• Applied Biological Chemistry
• /
• v.47 no.2
• /
• pp.279-282
• /
• 2004

An antioxidant was isolated from Korean mistletoe (Viscum album var. coloratum) by consecutive purification using silica gel, Sephadex LH-20, and RP-HPLC. The active principle was identified as homo-flavoyadorinin-B (3',7-dimethoxyluteolin-4'-O-[apiosyl $(1{\rightarrow}2)$ glucoside]) by spectral analyses. It inhibited 74.6% of hydroxyl radical and 30.6% of superoxide anion radical at 0.01 mM; however, th~compound did not show any scavenging activity against hydrogen peroxide radical. At 0.1 mM, above compound scavenged superoxide anion radical about twice as effective as positive controls, BHT and ${\alpha}-tocopherol$. Radical scavenging activities of homo-flavoyadorinin-B on DPPH, hydroxyl, and hydrogen peroxide radicals were almost same with those of positive controls.

• Korean Chemical Engineering Research
• /
• v.61 no.1
• /
• pp.45-51
• /
• 2023

In order to improve the durability of the PEMFC(Proton Exchange Membrane Fuel Cells) polymer membrane, a radical scavenger and a support are used. In this study, the durability of membranes containing fucoidan extracted from seaweeds and tannic acid serving as a crosslinking agent is evaluated to improve chemical and physical durability. Physical durability is evaluated by measuring tensile strength, and chemical durability is measured by Fenton experiment. Membrane and electrode assembly (MEA) is prepared and mechanical and chemical durability are measured through accelerated durability evaluation in the cell. The tensile strength measurement showed that fucoidan and tannic acid can improve the mechanical durability of the membrane by improving the strain rate and yield strength. It is shown in Fenton experiment that fucoidan acts as a radical scavenger. As a result of the accelerated durability test in the unit cell, fucoidan improved both chemical and mechanical durability, increasing the accelerated durability evaluation time by 38.1% compared to the additive-free membrane. When tannic acid is added, the durability of the polymer membrane is improved by 13.9% by improving the mechanical durability.

• The Korean Journal of Food And Nutrition
• /
• v.15 no.2
• /
• pp.151-157
• /
• 2002

This study was carried out to investigate functional activities of the free radical scavenging and germ of Glycin max. Merrill fur cytotoxicity toward P338 and L1210 cells derived from mouse. Effect of crude saponin were examined to oxygen radicals and their scavenger enzymes in liver fractions of Spragae-Dawley(SD) rats. Male rats were fed basic diets of control and experiment diets of 0.5∼1.0% crude saponin. There were no significant differences in hydroxy radical($.$OH) formation of liver mitochondria and microsomes in 1.0% group, while $.$OH formations were significantly decrease in 0.5% and 1.0% saponin compared with control group. Their oxygen radical(O$_2$$\^$$.$/) scavenging activities were significantly decrease in liver cytosol of 0.5% and 1.0% saponin group compared with control group. Soybean germ saponin was isolated purified by the method of HPLC to investigate the cytotoxicity of mouse cells by using the MTT assay. SA-1 saponin fraction of soybean germ showed to inhibit toward growth cell of P338 and L1210 cells and its showed less than 50% cytotoxicity These results suggest that the saponin may play a effective role in attenuating a oxygen radical formations and increasing a scavenger enzyme activities.

• Journal of Life Science
• /
• v.14 no.2
• /
• pp.286-290
• /
• 2004

The antioxidant activities of the various fractions extracted from mustard leaf (Brassica juncea) and mustard leaf kimchi were determined by the radical scavenging effect on 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical. The fractions from dried mustard leaf, and fermented mustard leaf kimchi for 0 day and fermented mustard leaf kimchi for 5 days at 15$^{\circ}C$ were screened for the scavenging effects by using DPPH assay. The fractions prepared by the systematic extraction procedure with the solvents such as hexane, C $H_2$Cl$_2$, EtOAc, BuOH and $H_2O$ were used for the determination of free radical scavenging effects. The antioxidant activity of EtOAc and n-BuOH soluble fraction from mustard leaf and mustard leaf kimchi for 0 day had stronger than the others. During fermentation at 15$^{\circ}C$ for 5 days, the antioxidant activity was changed. C $H_2$Cl$_2$ and EtOAc soluble fraction showed more potent radical scavenger effects than the others. The difference or results were to the various supplements and fermentation process.

• Journal of Life Science
• /
• v.9 no.3
• /
• pp.276-281
• /
• 1999

This study was designed as a part of efforts to investigate the biochemical pollutant markers for diagnosis of marine pollutions by changes in oxygen radicals and their scavenger enzymes of the mussel (Mytilus coruscus) in South Sea of Korea. Protein contents in muscle of cultured mussel in South Sea were remarkably lower (4-14%, respectively) than those of wild mussel in Pohang of East Sea. Superoxide radical activities in muscle of cultured in South Sea were significantly higher 82∼138% than those of wild mussel in Pohang. Hydroxyl radical formations in muscle of cultured mussels in South Sea were significantly 9∼25% higher than those of wild mussels in Pohang. Superoxide dismutase (SOD) activities in muscle of cultured mussels in South Sea were significantly 16∼28% lower than those of wild mussels in Pohang. It is believed that significantly decrease of protein contents in muscle, remarkable increases of superoxide radical and hydroxyl radical in muscle of cultured mussels of South Sea may be used as a biochemical pollutant markers for diagnosis of marine pollutions. These results suggest that near-coastal water as well as neritic water of the south sea might be affected by pollutant.

• Textile Coloration and Finishing
• /
• v.4 no.2
• /
• pp.64-68
• /
• 1992

The charge-transfer(CT) complexes derived from phenothiazine as donor and quinonoid compounds as accepters were evaluated as coloring matter. Light fastness of the intermolecular charge-transfer(CT) complex dyes as well as absorption wavelength is an important factor when the complexes are applied to coloring matters. The photofading mechanism of CT complex dyes of phenothiazine and accepters were examined. The addition of effective radical scavenger, antioxidant and photostabilizer gave a remarkable enhancement of the photostability of CT dyes.

• Archives of Pharmacal Research
• /
• v.18 no.6
• /
• pp.381-384
• /
• 1995

Covalent binding of the reactive metabolites of SC_42867 to microsomal proteins has been examined. In the absence of inhibitor of cytochrome oxydase (.alpha.-naphtyl-isothiocyanate) or a radical scavenger (3-terthiobuty-4-hydroxyanisol), up to 4.0% of total redioactivity used in the assay could irreversibly bind to proteins. In the presence of an inhibitor, the highest percentage of covalent binding observed is 0.7% a significant decrease of the metabolism of SC42876 was observed. These results suggest in a cytochrome P-450 dependent generation of SC_42867 metabolites significantly take part in the covalent binding process.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.378.2-378.2
• /
• 2002

Phellinus linteus has been used as anti-tumor and immuno stimulating agents in folk remedies. From precipitate of MeOH ex. by activited guided fractionation. 5.8-epidioxy ergosta-6.22-dien-3ol. palmitic acid. linoleic acid, and methyl linolate. 3.4-dihydroxybenzoic acid methylester and 4-(3'4'-Dihydroxyphenyl)-3-butene-2one were isolated. DPPH method was used to examine of antioxidative activity of the isolated compounds. As the result, 3.4-dihydroxybenzoic acid methylester, and phenolic compound. 4-(3'4'-Dihydroxyphenyl) -3-butene-2one were found to be a scavenger of 1,1-diphenyl-2-picrylhydrzyl radical. (omitted)

• Natural Product Sciences
• /
• v.11 no.3
• /
• pp.119-122
• /
• 2005

In the course of searching for hepatoprotective agents from natural products, four compounds were isolated from the MeOH extract of Sanguisorbae Radix, as guided by their DPPH free radical scavenging activity. The structures were determined as 4,5-dimethoxy-3-hydroxybenzoic acid methyl ester (1), (+)-gallocatechin (2), methyl $6-O-galloyl-{\beta}-D-glucopyranoside$ (3), and pomolic acid $3-O-[{\alpha}-L-arabinopyranoside]-28-O-[{\beta}-D-glucopyranosyl]$ ester (ziyu-glycoside I) (4). Compounds 2 and 3 showed significant DPPH free radical scavenging effects, exhibiting $IC_{50}$ values of 11.4 and $13.0\;{\mu}M$, respectively. L-Ascorbic acid was used as a positive control and exhibited the $IC_{50}$ value of $50.3\;{\mu}M$. In evaluation of the hepatoprotective activity of the isolated compounds on drug-induced cytotoxicity, compound 2 showed the significant hepatoprotective effect with the $EC_{50}$ value of $91.84\;{\pm}\;11.0\;{\mu}M$ on tacrine-induced cytotoxicity in Hep G2 cells, while silybin, a positive control, exhibited $EC_{50}$ value of $122.4\;{\pm}\;12.5\;{\mu}M$.

• Journal of Environmental Science International
• /
• v.21 no.7
• /
• pp.845-853
• /
• 2012

Diethyl phthalate (DEP) is widely spread in the natural environment as an endocrine disruption chemicals (EDs). Therefore, in this study, ultrasound (US) and ultraviolet (UVC), including various applied power density (10-40 W/L), UV wavelengths (365 nm, 254 nm and 185 nm) and frequencies (283 kHz, 935 kHz) were applied to a DEP contaminated solution. The pseudo-first order degradation rate constants were in the order of $10^{-1}$ to $10^{-4}\;min^{-1}$ depending on the processes. Photolytic and sonophotolytic DEP degradation rate also were high at shortest UV wavelength (VUV) due to the higher energy of photons, higher molar absorption coefficient of DEP and increased hydroxyl radical generation from homolysis of water. Sonolytic DEP degradation rate increased with increase of applied input power and the dominant reaction mechanism of DEP in sonolysis was estimated as hydroxyl radical reaction by the addition of t-BuOH, which is a common hydroxyl radical scavenger. Moreover, synergistic effect of were also observed for sonophotolytic degradation with various UV irradiation.