scholarly journals Erratum: Diastereomeric difference of inclusion modes between (−)-epicatechin gallate, (−)-epigallocatechin gallate and (+)-gallocatechin gallate, with β-cyclodextrin in aqueous solvent. Takashi Ishizu, Shinya Kajitani, Hiroyuki Tsutsumi, Hideji Yamamoto and Kazunobu Harano.Magnetic Resonance in Chemistry, 2008; 46: 448-456

2008 ◽  
Vol 46 (10) ◽  
pp. 995-995
2004 ◽  
Vol 48 (1) ◽  
pp. 69-74 ◽  
Author(s):  
Cristina Paveto ◽  
María C. Güida ◽  
Mónica I. Esteva ◽  
Virginia Martino ◽  
Jorge Coussio ◽  
...  

ABSTRACT The trypanocidal action of green tea catechins against two different developmental stages of Trypanosoma cruzi is reported for the first time. This activity was assayed with the nonproliferative bloodstream trypomastigote and with the intracellular replicative amastigote parasite forms. An ethyl acetate fraction from Camellia sinensis green tea leaves, which contains most of the polyphenolic compounds and the maximal trypanocidal activity, was obtained by fractionation of the aqueous extract with organic solvents. The active compounds present in this extract were further purified by LH-20 column chromatography and were identified by high-performance liquid chromatography analysis with a photo diode array detector and gas chromatography coupled to mass spectroscopy. The following flavan-3-ols derivatives, known as catechins, were identified: catechin, epicatechin, gallocatechin, epigallocatechin, catechin gallate, epicatechin gallate, gallocatechin gallate, and epigallocatechin gallate. The purified compounds lysed more than 50% of the parasites present in the blood of infected BALB/c mice at concentrations as low as 0.12 to 85 pM. The most active compounds were gallocatechin gallate and epigallocatechin gallate, with minimal bactericidal concentrations that inhibited 50% of isolates tested of 0.12 and 0.53 pM, respectively. The number of amastigotes in infected Vero cells decreased by 50% in the presence of each of these compounds at 100 nM. The effects of the catechins on the recombinant T. cruzi arginine kinase, a key enzyme in the energy metabolism of the parasite, were assayed. The activity of this enzyme was inhibited by about 50% by nanomolar concentrations of catechin gallate or gallocatechin gallate, whereas the other members of the group were less effective. On the basis of these results, we suggest that these compounds could be used to sterilize blood and, eventually, as therapeutic agents for Chagas' disease.


Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1185
Author(s):  
Zeyi Ai ◽  
Shuyuan Liu ◽  
Fengfeng Qu ◽  
Haojie Zhang ◽  
Yuqiong Chen ◽  
...  

The transcellular transport and metabolism of eight green tea catechins (GTCs) were studied in Caco-2 monolayers, with the aim of investigating the effect of cis–trans isomerism on the membrane permeability and biotransformation of GTCs. The results showed that the catechin stereochemistry significantly affects the efflux transport rather than the absorption transport in the Caco-2 monolayers. The trans catechins showed a better transcellular permeability than their corresponding cis (epi) catechins in the efflux transport, as the efflux amount of trans catechins were all significantly higher than that of the cis (epi) catechins at each concentration and each time point tested. Moreover, the relative contents of the (+)-catechin (C)-O-sulfate, (+)-gallocatechin (GC)-O-sulfate, (−)-catechin gallate (CG)-O-sulfate, and (−)-gallocatechin gallate (GCG)-O-sulfate in the efflux transport were 2.67, 16.08, 50.48, and 31.54 times higher than that of the (−)-epicatechin (EC)-O-sulfate, (−)-epigallocatechin (EGC)-O-sulfate, (−)-epicatechin gallate (ECG)-O-sulfate, and (−)-epigallocatechin gallate (EGCG)-O-sulfate, respectively. It indicated that more metabolites were observed after the transcellular efflux of trans catechins. Furthermore, after two hours of incubation, the GTCs could significantly increase the expression of multidrug resistance-associated protein 2 (MRP2) and breast cancer-resistance protein (BCRP), and decrease the expression of P-glycoprotein in the Caco-2 cells. The regulation of GTCs on P-glycoprotein, MRP2, and BCRP could also be significantly influenced by the chemical and dimensional structure. In a conclusion, catechin stereochemistry significantly affects the transport and metabolism of GTCs when refluxed in the Caco-2 monolayers.


2019 ◽  
Vol 2 (2) ◽  
pp. 96-101
Author(s):  
Kota Noda ◽  
Eisuke Kato ◽  
Jun Kawabata

Diabetes is a chronic disease characterized by elevated blood glucose level.Reducing carbohydrate absorption from the intestinal tract is an effective strategy to control post-meal blood glucose level. Inhibition of intestinal α-glucosidase, involved in digestion of carbohydrates, is known as an approach to accomplish this. On the other hand, reduction of α-glucosidase amount is expected to work in the similar manner. However, none of the previousstudy pursues this approach. A convenient assay was developed to evaluate α-glucosidase amount employing Caco-2 cells, the intestinal epithelial cell model reported to express α-glucosidase. Sixty plants were screened and two candidate plants, Calluna vulgaris and Perilla frutescens var. crispa were found to reduce α-glucosidase expression. C. vulgaris extract was subjected to activity guided isolation. Proanthocyanidin was identified as the active principle which was analyzed by thiol decomposition to reveal the components as a mixture ofcatechin, epicatechin, epigallocatechin, and A type procyanidin dimer. The proanthocyanidin suppressed about 30% of α-glucosidase amount evaluated through convenient assay, and suppressed bulk of mRNA expression level of sucrase-isomaltase (SI) at 0.125 mg/mL. Several flavan-3-ol monomers were also tested, and epicatechin gallate and epigallocatechin gallate were found to suppress α-glucosidase amount significantly.


2019 ◽  
Vol 15 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Satheesh Babu Natarajan ◽  
Suriyakala Perumal Chandran ◽  
Sahar Husain Khan ◽  
Packiyaraj Natarajan ◽  
Karthiyaraj Rengarajan

Background: Tea (Camellia sinensis, Theaceae) is the second most consumed beverage in the world. Green tea is the least processed and thus contain rich antioxidant level, and believed to have most of the health benefits. </p><p> Methods: We commenced to search bibliographic collection of peer reviewed research articles and review articles to meet the objective of this study. </p><p> Results: From this study, we found that the tea beverage contains catechins are believed to have a wide range of health benefits which includes neuroprotective, anti-inflammatory, antiulcer, antiviral, antibacterial, and anti-parasitic effects. The four major catechin compounds of green tea are epigallocatechin (EGC), epicatechin (EC), epigallocatechin gallate (EGCG), and epicatechin gallate (ECG), of which EGCG is the major constituent and representing 50-80% of the total catechin content. And also contain xanthine derivatives such as caffeine, theophylline, and theobromine, and the glutamide derivative theanine. It also contains many nutritional components, such as vitamin E, vitamin C, fluoride, and potassium. We sum up the various green tea phytoconstituents, extraction methods, and its medicinal applications. </p><p> Conclusion: In this review article, we have summarized the pharmacological importance of green tea catechin which includes antioxidant potential, anti-inflammatory, antimicrobial, anticancer, antidiabetic and cosmetic application.


2020 ◽  
Vol 16 (7) ◽  
pp. 998-1004
Author(s):  
Aziz H. Rad ◽  
Raana B. Fathipour ◽  
Fariba K. Bidgoli ◽  
Aslan Azizi

Background and Objectives: Tea is considered one of the most consumed drinks around the world and the health benefits of it have recently attracted the attention of different researchers. It has also been proven beneficial in preventing the danger of some diseases like cancer and cardiovascular problems. Further, lipid oxidation is one of the major problems in food products. Considering the above-mentioned issues, the present review focused on various techniques used to extract polyphenols from different kinds of tea, as well as their use in the food industry. Results and Conclusion: Based on our findings in this review, the main components of tea are polyphenols that have health benefits and include catechins, epicatechin, epigallocatechin, epicatechin gallate, epigallocatechin gallate, gallic acid, flavonoids, flavonols, and theophlavins. From these components, catechin is regarded as the most beneficial component. Many techniques have been discovered and reformed to extract tea compounds such as solvent-based extraction, microwave-assisted water extraction, and ultrasound-assisted extraction techniques. Overall, the microwave-assisted water extraction method is a useful method for extracting tea polyphenols, which may be used in the meat, oil, and dairy industries.


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