• Preventive Nutrition and Food Science
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• v.13 no.3
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• pp.182-189
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• 2008

In this study, the effect of pH on the antioxidative activities of melanoidins formed as a result of the reaction between sugars, glucose (Glc) or fructose (Fru), and amino acids, L-asparagine (L-Asn) and D-asparagine (D-Asn) are examined. For this purpose, antioxidative activities were evaluated on the basis of reducing power, including ferric reducing/antioxidant power (FRAP) and free radical scavenging activity includes 1,1-diphenyl-2-picryl- hydrazil (DPPH) and 2,2'-azinobis(3-ethylbenothiazoline-6-sulfonic acid) diammonium salt (ABTS) and ferrous ion chelating activity. Ethylene diamine tetraacetate (EDTA) and trolox, a water-soluble analog of tocopherol, were used as reference antioxidant compounds. The antioxidative activities of the melanoidins at a pH of 7.0 were greater than those with a pHs of 4.0 and pH 10.0. Especially, it was found that the melanoidins formed from D-isomers are more effective antioxidants in different in vitro assays. The reducing power and chelating activity of the melanoidins formed from the Fru systems were higher than those of the melanoidins formed from the Glc systems. However, the ABTS radical scavenging activity of the melanoidins formed from the Glc systems were higher than those of the melanoidins formed from the Fru systems. In particular, the DPPH radical scavenging activity and the FRAP of the melanoidins showed different antioxidative activities according to pH level.

• Natural Product Sciences
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• v.17 no.1
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• pp.14-18
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• 2011

A chemical investigation of the marine-derived fungi Aspergillus versicolor led to the isolation of a new aromatic polyketide (1), The structure was elucidated by spectroscopic analysis, and its radical-scavenging activity, reducing power, and inhibitory activity to lipid oxidation were investigated. Those activities of compound 1 were compared with standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tertiarybutylhydroquinone (TBHQ), and ascorbic acid ($V_C$). Compound 1 showed antioxidant activity comparable to that of BHA, and siginificantly higher than that of BHT.

• Food Science and Biotechnology
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• v.16 no.5
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• pp.854-857
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• 2007

In this study, the crude methanol extract of mulberry leaves was fractionated with chloroform, ethyl acetate, n-butanol, and water, successively. The antioxidant activities of the fractions were examined with the 2-deoxyribose oxidation and linoleic acid peroxidation methods. The ethyl acetate fraction showed the strongest antioxidant activity. From it we isolated chlorogenic acid, caffeic acid, quercetin $3-O-{\beta}-D-glucopyranoside$, and kaempferol $3-O-{\beta}-D-glucopyranoside$ with preparatory octadecyl silane-high performance liquid chromatography (ODS-HPLC), and identified the compounds by nuclear magnetic resonance (NMR) and fast atom bombardment mass (FAB-MS) analyses. Overall, quercetin $3-O-{\beta}-D-glucopyranoside$ showed the strongest antioxidant activity by both the 2-deoxyribose oxidation and rat liver microsome peroxidation methods.

• Journal of Applied Biological Chemistry
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• v.48 no.3
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• pp.144-147
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• 2005

DPPH and ABTS radical scavenging, and tyrosinase inhibitory activities of bioactive compounds 1-4 isolated from Cedrela sinensis leaf were assessed. Structures of isolated compounds were established by UV, one- and two-dimensional NMRs, and mass spectroscopic methods.

• Natural Product Sciences
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• v.13 no.1
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• pp.11-16
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• 2007

Alcoholic extract of Spathodea campanulata P. aerial parts, and two of the isolated fractions from celite column showed strong antioxidant activity (92, 94 & 89% RSA, Radical Scavenging Activity). Phytochemical investigation of chloroform/EtOAc faction of this column led to the isolation of phenolic acids, caffiec acid (1), and ferulic acid (2), fraction EtOAc/MeOH on further fractionation afforded 3 Flavonoids, kampferol 3-O-glucoside (3), quercetin 3-methyl ether (4) and 8-methoxy kampferol 3-O-glucoside (5). The isolated constituents were identified by co chromatography with authentic samples, TLC, PC., UV, MS and $^1H-NMR$. Also the lipoidal matter of the plant was studied. The unsaponifiable matter was found to be mixture of hydrocarbons from $(C_{14}-C_{28})$, cholesterol, campasterol, stigmasterol, and ${\alpha}-amyrin$. Fatty acid methyl esters were found to contain 12 fatty acids. The fatty acids containing $C_{18}$ farmed ca.65% of the total mixture.

• KSBB Journal
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• v.29 no.4
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• pp.271-277
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• 2014

In this study, crude extract of the seagrass Zostera japonica, and its solvent-partitioned fractions were evaluated for their antioxidant activity. The crude extract was successively fractionated into n-hexane, 85% aqueous methanol (85% aq.MeOH), n-butanol (n-BuOH), and water fractions by liquid-liquid partition. These include DPPH radical scavenging, hydroxyl radical scavenging in HT-1080 cells, peroxynitrite scavenging, and protective effect on DNA damage caused by hydroxyl radicals generated. In all assays, except for DPPH radical, 85% aq.MeOH and n-BuOH fraction showed the strong antioxidant activity. These results suggest that Z. japonica may be used as a potential source of natural antioxidants for the development of cosmetic product or functional food in the future.

• Applied Biological Chemistry
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• v.33 no.2
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• pp.143-146
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• 1990

Yellowish and oily crude gingerol extract was obtained from ginger(Zingiber officinale rose)by ether, ether and hexane extraction. The major component was identified by TLC analysis to be gingerol. The crude gingerol extract thus obtained was found to have antioxidant activity. The crude gingerol extract showed a synergistic antioxidant activity when combined with citric acid. The maximum synergistic effect was observed at 0.04% citric acid. The activity of the antioxidants used was found to increase in the order of BHT, crude gingerol plus 0.04% citric acid, crude gingerol, BHA and tocopherols.

• Preventive Nutrition and Food Science
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• v.4 no.4
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• pp.221-225
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• 1999

Antioxidative compounds contained in roasted safflower seeds were investigated. Six phenolic compounds, N-feruloylserotonin, N-(p-coumaroyl) serotonin, matairesinol, 8'-hydroxyarctigenin, acacetin 7-Ο-β-D-glucoside(tilianine) and acacetin were isolated and identified from the extract of seeds. The inhibitory effects of six phenolic compounds on 1,1-dipheny1-2-picrylhydrazyl(DPPH) radical and lipid peroxidation induced by H₂O₂/FeSO₄in rat liver microsomes were determined. Two serotonins showed more potent DPPH radical scavenging activity, and a stronger inhibitory effect on the lipid peroxidation than that of α-tocopherol. In addition, acacetin and matairesinol also considerably inhibited lipid peroxidation, while 2-hydroxy-arctigenin and tilianine were inactive. These results suggest that phenolic compounds, including serotonins, lignans and flavonoids in the roasted safflower seeds can be used as potential dietary natural antioxidants.

• Journal of Ginseng Research
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• v.20 no.2
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• pp.173-178
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• 1996

Aerobic cells are normally protected from the damage of free radicals by antioxidative on , zymes such as superoxide dismutase (SOD), catalase, glutathione (GSH) peroxidase, GSH S- transferase and GSH reductase which scavenge free radicals as well as nonenzymatic antioxidants such as ceruloplasmin, albumin and nonprotein-SH including GSH. The effects of each component (ginsenoside $Rb_1$, $Rb_2$, Rc, Rd, Re, $Rb_1$, Rf, $Rh_1$ and $Rh_2$) of red ginseng on the antioxidative enzyme activities were investigated in the liver in order to screen antioxidative components of red ginseng. Ginsenoside $Rb_1$ and Rc showed a tendency to increase GSH peroxidase activity, while ginsenoside Rc significantly decreased Cu,Zn-SOD activity. Especially, ginsenoside $Rh_2$ significantly increased catalase activity. These results suggest that ginsenoside $Rh_2$ is an important active component among total saponins of red ginseng.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.6
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• pp.613-622
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• 2018

This study investigated changes in the quality and antioxidant activity of soy sauce with added Saccharina japonica powder (FSP). Soy sauce was prepared with acid-hydrolyzed soy sauce, brewed soy sauce, honey, ginger, garlic, dried red pepper, ${\gamma}$-aminobutyric acid (GABA)-enriched sea tangle fermented in lactic acid, and 1% or 3% S. japonica powder by soy sauce volume. The color, pH, microbiology, amino nitrogen, free amino acids, antioxidant activity, and sensory qualities of the soy sauce were evaluated. There were no significant differences in the general characteristics or antioxidant activity. However, the addition of FSP to the soy sauce enhanced the delicate flavor. Furthermore, soy sauce containing FSP had higher levels of GABA (50 mg/100 mL), a biofunctional ingredient. Therefore, the development of seasoning soy sauce with enhanced functionality seems possible.