• Korean Journal of Pharmacognosy
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• v.37 no.4 s.147
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• pp.307-313
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• 2006

Reactive oxygen species (ROS) and formation of advanced glycation end products (AGEs) play an important role in the pathogenesis of diabetic nephropathy by hyperglycemia. To find natural agents improving diabetic nephropathy, 63 natural resources which used to the treatment of diabetes mellitus in a folk remedy were investigated with an in vitro system employing radical scavenging activity and inhibitory activity of AGEs formation. In results, the extracts of Aspalathus linearis, Rubus coreanus, Rosa rugosa, and Epimedium koreanum significantly inhibited the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical with $IC_{50}$ values less than $10{\mu}g/ml$. The extracts of Zea mays, Cucurbita moschata, Cudrania tricuspidata, and Aspalathus linearis effectively reduced the formation of AGEs compared with the positive control $N-acetyl-_L-cystenine$ (NAC) and aminoguanidine (AG). In addition, the extracts of Aspalathus linearis, Commelina communis, Cornus officinalis, and Lespodeza cuneata showed the all inhibitory activity against DPPH radical and AGEs formation. Also, these resources definitely showed the radical scavenging activity against peroxynitrite $(ONOO^-)$ and hydroxyl radical $({\cdot}OH)$ relating to high glucose-induced ROS production. Thus, these results suggest that some natural resources may regulate the initiation and progression of diabetic nephropathy through inhibition of ROS production and AGEs formation.

• Journal of Applied Biological Chemistry
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• v.55 no.3
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• pp.157-161
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• 2012

The aim of this research was to investigate the industrial application of Sedum sarmentosum. Antibacterial activities of the n-hexane, methylene chloride (MC), ethyl acetate, and n-butanol fractions of S. sarmentosum were tested against Escherichia coli, Staphylococcus aureus, and Helicobacter pylori. The MC fraction showed the strongest antibacterial activity against E. coli, with an inhibition zone greater than 13 mm in disc assays. At $100{\mu}g/mL$, all fractions scavenged more than 50% of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radicals (${\cdot}OH$). In particular, the MC fraction showed the strongest scavenging activity against DPPH and ${\cdot}OH$. In addition, we found that treatment with the MC fraction inhibited the growth of H. pylori and gastric adenocarcinoma cells. The present results suggest that the MC fraction of S. sarmentosum would play the promising protective role against pathogenic bacteria and free radicals.

• Natural Product Sciences
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• v.20 no.3
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• pp.137-145
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• 2014

The biological activities of licorice F1 (Glycyrrhiza glabra ${\times}$ G. uralensis) lines (G) were investigated, revealing strong radical scavenging activity targeting 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl (${\cdot}OH$) radicals. At a concentration of $100{\mu}g/mL$, most of the licorice F1 lines scavenged DPPH and ${\cdot}OH$ by more than 80%. Gs-1, -2, and -6 can be considered good scavengers of DPPH radical and G-7 have higher antioxidant activity against ${\cdot}OH$ radical. In addition, licorice F1 lines exerted effective anti-microbial activities against Escherichia coli (Gs-12, -17, and -18) and Staphylococcus aureus (Gs-3, -4, -5, -21, and -26). Moreover, Gs-2, - 20, -31, and -32 effectively inhibited the growth of Helicobacter pylori. Among licorice F1 lines, Gs-25 exhibited high anti-inflammatory effects on nitric oxide produced by lipopolysaccharide- and interferon-${\gamma}$-activated RAW 264.7 cells. Furthermore, Gs-1, -12, and -20 inhibited the growth of AGS human gastric adenocarcinoma cells by more than 60% at a concentration of $100{\mu}g/mL$ and Gs-5, -11, -19, and -32 showed inhibitory effects against rat lens aldose reductase ($IC_{50}$ values, 1.69, 6.07, 6.12, and $4.54{\mu}g/mL$, respectively). The total content of glycyrrhizin (1), glycyrrhetinic acid (2), glabridin (3), and isoliquiritigenin (4) in licorice F1 lines was high in Gs-11, -15, and -30. The present study therefore indicated that Gs-2, -26, -31, and -32 of licorice F1 possessing strong anti-oxidative, anti-microbial, anti-inflammatory, anti-cancer, and aldose reductase inhibitory effects may be used as a possible source material for natural health supplements in the future.

• Preventive Nutrition and Food Science
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• v.16 no.1
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• pp.89-94
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• 2011

The potential biological activities of water and ethanol extracts from two varieties of Rubus coreanus Miquel fruits produced in the Gochang-gun (GR) and Hoengseong-gun (HR) regions of Korea were examined. The hydroxyl radical ($\cdot$OH) scavenging activity, reducing power, lipid peroxidation inhibitory activity, and antiproliferative activity on cancer cells by these extracts were examined, and $\alpha$-amylase and $\alpha$-glucosidase inhibition assays were also performed. The EtOH extract from GR showed high hydroxyl radical scavenging activity ($EC_{50}=119.47{\pm}5.13\;{\mu}g/mL$), lipid peroxidation inhibitory activity ($EC_{50}=213.45{\pm}3.14\;{\mu}g/mL$) and a concentration dependence, with OD values ranging from 0.15 to 0.56 (50 to 200 ${\mu}g/mL$), for reducing power. The EtOH extract from GR has the highest antiproliferative activities on MDA-MB-231 and HepG2 cancer cells among four extracts. Meanwhile, all extracts showed certain $\alpha$-amylase and $\alpha$-glucosidase inhibition activities. These results indicate that extracts from two varieties of R. coreanus fruits have significant antioxidant, anti-diabetic and anti-tumorigenic activities, which suggest these extracts could be a potential source for pharmaceutical.

• The Korean Journal of Pharmacology
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• v.20 no.1 s.34
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• pp.1-11
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• 1984

The present study was performed to determine oxygen metabolites involved in cell-free MPO/$H_2O_2/Cl^-$ system by observing the effects of their scavengers on NADH oxidation and ethylene production from methional by the action of MPO prepared from human leukocytes. It was clearly demonstrated that NADH was oxidized by the cell-free MPO/$H_2O_2/Cl^-$ system as evidenced by complete inhibition of the oxidation of the substrate in the presence of eiher azide or catalase, or by omitting $Cl^-$. The MPO-mediated oxidation of NADH was completely abolished by a $^1O_2$ quencher, DABCO but not by $OH{\cdot}$ scavengers, mannitol, benzoate, formate and methanol. In ethylene assay, no ethylene was detected from methional in the MPO/$H_2O_2/Cl^-$ system with evident production of the gas by xanthine-oxidase and $Cu^{++}-H_2O_2$ systems which are suggested to generate $OH{\cdot}$. From the results obtained, it is concluded that $^1O_2$ is a major mediator with exclusion of $OH{\cdot}$ involvement in the cell-free MPO-mediated oxidation.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.04a
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• pp.40-40
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• 2005

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.3
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• pp.360-366
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• 2014

Kimchi is a Korean traditional fermented food with various health functionalities. However, the protective effects of kimchi against Alzheimer's disease (AD) have not been studied yet. In this study, the protective activities of kimchi extract against oxidative stress and AD were investigated in an amyloid beta ($A{\beta}$)-induced AD model using ICR mice. Kimchi extract exerted strong scavenging activities against 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radical. In addition, T-maze, object cognition, and water maze tests were carried out using the AD model. The $A{\beta}_{25-35}$-injected groups showed impairment of cognition and memory. However, the abilities of novel object recognition and new route awareness were improved by administration of kimchi extract (100 and 200 mg/kg/day) for 2 weeks. Furthermore, the results on water maze test indicated that kimchi extract exerted protective activity against cognitive impairment induced by $A{\beta}_{25-35}$. The present study suggested that kimchi protected against $A{\beta}$-induced impairment of memory and cognition as well as attenuated oxidative stress.

• Analytical Science and Technology
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• v.13 no.5
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• pp.659-665
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• 2000

The changes in $UV_{254}$ and concentrations of $H_2O_2$ formed by ozonation of aqueous humic acid in ozone/high pH, peroxone process and in the presence of radical scavenger, $HCO_3{^-}$ were investigated. This study confirmed that the formation of $H_2O_2$ by ozonation may undergo different reaction pathways compared to those of $UV_{254}$ reduction in the degradation of the humic acid. The concentration of $H_2O_2$ produced by ozonation was found to be increased with decreasing pH of the sample solution due to the higher stability of ozone molecules at acidic conditions. On the while, $UV_{254}$ reduction was found to be higher at alkaline conditions or larger amount of $H_2O_2$ additions as a radical promoter in which the producing of ${\cdot}OH$, ${\cdot}HO_2$ radicals can be more favorable. From the results, it has been suggested that the formation of $H_2O_2$ by ozonation depends mainly on the direct reactions of ozone with humic acid molecules, while $UV_{254}$ reduction is affected by both the indirect reactions of the radicals and direct reactions of ozone with humic acid.

• Environmental Engineering Research
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• v.18 no.1
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• pp.29-35
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• 2013

This study noted that the actual mechanism of N-nitrosodimethylamine (NDMA) photodecomposition in the presence of $H_2O_2$ is missing from the previous works. This study investigated a key unknown reactive species (URS) enhanced by the addition of $H_2O_2$ during the photolysis of NDMA with $H_2O_2$, not hydroxyl radicals. In order to provide experimental evidences in support of URS formation, we have mainly used p-nitrosodimethylaniline, methanol, and benzoic acid as well-known probes of ${\cdot}OH$ in this study. Both loss of PNDA and formation of hydroxybenzoic acids were dependent on NDMA concentrations during the photolysis in a constant concentration of $H_2O_2$. In particular, competition kinetics showed that the relative reactivity of an URS was at least identical with ${\cdot}OH$-like reactivity. In addition, the decay of NDMA was estimated to be about 65% by the direct UV light and about 35% by the reactive species or URS generated through the photolysis of NDMA and $H_2O_2$. Therefore, our data suggest that a highly oxidizing URS is formed in the photolysis of NDMA with $H_2O_2$, which could be peroxynitrite ($ONOO^-$) as a potent oxidant by itself as well as a source of ${\cdot}OH$.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1156-1159
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• 2008

The antioxidant activity of hot water extracts of various parts, the leaf, stem, and root of Synurus deltoides was evaluated by various antioxidant assays, including total phenolic content, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, hydroxyl radical (${\cdot}OH$) scavenging, superoxide dismutase (SOD), and xanthine oxidase (XOI) activities. The various antioxidant activities were compared with the standard antioxidants such as L-ascorbic acid, $\alpha$-tocopherol, and butylated hydroxyanisole (BHA). Among the different plant parts, stem has been found to possess the highest activity in all tested model systems, the activity decreased in the order stems>roots>leaves. These results indicate that stem extract could be used as potential source of natural antioxidant.