• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.4 s.54
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• pp.323-327
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• 2005

Although many studies have been performed to elucidate the molecular consequence of ultraviolet irradiation on an aging, little is known about the effect of natural products. Matrix metalloproteinases (MMPs) we known to play an important role in (a) photoaging. Hete we investigated the effect of $1,2,4,6-tetra-O-galloyl-{\beta}-{_D}-gluco- pyranose (1)$ and 3,4,5-trihydroxybenzoic acid (2) on the expression of MMP-1 in UVA-irradiated human skin fibroblasts (products), (on the) activity of MMP-1, and (on the) scavenging activities of free radicals. Compounds 1 and 2 were isolated from Melothria heterophylla (Cucurbitaceae). These compounds were found to scavenge free radicals and reactive oxygen species (ROS) and were measured to have the $SC_{50}$ values of $3.9{\mu}M\;and\;13.3{\mu}M$ against the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and $4.3{\mu}M\;and\; 4.0{\mu}M$ against superoxide radicals in the xanthine/xanthine oxidase system, respectively. Compounds 1 and 2 showed a dose-dependent inhibitory effect on the e):pression and activity of MMP-1 in the UVA-irradiated human skin fibroblasts. Therefore, we concluded that compounds 1 and 2 significantly inhibited MMP-1 expression at the protein level. Also, these compounds were determined to have a potent antioxidant activity. From these results, we suggest that these compounds nay be used as (a) new anti-aging agents for the photo-damaged skin.

• Korean Journal of Food Science and Technology
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• v.53 no.1
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• pp.12-18
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• 2021

The in vitro antioxidant activity of oregano seed fractions, fractionizing with 80% ethanol, n-hexane, ethyl acetate, n-butanol, and water, was evaluated, and their effects on edible oils were determined in corn oil at 180℃. The ethyl acetate fraction had the highest radical-scavenging activity. The ferric reducing antioxidant power activity and total phenol content of the ethyl acetate fraction were determined as 6,130 µmol ascorbic acid equivalents/g extract and 770 µmol tannic acid equivalents/g extract, respectively, which were significantly higher than those of the other fractions (p<0.05). Primary and secondary oxidation products in corn oil added with the ethyl acetate fraction of oregano seed significantly decreased by 1.5 and 1.26 times, respectively, compared with those in the control groups. The major volatile ingredients in the ethyl acetate fraction of oregano seeds were determined to be carvacrol, thymoquinone, and 3-cyclopentylcyl-cyclopentan-1-one. Ethyl acetate is a suitable solvent for extracting antioxidant compounds from oregano seeds and can be used as a natural antioxidant.

• Korean Journal of Food Science and Technology
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• v.35 no.1
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• pp.15-22
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• 2003

Nutritional compositions of three Tochukaso species (Paecilomyces tenuipes hosted by Larva and pupa, Cordyceps militaris, C. sinensis) were compared. Fruiting body and host fractions were separately analyzed. Fruiting body fraction of P. tenuipes (36.6%) hosted by larva was higher than that hosted by pupa (10.2%), an indication that the quality of the former is superior to the latter. Carbohydrate content of C. sinensis (39.6%) was $2.5{\sim}7$ times higher than those of others, probably due to the presence of polysaccharides. Protein and crude lipid contents of C. sinensis and C. militaris were 25.8 and 10.3%, and 75.1 and 3.9%, respectively. C. sinensis showed the lowest Ca content and $30{\sim}75$ times higher Fe content among the samples tested. Vitamin A content of C. militaris was 308.9 IU/100g, two fold higher than those of the other species. Saturated fatty acid content was the highest in P. tenuipes (pupa, 27.7%), whereas unsaturated fatty acid was the highest in P. tenuipes (larva, 83.3%). Aspartic acid, glutamic acid, and glycine were abundant in all species. Cordycepin content of C. militaris was $20{\sim}50$ times higher than those of the other species.

• Journal of the Korean Chemical Society
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• v.33 no.3
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• pp.281-286
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• 1989

The redox properties of benzophydroxamic acid (Hben) and its oxovanadium complex, $VO(Ben)_2$ has been studied by the use of polarograpy and cyclic voltammetry. The radical anions of Hben seem to be generated in acetone. The wave at -0.05V vs. Ag/AgCl electrode might be attributed to the formation of radical anion and the wave at -1.78V vs. Ag/AgCl electrode might be attributed the formation of radical dianion. The $VO(Ben)_2$ exhibits one oxidation wave at + 0.55V and two reduction waves at -0.15V and -1.30V vs. Ag/AgCl electrode; the oxidation is reversible one electron process $(VO(ben)_2 {\rightleftharpoons} VO(ben)^+ + e)$. The reduction wave at -0.15V is quasireversible and is arised from the formation of radical anion,$VO(Ben)_2^-$. The second reduction wave at -1.30V is irreversible and this reduction process produces vanadium(III). This oxygen containing ligand of Hben seems to reduce the stability of + 4 oxidation state of vanadium while the sulfur or nitrogen donor of the ligands stabilize the + 4 oxidation state of vanadium when comparisons are made among several oxovanadium complexes.

• Journal of the Korean Applied Science and Technology
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• v.38 no.5
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• pp.1302-1313
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• 2021

In this study, Gami-Sumiwon (GS; Cynanchi wilfordii R., Angelica gigantis R., Lycium chinense M., Betula platyphylla S., Cryptotympana atrata F. and Carthamus tinctorius L.) and/or Sinomenium acutum R. (SC) was extracted with 70% ethanol or water. And We investigated the antioxidant activity effect of GS±SC. The following experimental techniques were used to evaluate the antioxidant efficacy of GS±SC. HPLC chromatogram, heavy metal content, ABTS/DPPH radical scavenging analysis, SOD-like activity assay, FACS, and NO assay. As a result of the experiment, the sinomenine content was found to be higher in DW extracts, and decursin was found to be higher in 80% ethanol extracts. And, the amount of heavy metals in all extracts was below the standard value. ABTS, and DPPH radical scavenging activity was identified that GS±SC(EtOH) was found to have a higher scavenging activity than GS±SC(DW). But, SOD showed the opposite result. No cytotoxicity of GS was observed on Raw 264.7 cells at concentration of 1~100 ㎍/㎖. The ROS production was significantly decreased that GS±SC(DW) was found to have a higher scavenging activity than GS±SC(EtOH). However, NO production showed the opposite result. Looking at the results of SOD and ROS analysis, SC does not seem to have a function of prevention. SC is thought to have an effect on the removal of free radicals generated after oxidative stress. This result objectively confirmed the antioxidant effect of GS±SCs. We will continue to conduct in-depth research. Therefore, it is believed that the possibility of using GS±SCs as a functional material can be established. The more diverse the objectives, the higher the value of GS utilization is thought to be.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.1
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• pp.40-46
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• 2007

A laboratory scale experiment on phenol conversion properties by pulsed corona discharge process was carried out. Effects of operating parameters such as applied voltage, input oxygen, and electrode geometry on phenol conversion and solution properties were investigated. Electrical discharges generated in liquid phase increased the liquid temperature by heat transfer from current flow, decreased the pH value by producing various organic acids from phenol degradation, and increased conductivity by generating charge carriers and organic acids. The oxygen supply enhanced the phenol conversion through the ozone generation dissolution and the production of OH radicals. Series type electrode configuration induced more ozone production than reference type configuration because it produced gas phase discharges as well as liquid phase discharges. Therefore, the higher phenol conversion and TOC(total organic carbon) removal efficiency were obtained in series type configuration.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.6
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• pp.28-38
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• 2019

To investigate the relation between flame structure and combustion dynamic characteristics in bi-swirl coaxial injectors for a liquid rocket engine, combustion experiments were performed using gaseous methane and gaseous oxygen. CH* radicals and pressure fluctuations were simultaneously measured by changing the injector geometries such as recess length/orifice diameter and the flow conditions such as equivalence ratio/oxidizer mass flow rate. As the injector geometries affected the velocities and mixing of the propellants, the change in flame structures was observed. From a result of the frequency analysis, it was confirmed that combustion dynamic characteristics varied according to the injector geometry/flow condition and combustion instabilities could occur under specific recess length/flow conditions.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.99.1-99.1
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• 2017

$TiO_2$는 기계적, 화학적 안정성이 높아 가혹한 화학적 환경 또는 고온 운전 조건에서 훌륭한 내구성을 보여주어 산업적으로 일찍이 널리 이용되어 왔다. 예를 들어, 염소발생 (chlorine evolution reaction) 또는 산소발생반응은 (oxygen evolution reaction) 염소 또는 산소 라디칼에 전극이 지속적으로 노출되기에 강한 내부식성을 지닌 전극재가 요구되었고, 그 결과 $TiO_2$를 골조로 한 불용성전극 (dimensionally stable anode)이 개발되어 이용되고 있다. 그러나, $TiO_2$는 절연성이 높은 금속 산화물 재료이기 때문에 넓은 표면적 획득 및 촉매제 사용을 통해 소재의 단점을 극복해야만 한다. 넓은 반응 표면적 획득의 한 방법으로써 전기화학적 양극산화 (electrochemical anodization)를 통한 $TiO_2$ 나노튜브 제조법은 경제적이면서도 구조 제어도 간편한 방법이다. $TiO_2$ 나노튜브는 100nm 전후의 기공 크기를 가짐과 동시에 매우 높은 종횡비를 지니고 있어 넓은 반응 표면적 획득에 특히 유리하다. 그러나, 이 높은 종횡비는 촉매 도입을 어렵게 하는 저해요소가 되기도 한다. 이러한 문제를 해결하기 위하여 다양한 방법들이 연구되었으나 대부분이 번거롭거나 비싼 후단공정을 필요로 한다. 본 연구에서는 $TiO_2$ 나노튜브에 촉매를 도핑하기 위한 간단한 전기화학적 방법으로, 단일공정 양극산화법 (single-step anodization)과 전압충격법 (potential shock), 그리고 저전압충격법 (under potential shock)을 연구하였으며 이에 적용 가능한 촉매제의 종류를 소개한다. 또한, 촉매의 성질에 따른 응용분야와 그 성능평가 결과를 제시한다.

• Applied Biological Chemistry
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• v.43 no.1
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• pp.46-51
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• 2000

The resistance of Cornyza bonariensis to herbicide paraquat was investigated by evaluating the activities of three enzymes concerning in scavenging paraquat-generated toxic oxygen species such as superoxide radical and hydrogen peroxide in resistant and susceptible biotypes. Conyza bonariensis inhabited in cultivated area was more tolerant to paraquat than that of uncultivated area. This is the first report that a biotype of Cornyza bonariensis has appeared in an area with repeated paraquat treatments of Korea. Superoxide dismutase activity of resistant biotype was 20% higher as 150 than that of susceptible biotype. Ascorbate peroxidase activity of resistant biotype was 44% higher than that of susceptible biotype. Glutathione reductase activity of resistant biotype was 64% higher than that of susceptible biotype. It can be concluded from above results that the resistance of Conyza bonariensis to paraquat depends partially on the toxic oxygen species-scavenging efficiency of protective multienzymatic system which is composed of three enzymes, superoxide dismutase, ascorbate peroxidase, and glutathione reductase.

• Journal of Life Science
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• v.8 no.1
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• pp.91-96
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• 1998

Pine(Pinus densiflora Sieb et Zucc.) is one of rhe popular plant drugs which has been used as a medicine in Asia. To investigate the effect of pine needle extract (PNE) on oxygen radicals and their scavenger enzymes in brain membranes of Sprague- Dawley (SD), make SD rats were fed basic diets(control group), and experimental diets (PNE group) with 0.5 and 1.0% of PNE 6 weeks. Mitochondrial hydroxyl radical levels in brain of 0.5%-PNE and 1.0%-PNE groups were significantly inhibited to 30% and 25%, respectively, and microsomal hydrogen peroxide levels in brain of 0.5%-PNE and 1.0%-PNE groups were significantly inhibited to 15% compared with control group. Cytosolic superoxide rdical levels in 1.0%-PNE group were significantly inhibited to 20% compared with control group. Lipid peroxide(LPO) levels in brain mitochondria of 0.5%-PNE and 1.0%-PNE groups were significantly lower(25% and 35%) than that in control group. Mn-superoxide disumtase (SOD) activities in brain of 0.5%-PNE and 1.0%-PNE groups were significantly higher(18% and 12%) than those in control groups, but Cu,Zn-SOD activities in brain of 0.5%-PNE were significantly activated to 15% compared with control group. Glutathione peroxidase(GSHPx) activities in brain of 1.5%-PNE and 1.0% PNE groups were significantly higher(14% and 12%) than those in control group. These results suggest that more beneficial effects such as inhibition of oxygen radicals and lipid peroxide(LPO). and oncreases of scavenger enzymes in brain membranes of SD rats may be effectively modulated by administration of pine needle extract (PNE)