scholarly journals Preparation and α-Glucosidase Inhibitory Activity of Gallic Acid-Dextran Conjugate

2020 ◽  
Vol 15 (8) ◽  
pp. 1934578X2094128
Author(s):  
Yuxiang Ma ◽  
Benguo Liu
Keyword(s):  
Molecular Weight ◽  
Gallic Acid ◽  
Inhibitory Activity ◽  
Spectroscopic Analysis ◽  
Average Molecular Weight ◽  
Plant Food ◽  
Magnetic Resonance Spectroscopic Analysis ◽  
Acid Polysaccharide ◽  
First Time ◽  
Dextran Conjugate

Phenolic acid-polysaccharide conjugates, produced in plant food and medicine processing, are thought to account for the α-glucosidase inhibitory activity of the final products. However, this speculation lacks experimental support because of the complexity of the plant system and the polysaccharide structure. In this study, with dextran (average molecular weight, 1000) as the skeleton, a gallic acid-dextran conjugate was synthesized and confirmed by ultraviolet, infrared, and nuclear magnetic resonance spectroscopic analysis for the first time. Furthermore, this gallic acid-dextran conjugate showed inhibition of α-glucosidase due to galloyl groups in a mixed competitive and noncompetitive inhibition mode, whose performance was superior to that of acarbose.

scholarly journals Chemical constituents of Euphorbia tirucalli L.

2019 ◽  
Vol 2 (5) ◽  
pp. 76-82
Author(s):  
Dung Thi Kim Le ◽  
Hao Xuan Bui ◽  
Tuyet Thi Anh Nguyen ◽  
Tuyen Nguyen Kim Pham ◽  
Huy Thuc Duong
Keyword(s):  
Thin Layer ◽  
Gallic Acid ◽  
Spectroscopic Analysis ◽  
Chemical Constituents ◽  
Normal Phase ◽  
Chemical Structures ◽  
Euphorbia Tirucalli ◽  
Arjunolic Acid ◽  
First Time ◽  
Layer Chromatography

Euphorbia tirucalli has not been chemically studied much in Vietnam. This research described the isolation and elucidation of compounds isolated from the plant collected in Binh Thuan. Multiple chromatographic methods were applied, including normal phase silica gel column chromatography and thin-layer chromatography. Seven compounds were isolated and their chemical structures were elucidated by spectroscopic analysis as well as comparing their data with the ones in the literature. They are arjunolic acid (1), eriodictyol (2), quercitrin (3), afzelin (4), scopoletin (5), 3,3′,4- trimethylellagic acid (6), and gallic acid (7). Among them, compound 1 a major component was isolated for the first time in Euphorbia genus, while three compounds 2, 4, and 5 were isolated from this species for the first time.

scholarly journals Synthesis of hydroxyl terminated liquid natural rubber by oxidative depolymerization of deproteinized natural rubber

2016 ◽  
Vol 54 (3) ◽  
pp. 340 ◽  
Author(s):  
Le Duc Giang ◽  
Dinh Long Mong Thao ◽  
Hoang Thi Huong ◽  
Le Thi Thu Hiep
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Chemical Structure ◽  
Spectroscopic Analysis ◽  
Average Molecular Weight ◽  
Analytical Data ◽  
Ammonium Persulfate ◽  
Weight Average Molecular Weight ◽  
Liquid Natural Rubber ◽  
Deproteinized Natural Rubber

Hydroxyl terminated liquid natural rubber (HTLNR) was prepared by the depolymerization of deproteinized natural rubber (DPNR) in mixture of toluene and water at 60oC for 24 hours in the presence of ammonium persulfate as an initiator and tetrahydrofuran (THF) as a homogenizing agent. GPC analysis revealed that the number-average molecular weight (Mn) and weight-average molecular weight (Mw) of HTLNR were found to be 4.334×103 g/mol and 11.702×103 g/mol, respectively, with polydispersity index (PDI) of  2.7. The chemical structure of HTLNR was determined by FTIR and 1H-NMR and 13C-NMR spectroscopic analysis. The mechanism of depolymerization and hydroxylation of NR to form HTNR based on the analytical data is also suggested in this study.

scholarly journals Phenolic compounds from the lichen Parmotrema tinctorum

2021 ◽  
Vol 24 (1) ◽  
pp. 1842-1846
Author(s):  
Huynh Bui Linh Chi ◽  
Van Muoi Bui ◽  
Thi Quynh Nhu Phan ◽  
Kim Phi Phung Nguyen
Keyword(s):  
Inhibitory Activity ◽  
Spectroscopic Analysis ◽  
Published Data ◽  
Anticancer Activities ◽  
Chemical Structures ◽  
Diphenyl Ethers ◽  
Pure Compounds ◽  
First Time ◽  
Parmotrema Tinctorum ◽  
Gyrophoric Acid

Introduction: The metabolites of lichens concentrated depsidones, depsides, and diphenyl ethers were possessed antibiotic, antifungal, antiviral, antitumor, and anticancer activities. Parmotrema tinctorum (Despr. ex Nyl.) Hale, a species of foliose lichen, is widely distributed in Lam Dong province, Vietnam. Herein, this paper describes the isolation and structure elucidation of seven compounds isolated from this lichen. Methods: Phytochemical investigations of the ethyl acetate extract of the lichen P. tinctorum led to the isolation of seven pure compounds. Their chemical structures were elucidated by extensive HR-ESI-MS and NMR spectroscopic analysis and comparison with previously published data. Results: Seven compounds, namely orcinol (1), orsellinic acid (2), methyl orsellinate (3), methyl heamatomate (4), lecanorin (5), lecanoric acid (6), and gyrophoric acid (7). These compounds were determined the α-glucosidase inhibitory activity. Conclusions: Compound 7 was determined for the first time in P. tinctorum, and this was also the first time these compounds were determined the α-glucosidase inhibitory activity.

First GPC results of terpyridine based chain extended supramolecular polymers: comparison with viscosity and analytical ultracentrifugation

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Michael A. R. Meier ◽  
Harald Hofmeier ◽  
Caroline H. Abeln ◽  
Christos Tziatzios ◽  
Mircea Rasa ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Analytical Ultracentrifugation ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Supramolecular Polymers ◽  
Supramolecular Polymer ◽  
Poly Ethylene ◽  
A Chain ◽  
First Time ◽  
Good Agreement

AbstractThe molecular weight of an extended metallo-supramolecular polymer, based on a α,ω-bis-terpyridine-poly(ethylene glycol) polymer linked via ruthenium(II) ions, was determined by gel permeation chromatography, viscosimetry as well as analytical ultracentrifugation. An optimized GPC method was applied for the first time to this kind of chain extended supramolecular polymers and the obtained results showed a good agreement with viscosimetry and analytical ultracentrifugation. A chain extended polymer with an average molecular weight of around 140 000 was found. These results clearly demonstrate that well-soluble high-molecular-weight metal-containing coordination polymers that are based on well-defined telechelics can be synthesized and fully characterized.

The Research of Second Acid Fracturing Temporary Plugging Agent in Long Interval Gas Well of Puguang

2012 ◽  
Vol 629 ◽  
pp. 370-375
Author(s):  
Cheng Yu Zhou ◽  
Dong Wang ◽  
Hong Liu ◽  
Wei Xiong
Keyword(s):  
Molecular Weight ◽  
Spectroscopic Analysis ◽  
Polyester Fibre ◽  
Average Molecular Weight ◽  
Scanning Calorimetry ◽  
Gas Well ◽  
Acid Fracturing ◽  
Infrared Spectroscopic Analysis ◽  
Series Of Experiments ◽  
Temporary Plugging Agent

On the basis of physical truth of long Interval gas well in Puguang, it proposes a technology for adding temporary plugging agent in the second acid fracturing fluid. The CKHG-1 system and polyester fibre solid intensifier have been synthetized and taken infrared spectroscopic analysis. A series of experiments have been done such as density, molecular weight, differential scanning calorimetry, scanning electron microscopy, acid soluble rate and core flowing experiment. The results were obtained through tests, including temporary plugging agent density of 1.2297 g/ml, average molecular weight of 1.27×105, glass-transition temperature of 61°C, temporary plugging particles covering fixed effect was ideal, acid soluble rate after four hours of 95%, temporary plugging rate >99%. They can meet actual conditions in worksite.

scholarly journals Low Molecular Weight Oligosaccharide from Panax ginseng C.A. Meyer against UV-Mediated Apoptosis and Inhibits Tyrosinase Activity In Vitro and In Vivo

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yu-Lin Dai ◽  
Di Yang ◽  
Lai-Hui Song ◽  
Hong-Mei Yang ◽  
Jiang-Bo Yu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Inhibitory Activity ◽  
Average Molecular Weight ◽  
Inhibitory Effects ◽  
Zebrafish Model ◽  
Tyrosinase Inhibitory Activity ◽  
Black Ginseng ◽  
White Ginseng

To find new anti-UV and whitening agents, 21 fractions isolated from three preparations of ginseng (white, red, and black ginseng) were screened, and their antioxidant effects on AAPH- or H2O2-induced damage were investigated. Furthermore, the protective effect against UV-mediated apoptosis and the tyrosinase inhibitory activity of the targeted fractions were evaluated in vitro and in a zebrafish model. Among all fractions, F10 from white ginseng was selected as having the strongest anti-UV and antimelanogenesis activities. This fraction exhibited excellent inhibitory effects on the pigmentation of zebrafish, which may be due to its potential tyrosinase inhibitory activity. Additionally, the chemical composition of F10 was evaluated by UPLC-MS and NMR instruments. The results indicated that F10 had a carbohydrate content of more than 76%, and the weight-average molecular weight was approximately 239 Da. Disaccharide sucrose was the main active compound in F10. These results suggest that F10 could be used as an ingredient for whitening cosmetics and regarded as an anti-UV filter in the future.

The Structure of Radiation Cross-Linked Poly (ethylene oxide) Gels

1971 ◽  
Vol 29 ◽  
pp. 76-77
Author(s):  
C. E. Cluthe ◽  
G. G. Cocks
Keyword(s):  
Molecular Weight ◽  
Ethylene Oxide ◽  
Parallel Plate ◽  
Average Molecular Weight ◽  
Radical Reaction ◽  
Free Radical Reaction ◽  
Nitrogen Gas ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Initial Viscosity

Aqueous solutions of a 1 weight-per cent poly (ethylene oxide) (PEO) were degassed under vacuum, transferred to a parallel plate viscometer under a nitrogen gas blanket, and exposed to Co60 gamma radiation. The Co60 source was rated at 4000 curies, and the dose ratewas 3.8x105 rads/hr. The poly (ethylene oxide) employed in the irradiations had an initial viscosity average molecular weight of 2.1 x 106.The solutions were gelled by a free radical reaction with dosages ranging from 5x104 rads to 4.8x106 rads.

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