• 한국식품과학회지
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• 제40권5호
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• pp.485-490
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• 2008

본 연구는 유기농 녹차 음료를 개발하기 위해 유기농 다엽의 카테킨류 함량을 비롯한 물리화학적 특성을 분석하였다. 다엽은 일체의 화학비료와 농약을 사용하지 않고 유기농 기법으로 재배한 시료를 사용하였고 채취시기가 다른 4월, 5월, 6월차와 반발효차를 수매하여 실험에 사용하였다. HPLC를 이용하여 다엽의 카테킨류 함량을 정량 정성 분석하였으며 녹차추출물의 색도와 pH를 측정하였다. 0.5%의 4월, 5월, 6월, 반발효차의 카테킨류는 각각 66.24, 29.19, 57.11, 5.27 ${\mu}g/mL$을 함유하고 있었으며, 카테킨류 중에서 EGCg의 함량이 가장 높았으나 EGC는 검출되지 않았다. 유기농 녹차 음료의 생산을 위해 카테킨류의 함량, 다엽의 가격, 수확량을 고려하여 6월차를 선택하였다. 6월차를 0.05, 0.1, 0.2, 0.5%로 추출하여 카테킨류를 정량한 결과, 0.1, 0.2, 0.5%는 0.05%에 비해 각각 1.50, 11.78, 41.09배 증가하였다. 6월차는 농도가 증가할수록 밝기가 증가하였고, 가장 밝고 녹색과 황색의 색이 짙었다. 반발효차의 pH는 5.83이었으며 나머지는 6.33-6.38의 범위를 가졌다. 6월차의 기호도 및 관능평가를 실시한 결과, 색상 기호도는 0.1%, 향기호도와 전체적인 기호도는 0.2% 추출물이 가장 우수한 평가를 받았고 단맛, 신맛, 떫은 맛의 정도를 평가한 결과 0.2%가 음용하기에 가장 적절하리라 사료된다. 또한 음료 제작 후, 저장 기간에 따른 녹차의 색 변화를 줄이기 위해 저장성 실험 결과 탄산수소나트륨을 0.03%를 첨가할 필요가 있다.

• Journal of Applied Biological Chemistry
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• 제66권
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• pp.424-435
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• 2023

본 연구 결과 DPPH 라디칼 소거 활성은 갈랑가 뿌리 70% 에탄올 추출물(AG.E) 100 ㎍/mL 농도에서 81.8%이었으며 ABTS⁺ 라디칼 소거 활성은 AG.E 50 ㎍/mL의 낮은 농도에서 L-Ascorbic acid (AA)와 유사한 99.8%로 확인되었다. 항노화 활성을 측정하기 위하여 collagenase와 elastase 저해 활성을 측정한 결과 둘 모두에서 AG.E는 50 ㎍/mL의 낮은 농도부터 epigallocatechin (EGCG)보다 더 높은 저해 효과를 나타내었다. 특히 500 ㎍/mL 농도에서 EGCG 대비 3배 이상의 저해 효과를 보였다. CCD-986sk 세포내에서 AG.E의 항노화 효과를 검증하기 위해 UVB로 자극한 다양한 실험에서도 우수한 항노화 효과가 얻어졌다. RT-PCR을 통한 유전자 발현 분석 실험에서 COL1A mRNA 발현량은 AG.E 20 ㎍/mL 저농도에서 무첨가 대비 2.90배 증가시키는 결과가 얻어져 항노화관련 우수한 기능성 소재로 개발 가능성이 확인되었다. 제형에 소재의 적용 시 생리활성의 경시적 보전성에 대한 기초 연구로서 AG.E 및 AA등을 안정한 W/O type emulsion에 첨가하여 25 ℃ 항온조에 보관하면서 1일차, 30일차, 60일차에 DPPH와 ABTS+ 라디칼소거 활성을 측정한 결과 모두 경시적으로 항산화 효과가 높은수준 유지됨을 확인하였다.

• 한국식품과학회지
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• 제47권4호
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• pp.419-424
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• 2015

제주, 보성, 하동산 차엽의 우전, 세작, 중작 및 대작 상품명을 쓰고 있는 시판 잎 녹차의 색은 녹차 등급이 높을수록 즉 채엽시기가 빠를수록 L값과 녹색도인 -a값이 높게 나타났으며 제주산 녹차가 보성 및 하동산 녹차에 비해 L값과 b값이 높은 것으로 나타났다. 카테킨 분석 결과 EGC 함량은 차엽 산지에 관계없이 채엽시기가 늦어짐에 따라 유의적으로 증가하였으며, 카테킨, GCg, ECg 함량은 유의적으로 감소하였다. 카테킨류 중 EGCg 함량이 95.39-116.25 mg/g으로 가장 높았으며 특히 보성산 녹차가 다른 지역에 비해 유의적으로 높게 나타났다. 카페인, 테오브로민 및 테아닌 함량은 모든 차엽에서 채엽시기에 따라 유의적으로 감소하는 경향을 보였으며 특히 제주산 우전의 카페인, 테오브로민 및 테아닌 함량은 각각 33.43, 17.84, 20.84 mg/g으로 가장 높게 함유되어 있었다. 산화방지 활성은 측정방법에 상관없이 등급이 높은 우전에서 높게 나타났으며 제주 및 하동산 녹차의 경우 채엽시기가 늦어짐에 따라 유의적으로 감소하였으나 보성산 녹차는 채엽시기에 따라 유의적으로 증가하였다. 녹차의 주요 산화방지 성분인 개별 카테킨 함량과 산화방지 활성과의 상관관계를 분석한 결과 DPPH 활성은 EGCg, ECg 및 총카테킨 함량과 양의 상관관계가 있는 것으로 나타났으며 ABTS 활성은 EGC 함량과는 음의 상관관계 그리고 카테킨, GCg 및 ECg 함량과는 양의 상관관계가 있는 것으로 나타났다.

• 대한약침학회지
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• 제19권4호
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• pp.312-318
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• 2016

Objectives: Bacterial resistant infections have become a global health challenge and threaten the society's health. Thus, an urgent need exists to find ways to combat resistant pathogens. One promising approach to overcoming bacterial resistance is the use of herbal products. Green tea catechins, the major green tea polyphenols, show antimicrobial activity against resistant pathogens. The present study aimed to investigate the effect of catechins, green tea extract, and methylxanthines in combination with gentamicin against standard and clinical isolates of Staphylococcus aureus (S. aureus) and the standard strain of Pseudomonas aeruginosa (P. aeruginosa). Methods: The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values of different agents against bacterial strains were determined. The interactions of green tea extract, epigallate catechin, epigallocatechin gallate, two types of methylxanthine, caffeine, and theophylline with gentamicin were studied in vitro by using a checkerboard method and calculating the fraction inhibitory concentration index (FICI). Results: The MICs of gentamicin against bacterial strains were in the range of $0.312-320{\mu}g/mL$. The MIC values of both types of catechins were $62.5-250{\mu}g/mL$. Green tea extract showed insufficient antibacterial activity when used alone. Methylxanthines had no intrinsic inhibitory activity against any of the bacterial strains tested. When green tea extract and catechins were combined with gentamicin, the MIC values of gentamicin against the standard strains and a clinical isolate were reduced, and synergistic activities were observed (FICI < 1). A combination of caffeine with gentamicin did not alter the MIC values of gentamicin. Conclusion: The results of the present study revealed that green tea extract and catechins potentiated the antimicrobial action of gentamicin against some clinical isolates of S. aureus and standard P. aeruginosa strains. Therefore, combinations of gentamicin with these natural compounds might be a promising approach to combat microbial resistance.

• Journal of Periodontal and Implant Science
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• 제46권4호
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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.

• KSBB Journal
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• 제31권4호
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• pp.228-236
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• 2016

The aim of this study was to characterize the hemolytic Aeromonas sp. MH-8 exposed to green tea catechin, epigallocatechin gallate (EGCG). Initially, the hemolytic Aeromonas sp. MH-8 was enriched and isolated from stale fish. Bactericidal effects of MH-8 exposed to EGCG ranging from 1 mg/mL to 4 mg/mL were monitored, and complete bactericidal effects were achieved within 3 h at 3 mg/mL and higher concentrations. SDS-PAGE with silver staining revealed that the amount of lipopolysaccharides increased or decreased in the strain MH-8 treated to different concentrations and exposing periods of EGCG in exponentially growing cultures. The stress shock proteins (70-kDa DnaK and 60-kDa GroEL), which might contribute to enhancing the cellular resistance to the cytotoxic effect of EGCG, were induced at different concentrations of EGCG exposed to cell culture of MH-8. Scanning electron microscopic analysis demonstrated the presence of irregular rod shapes with umbilicated surfaces for cells treated with EGCG. 2-DE of soluble protein fractions from MH-8 cultures showed 18 protein spots changed by EGCG exposure. These proteins involved in chaperons (e.g., DnaK, GroEL and trigger factor), enterotoxins (e.g., aerolysin and phospholipase C precursor), LPS synthesis (e.g., LPS biosynthesis protein and outer membrane protein A precursor), and various biosynthesis and energy metabolism were identified by peptide mass fingerprinting using MALDI-TOF. In consequence, EGCG was found to have substantial antibacterial effects against food-poisoning causing bacterium, hemolytic Aeromonas sp. MH-8. Also the results provide clues for understanding the mechanism of EGCG-induced stress and cytotoxicity on Aeromonas sp. MH-8.

• Natural Product Sciences
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• 제13권1호
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• pp.68-77
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• 2007

The aim of the present study was to examine the effects of green tea extract (CUMS6335) on the release of CA evoked by cholinergic stimulation and direct membrane-depolarization in the perfused model of the adrenal gland isolated from the spontaneously hypertensive rats (SHRs), and to establish the mechanism of action. Furthermore, it was also to test whether there is species difference between animals, and between CUMS6335 and EGCG, one of biologically the most powerful catechin compounds found in green tea. CUMS6335 $(100\;{\mu}g/ml)$, when perfused into an adrenal vein for 60 min, time-dependently inhibited the CA secretory responses evoked by ACh (5.32mM), high $K^+$(56 mM), DMPP $(100\;{\mu}M)$, and McN-A-343 $(100\;{\mu}M)$ from the isolated perfused adrenal glands of SHRs. However, CUMS6335 itself did fail to affect basal catecholamine output. Also, in adrenal glands loaded with CUMS6335 $(100\;{\mu}g/ml)$, the CA secretory responses evoked by Bay-K-8644 $(10\;{\mu}M)$ and cyclopiazonic acid $(10\;{\mu}M)$ were also inhibited in a relatively time-dependent fashion. However, in the Presence of EGCG $(8.0\;{\mu}g/ml)$ for 60 min, the CA secretory response evoked by ACh, high $K^+$, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid were not affected except for last period. Collectively, these results indicate that CUMS6335 inhibits the CA secretion evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors as well as by direct membrane-depolarization from the perfused adrenal gland of the SHR. It seems that this inhibitory effect of CUMS6335 is exerted by blocking both the calcium influx into the rat adrenal medullary chromaffin cells and the uptake of $Ca^{2+}$ into the cytoplasmic calcium store, which are at least partly relevant to the direct interaction with the nicotinic receptor itself. It seems likely that there is much difference in mode of the CA-releasing action between CUMS6335 and EGCG.

• Biomolecules & Therapeutics
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• 제16권4호
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• pp.410-415
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• 2008

Previously, we identified albumin as an inhibitory factor in serum for cell adhesion of T cells such as human Jurkat T and primary cultured human T cells. In the present study, we found that other hematopoietic cell lines including U-937 human monocytes, THP-1 human monocytes, K-562 promyelocytic leukemia cells, and HL-60 human leukemia cells, also adhere to tissue culture flasks when serum is withdrawn, and albumin exerts an inhibitory effect on cell adhesion by those cells, implying that this inhibition is a common phenomenon in hematopoietic cells. Furthermore, we found that cell adhesion is inhibited by antioxidants such as (-)-epigallocatechin- 3-gallate (EGCG), morin, and a-tocopherol. Our results suggest that albumin may inhibit basal cell adhesion of hematopoietic cells and that the oxidative balance in the plasma may be important for cell adhesion of hematopoietic cells in vivo.

• Archives of Pharmacal Research
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• 제25권5호
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• pp.561-571
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• 2002

The action mechanisms of several chemopreventive agents derived from herbal medicine and edible plants have become attractive issues in cancer research. Tea is the most widely consumed beverage worldwide. Recently, the cancer chemopreventive actions of tea have been intensively investigated. It have been demonstrated that the active principles of tea were attributed to their tea polyphenols. Recently, tremendous progress has been made in elucidating the molecular mechanisms of cancer chemoprevention by tea and tea polyphenols. The suppression of various tumor biomarkers including growth factor receptor tyrosine kinases, cytokine receptor kinases, P13K, phosphatases, ras, raf, MAPK cascades, NㆍFB, IㆍB kinase, PKA, PKB, PKC, c-jun, c-fos, c-myc, cdks, cyclins, and related transducing proteins by tea polyphenols has been studied in our laboratory and others. The IㆍB kinase (IKK) activity in LPS-activated murine macrophages (RAW 264.7 cells) was found to be inhibited by various tea polyphenols including (-) epigallocatechin-3-gallate (EGCG), theaflavin (TF-1), theaflavin-3-gal-late (TF-2) and theaflavin-3,3'-digallate (TF-3). TF-3 inhibited IKK activity in activated macrophages more strongly than did the other tea polyphenols. TF-3 inhibited both IKK1 and IKK2 activity and prevented the degradation of IㆍBㆍand IㆍBㆍin activated macrophage cells. The results suggested that the inhibition of IKK activity by TF-3 and other tea polyphenols could occur by a direct effect on IKKs or on upstream events in the signal transduction pathway. TF-3 and other tea polyphenols blocked phosphorylation of IB from the cytosolic fraction, inhibited NFB activity and inhibited increases in inducible nitric oxide synthase levels in activated macrophage. TF-3 and other tea polyphenols also inhibited strongly the activities of xanthine oxidase, cyclooxygenase, EGF-receptor tyrosine kinase and protein kinase C. These results suggest that TF-3 and other tea polyphenols may exert their cancer chemoprevention through suppressing tumor promotion and inflammation by blocking signal transduction. The mechanisms of this inhibition may be due to the blockade of the mitogenic and differentiating signals through modulating EGFR function, MAPK cascades, NFkB activation as wll as c-myc, c-jun and c-fos expression.

• Archives of Pharmacal Research
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• 제28권7호
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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.