• Korean Journal of Clinical Laboratory Science
• /
• v.46 no.2
• /
• pp.75-78
• /
• 2014

Green tea and tea polyphenols have been studied extensively as cancer chemopreventive agents in recent years. Epigallocatechin-3-gallate (EGCG) is widely recognized as a powerful antioxidant and a free radical scavenger. The purpose of this study was to evaluate the protective effects of green tea catechins (GTC) on the Bleomycin- and Cyclophosphamide-induced cytotoxicity. Cell viability was measured by MTT assay. In the protective effect of GTC, the cell viability was significantly increased by the treatment of GTC. Furthermore, GTC showed the higher protective effect than EGCG and vitamin E. These results suggest that GTC has the protective effect which is related to the prevention of cancer. Our studies show that the continuous presence of EGCG can reduce radical-induced DNA damage in Chinese hamster lung fibroblast cells (CHL cells).

• Journal of Pharmacopuncture
• /
• v.10 no.1 s.22
• /
• pp.121-135
• /
• 2007

Objectives : This study was carried out to examine protective effect of wild ginseng extract on HepG2 human hepatoma cell line against tert-Butyl hydroperoxide (t-BHP)-induced oxidative damage. Methods : To evaluate protective effect of wild ginseng extract against t-BHP induced cytotoxicity, LDH level and activity of glutathione peroxidase and reductase were measured. Gene expression was also measured using DNA microarray. Results : Wild ginseng extract showed a significant protective effect against t-BHP-induced cytotoxicity in HepG2 cell line. It is not, however, related with the activities of glutathione peroxidase and glutathione reductase. Analysis of gene expression using DNA chip, demonstrated that 28 genes were up-regulated in t-BHP only group. Five genes - selenoprotein P, glutathione peroxidase 3, sirtuin 2, peroxiredoxin 2, serfiredoxin 1 homolog - may be related with the protective effect of wild ginseng extract. Conclusions : Based on the results, a protective effect of wild ginseng extract against t-BHP-induced oxidative damage in HepG2 cell line is not associated with the activities of glutathione peroxidase and glutathione reductase, but with the expression of selenoprotein P, glutathione peroxidase 3, sirtuin 2, peroxiredoxin 2, and serfiredoxin 1 homolog.

• Biomolecules & Therapeutics
• /
• v.4 no.4
• /
• pp.428-436
• /
• 1996

The protective effect of Carthamus tinctorius L. Semen on the carbon tetrachloride induced liver damaged rats were studied. First, methanol extract was prepared and the extract was fractionated with hexane, $CHCl_3$, BuOH and $H_2O$ respectively. Animals were divided into 6 groups and each group was treated with each fraction respectively. To investigate the hepato-protective effect of Carthamus tinctorius L. Semen AST, ALT, albumin, TP, cholesterol, TG, creatinine and total bilirubin values were measured in each treated group and compared with those of control group. GST activity was increased in BuOH group compared with the control group. In malondialdehyde levels, all fractions was decreased compared with the control group. In histopathologic examination, hexane and $H_2O$ fractions of Carthamus tinctorius L. Semen observed mild degree of ballooning degeneration. The results show the protective effect of Hexane,$CHCl_3$, BuOH and $H_2O$ fractions on hepatotoxicity of $CHl_4$ by decreasing ALT, AST, bilirubin, cholesterol, TG and BUN. It seems that the decrease of MDA are related to the recovery effect. The protective effects of Carthamus tinctorius L. Semen fractions in hepatotoxic pathogenesis by $CHl_4$ was suggested in blood chemistry analysis and histopathologic examination.

• Natural Product Sciences
• /
• v.12 no.3
• /
• pp.134-137
• /
• 2006

Four lignan compounds including gomisin J (1), schizandrin (2), gomisin A (3), and angeloyl gomisin H (4) have been isolated from the MeOH extract of Schizandra chinensis fruits. The evaluation for protective effect of compounds 1-4 against tert-butyl hydroperoxide (t-BHP)-induced cytotoxicity in hippocampal HT22 cell line was conducted. Compound 1 showed significant protective effect with an $EC_{50}$ value of $43.3{\pm}2.3\;{\mu}M$, whereas compounds 2-4 were inactive. Trolox, one of the well-known antioxidant, used as a positive control, and also showed protective effect with an $EC_{50}$ value of $213.8{\pm}8.4\;{\mu}M$. These results suggest that compound 1 may possess the neuroprotective activity against oxidant-induced cellular injuries.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.24 no.6
• /
• pp.1042-1052
• /
• 2010

This study aimed to evaluate the protective effects of Mundongcheongpye-eum (MCE) on elastase-induced lung injury. The extract of MCE was treated to A549 cells and elastase-induced lung injury mice model. Then, various parameters such as cell-based cyto-protective activity and histopathological finding were analyzed. MCE showed a protective effect on elastase-induced cytotoxicity in A549 cells. This effect was correlated with analysis for caspase 3 levels, collagen and elastin contents, protein level of cyclin B1, Cdc2, and Erk1/2, and gene expression of TNF-${\alpha}$ and IL-$1{\beta}$ in A549 cells. MCE treatment also revealed the protective effect on elastase-induced lung injury in mice model. This effect was evidenced via histopathological finding including immunofluence stains against elastin, collagen, caspase 3, and protein level of cyclin B1, Cdc2, and Erk1/2 in lung tissue. These data suggest that MCE has a pharmaceutical properties on lung injury. This study would provide an scientific evidence for the efficacy of MCE for clinical application to patients with chronic obstructive pulmonary disease.

• Journal of Korean society of Dental Hygiene
• /
• v.22 no.4
• /
• pp.259-272
• /
• 2022

Objectives: To identify the factors influencing the turnover intention of registered South Korean dental hygienists and analyze the effect sizes. Methods: Overall, 54 studies based on criteria of PICO from 1 January 2000 to 11 January 2022 were extracted. The factors related to turnover intention were applied to the ecological system theory and categorized. Subsequently, the effect size of the correlations was comprehensively meta-analyzed by dividing it into protective and risk factors depending on the negative or positive correlation direction. Results: For the overall effect size, the protective factor (ES_r=-0.458) was higher than the risk factor (ES_r=0.352). In the protective factors, organizational commitment and perceived organizational support belonging to the microsystem yielded the largest effect size. Furthermore, as for risk factors, burnout, job stress, work harassment, role conflict, and emotional labor belonging to the microsystem showed a moderate effect size. Conclusions: Factors belonging to the microsystem demonstrated a large effect size in both protection and risk factors for dental hygienists' turnover intention. Additionally, the factor showing the largest effect size was protective factor categorized into a microsystem.

• Journal of Digital Convergence
• /
• v.15 no.12
• /
• pp.59-70
• /
• 2017

The purpose of this study was to investigate whether there is a moderating effect of protective factors on risk factors in affecting school adjustment of immigrant youths. For this purpose, this study analyzed 69,720 youths who weighed 6,079 children of youths ages 9-24 among the 2015 National Survey of Multicultural Families. From the results of the analysis, first, the discrimination experience, school violence and depression, which are risk factors of immigrant youths, all had negative effects on school adjustment. Parental relations, self-esteem, Korean language ability, and nationality acquisition, which are protective factors, all had a positive effect on school adjustment. Second, among the three risk factors in the school adjustment of immigrant youths, self-esteem and nationality acquisition variables were analyzed as the protective factors moderating depression, and the protective factors controlling school violence were analyzed as parental relationship, self-esteem, Korean ability and nationality acquisition variables. Based on the results of the analysis, decrease in immigrant youths' depression, coping with academic violence, and development and support of various competency development programs were suggested as major social welfare practices.

• Applied Chemistry for Engineering
• /
• v.29 no.1
• /
• pp.49-55
• /
• 2018

In this study, we investigated the cellular protective effects and mechanisms of nicotiflorin and its aglycone kaempferol isolated from Annona muricata. The protective effect of these components against $^1O_2$-induced cell damage was also studied by using L-ascorbic acid and (+)-${\alpha}$-tocopherol as controls. Kaempferol exhibited the most potent protective effect, followed by (+)-${\alpha}$-tocopherol and nicotiflorin. L-Ascorbic acid did not exhibit any cellular protective effects. To elucidate the mechanism underlying protective effects, the quenching rate constant of the singlet oxygen, free radical-scavenging activity, ROS-scavenging activity, and uptake ratio of the erythrocyte membrane were measured. The results showed that the cell membrane penetration is a key factor determining the cellular protective effect of kaempferol and its glycoside nicotiflorin. The result from L-ascorbic acid demonstrated that the cellular protective effect of a compound depends on its ability to penetrate the cell membrane and is independent of its antioxidant capacity. In addition, it is suggested that cellular protective effects of kaempferol and (+)-${\alpha}$-tocopherol depend not only on the cell permeability, but also on free radical- and ROS-scavenging activities. These results indicate that the cell permeability and free radical- and ROS- scavenging activities of antioxidants are major factors affecting the protection of cell membranes against the oxidative damage induced by photosensitization reaction.

• Korean Journal of Hazardous Materials
• /
• v.6 no.2
• /
• pp.55-61
• /
• 2018

In this study, the molten metal protective performance of various molten metal protective clothing materials such as herringbone twill laminated aluminium foils, oxydized-polyacrylonitrile laminated with aluminium deposited polyethylene terephthalate films, twill fabric laminated with aluminium deposited polyethylene terephthalate films and nonwoven laminated with aluminum deposited polyethylene terephthalate films, were evaluated according to modified EN ISO 9185. The results showed that the molten metal protective performance of tested samples improved with the increase in fabric structure density, weight and thickness. In addition the effect of the thickness of aluminum foil on the molten metal protective performance is not significant. It was found the fabric is more important in the molten metal splash protective clothing.

• Fire Science and Engineering
• /
• v.31 no.2
• /
• pp.17-23
• /
• 2017

The test methods using convection (flame) and radiation heat sources were compared to evaluate the thermal protective performance of the firefighter's protective clothing. In particular, the influence of the outer shell, mid-layer, and lining constituting the firefighter's protective clothing on the thermal protective performance was compared for convection and radiation heat sources. Tests for the thermal protective performance were carried out according to KS K ISO 9151 (convection), KS K ISO 6942 (radiation), and KS K ISO 17492 (convection and radiation). When tested under the same incident heat flux conditions ($80kW/m^2$), the heat transfer index ($t_{12}$ and $t_{24}$) for the radiation heat source was higher than that for the convection heat source. This means that radiation has a lesser effect than convection. For the convection heat source, the lining had the greatest effect on the thermal protective performance, followed by the mid-layer and the outer shell. On the other hand, for the radiation heat source, the effect on the thermal protective performance was great in the order of lining, outer shell, and mid-layer. Convection and radiation have fundamentally different mechanisms of heat transfer, and different heat sources can lead to different thermal protective performance results depending on the material composition. Therefore, to evaluate the thermal protective performance of the firefighter's protective clothing, it is important to test not only the convection heat source, but also the radiation heat source.