scholarly journals Biodegradable and Biocompatible Silatrane Polymers

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1893
Author(s):  
Vladislav Istratov ◽  
Valerii Vasnev ◽  
Galy Markova
Keyword(s):  
Molecular Weight ◽  
Biological Activity ◽  
Antifungal Activity ◽  
Seed Germination ◽  
Aqueous Solutions ◽  
Surface Activity ◽  
Chemical Structure ◽  
Amphiphilic Polymers ◽  
Hydroxyl Groups ◽  
Hydrophobic Properties

In this study, new biodegradable and biocompatible amphiphilic polymers were obtained by modifying the peripheral hydroxyl groups of branched polyethers and polyesters with organosilicon substituents. The structures of the synthesized polymers were confirmed by NMR and GPC. Organosilicon moieties of the polymers were formed by silatranes and trimethylsilyl blocks and displayed hydrophilic and hydrophobic properties, respectively. The effect of the ratio of hydrophilic to hydrophobic organosilicon structures on the surface activity and biological activity of macromolecules was studied, together with the effect on these activities of the macromolecules’ molecular weight and chemical structure. In particular, the critical micelle concentrations were determined, the effect of the structure of the polymers on their wetting with aqueous solutions on glass and parafilm was described, and the aggregation stability of emulsions was studied. Finally, the effect of the polymer structures on their antifungal activity and seed germination stimulation was examined.

Terpenes, Phenylpropanoids, Sulfur and Other Essential Oil Constituents as Inhibitors of Cholinesterases

2020 ◽  
Vol 27 (26) ◽  
pp. 4297-4343 ◽  
Author(s):  
Franko Burčul ◽  
Ivica Blažević ◽  
Mila Radan ◽  
Olivera Politeo
Keyword(s):  
Molecular Weight ◽  
Biological Activity ◽  
Essential Oils ◽  
Functional Groups ◽  
Organic Compounds ◽  
Chemical Structure ◽  
Low Molecular Weight ◽  
Active Compounds ◽  
Oxygenated Compounds ◽  
Nitrogen Containing Compounds

: Essential oils constituents are a diverse family of low molecular weight organic compounds with comprehensive biological activity. According to their chemical structure, these active compounds can be divided into four major groups: terpenes, terpenoids, phenylpropenes, and "others". In addition, they may contain diverse functional groups according to which they can be classified as hydrocarbons (monoterpenes, sesquiterpenes, and aliphatic hydrocarbons); oxygenated compounds (monoterpene and sesquiterpene alcohols, aldehydes, ketones, esters, and other oxygenated compounds); and sulfur and/or nitrogen containing compounds (thioesters, sulfides, isothiocyanates, nitriles, and others). : Compounds that act as cholinesterase inhibitors still represent the only pharmacological treatment of Alzheimer´s disease. Numerous in vitro studies showed that some compounds, found in essential oils, have a promising cholinesterase inhibitory activity, such as α-pinene, δ-3-carene, 1,8-cineole, carvacrol, thymohydroquinone, α- and β-asarone, anethole, etc. : Essential oils constituents are a diverse family of low molecular weight organic compounds with comprehensive biological activity. According to their chemical structure, these active compounds can be divided into four major groups: terpenes, terpenoids, phenylpropenes, and "others". In addition, they may contain diverse functional groups according to which they can be classified as hydrocarbons (monoterpenes, sesquiterpenes, and aliphatic hydrocarbons); oxygenated compounds (monoterpene and sesquiterpene alcohols, aldehydes, ketones, esters, and other oxygenated compounds); and sulfur and/or nitrogen containing compounds (thioesters, sulfides, isothiocyanates, nitriles, and others).

Chromatographic parameters, pKa, and surface activity of a series of hydrochlorides of perhydroazepinylethyl esters of alkoxyphenylcarbamic acids and their relation to anaesthetic activity

1985 ◽  
Vol 50 (5) ◽  
pp. 1133-1140 ◽  
Author(s):  
Marie Blešová ◽  
Jozef Čižmárik ◽  
Mária Bachratá ◽  
Želmíra Bezáková ◽  
Alois Borovanský
Keyword(s):  
Biological Activity ◽  
Regression Analysis ◽  
Aqueous Solutions ◽  
Surface Activity ◽  
Local Anaesthetic ◽  
Chemical Properties ◽  
Surface Tensions ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Chromatographic Parameters

Hydrochlorides of perhydroazepinylethyl esters of alkoxyphenylcarbamic acids were separated by adsorption and partition TLC. The surface tensions, γ, of aqueous solutions of the compounds were measured and the values of pKa were determined. The relation between structure and physico-chemical properties has been confirmed by the dependences of RM and γ on the number of carbon atoms in the alkoxyl chain. Employing the method of regression analysis, the physico-chemical parameters of lipophilicity and the surface activity were correlated, and their effect on biological activity (relative local anaesthetic efficacy) has been assessed.

scholarly journals Manufacturing technology of low-molecular-weight chitosan based on enzymatic hydrolysis

2021 ◽  
Author(s):  
E.I. Kovaleva ◽  
A.I. Albulov ◽  
M.A. Frolova ◽  
V.P. Varlamov ◽  
A.V. Grin
Keyword(s):  
Molecular Weight ◽  
Biological Activity ◽  
Enzymatic Hydrolysis ◽  
Aqueous Solutions ◽  
High Molecular Weight ◽  
The Body ◽  
Low Molecular Weight ◽  
High Molecular Weight Polymer ◽  
Low Molecular Weight Chitosan ◽  
Chitin And Chitosan

Chitosan is natural high molecular weight polymer of D-glucosamine and N-acetyl - D - glucosamine connected by 1,4 - b - glycoside bond with a molecular mass of 1000 kDa (and above), practical use is difficult because of high viscosity of its aqueous solutions even at low concentrations, and lack of solubility at neutral pH and, consequently, low biological activity. To reduce viscosity, improve the solubility and enhance biological activity of high molecular weight chitosan subjected to depolymerization. Chitosan, like other polysaccharides, is characterized by a hydrolysis reaction, which is due to the presence of glycoside bonds in the molecule that are lable to hydrolyzing agents, for example, aqueous solutions of acids, alkalis, as well as to the effect of some hydrolases. During hydrolysis, glycoside bonds are broken and, as a result, the molecular weight of chitosan decreases. However, these processes are accompanied by the formation of significant amounts of toxic products and require very costly disposal of waste before it is discharged into the environment. Chitin and chitosan are natural biopolymers and their synthesis, modification and degradation are associated with enzymatic transformations. It is the biodegradability to the usual substances for the body that is one of the main advantages of chitosan. It is obvious that the most appropriate method is the enzymatic hydrolysis of chitosan. As enzyme preparations for the degradation of chitin and chitosan, enzyme complexes of various origins are used. These can be enzymes from crab or krill hepatopancreas complexes, as well as pancreatin from the pancreas of cattle. But more often for this purpose, enzymes complexes with chitinolytic activity of microbiological origin are used. In this study, low-molecular-weight chitosan was obtained by enzymatic hydrolysis using the extracellular chitinolytic complex of Streptomyces kurssanovii. The resulting chitosan had a medium-viscosity molecular weight of 25-40 kDa. Carrying out two stages of fractionation (stepwise acidification and separation on membranes) made it possible to obtain chitosan fractions with a narrow distribution by molecular weight.

Composition of low molecular weight impurities in dimethylmethylpheylsiloxane rubbers with terminal hydroxyl groups

2020 ◽  
Vol 86 (11) ◽  
pp. 20-27
Author(s):  
A. M. Filippov ◽  
N. Yu. Semenkova ◽  
S. M. Gorelov ◽  
T. I. Shulyatieva ◽  
P. A. Storozhenko
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Hydroxyl Groups

Complexes of Cu (II) with a-Ketoglutaric Acid and 1- (o-tolyl) Biguanide Synthesis, characterization and biological Activity

2019 ◽  
Vol 70 (10) ◽  
pp. 3603-3610
Author(s):  
Madalina Mihalache ◽  
Cornelia Guran ◽  
Aurelia Meghea ◽  
Vasile Bercu ◽  
Ludmila Motelica ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Biological Activity ◽  
Candida Albicans ◽  
Antifungal Activity ◽  
Copper Complexes ◽  
Substrate Adhesion ◽  
Inert Substrate

The three copper complexes having a-ketoglutaric acid (H2A) and 1- (o-tolyl) biguanide (TB) ligands have been synthesized and characterized. The proposed formulas for these complexes are: [Cu(TB)(HA)]Cl (C1), [Cu(TB)(HA)CH3COO]�H2O (C2) and [Cu(TB)(HA)](NO3) (C3) where HA represents deprotonated H2A. The complexes obtained were tested for antibacterial activity against Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853, antifungal activity on Candida albicans ATCC 10231 and antitumor activity on HeLa tumor cells. Due to the antitumor, antifungal, antimicrobial activity and inhibition of inert substrate adhesion, complexes synthesized could be used for potential therapeutic applications.

Synthesis and Biological Activity of Embelin and its Derivatives: An Overview

2020 ◽  
Vol 20 (5) ◽  
pp. 396-407 ◽  
Author(s):  
Zhaojun Sheng ◽  
Siyuan Ge ◽  
Min Gao ◽  
Rongchao Jian ◽  
Xiaole Chen ◽  
...  
Keyword(s):  
Biological Activity ◽  
Biological Effects ◽  
New Drugs ◽  
Hydroxyl Groups ◽  
Carbonyl Groups ◽  
Cellular Mechanisms ◽  
Embelia Ribes ◽  
Naturally Occurring ◽  
Ic50 Value ◽  
Apoptosis Protein

Embelin is a naturally occurring para-benzoquinone isolated from Embelia ribes (Burm. f.) of the Myrsinaceae family, and contains two carbonyl groups, a methine group and two hydroxyl groups. With embelin as the lead compound, more than one hundred derivatives have been reported. Embelin is well known for its ability to antagonize the X-linked inhibitor of apoptosis protein (XIAP) with an IC50 value of 4.1 μM. The potential of embelin and its derivatives in the treatment of various cancers has been extensively studied. In addition, these compounds display a variety of other biological effects: antimicrobial, antioxidant, analgesic, anti-inflammatory, anxiolytic and antifertility activity. This paper reviews the recent progress in the synthesis and biological activity of embelin and its derivatives. Their cellular mechanisms of action and prospects in the research and development of new drugs are also discussed.

scholarly journals Reactivity of Aliphatic and Phenolic Hydroxyl Groups in Kraft Lignin towards 4,4′ MDI

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2131
Author(s):  
Leonardo Dalseno Antonino ◽  
Júlia Rocha Gouveia ◽  
Rogério Ramos de Sousa Júnior ◽  
Guilherme Elias Saltarelli Garcia ◽  
Luara Carneiro Gobbo ◽  
...  
Keyword(s):  
Experimental Work ◽  
Chemical Structure ◽  
31P Nmr ◽  
Kraft Lignin ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Diphenylmethane Diisocyanate ◽  
Complex Chemical ◽  
Heterogeneous Reactivity ◽  
Phenolic Hydroxyl Groups

Several efforts have been dedicated to the development of lignin-based polyurethanes (PU) in recent years. The low and heterogeneous reactivity of lignin hydroxyl groups towards diisocyanates, arising from their highly complex chemical structure, limits the application of this biopolymer in PU synthesis. Besides the well-known differences in the reactivity of aliphatic and aromatic hydroxyl groups, experimental work in which the reactivity of both types of hydroxyl, especially the aromatic ones present in syringyl (S-unit), guaiacyl (G-unit), and p-hydroxyphenyl (H-unit) building units are considered and compared, is still lacking in the literature. In this work, the hydroxyl reactivity of two kraft lignin grades towards 4,4′-diphenylmethane diisocyanate (MDI) was investigated. 31P NMR allowed the monitoring of the reactivity of each hydroxyl group in the lignin structure. FTIR spectra revealed the evolution of peaks related to hydroxyl consumption and urethane formation. These results might support new PU developments, including the use of unmodified lignin and the synthesis of MDI-functionalized biopolymers or prepolymers.

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