• The Journal of the Korean dental association
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• v.53 no.7
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• pp.485-499
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• 2015

Purpose: Delayed intentional replantation was introduced as a new alternative to treat the teeth with severe periodontal involvement. The purpose of this study was to elucidate the possibility of delayed intentional replantation and establish theoretical backgrounds. Materials and Methods: Studies were performed into the following two subjects; (1)Clinical evaluation of patients who underwent delayed intentional replantation using clinical and radiographic data. Severe periodontitis involved teeth were carefully extracted and proper time for delayed replantation was evaluated by analyzing inflammation markers (IL-6, TNF-${\alpha}$). (2) Theoretical studies for efficacy of delayed intentional replantation using (-)-Epigallocatechin-3-gallate (EGCG) for preservation of periodontal ligament cells on root surface by minimizing inflammation and treatment of inflammatory extraction sockets. Results: Meaningful success ratio and survival rate were found in delayed intentional replantation showing reduced bone loss and maintained bone level. Additionally, viability of EGCG applied periodontal ligament cells was much higher than control group. Also, EGCG promoted healing of inflammatory extraction sockets by inhibiting inflammatory cell proliferation. Conclusion: Within the limitations of this study, 1-2 weeks after extraction is an appropriate time to do delayed intentional replantation. Also, EGCG provides helpful effects on viability of periodontal ligament cells and periodontium.

• Journal of Life Science
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• v.17 no.10
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• pp.1354-1360
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• 2007

Theaflavins (TF) and thearubigins (TR) are constituents of tea pigments which are polyphenols derived from Korean fermentation tea. After TF, TR and [(-) epigallocatechin-3-gallate](EGCG) have been applied to macrophage cell line (RAW264.7) nitric oxide (NO) synthesis and cytokines production were estimated. Cytokines production by enzyme linked immune-sorbent assay (ELISA) determined. NO production was increased by about 1.5-folds at the dose of $80\;{\mu}g/ml$ compared to control and lipopolysaccharide (LPS) stimulation when TF, TR and EGCG were applied to a RAW264.7 cell. Interleukin-6 (IL-6), Tumor necrosis factor ($TNF-{\alpha}$) and granulocyte-macrophage colony stimulating factor (GM-CSF) increased depended on concentrations of TF, TR and EGCG. The production of tumor necrosis $factor-{\alpha}$ increased highly in TR, TF and EGCG group with LPS. These results suggest that TF, TR and EGCG have immune-enhancement effect through the cytokine production. TF, TR and EGCG inhibited cancer cell viability, the anticancer effect of these polyphenols may explain the anti-tumor promotion action and antioxidant activity of these tea constituents.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.177-182
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• 2006

Polyphenol oxidase (PPO) was isolated from the flesh of Fuji apples by DEAE-Cellulose, ammonium sulfate precipitation, phenyl-Sepharose CL-4B, and Sephdex G-100 chromatography. The molecular mass of the purified PPO was estimated to be 40 kDa by SDS polyacrylamide gel electrophoresis. With regard to substrate specificity, maximum activity was achieved with chlorogenic acid as substrate, followed by catechin and catechol whereas, there was no detectable activity with hydroquinic acid, resorcinol, or tyrosine as substrate. The optimum pH and temperature with catechol as substrate were 6.5 and $35^{\circ}C$, respectively. The enzyme was most stable at pH 6.0 and unstable at acidic pH. The enzyme was stable when it was heated to $45^{\circ}C$ but heating at $50^{\circ}C$ for more than 30 min caused 50% loss of activity. Reduced $ZnSO_4$, L-cystein, epigallocatechin-3-o-gallate (EGCG), and gallocatechin gallate (GCG) also inhibited activity.

• Archives of Pharmacal Research
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• v.28 no.7
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• pp.784-790
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• 2005

In this study, we evaluate the effects of (-)-epigallocatechin-3-gallate (EGCG) on ultraviolet B(UVB)-irradiated living skin equivalents (LSEs). Histologically, UVB irradiation induced thinning of the LSE epidermis, whereas EGCG treatment led to thickening of the epidermis. Moreover, EGCG treatment protected LSEs against damage and breakdown caused by UVB exposure. Immunohistochemically, UVB-exposed LSEs expressed p53, Fas, and 8-hydroxy-deoxyguanosine (8-OHdG), all of which are associated with apoptosis. However, EGCG treatment reduced the levels of UVB-induced apoptotic markers in the LSEs. In order to determine the signaling pathways induced by UVB, Western blot analysis was performed for both c-Jun $NH_2$-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK), which are associated with UVB-induced oxidative stress. UVB activated JNK in the epidermis and dermis of the LSEs, and EGCG treatment reduced the UVB-induced phosphorylation of JNK. In addition, p38 MAPK was also found to have increased in the UVB-exposed LSEs. Also, EGCG reduced levels of the phosphorylation of UVB-induced p38 MAPK. In conclusion, pretreatment with EGCG protects against UVB irradiation via the suppression of JNK and p38 MAPK activation. Our results suggest that EGCG may be useful in the prevention of UVB-induced human skin damage, and LSEs may constitute a potential substitute for animal and human studies.

• Molecules and Cells
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• v.41 no.2
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• pp.73-82
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• 2018

Cancer preventive activities of green tea and its main constituent, (-)-epigallocatechin gallate (EGCG) have been extensively studied by scientists all over the world. Since 1983, we have studied the cancer chemopreventive effects of EGCG as well as green tea extract and underlying molecular mechanisms. The first part of this review summarizes groundbreaking topics with EGCG and green tea extract: 1) Delayed cancer onset as revealed by a 10-year prospective cohort study, 2) Prevention of colorectal adenoma recurrence by a double-blind randomized clinical phase II trial, 3) Inhibition of metastasis of B16 melanoma cells to the lungs of mice, 4) Increase in the average value of Young's moduli, i.e., cell stiffness, for human lung cancer cell lines and inhibition of cell motility and 5) Synergistic enhancement of anticancer activity against human cancer cell lines with the combination of EGCG and anticancer compounds. In the second part, we became interested in cancer stem cells (CSCs). 1) Cancer stem cells in mouse skin carcinogenesis by way of introduction, after which we discuss two subjects from our review on human CSCs reported by other investigators gathered from a search of PubMed, 2) Expression of stemness markers of human CSCs compared with their parental cells, and 3) EGCG decreases or increases the expression of mRNA and protein in human CSCs. On this point, EGCG inhibited self-renewal and expression of pluripotency-maintaining transcription factors in human CSCs. Human CSCs are thus a target for cancer prevention and treatment with EGCG and green tea catechins.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.2
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• pp.253-261
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• 2004

Ginsenosides and green tea extracts show a variety of biomedical efficacies such as anti-aging, anti-oxidation and anti-tumor-promotion effects. (-)-Epigallocatechin-3-gallate (EGCG) has been reported to inhibit the UVB-induced apoptosis by increasing the Bcl-2-to-Bax ratio. We have previously shown that ginsenoside Fl protects human HaCaT cells from ultraviolet-B (UVB)-induced apoptosis by maintaining constant levels of Bcl-2 and Brn-3a. Here, we investigate the combined effect of ginsenoside Fl and EGCG on the protection of human HaCaT keratinocyte against UVB-induced apoptosis. When treated individually, although 5 ${\mu}$M ginsenoside Fl and 50${\mu}$M EGCG protected cells from UVB-induced apoptosis, 2${\mu}$M ginsenoside Fl or 10${\mu}$M EGCG treatment showed very little protection effect. However, cotreatement of 2${\mu}$M ginsenoside Fl and 10${\mu}$M EGCG successfully protected HaCaT cells from UVB-induced cell death. As expected, combining ginsenoside Fl and EGCG efficiently prevented UVB-induced decrease of Bcl-2 and Brn-3a expression. In addition, cotreatment with ginsenoside F1 and EGCG prevented the dephosphorylation of Rb, whereas individual treatment with ginsenoside Fl or EGCG failed to prevent the dephosphorylation of Rb even at high concentrations.

• Journal of Periodontal and Implant Science
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• v.46 no.4
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• pp.244-253
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• 2016

Purpose: The aim of this study was to characterize the healing in the grafted calvarial defects of rats after adjunctive hyperbaric oxygen therapy. Methods: Twenty-eight male Sprague-Dawley rats (body weight, 250-300 g) were randomly divided into two treatment groups: with hyperbaric oxygen therapy (HBO; n=14) and without HBO (NHBO; n=14). Each group was further subdivided according to the bone substitute applied: biphasic calcium phosphate (BCP; n=7) and surface-modified BCP (mBCP; n=7). The mBCP comprised BCP coated with Escherichia-coli-derived recombinant human bone morphogenetic protein-2 (ErhBMP-2) and epigallocatechin-3-gallate (EGCG). Two symmetrical circular defects (6-mm diameter) were created in the right and left parietal bones of each animal. One defect was assigned as a control defect and received no bone substitute, while the other defect was filled with either BCP or mBCP. The animals were allowed to heal for 4 weeks, during which those in the HBO group underwent 5 sessions of HBO. At 4 weeks, the animals were sacrificed, and the defects were harvested for histologic and histomorphometric analysis. Results: Well-maintained space was found in the grafted groups. Woven bone connected to and away from the defect margin was formed. More angiogenesis was found with HBO and EGCG/BMP-2 (P<0.05). None of the defects achieved complete defect closure. Increased new bone formation with HBO or EGCG/BMP-2 was evident in histologic evaluation, but it did not reach statistical significance in histometric analysis. A synergic effect between HBO and EGCG/BMP-2 was not found. Conclusions: Within the limitations of this study, the present findings indicate that adjunctive HBO and EGCG/BMP-2 could be beneficial for new bone formation in rat calvarial defects.

• Journal of Life Science
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• v.27 no.4
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• pp.476-481
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• 2017

Polyphenols are secondary metabolites produced by higher plants and have been used as antiallergic, anticancer, antihypertensive, antiinflammatory, antimicrobial and antioxidant agents. They are generally divided into flavonoids and non-flavonoids. The antimicrobial activity of flavonoids are stronger than that of non-flavonoids. The skeleton structures of flavonoids possessing antimicrobial activity are chalcone, flavan-3-ol (catechin), flavanone, flavone, flavonol and proanthocyanidin. The flavonols are shown antibacterial activity against several gram-positive bacteria (Actinomyces naeslundii, Lactobacillus acidophilus and Staphylococcus aureus) and gram-negative bacteria (Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella melaninogenica and Prevotella oralis). Among of non-flavonoids, caffeic acids, ferulic acids and gallic acids showed antimicrobial activity against gram-positive (Listeria monocytogenes and S. aureus) and gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). These are found to be more efficient against the E. coli, L. monocytogenes, P. aeruginosa and S. aureus than antibiotics such as gentamicin and streptomycin. The kaempferol and quercetin showed synergistic effect with ciprofloxacin and rifampicin against S. aureus and methicillin resistant S. aureus (MRSA). Epigallocatechin gallate (EGCG) acts synergistically with various ${\beta}-lactam$ antibiotics against MRSA. In particular, the epicatechin, epigallocatechin (EGC), EGCG and gallocatechin gallate from Korean green tea has antibacterial activity against MRSA clinical isolates and the combination of tea polyphenols and oxacillin was synergistic for all the clinical MRSA isolates.

• Applied Biological Chemistry
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• v.35 no.4
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• pp.276-280
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• 1992

Quantutative analysis of catechins by HPLC was studied. When the mobile phase was switched from the conventional(AOAC) Methanol, Acetonitril and Acetic acid solution in $H_2O$ to 0.06% Phosphate solution with Acetonitrile, N,N-Dimethyl formamide, and Ethyl acetate, retention time could be reduced from 45 min to 28 min, especially, we obtained sharper chromatogram of the compounds, either (-)EGCG or (-)ECG, which resulted in minimization of analytical erros. CVs of retention time $(0.32{\sim}3.97%)$ and peak area $(1.61{\sim}7.01%)$ indicated that the data were more reliable. Content of catechins in commerical teas analyzed by the method was $120.3{\sim}153.7\;mg/g$ in green teas which was about 4 times that in black tea.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.464-469
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• 2008

In human beings, it is known that there is a correlation between the occurrence of acne and the ability to suppress sebum. Sebosuppression may be related to the inhibition of sebocyte proliferation, differentiation, and lipogenesis in sebaceous glands. To investigate the skin sebosuppressive activity of green tea extract, the in vivo effects of its flavonoid compounds on the androgen-dependent stimulation of pigmented macules in hamsters and performed in vitro experiments with human primary sebocytes were examined. Our results imply a dual activity of skin sebosuppression by green tea flavonoids; some catechins including epigallocatechin-3-gallate (EGCG) and gallocatechin-3-gallate (GCG) may reduce the differentiation of sebocytes by inhibiting PPAR-${\gamma}1$ mRNA expression, whereas some flavonol glycosides including kaempferol may inhibit lipogenesis in sebaceous glands by decreasing levels of the mature form of sterol-sensitive response elements binding protein-1c (SREBP-1c). Therefore, green tea is a potentially effective material for use in the development of health foods or cosmetics for skin sebosuppression.