• Journal of the Korean Chemical Society
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• v.57 no.2
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• pp.246-251
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• 2013

With -$OCH_2CO$- as a linker, a non ${\beta}$-substituted cationic bisporphyrin (4a) and a ${\beta}$-substituted cationic bisporphyrin (4b) were prepared through methylation of the intermediate which was obtained from ${\beta}$-amino-5,10,15,20-tetra (4-cyanophenyl) porphyrin or 5-hydroxylphenyl-10,15,20-tris(4-cyanophenyl) reacting with 5-hydroxy-10,15,20-trispyridinylporphyrin. Their structures were confirmed by $^1H$ NMR, IR, UV-vis, MS and elemental analysis. DNA photocleavage ability and the singlet oxygen ability of those cationic bisporphyrins were investigated. DNA photocleavage activity of ${\beta}$-substituted cationic bisporphyrin was significantly weaker than that of $H_2TMPyP$, but similar to that of non ${\beta}$-substituted cationic bisporphyrin. While 4a and 4b showed substantial photocleavage activities toward DNA, with 68% and 66% observed at 10 ${\mu}M$. The assessment of indirectly measured $^1O_2$ production rates against $H_2TMPyP$ were described and the relative singlet oxygen production yields were: free cationic bisporphyrins > $H_2TMPyP$. The results showed the cationic bisporphyrins with ${\beta}$-substitution and non ${\beta}$-substitution could be developed as potential photodynamic agents.

• Bulletin of the Korean Chemical Society
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• v.14 no.1
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• pp.107-109
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• 1993

Non-enzymatic glycosylation and fragmentation of collagen molecule were investigated by irradiating Ultraviolet A(UV-A) with or without scavengers of reactive oxygen species (ROS) in the presence of glucose. Non-enzymatic glycosylation was increased by UV-A at high concentration of glucose. It was reduced in the presence of the scavengers of superoxide radical and singlet oxygen, but not reduced in the presence of hydroxy radical scavenger. Fragmentation of collagen was increased by UV-A, but it was decreased in the presence of all ROS scavengers tested. Superoxide radical and singlet oxygen produced by autoxidation of glucose without UV-A may encounter the initial phase of glycosylation. Data presented here suggest that UV-A affects only on the fragmentation process, but all ROS except hydroxy radical act on both processes. It appears that hydroxy radical does not act on the glycosylation process.

• Journal of Photoscience
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• v.9 no.2
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• pp.412-414
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• 2002

Several peroxovanadium(V) complexes with an organic chelate ligand decompose spontaneously, depending on the nature of the chelate ligand. The self-decomposition reactions of the dinuclear peroxovanadium(V) complex with 2-oxo-l,3-diaminopropane-N,N,N',N'-tetraacetate (dpot) and the peroxovanadium(V) complexes with N-carboxymethylhistidinate (cmhist) and histamine-N,N-diacetate (histada) accompany the reduction of vanadium(V) to vanadium(IV). This implies that the peroxide anion acts as a reducing agent and thus the peroxide is oxidized in the decomposition process of the peroxovanadium(V) complexes. The oxidized dioxygen species have been characterized spectrophotometrically. Superoxide anion has been detected in 2-3 % yields using the reduction of cytochrome c method and chemiluminescence method utilized MCLA as a fluorescer. Singlet oxygen has also been detected in higher yields on the basis of chemiluminescence of tryptophan.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1608-1612
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• 2012

Singlet oxygen ($^1O_2$) is an important species for oxidation in biological processes. $^1O_2$ is implicated in the genotoxic effect, and plays an important role in the cell-signaling cascade and in the induction of gene expression. However, the rapid detection of $^1O_2$ in biological environments with sufficient specificity and sensitivity is hampered by its extremely low emission probability. Here, a layer-by-layer (LbL) film of CdTe quantum dots (QDs), polymers, and ascorbate have been designed as a rapid, highly selective, and sensitive fluorescence probe for $^1O_2$ detection. Upon reaction with $^1O_2$, the probe exhibits a strong photoluminescence (PL) response even at trace levels. This remarkable PL change should enable the probe to be used for $^1O_2$ detection in many chemical and biological systems and as an environmental sensor.

• Journal of Ginseng Research
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• v.14 no.2
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• pp.191-199
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• 1990

It has been well known that extended exposure to reactive oxygens causes severe damage to susceptible biomolecules. In this study, the effects of flavonoids including trifolin and kaempferol from Ginseng leaves on singlet oxygen induced photohemolysis of erythrocytes and free radical scavenging activities were investigated. Each flavonoid aglycone (5-50$\mu$M) such as kaempferol, quercetin or baicalein exhibited a high protective effect against the photohemolysis. They protected the cells by scavenging $^1O_2$ and free radicals Although the free radical scavenging activities of the flavonoid glycosides were not much lower than those of their corresponding aglycones, their insolubility into lipid bilayers of membrane made them less effective in preventing the photohemolysis induced by $^1O_2$. The $^1O_2$ and free radical scavenging activities of flavonoids were estimated by the decomposition of the flavonoid by $^1O_2$ and the bleaching of free radicals by the flavonoid, respectively. The solubilization of the flavonoid into micells or erythrocytes was deduced from spectrophotometric and microscopic observations. The cooperation of L-ascorbic acid and a flavonoid, and a possible involvement of lipoxygenase or cyclooxygenase in the photohemolysis mechanism were discussed.

• The Korean Journal of Pesticide Science
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• v.15 no.2
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• pp.87-96
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• 2011

To study solar activated insecticide, three types of dihydroxyl phosphorus(V) triazatetrabenzocorrole derivatives ($P(OH)_2TBCs$) including H, 4'-methoxy phenoxy, 4'-tert butyl phenoxy substituents were synthesized. The results show that slightly red-shift with introducing substituents was observed and singlet oxygen was generated by the sunlight. Based on photochemical properties, solar activated insecticidal activity tests against Liriomyza trifolii (Burgess) were carried out. Overall insecticidal activities were 100~85.7% in the concentration of 500ppm, and especially in the case of compound $P(OH)_2TBC$ the insecticidal activities was 100%.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.13 no.1
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• pp.45-71
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• 1987

${\beta}$-Carotene has been known as an effective quenching agent of singlet oxygen and the carotenoid pigments in general are expected to protect cells against photosensitized oxidations. We are determined the quenching rate constants of several Ketocarotenoids including capsanthin, capsanthin diester, astaxanthin and fucoxanthin, and the relative quenching actiyities against singlet oxygen were compared with those of ${\beta}$-carotene and reported carotenoids. Nevertheless the ketocarotenoids exhibited lower quenching rate constants than ${\beta}$-carotene, they showed more pronounced protective activitives than ${\beta}$-carotene against photohemlysis induced by singlet oxygen. Among the ketocarotenoids investigated, fucoxanthin indicated a significant protective activity for the cell. The results suggested that. 1) 1O2 may be alikely initiator of photohemolysis, but this reaction is followed by slow dark reactions involving secondary reactive species. 2) For protection of RBC against photodynamic action with carotenoids, carotenoids having functional groups such as -C=0 and -OH groups are most efficient. This suggests that partition of carotenoids between the buck and the mombrane and/or their specific binding to membrane proteins are more critical for the photo-protection by carotenoids than is a diffusional quenching of 1O2.

• Journal of Plant Biotechnology
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• v.49 no.3
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• pp.257-270
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• 2022

The aim of this work was to prepare a new biodegradable polyhydroxybutyrate (PHB) submicron fiber mat loaded with hypericin-rich Hypericum perforatum raw extract by centrifugal spinning technology, an alternative approach to the traditional method of electrospinning to fabricate nanofibers or microfibers from solutions at high speed and low cost. Hypericins in methanol/acetone extract of H. perforatum were determined by UHPLC-MS/MS and HPLC/PDA. Submicron fiber mats composed of pure PHB or PHB enriched with H. perforatum extract were prepared using a pilot plant demonstrator for the centrifugal spinning technology and characterized by SEM. Singlet oxygen production was quantified by the 1,3-diphenylisobenzofuran (DPIBF) method in hexane. The results proved a significant production of singlet oxygen by the prepared submicron fiber mat. We also found a significant antibacterial activity against the bacterial strain Escherichia coli CCM 5417 by a method in accordance with JIS Z 2801/ISO 22196 standards. The H. perforatum extract-enriched PHB submicron fiber mats showed potential for the development of self-cleaning and antimicrobial air filters.

• Food Science and Preservation
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• v.23 no.3
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• pp.387-392
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• 2016

The antioxidant activities of brownish natural dyeing agents, extracted from seven kinds of plants, were tested. Total polyphenol content, DPPH and ABTS radical scavenging activities, and singlet oxygen quenching effect were determined for hot water extracts and floral waters of plants. DPPH and ABTS radical scavenging activites increased with increasing amounts of the extracts from Uncaria gambir R. and Terminalia chebula R. displayed remarkable scavenging effects at concentrations below 0.1 mg/mL, in comparison with the positive control, ascorbic acid. However, antioxidant effects of the floral water, obtained from steam distillation of tested plants, were inefficient at concentration below 0.2 mg/mL. In particular, the natural dyeing agent effectively suppressed singlet oxygen induced by photosensitizer in in vitro assay systems. The concentrations ($IC_{50}$) required to exert 50% of singlet oxygen were 120 and $190{\mu}g/mL$ for hot water extracts from Uncaria gambir R. and Phellinus linteus, respectively. Among all the tested samples, the Uncaria gambir R. and Phellinus linteus extracts contained higher amount of total phenolic contents. The results suggest that naturally occurring dyeing agents are beneficial as natural antioxidants, encouraging further extensive studies.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.2
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• pp.124-130
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• 2013

Of all the brominated flame retardants (BFRs), TBBPA has the largest production volume (50% of the BFRs in current use). It is interest to investigate how they may degrade, because of it can pose an environmental hazard. By using UV-A (${\lambda}=352nm$ ), we have found that the UV-A irradiation increased the photodecomposition reaction rate of TBBPA in an intensity-dependent manner. We also observed 2,6-dibromo-p-benzosemiquinone radical ($a_{2H}=2.36G$, g = 2.0056) generated from TBBPA by reaction with singlet oxygen ($^1O_2$). On the other hand, when an aqueous preparation of HA was irradiated in the presence of TBBPA, the typical spectrum of semiquinone radical was detected by electron spin resonance (ESR). And then, we have found that the photodecomposition rate of TBBPA is decreased in depend on HA concentration. Radical formation and the reactive rate of TBBPA were inhibited by sodium azide used as a singlet oxygen quencher. Therefore we report that a similar $^1O_2$-induced oxidation can be initiate in aqueous solutions of TBBPA dissolved in humic acid (HA) by the UV-A irradiation (${\lambda}=352nm$). From these results, we suggest that the reaction rate of HA with $^1O_2$ is faster than that of TBBPA with $^1O_2$.