural antioxidant without affecting meat quality traits.

• Food Science of Animal Resources
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• v.43 no.1
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• pp.46-60
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• 2023

Slaughterhouse blood is a by-product of animal slaughter that can be a good source of animal protein. This research purposed to examine the functional qualities of the blood plasma from Hanwoo cattle, black goat, and their hydrolysates. Part of the plasma was hydrolyzed with proteolytic enzymes (Bacillus protease, papain, thermolysin, elastase, and α-chymotrypsin) to yield bioactive peptides under optimum conditions. The levels of hydrolysates were evaluated by 15% sodium dodecyl sulfate polyacrylamide gel electrophoresis. The antioxidant, metal-chelating, and angiotensin I-converting enzyme (ACE) inhibitory properties of intact blood plasma and selected hydrolysates were investigated. Accordingly, two plasma hydrolysates by protease (pH 6.5/55℃/3 h) and thermolysin (pH 7.5/37℃/3-6 h) were selected for analysis of their functional properties. In the oil model system, only goat blood plasma had lower levels of thiobarbituric acid reactive substances than the control. The diphenyl picrylhydrazyl radical scavenging activity was higher in cattle and goat plasma than in proteolytic hydrolysates. Ironchelating activities increased after proteolytic degradation except for protease-treated cattle blood. Copper-chelating activity was excellent in all test samples except for the original bovine plasma. As for ACE inhibition, only non-hydrolyzed goat plasma and its hydrolysates by thermolysin showed ACE inhibitory activity (9.86±5.03% and 21.77±3.74%). In conclusion, goat plasma without hydrolyzation and its hydrolysates can be a good source of bioactive compounds with functional characteristics, whereas cattle plasma has a relatively low value. Further studies on the molecular structure of these compounds are needed with more suitable enzyme combinations.