• Bulletin of the Korean Chemical Society
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• 제26권5호
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• pp.747-754
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• 2005

Liquid chromatographic methods with UV and fluorescence detection have been used to determine the levels of (+)-catechin, (-)-epicatechin, (-)-epicatechin gallate, and (-)-epigallocatechin gallate in Korean green tea infusions. The extracts of Korean green tea leaves or powders in water at various temperatures (100 ${^{\circ}C}$, 80 ${^{\circ}C}$, 60 ${^{\circ}C}$) and time, were washed with chloroform and re-extracted to ethyl acetate. The ethyl acetate phase was dried and re-dissolved in methanol and analyzed. Five catechin compounds were separated by gradient elution. The flavonoids were found decomposed on prolonged extraction, thus exhaustive extraction by a Soxhlet apparatus was found useless for green tea. Some unknown components were found in the extracts at 100 ${^{\circ}C}$. When the green tea was filtered and re-extracted with new fresh water, still some flavonoids were extracted. However, the contents of flavonoids in the third extract were found negligible. The flavonoid extraction rate of green tea powders was higher than that of green tea leaves, but flavonoid decomposition of green tea powders was also faster than that of green tea leaves. The traditional way of drinking green tea was found appropriate in view of flavonoids intake.

• 한국식품저장유통학회지
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• 제24권6호
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• pp.871-878
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• 2017

제주산 녹차, 로즈마리, 레몬 잎, 조릿대 잎을 물과 에탄올을 이용해 다양한 조건에서 추출물을 제조하여 각 추출물에 대한 항산화 활성을 측정하였다. 그 결과, 녹차와 로즈마리 추출물이 레몬과 조릿대 잎 추출물과 비교하여 상대적으로 높은 항산화 활성을 보였다. 항산화 활성이 상대적으로 우수한 녹차와 로즈마리 추출물들을 두유에 첨가한 뒤, 혼합물의 항산화 활성을 측정하였다. 녹차 증류수 가압 가열 추출물과 상온 정치 추출물 10% 첨가한 두유에서 상대적으로 가장 높은 활성을 보였으며, 녹차 증류수 가압 가열 추출물과 상온 정치 추출물의 DPPH 라디칼 소거능은 각각 $85.1{\pm}2.3%$, $84.4{\pm}2.0%$을, ABTS 라디칼 소거능은 각각 $73.4{\pm}2.8%$, $81.3{\pm}4.8%$로 확인되었다. 한편, 로즈마리 증류수 가압 가열 추출물 10% 첨가한 두유에서 무첨가 두유에 비해 더 높은 DPPH 라디칼 소거능이 확인되었으며, ABTS 라디칼 소거능은 무첨가 두유와 유사했다. 따라서 녹차 증류수 가압 가열추출물과 상온 정치 추출물, 그리고 로즈마리 증류수 가압 가열 추출물을 두유에 첨가 시 항산화 활성이 향상된 고부가가치 두유제품 개발 제발이 가능할 것으로 기대된다.

• 한국식품영양과학회지
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• 제28권1호
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• pp.100-106
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• 1999

Use of chemical preservative for controlling harmful microorganisms in food products has been debated due to public concerns about food quality because of perceived toxic and carcinogenic potential. Thus, use of non toxic natural antimicrobial agents has become essential. This study was investigated to determine the antimicrobial activity of water or ethanol extract of commercially available tea, and of solvent fractionated ethanol extracts obtained from steamed green tea. Both of water and ethanol extracts of green tea(steamed or roasted), oolong tea and black tea exhibited strong antimicrobial activity against gram positive and negative bacteria, but not effective against yeast and mold. Also, antimicrobial activity of ethanol extract of 4 different kinds of tea was stronger than that of water extract. Among 4 different tea, ethanol extract of steamed green tea was further fractionated. One thousand g/disk buthanol extract had the strongest antimicrobial activity against bacteria and mold. The concentration of the antimicrobial activity of buthanol extract in tested microorganisms ranged from 125~1000 g/disk except for Rhizopus javanicus. Antimicrobial activity of buthanol extract of steamed green tea was not destroyed by heating at 100oC for 60 min and at 121oC for 15 min, which is very stable over heat treatment. The inhibitory effect of the buthanol extract on the growth of Listeria monocytogenes and Staphylococcus aureus was investigated. Growth of both strains was started in the presence of 250 and 500 g/ml after 12 and 24 hour respectively, whereas complete inactivation of both strains was occurred in the presence of 1000 g/ml.

• 한국임상약학회지
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• 제28권4호
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• pp.342-346
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• 2018

Background: Green tea extracts are approved as nonprescription drug and available as health functional foods, health foods, and beverages. Clinical information on the products is lacking. Methods: Information about the products on green tea nonprescription drugs was obtained from the website of the Korea Pharmaceutical Information Center. The Naver, i.e., a top ranking online search portal, was used for compiling the list of the health functional food products using key words of 'green tea catechin' on August 23, 2018. The recommended daily dosages of catechins were calculated as 30% of the total dried mass of green tea and about 50% of the catechins were considered as epigallocatechin gallate (EGCG). Results: A total of two types of nonprescription drugs containing green tea powder or extracts, nine health functional food products, and three types of health foods were found. The regulatory requirements of the EGCG exceeding 800 mg were reported to be associated with adverse effects of elevated liver enzyme. If consumers take several green tea products concurrently, such as nonprescription drugs with health functional foods or health foods, it could exceed the recommended amount of EGCG. Conclusion: The concurrent use of green tea products as nonprescription drugs, health functional foods, and healthy foods may lead to an increased exposure to EGCG. Pharmacists should be aware the availability of various types of green tea products and the potential risk of liver toxicity due to excessive consumption of EGCG.

• 한국염색가공학회지
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• 제18권1호
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• pp.10-19
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• 2006

Despite several recent attempts to measure the concentration of individual catechins by HPLC, it has not been so easy to separate catechins accurately. The aim of the present work is to provide a proper condition for separating each component of catechins by HPLC analysis, and also to evaluate the experimental variables including color differences, and metal ion contents after dyeing and mordanting. Four kinds of Catechins, (-)-epicatechin(EC), (-)-epicatechin gallate(ECG), (-)-epigallocatechin(EgC), (-)-epigallocatechin gllate(EgCG) were isolated from the residues after dyeing. Catechins in Korean green tea leaves are richer when e tea leaves are younger. Higher concentration of catechins owes it to e way it is processed. The contents of catechins adsorbed in silk fabrics after dyeing were in order of EGCG>ECG>EGC>EC. We have found $68\%$ uptake of EGCG, and 116.8mg of EGCG in the silk fabrics after it was dyed with $1\%$ Korean green tea extracts. The absorbance intensity and K/S values of dyed silk fabrics were increased with dyeing temperature and time. Only the surface color of the silk fabric dyed with green tea extracts was yellowish red, but it changed from yellowish red to red with an increase in the mordant concentration. Post-mordanted silk fabrics with ferrous sulfate changed from yellowish red to red and purple color shade. In a practical evaluation, there is no significant change in color after twenty times of the continuous dry cleaning process. However, post-mordanted fabrics with ferrous sulfate faded the brightness of color after dry cleaning. Dyeing silk fabrics with a Korean tea extract reduced the metal ion contents in the silk fabrics when compared to the untreated silk fabrics. Metal contents in silk fabrics dyed and post-mordanted with $1\%$ each metal solution were 0.194 ppm for Aluminum, 1.601ppm for Copper, and 0.334 ppm for Iron. After the post-mordanting process, the heavy metal ion absorption increased, which was mainly attributed to the catechins and polyphenols in dyed silk fabrics.

• KSBB Journal
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• 제16권2호
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• pp.163-169
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• 2001

This study was undertaken to evaluate the effects of green and taste teas on the in-vitro antimicrobial activity and vacuolating toxin titer of Helicobacter pylori. Crude aqueous extracts prepared by adding 2 g of tea leaf or powder to 100 ml of boiling distilled water, and sterilized by passing through a 0.22 $mutextrm{m}$ membrane filter. Green tea, coffee, and ginger tea showed bactericidal activity on H. pylori within 3 hours. Black tea and ssangwha tea also showed bactericidal activity on H. pylori in 24 hours. Arrowroot tea show no bactericidal effect on H. pylori after 48 hours. Two fold diluted green tea and coffee decreased(1/10,000cfu) the growth of H. pylori in 24 hours, but the two fold diluted black tea, ssangwha tea, and ginger tea showed suppression effect upon of(1/10cfu) H. pylori in 24 hours. The two-fold and 10-fold diluted green tea, coffee and two-fold diluted black tea abrogated the vacuolating toxin titer of H. pylori, but the two-fold and 10-fold diluted ginger, ssangwha, ginseng, and arrowroot tea only reduced the vacuolating toxin titer of H.pylori from 1/2 to 1/8. These result suggest that green tea and coffee have effective antibacterial or bactericidal effects on H.pylori, and that they also have a neutralization effect upon the vacuolating toxin of H.pylori.

• Food Science and Biotechnology
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• 제14권1호
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• pp.46-48
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• 2005

Growth inhibitory effects of ethanol extracts of green tea and pine needles on Bacillus stearothermophilus isolated from spoiled red bean paste were detected at concentrations higher than 750 ppm, and antimicrobial activity of pine needle extract was slightly higher than that of green tea exract. Growth inhibitory effect of pine needle extract in nutrient broth adjusted to pH 6.0, water-activity 0.92, and $45\;^{\circ}$Brix was observed at 500 ppm. These results indicated growth of B. stearothermophilus could be inhibited by adding pine needle and green tea extracts.

• 한국식품영양과학회지
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• 제37권11호
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• pp.1382-1388
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• 2008

9월에 수확하여 엽차용 녹차로 시판되는 보성산 녹차를 온수, $80^{\circ}C$ 열수, 70% ethanol 용액으로 추출하고, 70% ethanol 추출물을 다시 hexane, chloroform, ethyl acetate, butanol로 분획한 다음 녹차 추출물과 분획물의 그램 양성균과 그램 음성균 8종에 대한 항균활성에 대하여 조사를 하였다. 녹차의 추출 수율은 70% ethanol 추출물은 33.0%, ethyl acetate 분획물은 11.2%를 보였다. 8종의 세균에 대한 녹차 추출물 간의 항균활성은 70% 에탄올 추출물의 경우 수 추출물에 비하여 Vibrio parahaemolyticus(V. parahaemolyticu) 및 Staphylococcus aureus(S. aureus)에 대하여 가장 높았다. 70% 에탄올 추출물로부터 여러 가지 용매를 달리하여 분획한 분획물 간의 항균활성은 70% ethanol 추출물에 비하여 ethyl acetate 분획물의 경우 Klebsiella pneumoniae, V. parahaemolyticus, S. aureus, Bacillus subtilis(B. subtilis) 및 Streptococcus mutans(S. mutans)와 같은 5종의 세균에 대하여 높았다. 70% ethanol 추출물 유래 ethyl acetate 분획물의 MIC는 B. subtilis의 경우 $5\;{\mu}L$/disc이었고, S. aureus 와 S. mutans의 경우 $3\;{\mu}L$/disc이었으며, V. parahaemolyticus의 경우 $3\;{\mu}L$/disc 이하로 아주 낮았다. Ethyl acetate 분획물의 첨가 농도에 따른 항균효과는 B. subtilis와 S. mutans 두 균종에서 확연히 나타났고 B. subtilis는 0.05% 이상의 첨가로 24시간 증식시켰을 때 control에 비하여 균증식이 90% 이상 억제됨을 보였으며, S. mutans는 동일한 균증식 억제 효과를 얻기 위하여 0.1% 이상의 ethyl acetate 분획물 농도가 요구되었다. Ethyl acetate 분획물의 열처리($121^{\circ}C$, 20분)는 균종에 따라 10%정도의 항균활성을 감소시켰다. 이와 같은 결과를 종합할 때 9월에 채엽된 저렴한 녹차로 천연 항균제 혹은 식품보존료의 개발은 충분한 잠재력이 있는 것으로 판단되었다.

• Archives of Pharmacal Research
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• 제21권3호
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• pp.348-352
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• 1998

Different bacteria wwere seperated from saliva and teeth of cariogenic patients and identified by a variety of morphological and biochemical tests. Extracts of green tea strongly inhibited Escherichia coli, Streptococcus salivarius and Streptococcus mutans. The antibacterial effect of green and black tea extracts were compared with those of amoxicillin, cephradine and eugenol.

• 한국식품저장유통학회지
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• 제9권4호
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• pp.406-410
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• 2002

김치제조시 녹차의 첨가방법이 발효특성과 관능적 품질에 미치는 영향을 조사하기 위하여 1%의 녹차추출물를 함유하는 소금물로 절인 후 담근 김치(I), 절임배추를 1% 녹차추출 물에 일정시간 담금후 제조한 김치(II), 녹차 1%를 양념과 혼합하여 담근 김치(III)의 3가지 방법으로 김치를 제조한 후 1$0^{\circ}C$에서 숙성시키면서 pH, 산도, 균수, 색상 및 관능적 품질을 조사하였다. 대조구의 pH는 숙성중 I~III의 경우보다 낮아 녹차처리구가 숙성이 지연되었다. 산도의 경우도 pH와 역으로 pH의 결과와 일치하였다. 그러나 녹차처리방법에 따른 큰 차이는 보이지 않았다. 대조구의 총균수와 젖산균수는 각각 6.16~9.29 및 4.59~8.42 log cfu/mL로I~III의 5.40~8.38 및 4.99~8.07 log cfu/mL보다 높았다. 김치조직의 L＊값은 I< II