• Korean Journal of Oriental Medicine
• /
• v.3 no.1
• /
• pp.229-239
• /
• 1997

The superoxide anion radical$(O_2)$ poses a threat to macromocules and cell organelles of the living cells. This toxicity damage to all groups of proteins results in loss of enzyme function concerned with metabolism and ion transport, and peroxidation of unsaturated fatty acids and cholesterol results in a change of permeability characteristics of the membrane, and oxidative of nucleic acids results in genomic damage and thereby cause mutation, potential carcinogenesis and somatic damage that produce cellular aging Superoxide dismutase(SOD) has received substantial attention as a potential therapeutic agent. It has been investigated as a possible agent for the prevention of ontogenesis, the reduction of cytotoxic effect of anticancer drugs, and protection against damage in ischemic tissue. It is suggest that $O_2$ is concerned with cellular aging, thereafter we need to investigate herb that activated to SOD.

• Korean Journal of Pharmacognosy
• /
• v.33 no.3 s.130
• /
• pp.173-176
• /
• 2002

In search for the plant-derived antioxidant compound, it was found that the EtOAc, BuOH extracts obtained from the leaves parts of Oryza sativa L. which exhibited a significant antioxidant activity from 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical cleavage. Activity-guided fractionation on the basis of the inhibitory activity upon the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical cleavage. and repeated column chromatography afforded several antioxidant compounds from Oryza sativa L. The structures and stereochemistry of these compounds were established on the basis of analysis of spectra and some chemical transformations as follows: 5,7-dihydroxy- 8-methoxyflavone, $acacetin-7-O-{\beta}-rutinoside$, $pectolinarigenin-7-O-{\beta}-rutinoside$. At antioxidant activity test for isolated three compounds, antioxidant activity was showed too.

• Food Science and Biotechnology
• /
• v.18 no.1
• /
• pp.167-171
• /
• 2009

This study examined the antioxidative activity of delphinidin, a kind of anthocyanidin from eggplant. Cellular protective potential from oxidative damage by nitric oxide (NO), superoxide anion ($O_2^-$), and peroxynitrite ($ONOO^-$) using epithelial cell line LLC-PK1 cell as well as in vitro radical scavenging effects were investigated. Delphinidin showed strong in vitro radical scavenging effects against NO, $O_2^-$, and hydroxyl radical (${\cdot}OH$) in dose-dependent manners. In addition, delphinidin increased cell viability in LLC-PK1 cells in a concentration-dependent manner when viability was reduced by $ONOO^-$-induced oxidative damage. To elucidate the protective mechanisms of delphinidin from $ONOO^-$, sodium nitroprusside (SNP), and pyrogallol were also employed to generate NO and $O_2^-$, respectively. The treatment of delphinidin recovered reductions in cell viability caused by SNP and pyrogallol, indicating that delphinidin can attenuate oxidative stress induced by NO and $O_2^-$. The present study suggests that delphinidin is a promising anti oxidative agent.

• Archives of Pharmacal Research
• /
• v.28 no.5
• /
• pp.529-533
• /
• 2005

In the course of searching for hepatoprotective agents from natural products, six compounds were isolated from the MeOH extract of the leaves of Juglans sinensis, as guid ed by their DPPH free radical scavenging activity. The structures were determined as juglanoside B (1), quercetin 3-O-${\alpha}$-L-arabinofuranoside (avicularin, 2), quercetin 3-O-${\alpha}$-L-arabinopyranoside (guaijaverin,3), quercetin 3-O-${\alpha}$-L-rhamnopyranoside (quercitrin,4), (+)-catechin (5) and quercetin 3-O-${\beta}$- D-galactopyranoside (hyperin,6). Compounds 2-6 showed significant DPPH free radical scavenging effects. An evaluation for the hepatoprotective activity of the isolated compounds on drug-induced cytotoxicity was conducted, and compounds 1, 2, and 5 showed protective effects against nitrofurantoin-induced cytotoxicity, and compound 5 also exhibited a moderate protective effect on amiodarone-induced cytotoxicity in Hep G2 cells.

• Archives of Pharmacal Research
• /
• v.20 no.2
• /
• pp.148-154
• /
• 1997

The antioxidant activity of Artemisia iwayomogi was determined by measuring the radical scavenging effect on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical. The methanol extract of A. iwayomogi showed strong antioxidant activity, and thus fractionated with several solvents. The antioxidant activity potential of the individual fraction was in the order of ethyl acetate > n-butanol > water > chloroform > n-hexane fraction. The ethyl acetate and n-butanol soluble fractions exhibiting strong antioxidant activity were further purified by repeated sitica get and Sephadex LH-20 column chromatography. Antioxidant chlorogenic acid was isolated as one of the active principles from the n-butanol fraction, together with the inactive components, 1octacosanol, scopoletin, scopolin, apigenin $7, 4^{I}$-di-O-methylether, luteolin $6, 3^{I}$-di-O-methylether (jaceosidin), apigenin methylether (genkwanin), 2, 4-dihydroxy-6-methoxyacetophenone $4-O-{\beta}-$D-glucopyranoside and quebrachitol. The antioxidant activity of chlorogenic acid was comparable to that of L-ascorbic acid, which is a well known antioxidant.

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

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.7 no.7
• /
• pp.1563-1568
• /
• 2003

The introduction of invasive marine species of living things into new environments by ship's ballast water, attached to ships' hulls and via other vectors has been identified as one of the four greatest threats to the world's oceans by Global Environment Facility(GEF). Making use of the new technology of alpha-AL$_2$O$_3$ dielectric barrier layer, the strong electric-field gas discharge was introduced and obtained between micro-gap electrodes at high pressure (∼105㎩) of $O_2$ in air and $H_2O$ in seawater. The mixed air with $H_2O$ could be ionized and dissociated into large numbers of activated particles of OH, $O_2$＋, O(1D), HO$_2$ and so on, and then dissolved into the ballast water to form dissolved hydroxyl radical with the concentration of ∼20mg/L. Therefore, the invasive marine species was treated effectively through the hydroxyl radical dissolved pipeline of ballast water by strong electric -field discharge.

• Macromolecular Research
• /
• v.17 no.3
• /
• pp.174-180
• /
• 2009

Chemical modification of titanium/titanium oxide (Ti/$TiO_2$) substrates has recently gained a great deal of attention because of the applications of Ti/$TiO_2$-based materials to biomedical areas. The reported modification methods generally involve passive coating of Ti/$TiO_2$ substrates with protein-resistant materials, and poly(ethylene glycol) (PEG) has proven advantageous for bestowing a nonbiofouling property on the surface of Ti/$TiO_2$. However, the wider applications of Ti/$TiO_2$ based materials to biomedical areas will require the introduction of biologically active moieties onto Ti/$TiO_2$, in addition to nonbiofouling property. In this work, we therefore utilized surface-initiated polymerization to coat the Ti/$TiO_2$ substrates with polymers presenting the nonbiofouling PEG moiety and subsequently conjugated biologically active compounds to the PEG-presenting, polymeric films. Specifically, a Ti/$TiO_2$ surface was chemically modified to present an initiator for atom transfer radical polymerization, and poly(ethylene glycol) methacrylate (pEGMA) was polymerized from the surface. After activation of hydroxyl groups of poly(pEGMA) (pPEGMA) with N,N'-disuccinimidyl carbonate, biotin, a model compound, was conjugated to the pPEGMA films. The reactions were confirmed by infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle goniometry, and ellipsometry. The biospecific binding of target proteins was also utilized to generate micropatterns of proteins on the Ti/$TiO_2$ surface.

• Bulletin of the Korean Chemical Society
• /
• v.15 no.5
• /
• pp.349-353
• /
• 1994

The CN radical was generated in a jet with an inert buffer gas, helium from high voltage dc discharge of the precursor $CH_3CN$. The Fourier transform emission spectra of the O-O band of the $(B^2{\Sigma}^+{\to}X^2{\Sigma}^+)$ transition of CN have been obtained with a Bruker IFS-120HR spectrometer. The spectra show an anomalous distribution of rotational intensity which cannot be explained by a simple Boltzmann distribution. The analysis of the transition frequencies provides molecular constants with high accuracy for both the ground and the excited electronic states of the CN radical.

• Journal of Korean Society of Water and Wastewater
• /
• v.12 no.3
• /
• pp.55-64
• /
• 1998

The degradation efficiency of chlorophenolic compounds in $TiO_2/H_2O_2$ combined system was compared with that of in $TiO_2$ sole system. As a result, the addition of hydrogen peroxide in photocatalytic oxidation reaction greatly enhanced the degradation efficiency of chlorophenolic compounds due to the availability of the hydroxyl radical formed on the $TiO_2$ surface. The hydrogen peroxide under UV illumination produces hydroxyl radicals that appear to be another source of hydroxyl radical formation. These results indicated the $TiO_2/H_2O_2$ combined system shows higher degradation efficiency than the $TiO_2$ sole system. Compared to another oxidation reaction, hydrogen peroxide assisted photocatalytic oxidation is more promising in practical aspect.