• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.62-62
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• 2019

Natural substances have various physiological activities. Substances isolated from natural substances are known to be safer and more potent than pharmaceuticals. Potatoes not only act as energy sources but also contain active ingredients such as vitamins and minerals. In particular, the potato contains a large amount of polar compounds, including the saponin in the polar compounds, and the physiological activity of the saponins, such as immunity enhancement, antioxidant and anti-inflammatory is known. In this study, the antioxidative activity of polar compounds from five potatoes was examined by chemical base anti-oxidation assay and cell based anti-oxidation assay. In the chemical base anti-oxidation assay, DPPH experiment showed activity in the order of Hongyoung, Haryung, Seohong, Sumi, and Jayoung. In the LPA experiment, IC50 was lower in the order of Jayoung, Seohong, Sumi, Hongyoung, and Haryung. In the cell based anti-oxidation assay, the smallest amount of ROS was generated when the compound was derived from Haryung and hongyoung, and strong SOD activity was observed in Sumi and Jayoung. The results of this study reveal the antioxidative effect of polar compounds extracted from various kind of potatoes, which will enable the acquisition of new bioactive candidates and the establishment of new profit generation models for farmers.

• Clean Technology
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• v.17 no.4
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• pp.370-378
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• 2011

Catalytic activity of $V_2O_5-WO_3/TiO_2$-based SCR catalyst was examined for the oxidation of gas-phase elemental mercury to oxidized mercury. Mercury species was not detected on the commercial SCR catalyst after the oxidation reaction of elemental mercury, regadless of the presence of HCl acting as oxidant and the reaction conditions. This suggests that elemental mercury oxidation by HCl could occur via a Eley-Rideal mechanism with gas phase or weakly-bound mercury on the surface of $V_2O_5-WO_3/TiO_2$ SCR catalyst. The activity for mercury oxidation was significantly increased with the increase of $V_2O_5$ loading, which indicates that $V_2O_5$ is the active site. However, turnover frequency for mercury oxidation was decreased with the increase of $V_2O_5$ loading, indicating the activity for mercury oxidation was strongly dependent on the surface structure of vanadia species. The activity for oxidation of elemental mercury under SCR condition was much less than that under oxidation condition at the same HCl concentration and reaction temperature.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.164-164
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• 2013

Among multicomponent nanostructures, hybrid nanocatalysts consisting of metal nanoparticle-semiconductor junctions offer an interesting platform to study the role of metal-oxide interfaces and hot electron flows in heterogeneous catalysis. In this study, we report that hot carriers generated upon photon absorption significantly impact the catalytic activity of CO oxidation. We found that Pt-CdSe-Pt nanodumbbells exhibited a higher turnover frequency by a factor of two during irradiation by light with energy higher than the bandgap of CdSe, while the turnover rate on bare Pt nanoparticles didn't depend on light irradiation. We also found that Pt nanoparticles deposited on a GaN substrate under light irradiation exhibit changes in catalytic activity of CO oxidation that depends on the type of doping of the GaN. We suppose that hot electrons are generated upon the absorption of photons by the semiconducting nanorods or substrates, whereafter the hot electrons are injected into the Pt nanoparticles, resulting in the change in catalytic activity. We discuss the possible mechanism for how hot carrier flows generated during light irradiation affect the catalytic activity of CO oxidation.

• Journal of Microbiology and Biotechnology
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• v.16 no.3
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• pp.399-407
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• 2006

In this study, an electrical conductive carbon fiber was used as a biofilter matrix to electrochemically improve the biofilter function. A bioreactor system was composed of carbon fiber (anode), titanium ring, porcelain ring, inorganic nutrient reservoir, and VOC reservoir. Electric DC power of 1.5 volt was charged to the carbon fiber anode (CFA) to induce the electrochemical oxidation potential on the biofilter matrix, but not to the carbon fiber (CF). We tested the effects of electrochemical oxidation potential charged to the CFA on the biofilm structure, the bacterial growth, and the activity for metabolic oxidation of VOCs to $CO_2$, According to the SEM image, the biofilm structure developed in the CFA appeared to be greatly different from that in the CF. The bacterial growth, VOCs degradation, and metabolic oxidation of VOCs to $CO_2$ in the CFA were more activated than those in the CF. On the basis of these results, we propose that the biofilm structure can be improved, and the bacterial growth and the bacterial oxidation activity of VOCs can be activated by the electrochemical oxidation potential charged to a biofilter matrix.

• Preventive Nutrition and Food Science
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• v.9 no.2
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• pp.167-173
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• 2004

The aim of this study was to investigate the antioxidant effect of medicinal plants used by diabetic patients. Fourteen medicinal plants were selected and antioxidant activity such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, inhibition effect of linoleic acid autoxidation and low density lipoprotein (LDL) oxidation, thiobarbituric acid (TBA) value were measured. The Cornus officinalis had DPPH radical scavenging activity of 84.79%, which was higher than the 78.79% for $\alpha$-tocopherol. Rosa rugosa Thunberg, Pueraria thundergiana Bentham, Artemisia princeps var. orientalis and Sasamorpha purpurascens Nakai also had high values. Extracts with higher DPPH radical scavenging activities had higher total phenol concentrations, and positive correlations between these parameters were found. Inhibitory activities of linoleic acid autoxidation, LDL oxidation and TBA value, used as indices of oxidative stress, were observed in most of the selected medicinal plants. The highest inhibitory activity for TBA value was observed in the extract of Pueraria thundergiana Bentham. Rosa rugosa Thunberg (75.50 %), Sasamorpha purpurascens Nakai (74.00 %), and Cornus officinalis (73.00 %) all had high antioxidant activity against linoleic acid autoxidation, similar to that of $\alpha$-tocopherol. The same 3 plants also had high in inhibitory activity against LDL oxidation. Therefore, we demonstrated that medicinal plants used as folk remedy by diabetic patients had antioxidant activity. Especially, Rosa rugosa Thunberg, Cornus officinalis, Pueraria thundergiana Bentham, Arlemisia princeps var. orientalis, and Sasamorpha purpurascens Nakai had high phenol concentrations which resulted in high values for DPPH radical scavenging. These same plants exhibited high values for inhibitory activities for TBA value, linoleic acid autoxidation and LDL oxidation, indices associated with lipid peroxidation.

• Preventive Nutrition and Food Science
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• v.7 no.2
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• pp.151-156
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• 2002

Antioxidant activity or green tea extracts (GTE) was evaluated in soybean oil (SBO), rice bran oil (RBO) and winterized rice bran oil (WRBO) stored at 63$^{\circ}C$ for 36 days. Lipid oxidation of the oils was determined using the active oxygen method (AOM), peroxide value (POV), change in unsaturated free fatty acid concentrations and by sensory evaluation. SBO had a higher concentration of the polyunsaturated fatty acids, linoleic and linolenic acid than RBO and WRBO. WRBO and RBO were more stable against lipid oxidation than SBO. Addition of GTE (200 ppm) to the stored oils, increased the induction period (IP) in AOM, reduced the increase in POV, and lessened the change in unsaturated fatty acids. Furthermore, GTE prevented the development of rancid flavors resulting from storage, all of which demonstrate the protective antioxidative activity of GTE. However, oil color became darker in the GTE treated oils. The antioxidant protection of GTE was most effective in RBO.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.800-807
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• 2001

This study was designed to investigate the antioxidative activity of a substance isolated from. The antioxidative activity of procyanidine was higher than that of dl-tocopherol and BHA on low-density lipoprotein (LDL) oxidation by thiobarbituric acid reactive substance (TBARS). Procyanidine inhibited the copper-mediated oxidation of human LDL in a dose dependent manner with almost complete inhibition at $60{\mu}g/mL$. Procyanidine at a concentration of $80{\mu}g/mL$ in hibited oxidation of LDL induced by J774. LDL oxidized by copper-mediated or cell-induced oxidation was degraded at a much greater rate than native LDL. These results suggested the importance of further research to procyanidine in the investigation of atherosclerosis and free radical-induced injury.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.1
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• pp.48-52
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• 2000

An autotrophic sulfur oxidizer, Thiobacillus sp. ASWW-2, was isolated from activated sludge, and its sulfur oxidation activity was characterized. Thiobacillus sp. ASWW-2 could oxidize elemental sulfur on the broad range from pH 2 to 8. When 5-50 g/L of elemental sulfur was supplemented as a substrate, the growth and sulfur oxidation activity of Thiobacillus sp. ASWW-2 was not inhibited. The specific sulfur oxidation rate of strain ASWW-2 decreased gradually until sulfate was accumulated in medium up to 10 g/L. In the range of sulfate concentration from 10 g/L to 50 g/L, the sulfur oxidation rate could keep over $2.0g-S/g-DCW{\cdot}d$. It indicated that Thiobacillus sp. ASWW-2 has tolerance to high concentration of sulfate.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.5
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• pp.366-371
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• 2000

The aim of this study was to investigate the efficiency of the pentagalloic acid compound in inhibiting the metal ions and cell lines that mediate in low density lipoprotein (LDL) oxidation. Pentagalloic acid prolonged the lag time preceeding the onset of conjugated diene formation. In chemically induced LDL oxidation by Cu$^2$(sup)+ plus hydrogen peroxide or peroxyl radical generated by 2, 2-azo-vis (2-amidino propane) hydrochloride (AAPH), pentagalloic acid inhibited LDL oxidation as monitored by measuring the thiobarbituric acid reactive substances(TBARS), malondialdehyde(MDA), and gel electrophoretic mobility. The physiological relevance of the antioxidative activity was validated at the cellular level where pentagalloic acid inhibited mouse macrophage J774 and endothelial cell-mediated LDL oxidation. When compared with several other antioxidants, pentagalloic acid showed a much higher ability than naturally occuring antioxidants, ${\alpha}$-tocopherol and ascorbic acid, and the synthetic antioxidant, probucol.

• Bulletin of the Korean Chemical Society
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• v.31 no.1
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• pp.151-156
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• 2010

In this paper, we characterized bimetallic Pt-Ru/C alloy catalysts having four different compositions and compared the catalytic activities of the prepared alloys for CO oxidation. ICP-AES, EDS, XRD, TEM, and XAS were used to investigate the composition, degree of alloying, particle size, and electronic structure of the prepared Pt-Ru/C catalysts. Those results indicated the synthesis of the alloy catalysts with intended composition and uniform size. The electrochemical study of the characterized alloys showed higher catalytic activity for CO oxidation than that of the commercial Pt/C (E-TEK, Inc., 20 wt %) catalyst. Especially, it was shown that the alloy catalyst with Ru composition of 50 atomic % gave the highest catalytic activity for CO oxidation.