• The Korean Journal of Physiology and Pharmacology
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• v.25 no.1
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• pp.51-58
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• 2021

Oxidative stress-induced neurodegeneration is one of several etiologies underlying neurodegenerative disease. In the present study, we investigated the functional role of histone methyltransferase G9a in oxidative stress-induced degeneration in human SH-SY5Y neuroblastoma cells. Cell viability significantly decreased on H2O2 treatment; however, treatment with the G9a inhibitor BIX01294 partially attenuated this effect. The expression of neuron-specific genes also decreased in H2O2-treated cells; however, it recovered on G9a inhibition. H2O2-treated cells showed high levels of H3K9me2 (histone H3 demethylated at the lysine 9 residue), which is produced by G9a activation; BIX01294 treatment reduced aberrant activation of G9a. H3K9me2 occupancy of the RE-1 site in neuron-specific genes was significantly increased in H2O2-treated cells, whereas it was decreased in BIX01294-treated cells. The differentiation of H2O2-treated cells also recovered on G9a inhibition by BIX01294. Consistent results were observed when used another G9a inhibitor UCN0321. These results demonstrate that oxidative stress induces aberrant activation of G9a, which disturbs the expression of neuron-specific genes and progressively mediates neuronal cell death. Moreover, a G9a inhibitor can lessen aberrant G9a activity and prevent neuronal damage. G9a inhibition may therefore contribute to the prevention of oxidative stress-induced neurodegeneration.

• Journal of the Korean Applied Science and Technology
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• v.39 no.5
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• pp.710-719
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• 2022

This study attempted to investigate the possibility of Passiflora caerulea extract as a cosmetic material by measuring its antioxidant activities and melanin biosynthesis-inhibiting effects. For this, the substance was extracted with 70% ethanol, and ABTS radical scavenging activities were measured, using the TEAC assay. In addition, cell viability through the neutral red assay, ROS inhibition and inhibition of melanin biosynthesis were analyzed, and the results found the followings: In terms of ABTS radical scavenging activities of the extract, dose-dependent scavenging activities were observed. In trolox used as a positive control group and 0.1 mg/mL, similar radical scavenging activities were found. The production of ROS through CFDA was inhibited in a dose-dependent fashion. Furthermore, inhibition of melanin biosynthesis induced by 𝛼-MSH was confirmed. Therefore, it is reasonable to conclude that Passiflora caerulea extract has a potential as a cosmetic ingredient.

• Journal of Life Science
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• v.23 no.11
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• pp.1342-1350
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• 2013

We examined the effect of hydrogen sulfide ($H_2S$) in chemical hypoxia-induced injury in mouse hepatocytes. Cell viability was significantly decreased by cobalt chloride ($CoCl_2$), a well-known hypoxia mimetic agent in a time- and dose- dependent manner. Sodium hydrosulfide (NaHS, a donor of $H_2S$) pretreatment before exposure to $CoCl_2$ significantly attenuated the $CoCl_2$-induced decrease of cell viability. $CoCl_2$ treatment resulted in an increase of intracellular ROS generation, which is inhibited by NaHS or N-acetyl-cysteine (NAC, a ROS scavenger), and p38 MAPK phosphorylation, which is also blocked by NaHS or NAC. The $CoCl_2$-induced increase of the Bax/Bcl-2 ratio was attenuated by NaHS, NAC, and SB 203580 (p38 MAPK inhibitor). The $CoCl_2$-induced decrease of cell viability was also attenuated by NaHS, NAC, and SB 203580 pretreatment. Additionally, NaHS inhibited the $CoCl_2$-induced COX-2. Similar to the effect of NaHS, NAC blocked $CoCl_2$-induced COX-2 expression. Furthermore, NS-398 (a selective COX-2 inhibitor) attenuated not only the $CoCl_2$-induced increase of the Bax/Bcl-2 ratio, it also decreased cell viability. Taken together, $H_2S$ protects primary cultured mouse hepatocytes against $CoCl_2$-induced cell injury through inhibition of the ROS-activated p38 MAPK cascade and the COX-2 pathway.

• Korean Journal of Clinical Laboratory Science
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• v.53 no.4
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• pp.363-370
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• 2021

This study was conducted to evaluate the dermal cytotoxicity of lead acetate (LA) and other heavy metal compounds, and the protective effect of Lespedeza bicolor (LB) extract on LA-induced cytotoxicity in cultured B16-/F10 melanoma cells. The study evaluated the antioxidative effects of LB due to its electron-donating ability (EDA), inhibitory effects on melanization and improving cell viability. LA significantly decreased cell viability in a dose-dependent manner, and the XTT₅₀ value was determined at 52.7 µM in the studied cultures. Based on the Borenfreund and Puerner's toxicity criteria, LA was estimated to be highly cytotoxic. LA-induced cytotoxicity and cell damage was reversed by the antioxidant activity of kaempferol (KAE), thereby remarkably improving cell viability. A study of the protective effects of the LB extract on LA-induced cytotoxicity showed that the LB extract remarkably increased cell viability in the LA-treated group, and also inhibited the EDA and the total amount of melanin. The above results suggest oxidative stress-mediated cytotoxicity of LA. In the study, LB extract effectively prevented LA-induced cytotoxicity via its antioxidative activity and inhibition of melanization. In conclusion, natural resources like LB extracts may be useful agents for the prevention of oxidative stress-mediated cytotoxicity and melanization by heavy metallic compounds such as LA.

• BMB Reports
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• v.42 no.2
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• pp.96-100
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• 2009

Aromatic (ar)-turmerone from turmeric oil displays anti-tumorigenesis activity that includes inhibited cell proliferation. This study investigated ar-turmerone-mediated apoptotic protein activation in human lymphoma U937 cells. Ar-turmerone treatment inhibited U937 cell viability in a concentration-dependent fashion, with inhibition exceeding 84%. Moreover, the treatment produced nucleosomal DNA fragmentation and the percentage of sub-diploid cells increased in a concentration-dependent manner; both are hallmarks of apoptosis. The apoptotic effect of ar-turmerone was associated with the induction of Bax and p53 proteins, rather than Bcl-2 and p21. Activation of mitochondrial cytochrome c and caspase-3 demonstrated that the activation of caspases accompanied the apoptotic effect of ar-turmerone, which mediated cell death. These results suggest that the apoptotic effect of ar-turmerone on U937 cells may involve caspase-3 activation through the induction of Bax and p53, rather than Bcl-2 and p21.

• Biomolecules & Therapeutics
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• v.11 no.2
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• pp.112-118
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• 2003

1-Methylated $\beta$-carbolines (harmaline and harmalol) and antioxidants (N-acetylcysteine and ascorbate) reduced the loss of cell viability in differentiated PC 12 cells treated with 5 mM glutamate. $\beta$-Carbolines prevented the glutamate-induced decrease in mitochondrial membrane potential, cytochrome c release and caspase-3 activation in PC 12 cells. $\beta$-Carbolines reduced the formation of reactive oxygen species and depletion of glutathione due to glutamate in PC12 cells. $\beta$-Carbolines revealed a scavenging action on hydrogen peroxide and reduced the iron and EDTA-mediated degradation of 2-deoxy-D-ribose. The results suggest that I-methylated $\beta$-carbolines attenuate the cytotoxic effect of glutamate on PC12 cells by reducing the alteration of mitochondrial membrane permeability that seems to be mediated by oxidative stress.

• The Journal of Korean Medicine
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• v.24 no.1
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• pp.190-201
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• 2003

Object : This study was designed to investigate the effects of Chungganhaeju-tang (Qingganjiejiu-tang) on cytotoxicity, growth inhibition, apoptosis and expression of cytokine in damaged HepG2 cells. Method : Toxicity on HepG2 cell induced by ethanol and acetaldehyde was measured for viability, cell growth, DNA replication and generation of apoptosis and cytokine. The recovery of the cell activity by Chungganhaeju-tang was estimated for the measured parameters using PCR with different cycle numbers, DNA gel-electrophoresis, and densitometric analysis, Results : Chungganhaeju-tang improves the recovery of HepG2 cells damaged by ethanol or acetaldehyde. The suppressed DNA synthesis of the cell damaged by ethanol or acetaldehyde is improved by Chungganhaeju-tang. A liver-protection effect was shown by the reduction of apoptosis and $TNF-{\alpha},{\;}IL-1{\beta}$ expressions that are induced by ethanol or acetaldehyde. Conclusion : The result indicates that Chungganhaeju-tang reduces toxicity induced by ethanol or acetaldehyde and recovers damaged liver function.

• Biomedical Science Letters
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• v.16 no.4
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• pp.331-339
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• 2010

This study aims to evaluate the effect of Photodynamic Therapy (PDT) against methicillin-resistant Staphylococcus aureus with high-level mupirocin resistance (Hi-Mup MRSA). To examine the antimicrobial effect of photogem-mediated PDT against Hi-Mup MRSA, CFU quantifications, bacteria cell viability tests, and disk diffusion antimicrobial susceptibility tests were evaluated. In addition, one of PDT mechanisms was investigated by accumulating photogem ($10\;{\mu}g/ml$) in Hi-Mup MRSA. Photogem-mediated PDT properly inhibited the colony formation of Hi-Mup MRSA. Viable bacteria decreased greatly after a PDT application with photogem $10\;{\mu}g/ml$ at energy density $15\;J/cm^2$. The diameter of the inhibition zone around susceptible disks increased after PDT. In addition, we confirmed the accumulation of photogem in bacteria through fluorescent images. These results demonstrated that excellent photosensitization of Hi-Mup MRSA can be achieved using photogem with 630 nm LED irradiation. Thus, PDT may make survival Hi-Mup MRSA inactive.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.19 no.3 s.31
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• pp.13-21
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• 2006

Object : We investigated the effect of Gamiokyaek-tang (GOYT) on immediate type hypersensitivity. Methods : We investigated anti-dinitrophenyl (DNP) IgE-mediated passive cutaneous anaphylaxis and acetic acid-induced vascular permeability in rodents. Also perfonned MTT assay and b-hexosaminidase activity is measured in RBL-2H3. Results : GOYT inhibited passive cutaneous anaphylaxis and acetic acid-induced vascular permeability by oral administration. All the concentrations of GOYT from 0.1 to 5 mg/ml didn't have an effect on cell viability and cytotoxicity. b-hexosaminidase release in RBL-2H3 was significantly reduced by 2 and 5 mg/ml of GOYT. Conclusion : These results indicate that GOYT have inhibition effects on immediate type hypersensitivity .

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.16 no.2
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• pp.79-95
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• 2003

Objectives: This study was performed to investigate the depigmentation effects of Salt, Acetum, Sesami Semen Nigrum. Methods: Inhibition of tyrosinase activity, melanin production & cell viability in cultured B16 melanoma cells, UV screen and cytoprotective effects on PC12 cells injured by hydrogen peroxide were measured. Results: Salt, Acetum, Sesami Semen Nigrum did not show any inhibitory effects of tyrosinase activity & melanin production in melanoma cells, UV screen and cytoprotective effects on PC12 cells injured by hydrogen peroxide. Conclusions: This study shows that Salt, Acetum, Sesami Semen Nigrum which were generally used for the addition in external application do not have the depigmentation effects. Following this, the depigmentation effects of the other addition which were generally used for external application shoud be examined.