• Title/Summary/Keyword: green tea catechin

Search Result 168, Processing Time 0.038 seconds

Changes of Some Chemical Compounds of Korean (Posong) Green Tea according to Harvest Periods (보성산 녹차의 채엽시기에 따른 화학 성분의 변화)

  • Kim, Sang-Hee;Han, Dae-Seok;Park, Jong-Dae
    • Korean Journal of Food Science and Technology
    • /
    • v.36 no.4
    • /
    • pp.542-546
    • /
    • 2004
  • Changes in contents of catechins, caffeine, free amino acids, and minerals in green tea loaves according to harvest periods were compared. Total catechin content increased from 40.61 to 52.04 mg/g, while that of caffeine decreased from 17.56 to 14.61 mg/g according to harvest periods. Regardless of harvest periods, composition of catechins was epigallocatechin (EGC)>epigallocatechin gallate (EGCg)>epicatechin (EC)>gallocatechin (GC)>epicatechin gallate (ECg)>catechin (C)>gallocatechin gallate (GCg)>catechin gallate (Cg). Free amino acid content in green tea leaves was highest in young loaves, and gradually decreased according to harvest periods. Theanine content was markedly decreased with leaf aging, suggesting taste of green tea may be changed from mild to bitter with increasing harvest period. Analyses of mineral elements in green tea leaves showed that Fe, Mn, and Mg increased with leaf aging, while Cu showed opposite trend. Results reveal that content of some chemical compounds in Korean (Posong) green tea was highly dependent on harvest period.

Antioxidant Activity of Korean Green and Fermented Tea Extracts (국내산 녹차 및 후발효차 추출물의 항산화 효과)

  • Shon Mi-Yae;Kim Sung-Hee;Nam Sang-Hae;Park Seok-Kyu;Sung Nak-Ju
    • Journal of Life Science
    • /
    • v.14 no.6 s.67
    • /
    • pp.920-924
    • /
    • 2004
  • The beneficial effects of green and fermented tea are generally attributed to some antioxidant activities including superoxide dismutase (SOD)-like ability and scavenging activity originated from their phenolic compounds and flavonoids. Content of total flavonoid of green tea $(413.3\;{\mu}g/g)$ was similar to those of fermented tea $(405.7\;{\mu}g/g)$. Content of total phenol of green tea $(46.8\;{\mu}g/g)$ was higher than those of fermented tea $(23.5\;{\mu}g/g)$. Major catechin compounds of hot water extract in green tea was EGCG, including EGC, Gc, catechin and catechol. EGCG was not detected .in fermented tea. SOD-like ability was increased in proportional to added concentration of hot water extract. The scavenging activities of hydroxyl radical at $3000\;{\mu}g/ml$ of green and fermented teas were found up to $60\%$. Hot water extract of green tea was more effective in scavenging activity than that of fermented tea.

Desmutagenicity of Tea Extracts from Green Tea, Oolong Tea and Black Tea (녹차, 오룡차 및 홍차 추출물의 돌연변이원성 억제작용)

  • 김선봉;여생규;김인수;안철우;박영호
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.24 no.1
    • /
    • pp.160-168
    • /
    • 1995
  • Desmutagenicities against 2-amino-1-methyl-6-phenylimidazo[4, 5-b] pyridine(PhIP) and 2-amino-3, 8-dimethylimidazo[4, 5-f]quinoxaline(MelQx) of tea extracts (steamed green tea, roasted green tea, oolong tea and black tea) were investigated. All the fractions obtained from tea extracts showed strong desmutagenic activity against PhIP and MeIQx toward S. typhimurium TA 98 in the presence of the S-9 mix. The crude catechin fraction exhibited the strongest desmutagenic activity. Among these tea extracts, black tea especially exhibited the strongest desmutagenic activity and the activity was 70.9~91.0% against PhIP and 92.2~98.8% against MelQx at a concentration(0.5~1.0mg/plate) for drinking. The activity of authentic catechins of (-)-EGC, (-)-EGCg, (-)-ECg and (-)-EC were 79.5%, 60.2%, 46.1% and 43.5% against PhIP, and were 52.3%, 11.6%, 8.2% and 22.1% against MelQx by addition of 1.0mg/plate, respectively. The desmutagenic activity was supposedly due to the (-)-EGCg, (-)-EGC and (-)-EC in tea polyphenols, and the browning materials. The desmutagenicity was stronger when mutagens were preincubated with S-9 mix after reaciton with black tea extracts than when preincubated with them after reaction with S-9 mix. The desmutagenicity of tea extracts was rather expressed by reacting directly with mutagens than by deactivating the activated forms of mutagens.

  • PDF

Clinical Information on Green Tea Extract Used for Weight Loss (체중감량 목적으로 사용되는 녹차추출물의 임상정보)

  • Youn, Youngjin;Shin, Sangyoon;Jeong, Kyeong Hye;Lee, Euni
    • Korean Journal of Clinical Pharmacy
    • /
    • v.28 no.4
    • /
    • pp.342-346
    • /
    • 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.

Separation of Caffeine and Catechin Compounds from Green Tea by Quercetin Molecular Imprinted Solid-Phase Extraction (케르세틴 분자각인 고정상 추출을 이용한 녹차에서 카페인 및 카테킨 화합물의 분리)

  • Jin, Yin-Zhe;Row, Kyung-Ho
    • Journal of the Korean Chemical Society
    • /
    • v.51 no.2
    • /
    • pp.165-170
    • /
    • 2007
  • In this work, caffeine and some catechin compounds such as +C, EGC and EGCG were extracted from green tea using quercetin molecular imprinted polymers in solid-phase extraction. For synthesis of MIP, quercetin as the templates, MAA as the monomer, EGDMA as the crosslinker and AIBN as the initiator were used. For extraction of caffeine and catechin compounds from green tea, the solid-phase extractions of a load followed by wash and elution procedures were done with water, methanol and methanol:acetic acid=90:10 (vol.%) as the solvents, respectively. HPLC analysis (C18 column, 5 μm, 250×4.6 mm) with the mobile phase of methanol:water=40:60 (vol.%) at a flow rate of 0.5 ml/min was adopted for the quantitative determination. By solid-phase extraction, the resolutions of caffeine and some catechin compounds from green tea were increased. The quercetin-MIP had higher selectivity to +C compounds.

Extraction and Purification of EGCG(Epigallocatechin Gallate) from Green Tea (녹차로부터 EGCG(Epigallocatechin Gallate)의 추출 및 정제)

  • Gang, Ji-Hun;Park, Yeong-Gwang;Jeong, Seong-Taek;No, Gyeong-Ho
    • KSBB Journal
    • /
    • v.14 no.5
    • /
    • pp.517-522
    • /
    • 1999
  • A green tea used in this experiment was cultivated at Bosung (Chonnam) and purchased from a domestic market. The extract at 5$0^{\circ}C$ water from the powder of green tea partitioned with chloroform and ethyl acetate. The resulting solution was further purified with a chromatographic column (4.6$\times$250 mm, 15${\mu}{\textrm}{m}$, Lichrospher 100RP-18). Finally separation was achieved on a $\mu$-Bondapak $C_18$(3.9$\times$300mm, 10${\mu}{\textrm}{m}$) column. The elution order of the catechin compounds contained in the green tea was EGC(Epigallocatechin, C(catechin), EC(Epicatechin), EGCG(Epigallocatechin Gallate) and ECG(Epicatechin Gallate). From the experimental results the mobile phase for isolating EGCG from the extract consisted of 0.1% acetic acid in water/acetonitrile, 87/13%(v/v). The flow rate of mobile phase was 1.0 $m\ell$/min, and UV wavelength was fixed at 280 nm. 121.3 mg of EGCG, higher than 98% of purity, was obtained from 5 g of dry green tea.

  • PDF

Dyeing Characteristics and UV Protection Property of Green Tea Dyed Cotton Fabrics - Focusing on the Effect of Chitosan Mordanting Condition-

  • Kim Sin-Hee
    • Fibers and Polymers
    • /
    • v.7 no.3
    • /
    • pp.255-261
    • /
    • 2006
  • There is increasing interest in the many beneficial aspects of green tea to human such as anti-carcinogenic, anti-aggregant, anti-allergic, anti-bacterial, anti-mutagenic, and anti-oxidant activities. Besides these beneficial aspects, it has been reported that green tea ingredients, especially polyphenolic families (i.e., catechin), have some UV protection property both in vivo and in topical applications. In this study, green tea extract was used as a dyeing stock for cotton and the UV protection property of the dyed cotton fabric was examined. To increase the affinity of cotton fiber to the polyphenolic components in the green tea extract, a natural biopolymer, chitosan, was used as mordanting agent. The effects of chitosan concentration in mordanting on the dyeing characteristics and the UV protection property were examined. Chitosan mordanted green tea dyed cotton showed better dyeing characteristic and higher UV protection property compared with the unmordanted green tea dyed cotton. As the chitosan concentration in mordanting increased, the dyeing efficiency and the UV protection property also increased. Therefore, adapting chitosan mordanting in green tea dyeing can increase the UV protection property of cotton fabrics to some extent.

Protective Effect of Green Tea Extract, Catechin on UVB-Induced Skin Damage (녹차추출물 성분 catechin이 자외선에 의해 손상된 피부에 미치는 영향)

  • 이은희;이종권;홍진태;정경미;김용규;이선희;정수연;이용욱
    • Journal of Food Hygiene and Safety
    • /
    • v.16 no.2
    • /
    • pp.117-124
    • /
    • 2001
  • The main constituent of green tea, catechins have been reported to have numberous biological anti-vites including antimutagenic, antibacterial, hypocholesterolemic, antioxidant and antitumor properties. In the present study, we examined the protective effect of catechin on UVB-induced skin damage. Catechin (3 mg/mouse) was topically treated to dorsal area of SHK-1 hairless mouse daily for 2 weeks. UVB (100 mJ/$\textrm{cm}^2$) was also treated soon after application of catechin alone or with catechin for 2 weeks. Catechin reduced UVB-induced infiltration of inflammatory cells, fibrosis of cells and collagen-fiber formation. In addition, catechin also prevented UVB-induced DNA fragmentation and apoptosis cell number, but not changed p53 level. Furthermore catechin inhibited UVB-induced cell proliferation. There results showed that catechin have preventive effect aganinst UVB-induced skin damages. and these effects could contribute to the antitumor promoters activity.

  • PDF

Solid-Phase Extraction of Caffeine and Catechin Compounds from Green Tea by Caffeine Molecular Imprinted Polymer

  • Jin, Yinzhe;Row, Kyung-Ho
    • Bulletin of the Korean Chemical Society
    • /
    • v.28 no.2
    • /
    • pp.276-280
    • /
    • 2007
  • In this work, caffeine and some catechin compounds + C, EC, EGC, and EGCG were extracted from green tea by using molecular imprinted polymers (MIP) as sorbent materials in a solid-phase extraction (SPE) process known as MISPE (molecular imprinted solid-phase extraction). For synthesis of MIP, caffeine was employed as the template, MAA as the monomer, EGDMA as the crosslinker, and AIBN as the initiator. A solution of caffeine (0.2 mg/mL in methanol) was utilized in the solid extraction cartridges following loading, washing, and elution procedures with acetonitrile, methanol, and methanol-acetic acid (90/10, %v/v) as the solvents, respectively. This solid-phase extraction protocol was applied for the extraction of caffeine and some catechin compounds from green tea. A comparison was made between the results obtained with the MIP cartridges and a traditional C18 reversed-phase cartridge. It was thereupon found that the recovery of caffeine by the MIPbased sorbent used in this work was almost two and four times greater than that by a commercially available C18 material. A quantitative analysis was conducted by high performance liquid chromatography (HPLC) using a C18 column (5 μm, 250 × 4.6 mm) with methanol/water (40/60, %v/v) as the mobile phase at a flow rate of 0.5 mL/min.