• Journal of the Korean Chemical Society
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• v.59 no.2
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• pp.136-141
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• 2015

We have discovered that quercetin, once coated on the CdSe and CdSe-CdS quantum dots (QDs), becoming highly water soluble. In the present work, we have successfully synthesized CdSe/CdS/N-Acetyl-L-Cysteine(NAC)/Quercetin nano-composites in the aqueous solution. The products were characterized using UV-vis spectroscopy, X-ray powder diffraction, fluorescence spectroscopy, and Fourier transform infrared spectroscopy. The transmission electron microscopy (TEM) tests indicated that our nano-composite products are highly stable with homogeneous particle size and great monodispersity. Quercetin coated nano-composite CdSe/CdS/NAC/Quercetin showed different fluorescence behavior from that of CdSe/CdS/NAC. Most amazingly, the synthesized CdSe/CdS/NAC/Quercetin nano-composite exhibits strong antibacterial activity. The combination of the strong fluorescence and its antibacterial activity makes the quercetin modified quantum dots as a potential candidate for cancer targeted therapy and other cancer treatments.

• Clinical and Experimental Reproductive Medicine
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• v.48 no.4
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• pp.316-321
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• 2021

Objective: Amino acids can protect sperm structure in cryopreservation due to their antioxidant properties. Therefore, the present study aimed to investigate the protective effect of L-carnitine (LC) and N-acetyl cysteine (NAC) on motility parameters, plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), DNA damage, and human sperm intracellular reactive oxygen species (ROS) during vitrification. Methods: Twenty normal human sperm samples were examined. Each sample was divided into six equal groups: LC (1 and 10 mM), NAC (5 and 10 mM), and cryopreserved and fresh control groups. Results: The groups treated with LC and NAC showed favorable findings in terms of motility parameters, DNA damage, and MMP. Significantly higher levels of intracellular ROS were observed in all cryopreserved groups than in the fresh group (p≤0.05). The presence of LC and NAC at both concentrations caused an increase in PMI, MMP, and progressive motility parameters, as well as a significant reduction in intracellular ROS compared to the control group (p≤0.05). The concentrations of the amino acids did not show any significant effect. Conclusion: LC and NAC are promising as potential additives in sperm cryopreservation.

• Journal of Korean society of Dental Hygiene
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• v.21 no.5
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• pp.545-553
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• 2021

Objectives: This study aimed to investigate the cytotoxicity of Nexus RMGIC, an indirect restorative cement, on cell survival rate and reactive oxygen species (ROS) production in periodontal stem cells (PDSCs). Methods: PDSCs were incubated with serially diluted Nexus RMGIC eluates with and without the addition of N-acetyl-cysteine (NAC). Cell survival was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The ROS generation was determined by measuring the fluorescence intensity for 2',7'-dichlorofluorescin diacetate. Results: Nexus RMGIC exposure decreased cell proliferation and cell survival rate in a dose-dependent manner (1:8, 1:4, 1:2, 1:1) in PDSCs. The cytotoxicity of Nexus RMGIC was inhibited by treatment with 10-mM NAC. In addition, the production of ROS was detected by immunofluorescence after PDSCs were exposed to Nexus RMGIC. However, ROS generation was significantly suppressed in the NAC pretreatment compared with the Nexus RMGIC group. Conclusions: Nexus RMGIC increased the cytotoxicity and ROS generation. ROS was involved in Nexus RMGIC-induced cell toxicity.

• 대한방사선방어학회:학술대회논문집
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• 2009.04a
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• pp.174-175
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• 2009

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• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3421-3424
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• 2011

The endogenous neurotoxin, 1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (salsolinol), has been considered a potential causative factor for the pathogenesis of Parkinson's disease (PD). In this study, we examined oxidative modification of neurofilament-L (NF-L) induced by salsolinol. When disassembled NF-L was incubated with salsolinol, the aggregation of protein was increased with the concentration of sasolinol. The formation of carbonyl compound was obtained in salsolinol-mediated NF-L aggregates. This process was protected by free radical scavengers, such as N-acetyl-L-cysteine and glutathione. These results suggest that the aggregation of NF-L is mediated by salsolinol via the generation of free radicals. We also investigated the effects of copper ion on salsolinol-mediated NF-L modification. In the presence of copper ions, salsolinol enhanced the modification of NF-L. We suggest that salsolinol might be related to abnormal aggregation of NF-L which may be involved in the pathogenesis of neurodegenerative diseases and related disorders.

• Journal of Life Science
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• v.23 no.1
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• pp.79-83
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• 2013

A biofertilizer, BIOACTIVE, was manufactured by N-acetyl-thioproline (ATCA) and mineral phosphate solubilizing bacteria. The growth promoting effect of the biofertilizer on lettuce was evaluated under three different pot conditions, and its stability was assessed in the field. According to the results of the pot experiments, plant growth was improved compared with that of control: 128%, 122%, and 153% for the leaf number, leaf length, and leaf mass, respectively. Applying the manufactured biofertilizer increased the concentration of phosphate: 118% and 132% in the cultivation soil and plant cells, respectively. These show that BIOACTIVE may have potential as an effective biofertilizer in agriculture.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.27 no.1
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• pp.17-27
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• 2001

A cell-based assay system for monitoring NF-$textsc{k}$B activity was developed to determine the influence of activated NF-$textsc{k}$B in human HaCaT cells. The pNF-$textsc{k}$B-SEAP-NPT plasmid that permits expression of the secreted alkaline phosphatase (SEAP) reported gene in response to the NF-$textsc{k}$B activity and contains neomycin phosphotransferase (NPT) gene for the geneticin resistance in host cells was constructed and transfected into human keratinocyte cell line HaCaT. Human HaCaT transfectant cells secreted the SEAP enzyme into the culture medium in a time-dependent manner until 72h. NF-$textsc{k}$B activities were measured in the SEAP reporter gene assay using a fluorescent detection method. The treatment of HaCaT cell transfectants with known antioxidants [e.g., N-acetyl-L-cysteine and vitamin C] showed inhibition of NF-$textsc{k}$B activity in a time-and concentration-dependent manner. The phorbol 12-myristate 13-acetate (PMA) known as a stimulator of NF-$textsc{k}$B expression demonstrated that it increased NF-$textsc{k}$B activity in a time- and concentration-dependent manner. This assay system could be used to determine the quantitative measurement of NF-$textsc{k}$B activity in the human skin and allow the screening of anti-inflammatory agents from various synthetic chemicals and natural products for dermatological purpose. Abbrevitions used: NF-$textsc{k}$B, nuclear factor kappa B; I-$textsc{k}$B, Inhibitory kappa B; SEAP, secreted alkaline phosphatase; NPT, neomycin phosphotransferease; PCR, polymerase chain reaction: dNTP, deoxynucleoside triphosphates; DMEM, dulbecco’s modified eagle medium; FBS, fetal bovine serum; PBs, phosphate-buffered saline; MUP, 4-methylumbellifery phosphate; NAC, N-acetyl-L-cysteine; DMSO, dimethyl sulfoxide; PMA, phorbol 12-myristate 13-acetate.

• Food Science and Biotechnology
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• v.15 no.3
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• pp.437-440
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• 2006

To explore the possible usefulness of ${\beta}$-glucans as natural antioxidants, the antioxidant profiles of ${\beta}$-glucan, extracted from Saccharomyces cerevisiae KCTC 7911, and water soluble and insoluble mutant ${\beta}$-glucan, isolated from yeast mutant S. cerevisiae IS2, were examined by five different in vitro evaluation methods: lipid peroxidation value (POV), nitric oxide (NO), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, reducing power, and ${\beta}$-carotene diffusion assay. The antioxidant activities of all ${\beta}$-glucans evaluated in POV test were comparable to or better than that of the known antioxidant, vitamin C. Remarkably, the ${\beta}$-glucan and water insoluble mutant ${\beta}$-glucan possessed 2.5-fold more potent activity than vitamin C at a dosage of 2 mg. Although vitamin C showed 100-fold greater activity than all ${\beta}$-glucans in NO and DPPH tests for measuring the radical scavenging capacity, all ${\beta}$-glucans revealed higher radical scavenging activity than the known radical scavenger, N-acetyl-L-cysteine (NAC), in DPPH test. The water insoluble mutant ${\beta}$-glucan had 2.6- and 5-fold greater antioxidative activity than water soluble ${\beta}$-glucan in NO and DPPH tests, respectively, showing that all ${\beta}$-glucans were able to scavenge radicals such as NO or DPPH. While all ${\beta}$-glucans revealed lower antioxidant profiles than vitamin C in both reducing power activity and ${\beta}$-carotene agar diffusion assay, the ${\beta}$-glucan and water insoluble mutant ${\beta}$-glucan did show a marginal reducing power activity as well as a considerable ${\beta}$-carotene agar diffusion activity. These results confirmed the potential usefulness of these ${\beta}$-glucans as natural antioxidants.

• Parasites, Hosts and Diseases
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• v.57 no.2
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• pp.83-92
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• 2019

Based on the reactive oxygen species (ROS) regulatory properties of diphenyleneiodonium (DPI), we investigated the effects of DPI on host-infected T. gondii proliferation and determined specific concentration that inhibit the intracellular parasite growth but without severe toxic effect on human retinal pigment epithelial (ARPE-19) cells. As a result, it is observed that host superoxide, mitochondria superoxide and $H_2O_2$ levels can be increased by DPI, significantly, followed by suppression of T. gondii infection and proliferation. The involvement of ROS in anti-parasitic effect of DPI was confirmed by finding that DPI effect on T. gondii can be reversed by ROS scavengers, N-acetyl-L-cysteine and ascorbic acid. These results suggest that, in ARPE-19 cell, DPI can enhance host ROS generation to prevent T. gondii growth. Our study showed DPI is capable of suppressing T. gondii growth in host cells while minimizing the un-favorite side-effect to host cell. These results imply that DPI as a promising candidate material for novel drug development that can ameliorate toxoplasmosis based on ROS regulation.

• Bulletin of the Korean Chemical Society
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• v.28 no.1
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• pp.77-80
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• 2007

As neurofilament proteins are major cytoskeletal components of neuron, abnormality of neurofilament is proposed in brain with neurodegenerative disorders such as Parkinson's disease (PD). Since oxidative stress might play a critical role in altering normal brain proteins, we investigated the oxidative modification of neurofilament-L (NF-L) induced by the reaction of cytochrome c with H2O2. When NF-L was incubated with cytochrome c and H2O2, the protein aggregation was increased in cytochrome c and H2O2 concentrationsdependent manner. Radical scavengers, azide, formate and N-acetyl cysteine, prevented the aggregation of NFL induced by the cytochrome c/H2O2 system. The formations of carbonyl group and dityrosine were obtained in cytochrome c/H2O2-mediated NF-L aggregates. Iron specific chelator, desferoxamine, prevented the cytochrome c/H2O2 system-mediated NF-L aggregation. These results suggest that the cytochrome c/H2O2 system may be related to abnormal aggregation of NF-L which may be involved in the pathogenesis of PD and related disorders.