Synthesis of B-ring-fluorinated (−)-epicatechin gallate derivatives

2020 ◽  
Vol 18 (21) ◽  
pp. 4024-4028
Author(s):  
David D. S. Thieltges ◽  
Kai D. Baumgarten ◽  
Carina S. Michaelis ◽  
Constantin Czekelius
Keyword(s):  
Kinetic Resolution ◽  
Convergent Sequence ◽  
Epicatechin Gallate

Electronically modified, fluorinated catechins and epicatechins are enantioselectively synthesized in a short, convergent sequence via kinetic resolution.

Search for Compounds Suppressing Intestinal α-Glucosidase Expression in Caco-2 Cells

2019 ◽  
Vol 2 (2) ◽  
pp. 96-101
Author(s):  
Kota Noda ◽  
Eisuke Kato ◽  
Jun Kawabata
Keyword(s):  
Blood Glucose ◽  
Intestinal Tract ◽  
Cell Model ◽  
Epigallocatechin Gallate ◽  
Calluna Vulgaris ◽  
Active Principle ◽  
Intestinal Epithelial ◽  
Mrna Expression Level ◽  
Epicatechin Gallate ◽  
Control Post

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.

Probing the Parallel Kinetic Resolution of Racemic Oxazolidinones using Quasi-enantiomeric Profens

2006 ◽  
Author(s):  
Jason Eames ◽  
Gregory Coumbarides ◽  
Marco Dingjan ◽  
Tony Flinn ◽  
Northern Northen ◽  
...  
Keyword(s):  
Kinetic Resolution ◽  
Parallel Kinetic Resolution

Catalyst- and Silane- Controlled Enantioselective Hydrofunctionalization of Alkenes by Cobalt-Catalyzed Hydrogen Atom Transfer and Radical-Polar Crossover

2020 ◽  
Author(s):  
Kousuke Ebisawa ◽  
Kana Izumi ◽  
Yuka Ooka ◽  
Hiroaki Kato ◽  
Sayori Kanazawa ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Absolute Configuration ◽  
Kinetic Resolution ◽  
Hydrogen Atom Transfer ◽  
Biologically Active ◽  
Atom Transfer ◽  
High Concentration ◽  
Chain Reaction ◽  
Radical Chain ◽  
Radical Chain Reaction

Catalytic enantioselective synthesis of tetrahydrofurans, which are found in the structures of many biologically active natural products, via a transition-metal catalyzed-hydrogen atom transfer (TM-HAT) and radical-polar crossover (RPC) mechanism is described herein. Hydroalkoxylation of non-conjugated alkenes proceeded efficiently with excellent enantioselectivity (up to 94% ee) using a suitable chiral cobalt catalyst, <i>N</i>-fluoro-2,4,6-collidinium tetrafluoroborate, and diethylsilane. Surprisingly, absolute configuration of the product was highly dependent on the steric hindrance of the silane. Slow addition of the silane, the dioxygen effect in the solvent, thermal dependency, and DFT calculation results supported the unprecedented scenario of two competing selective mechanisms. For the less-hindered diethylsilane, a high concentration of diffused carbon-centered radicals invoked diastereoenrichment of an alkylcobalt(III) intermediate by a radical chain reaction, which eventually determined the absolute configuration of the product. On the other hand, a more hindered silane resulted in less opportunity for radical chain reaction, instead facilitating enantioselective kinetic resolution during the late-stage nucleophilic displacement of the alkylcobalt(IV) intermediate.

Transition Metal-Mediated Kinetic Resolution

2000 ◽  
Vol 4 (8) ◽  
pp. 869-885 ◽  
Author(s):  
Gregory R. Cook
Keyword(s):  
Transition Metal ◽  
Kinetic Resolution

Kinetic Resolution of (R,S)-atenolol with the Use of Lipases in Various Organic Solvents

2017 ◽  
Vol 14 (5) ◽  
Author(s):  
Adam Sikora ◽  
Wiktor Dariusz Sroka ◽  
Tomasz Siódmiak ◽  
Michal Piotr Marszall
Keyword(s):  
Organic Solvents ◽  
Kinetic Resolution

Versatile Health Benefits of Catechin from Green Tea (Camellia sinensis)

2019 ◽  
Vol 15 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Satheesh Babu Natarajan ◽  
Suriyakala Perumal Chandran ◽  
Sahar Husain Khan ◽  
Packiyaraj Natarajan ◽  
Karthiyaraj Rengarajan
Keyword(s):  
Green Tea ◽  
Camellia Sinensis ◽  
Health Benefits ◽  
Epigallocatechin Gallate ◽  
Extraction Methods ◽  
Major Constituent ◽  
Epicatechin Gallate ◽  
Wide Range ◽  
Green Tea Catechin ◽  
Anti Inflammatory

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.

Application of Tea Extract in Food Industry

2020 ◽  
Vol 16 (7) ◽  
pp. 998-1004
Author(s):  
Aziz H. Rad ◽  
Raana B. Fathipour ◽  
Fariba K. Bidgoli ◽  
Aslan Azizi
Keyword(s):  
Food Industry ◽  
Health Benefits ◽  
Epigallocatechin Gallate ◽  
Water Extraction ◽  
Ultrasound Assisted Extraction ◽  
Epicatechin Gallate ◽  
Microwave Assisted ◽  
Assisted Extraction ◽  
Main Components ◽  
Tea Extract

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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