scholarly journals Antioxidant Network Based on Sulfonated Polyhydroxyalkanoate and Tannic Acid Derivative

2021 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Laura Brelle ◽  
Estelle Renard ◽  
Valerie Langlois
Keyword(s):  
Gallic Acid ◽  
Tannic Acid ◽  
Water Soluble ◽  
Gel Formation ◽  
Ene Reaction ◽  
Inorganic Cations ◽  
Medium Chain Length ◽  
Physically Crosslinked ◽  
The Stability ◽  
Derivatives Of

A novel generation of gels based on medium chain length poly(3-hydroxyalkanoate)s, mcl-PHAs, were developed by using ionic interactions. First, water soluble mcl-PHAs containing sulfonate groups were obtained by thiol-ene reaction in the presence of sodium-3-mercapto-1-ethanesulfonate. Anionic PHAs were physically crosslinked by divalent inorganic cations Ca2+, Ba2+, Mg2+ or by ammonium derivatives of gallic acid GA-N(CH3)3+ or tannic acid TA-N(CH3)3+. The ammonium derivatives were designed through the chemical modification of gallic acid GA or tannic acid TA with glycidyl trimethyl ammonium chloride (GTMA). The results clearly demonstrated that the formation of the networks depends on the nature of the cations. A low viscoelastic network having an elastic around 40 Pa is formed in the presence of Ca2+. Although the gel formation is not possible in the presence of GA-N(CH3)3+, the mechanical properties increased in the presence of TA-N(CH3)3+ with an elastic modulus G’ around 4200 Pa. The PHOSO3−/TA-N(CH3)3+ gels having antioxidant activity, due to the presence of tannic acid, remained stable for at least 5 months. Thus, the stability of these novel networks based on PHA encourage their use in the development of active biomaterials.

The Effects of Some Aromatic Hydroxy Compounds on the Adsorption of Anionic Dyes by Nylon 6

1977 ◽  
Vol 47 (4) ◽  
pp. 244-249 ◽  
Author(s):  
C. C. Cook ◽  
M. Hajisharifi
Keyword(s):  
Tannic Acid ◽  
Nylon 6 ◽  
Sulphonic Acid ◽  
Water Soluble ◽  
Small Range ◽  
Carbonyl Groups ◽  
Anionic Dyes ◽  
Polymeric Compounds ◽  
Hydroxy Compounds ◽  
Derivatives Of

The wetfastness of anionic dyes on nylon fibers can be improved either by treatment with a tannic acid (a polygalloyl glucose)—potassium antimonyl tartrate complex—or with syntans (water-soluble polymeric compounds which usually contain sulphonic acid and phenolic groups). Both of these agents are thought to reduce diffusion of dye out of treated, dyed fiber and therefore should reduce diffusion of dye into treated, undyed fiber. The effect of these treatments on the rates of adsorption of C.I. Acid Reds 27, 41, and 102 by nylon 6 has been measured. The contribution of sulphonic acid, phenolic, and carbonyl groups to the restraining effects observed has been demonstrated by measuring the rates of adsorption of these same three dyes by nylon which has been pretreated with a small range of aromatic hydroxy compounds and certain derivatives of these.

Sorbitol enhances the physicochemical stability of B12 vitamers

2020 ◽  
Vol 90 (5-6) ◽  
pp. 439-447 ◽  
Author(s):  
Andrew Hadinata Lie ◽  
Maria V Chandra-Hioe ◽  
Jayashree Arcot
Keyword(s):  
Ascorbic Acid ◽  
Uv Light ◽  
Heat Exposure ◽  
Water Soluble ◽  
Uv Exposure ◽  
Physicochemical Stability ◽  
Before And After ◽  
The Stability

Abstract. The stability of B12 vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitol. The degradation losses of cyanocobalamin in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitol significantly prevented the loss of cyanocobalamin (p<0.05). Hydroxocobalamin and methylcobalamin exhibited degradation losses ranging from 24%–26% and 48%–76%, respectively; added sorbitol significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitol (p < 0.05). Heat exposure (100 °C, 60 minutes) caused a greater loss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (~15%) were prevented by adding sorbitol. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.

Tyrosine-Selective Bioconjugation with Iminoxyl Radicals

2020 ◽  
Author(s):  
Katsuya Maruyama ◽  
Takashi Ishiyama ◽  
Yohei Seki ◽  
Kounosuke Oisaki ◽  
Motomu Kanai
Keyword(s):  
Reaction Time ◽  
Steric Hindrance ◽  
Room Temperature ◽  
Water Soluble ◽  
Light Irradiation ◽  
Sodium Ascorbate ◽  
Iminoxyl Radical ◽  
Short Reaction Time ◽  
Modified Peptides ◽  
The Stability

A novel Tyr-selective protein bioconjugation using the water-soluble persistent iminoxyl radical is described. The conjugation proceeded with high Tyr-selectivity and short reaction time under biocompatible conditions (room temperature in buffered media under air). The stability of the conjugates was tunable depending on the steric hindrance of iminoxyl. The presence of sodium ascorbate and/or light irradiation promoted traceless deconjugation, restoring the native Tyr structure. The method is applied to the synthesis of a protein-dye conjugate and further derivatization to azobenzene-modified peptides.

Binding of calcium and lead ions to carboxystarch prepared by action of nitrogen dioxide on native starch and its 2,3-dialdehyde derivatives

1986 ◽  
Vol 51 (6) ◽  
pp. 1340-1351 ◽  
Author(s):  
Rudolf Kohn ◽  
Karol Tihlárik
Keyword(s):  
Nitrogen Dioxide ◽  
Alkaline Medium ◽  
Binding Capacity ◽  
Lead Ions ◽  
Carbonyl Groups ◽  
Weakly Alkaline ◽  
Exchange Cations ◽  
Counter Ions ◽  
The Stability ◽  
Derivatives Of

The binding of calcium and lead ions to carboxy derivatives of starch prepared by allowing nitrogen dioxide to act on native maize starch (procedure A) and on starch 2,3-dialdehyde derivatives of degrees of oxidation DO(d.a.) ≥ 0.94 (procedure B) was studied. The carboxy group content of the samples in the H+ form was 4.6 - 12.1 mmol g-1. The effect of alkaline medium on the stability of the carboxy derivatives and on their ability to bind and exchange cations was examined. The Ca2+ → 2K+ exchange was evaluated in terms of the decrease in the electrostatic free enthalpy Δ(Gel/N)KCa, determined by alkalimetric potentiometric titrations, and the binding of Pb2+ ions was evaluated in terms of the activity of the Pb2+ counter-ions determined in suspensions of Pb salts of the carboxy derivatives by means of an ion specific electrode. The IR and CD spectra revealed that the carboxystarch preparations obtained by procedure A contained, in addition to free carboxy groups, a considerable amount of carbonyl groups. During the conversion of the latter groups to the former, even in a weakly alkaline medium, the carboxy derivatives undergo an appreciable degradation and lose, to a great extent, their ability to bind and exchange cations. Procedure B, on the other hand, leads to highly selective starch and amylose carboxy derivatives, exhibiting a small amount of carbonyl groups and featuring a relative stability towards alkaline medium; their binding capacity is as high as 12 milliequivalents of cations per g of sample.

Potential anticonvulsants: Substituted N-benzylidene derivatives of 10-(4-aminopiperazino)-10,11-dihydrodibenzo[b,f]thiepins

1983 ◽  
Vol 48 (4) ◽  
pp. 1173-1186 ◽  
Author(s):  
Václav Bártl ◽  
Jiří Holubek ◽  
Emil Svátek ◽  
Marie Bartošová ◽  
Miroslav Protiva
Keyword(s):  
Acute Toxicity ◽  
Water Soluble ◽  
Hypotensive Activity ◽  
Anticonvulsant Effect ◽  
Maximal Electroshock ◽  
Soluble Salts ◽  
Sleeping Time ◽  
Central Depression ◽  
Derivatives Of ◽  
Electroshock Seizures

Reactions of 10-(4-aminopiperazino)-10,11-dihydrodibenzo[b,f]thiepins XIVa-XIVd with benzaldehyde, 3,4-dimethoxybenzaldehyde, 4-dimethylaminobenzaldehyde, salicylaldehyde, 3-ethoxy-4-hydroxybenzaldehyde, 2-(2-dimethylaminoethoxy)benzaldehyde, 3-(2-dimethylaminoethoxy)benzaldehyde and 3-ethoxy-4-(2-dimethylaminoethoxy)benzaldehyde afforded a series of 19 hydrazones IIIa-Xc. Some of them showed the expected anticonvulsant effect but only towards pentetrazole; antagonism of maximal electroshock seizures was not observed. In general, the products have a character of tranquillizers: in higher does they produce central depression, potentiate the thiopental sleeping time, have hypothermic action; in single cases antiamphetamine, antireserpine, antihistamine and cataleptic effects were observed. The water-soluble salts of the basic hydrazones VIIIa, VIIIc, IXc and Xc, administered parenterally, showed a rather high acute toxicity and revealed also adrenolytic and hypotensive activity.

Studies on the Coordination Reaction of VO2+ and Tannic Acid in the Tannin Extract Desulfurization

2012 ◽  
Vol 239-240 ◽  
pp. 1573-1576
Author(s):  
Zhu Qing Gao ◽  
Xiao Dong Cai ◽  
Kai Cheng Ling
Keyword(s):  
Stability Constants ◽  
Tannic Acid ◽  
Ph Value ◽  
Protonation Constants ◽  
Conditional Stability ◽  
Tannin Extract ◽  
Acid Effect ◽  
Different Temperatures ◽  
The Stability ◽  
Apparent Stability

At different temperatures, the protonation constants of tannic acid and the complex apparent stability constants between tannic acid and VO2+ were determined by using pH potentimetric method. The results showed that the protonation constants and the complex apparent stability constants slightly decreased with the raising temperature. In accordance with the pH value in the tannin extract technology, the conditional stability constants of the complex were calculated on the basis of the acid effect of tannic acid and the hydrolysis effect of VO2+. It was found that pH greatly affected the stability constants of the complex , so pH must be strictly controlled in the tannin extract technology.

scholarly journals Rust Conversion Performance of Phosphoric Acid-Gallic Acid in Vinyl Chloride Acrylic Emulsion

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 152
Author(s):  
Xin Wang ◽  
Qingjun Zhu ◽  
Xiangju Liu ◽  
Baorong Hou
Keyword(s):  
Phosphoric Acid ◽  
Gallic Acid ◽  
Vinyl Chloride ◽  
Salt Spray ◽  
Corrosion Current ◽  
Oxidation Reactions ◽  
Acrylic Emulsion ◽  
Conversion Performance ◽  
The Stability ◽  
Iron Complexation

This work studied the application of phosphoric acid-gallic acid in vinyl chloride acrylic emulsion and its rust conversion performance. The increase of phosphoric acid affected the stability of the system, leading to the rapid precipitation of flocculent precipitation. Rust conversion coating (RCC) showed the best synergistic conversion effect when gallic acid (GA) was 0.2 wt.% and phosphoric acid (PA) was 2 wt.%. XRD and FTIR analysis show that the components of adherent rust (AR) are α-FeOOH, γ-FeOOH and Fe3O4. The conversion products are ferric phosphate (FP) and ferric gallate (FG). The RCC can effectively treat the rusted steel (RS) produced by simulated marine atmospheric corrosion. The corrosion current density was reduced by three orders of magnitude, the adhesion reached 2.75 MPa, and the salt spray corrosion resistance was 20 days. The results of Raman, XPS, SEM and EDS show that the ionic dissolution of iron, complexation and further oxidation reactions occur at the interface between the adherent rust and the RCC. After rust conversion treatment, unreacted rust (UR) affects the further improvement of adhesion strength and anti-corrosion performance.

scholarly journals Effect of tannic and gallic acids alone or in combination with carbenicillin or tetracycline on Chromobacterium violaceum CV026 growth, motility, and biofilm formation

2015 ◽  
Vol 61 (7) ◽  
pp. 487-494 ◽  
Author(s):  
Devendra H. Dusane ◽  
Che O’May ◽  
Nathalie Tufenkji
Keyword(s):  
Antibacterial Activity ◽  
Gallic Acid ◽  
Tannic Acid ◽  
Bacterial Growth ◽  
Biofilm Formation ◽  
Opportunistic Pathogen ◽  
Chromobacterium Violaceum ◽  
Minimum Inhibitory Concentrations

Chromobacterium violaceum is an opportunistic pathogen that causes infections that are difficult to treat. The goal of this research was to evaluate the effect of selected tannins (tannic acid (TA) and gallic acid (GA)) on bacterial growth, motility, antibiotic (carbenicillin, tetracycline) susceptibility, and biofilm formation. Both tannins, particularly TA, impaired bacterial growth levels and swimming motilities at sub-minimum inhibitory concentrations (sub-MICs). In combination with tannins, antibiotics showed increased MICs, suggesting that tannins interfered with antibacterial activity. Sub-MICs of tetracycline or TA alone enhanced biofilm formation of C. violaceum; however, in combination, these compounds inhibited biofilm formation. In contrast, carbenicillin at sub-MICs was effective in inhibiting C. violaceum biofilm formation; however, in combination with lower concentrations of TA or GA, biofilms were enhanced. These results provide insights into the effects of tannins on C. violaceum growth and their varying interaction with antibiotics used to target C. violaceum infections.

1,3-dipolar cycloaddition in the synthesis of glycoconjugates of natural chlorins and bacteriochlorins

2009 ◽  
Vol 13 (03) ◽  
pp. 336-345 ◽  
Author(s):  
Mikhail A. Grin ◽  
Ivan S. Lonin ◽  
Anna A. Lakhina ◽  
Elena S. Ol'shanskaya ◽  
Alexey I. Makarov ◽  
...  
Keyword(s):  
Triple Bond ◽  
Tautomeric Form ◽  
Click Reaction ◽  
Copper Cation ◽  
Water Soluble ◽  
Dipolar Cycloaddition ◽  
Nmr Studies ◽  
Metal Free ◽  
Cu Complex ◽  
Derivatives Of

Glucose-, galactose- and lactose-containing photosensitizers based on derivatives of chlorophyll a and bacteriochlorophyll a were synthesized with the use of [3+2] cycloaddition between sugar azides and triple bond derivatives of chlorins and bacteriochlorins. Unlike bacteriochlorin cycloimide, chlorin was detected to form a Cu -complex during the click reaction. An approach to the synthesis of metal-free glycosylated chlorins was developed with the use of "protection" by Zn 2+ cation and subsequent demetalation. It is based on the action of alkynyl chlorin e6 derivative Zn -complex, which is resistant to the substitution by copper cation. Bacteriochlorin p cycloimide conjugate with per-acetylated β-D-lactose was obtained and shown to become water-soluble after unblocking of the lactose hydroxy functions. NMR studies allowed for the elucidation of structure, tautomeric form and conformation of the obtained compounds.

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