• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.9
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• pp.1419-1425
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• 2004

This study was performed to examine in vitro antioxidative activities such as DPPH radical scavenging activity, reducing power and tyrosinase inhibitory effect of various solvent fractions from Chionanthus retusa leaves. Ethyl acetate fraction showed potent antioxidative activity and tyrosinase inhibitory effect. The active compound was isolated from the butanol fraction by silica gel column chromatography and MPLC. The isolated compound was luteolin-4'-O-glucoside determined by $^1H$, $^{13}C$-NMR and 2D NMR. Compared with several antioxidant compounds, luteolin-4'-O-glucoside exhibited effective DPPH radical scavenging activity and reducing power in a concentration dependent manner. Bioassay with pure luteolin-4'-O-glucoside showed a dose-independent inhibitory effect on L-DOPA oxidation by mushroom tyrosinase and its $IC_{50}$ values were established as 23.2 ${\mu}g/mL$. Therefore, we may suggest that luteolin-4'-O-glucoside can be used as a food additive possessing the potent antioxidative activity and skin-whitening cosmetic material.

• Advances in Traditional Medicine
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• v.8 no.4
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• pp.329-338
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• 2008

The aim of the study is to investigate the antioxidant activity through, reducing power, 2, 2-diphenyl-1-picryl hydrazyl radical (DPPH), nitric oxide radical (NO), superoxide radical, hydrogen peroxide radical ($H_2O_2$) scavenging activity and the amount of total phenolic compounds of chloroform, ethyl acetate, methanol and aqueous extracts of the leaves of Talinum portulacifolium. Chloroform extract of leaves of T. portulacifolium showed highest antioxidant activity, with a direct relationship between activity and concentration of extracts ($15-240\;{\mu}g/mL$). Among all the extracts, the highest amount of the total polyphenolic compounds was found in the chloroform extract. Chloroform extract of T. portulacifolium showed an important free radical scavenging activity towards the DPPH, NO, Superoxide and $H_2O_2$ radicals, with $IC_{50}$ values of 133.26, 165.75, 156.34 and $135.29\;{\mu}g/mL$, respectively. In the lipid peroxidation assay, extracts of chloroform and ethyl acetate showed a remarkable inhibitory activity. The extracts showed significant activity in all the experiments but lower than the standard antioxidant, ascorbic acid.

• Journal of Food Hygiene and Safety
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• v.17 no.2
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• pp.106-116
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• 2002

The 70% ethanol extract of Alpinia officinarum and its major flavonoid, galangin showed strong antioxidative effect on the lipid peroxidation of ethyl linolate with Fenton's reagent and free radical scavenging effect to DPPH radical generation. However, they did not reveal any pro-oxidant effect on bleomycin-Fe(III) dependent DNA degradation. They also showed the protective effect against $H_2O$$_2$, KO$_2$ or UV-induced cytotoxicity in mammalian cells. They also showed the suppressive effect of DNA damage induced by $H_2O$$_2$ or KO$_2$ with dose-dependent manner in single cell gel electrophoresis(SCGE) assay. On the other hand, they have an anticlastogenic effect against adriamycin-induced micronucleated reticulocyte in peripheral blood of mice. These results suggest that the mechanism of inhibition by 70% ethanol extract of Alpinia officinarum and galangin against reactive oxygen species (ROS)-induced genotoxicity or cytotoxicity is due, at least partly, to their antioxidative and free radical scavenging properties without pro-oxidant effect. All these results indicate that 70% ethanol extract of Alpinia officinarum and galangin may be useful for protection against ROS-induced cytotoxicity and DNA damage.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.1025-1035
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• 2017

In this study, the hot water extract from Mulberry (Morus alba) Leaves fermented with Hericium erinaceum mycelium (MA-HE) was assessed for antioxidant activity. Radical scavenging activity of MA-HE evaluated using 2,2-diphenyl-1-picrylhydrazyl(DPPH) radical and 2,2'-azino-bis(3-ethyl-benzothiazoline-6-sulfonic acid)(ABTS) radical. MA-HE showed 63% DPPH radical scavenging activity at $500{\mu}g/mL$ and 98.27% ABTS radical scavenging activity at $250{\mu}g/mL$. MA-HE was shown to significantly inhibited DNA strand breakage induced by free radical. MA-HE also inhibited free radical-mediated human serum albumin modification. MA-HE effectively inhibited $H_2O_2$ induced cell death and significantly increased of the 8% cell survival at $100{\mu}g/mL$. MA-HE decreased intracellular reactive oxygen species (ROS) levels in $H_2O_2$-treated cells. The results suggested that MA-HE can contribute to antioxidant and protected cells from oxidative stress-induced cell injury.

• Journal of Microbiology and Biotechnology
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• v.28 no.12
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• pp.1982-1991
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• 2018

Ethanol accumulation inhibited the growth of Saccharomyces cerevisiae during wine fermentation. Autophagy and the release of reactive oxygen species (ROS) were also induced under ethanol stress. However, the relation between autophagy and ethanol stress was still unclear. In this study, expression of the autophagy genes ATG1 and ATG8 and the production of ROS under ethanol treatment in yeast were measured. The results showed that ethanol stress very significantly induced expression of the ATG1 and ATG8 genes and the production of hydrogen peroxide ($H_2O_2$) and superoxide anion (${O_2}^{{\cdot}_-}$). Moreover, the atg1 and atg8 mutants aggregated more $H_2O_2$ and ${O_2}^{{\cdot}_-}$ than the wild-type yeast. In addition, inhibitors of the ROS scavenging enzyme induced expression of the ATG1 and ATG8 genes by increasing the levels of $H_2O_2$ and ${O_2}^{{\cdot}_-}$. In contrast, glutathione (GSH) and N-acetylcystine (NAC) decreased ATG1 and ATG8 expression by reducing $H_2O_2$ and ${O_2}^{{\cdot}_-}$ production. Rapamycin and 3-methyladenine also caused an obvious change in autophagy levels and simultaneously altered the release of $H_2O_2$ and ${O_2}^{{\cdot}_-}$. Finally, inhibitors of the mitochondrial electron transport chain (mtETC) increased the production of $H_2O_2$ and ${O_2}^{{\cdot}_-}$ and also promoted expression levels of the ATG1 and ATG8 genes. In conclusion, ethanol stress induced autophagy which was regulated by $H_2O_2$ and ${O_2}^{{\cdot}_-}$ derived from mtETC, and in turn, the autophagy contributed to the elimination $H_2O_2$ and ${O_2}^{{\cdot}_-}$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.5
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• pp.524-529
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• 2006

Chemical compounds, hydrogen peroxide and nitrite-scavenging activities of Phellinus baumii (PB) were investigated to expand the utilization of PB as functional food material. Total mineral contents of PB was 534.3 mg% and potassium was the highest content being 224 mg%. Total and reducing sugars were 56.2% and 9.8%, respectively The contents of free amino acids (FAAs) were in a range of $16.9{\sim}765.5mg%$ with the major FAAs of phenylalanine, aspartic acid, glutamic acid, leucine, serine and valine. The contents of total phenolic compounds in methanol and hot water extracts of PB were 33.3 and 20.7 mg/100 mL, respectively and were higher than those of other solvent extracts. Hydrogen peroxide-scavenging activity (80%) of methanol extract at $10{\mu}g/mL$ for 30 min was similar to tocopherol (83.1%) as control. Nitrite-scavenging activity of extracts of methanol and hot water at 500 mg/mL and pH 1.2 were 57.3% and 51.8%, respectively and then their effects were increased by lowering pH. The present results showed that the methanol and water extracts of Phellinus baumii exhibited strong hydrogen peroxide and nitrite-scavenging activities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.9
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• pp.1379-1383
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• 2010

Nectarine beverage treated with cellulase and pectinase enzymes was measured for mineral contents, total flavonoids, and free amino acids and DPPH radical scavenging effect, nitrite scavenging effect. Total flavonoid contents of the no treatment, treated with pectinase, with cellulase, and with both measured 0.146 mg/mL, 0.167 mg/mL, 0.148 mg/mL and 0.171 mg/mL, respectively. DPPH was measured as 13.42% with no treatment and more than 28.98% with enzyme treatments. Nitrite scavenging effect with no treatment was 79% at pH 1.2. Whereas, it was measured above 90% while treated with enzymes at pH 1.2. And also, the nitrite scavenging effect was slightly higher at pH 3.0, pH 4.0 and pH 6.0 than no treatment. Results of free amino acids analysis revealed that, aspartic acid, serine, alanine, $\gamma$-aminobutylic acid, and glutamic acid were present with the amount ranging from 86.71% to 94.14% from total detected free amino acids. Ornithine and taurine were also observed from the beverages. The mineral contents, nitrogen element (T-N) of enzyme treatment of nectarine beverages were measured slightly higher than T-N of no treatment, however, the $P_2O_5$ was similar. Moreover, CaO, MgO and $K_2O$ in the beverages were measured above 45 mg/L, 85 mg/L and 2,133 mg/L, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.11
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• pp.1408-1413
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• 2017

The aim of this study was to investigate the antioxidant activities and protective effects of hot water extract from Curcuma longa L. (CLW) on oxidative stress-induced C2C12 myoblasts. Antioxidant activities of CLW were evaluated based on 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities. Protective effects of CLW on oxidative stress-induced C2C12 myoblasts were determined based on cytotoxicity, $H_2O_2$ protective activity, and intracellular reactive oxygen species (ROS) level. DPPH and ABTS radical scavenging activities represented by $SC_{50}$ were $188.5{\pm}3.0{\mu}g/mL$ and $92.0{\pm}0.9{\mu}g/mL$, respectively. Using C2C12 myoblasts, CLW treatment increased cell viability against oxidative stress-induced cell death. Further, CLW treatment reduced the intracellular ROS level in cells treated with $H_2O_2$. These results suggest that CLW might have the capability to protect oxidative stress-induced C2C12 myoblasts.

• Environmental Mutagens and Carcinogens
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• v.19 no.2
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• pp.116-121
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• 1999

Quercetin and its glycosides showed a strong free radical scavenging effect to DPPH radical generation. However, there were not big differences between quercetin aglycone and glycosides under experimental condition of this study. On the other hand, quercetin had pro-oxidant effect in bleomycin-dependent DNA assay. Quercetin aglycone and its glycosides, quercitrin inhibited $H_2$$O_2$- induced DNA damage in CHL cells. They also have an anticlastogenicity toward DNA breakage agent by radical generation like bleomycin. These results indicate that quercetin aglycone and its glycosides are capable of protecting the free radical generation induced by reactive oxygen species like $H_2$$O_2$. The mechanism of inhibition in hydrogen peroxide-induced genotoxicity may be due to their free radical scavenging properties. Therefore, quercetin aglycone and its glycosides may be useful chemopreventive agents by protecting of free radical generation which are involved in carcinogenesis and aging. However, quercetin and its glycosides must also carefully examined for pro-oxidant properties before being proposed for use in vivo.

• Journal of the Korean Chemical Society
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• v.56 no.3
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• pp.334-340
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• 2012

A new series of ethyl 2-(4-substitutedbenzylidene)-5-(3'-(ethoxycarbonyl)biphenyl-4-yl)-7-methyl-3-oxo-3,5-dihydro-2H-thiazolo[3,2-a]pyrimidine-6-carboxylate derivatives ($\mathbf{8a-j}$) were synthesized. The newly synthesized compounds were characterized by $\mathbf{IR}$, $^1\mathbf{H}$ $\mathbf{NMR}$, $^{13}\mathbf{C}$ $\mathbf{NMR}$, $\mathbf{LCMS}$ $\mathbf{mass}$ and $\mathbf{C}$, $\mathbf{H}$, $\mathbf{N}$ analyses. All newly synthesized compounds were screened for their In vitro antioxidant activity (Scavenging of hydrogen peroxide, Scavenging of nitric oxide radical, and Lipid peroxidation inhibitory activity), antibacterial (Escheria coli, Pseudonmonas aeruginosa (gram-negative bacteria), Bacillus subtillis, Staphylococcus aureus (gram-positive bacteria)) and antifungal (Candida albicans Aspergillus niger) studies.