scholarly journals Sericin Ameliorates the Properties of Poly(Vinyl Alcohol) Hydrogel Prepared by Simple Repeated Freeze-Thaw Process without the Use of Chemical Crosslinking

2018 ◽  
Vol 4 (3) ◽  
pp. 6 ◽  
Author(s):  
Pornanong Aramwit ◽  
Amorpun Sereemaspun ◽  
Rungnapha Yamdech
Keyword(s):  
Conformational Changes ◽  
Biological Activities ◽  
Polymer Concentration ◽  
Water Soluble ◽  
Poly Vinyl Alcohol ◽  
Freeze Thaw ◽  
Skin Keratinocytes ◽  
Thawing Process ◽  
Anti Oxidant ◽  
Interconnected Pores

Hydrogel of polyvinyl alcohol (PVA) and sericin can be easily produced using a repeated freeze-thaw process. The effects of polymer concentration (4-8 %wt), blending ratio of PVA/sericin (100/0-50/50), and the number of freeze-thawing cycle (4, 8, and 12 cycles) on chemical and physical properties of the hydrogels obtained were studied. We here showed that higher polymer concentration, higher PVA ratio, and more cycles of freeze-thawing produced the hydrogels with high gel (crosslinked) fraction (>90), wall-like structure, and high compressive modulus (100-170 kPa). When the sericin ratio was increased, the hydrogels showed less gel fraction (60-80), more porous structure with highly interconnected pores, and better swelling ability (up to 8-9 times of its original state). The formation of the PVA/sericin hydrogels was occurred by the conformational changes of both PVA and sericin. The secondary structures of PVA and sericin turned to more stable crystalline conformation during the freeze-thawing process, as confirmed by fourier transform infrared (FTIR) spectroscopic results. Furthermore, all hydrogels were not toxic to human skin keratinocytes (HaCaT) cells while the anti-oxidant activity of sericin component in hydrogels was confirmed. We concluded that the freeze-thawing process was a simple and effective technique for fabrication of PVA and sericin, which both are water-soluble, into the stable hydrogels without the use of any chemical solvents or further crosslinking. More importantly, sericin enhances the biological activities of the hydrogels, allowing the use of this hydrogel in various medical applications such as wound dressing.

scholarly journals Conducting Cytocompatible Scaffolds: Composite of Sodium Hyaluronate and Colloidal Particles of Conducting Polymers

2021 ◽  
Author(s):  
Thanh Huong Truong ◽  
Lenka Musilová ◽  
Věra Kašpárková ◽  
Daniela Jasenská ◽  
Petr Ponížil ◽  
...  
Keyword(s):  
Conducting Polymers ◽  
Colloidal Particles ◽  
Sodium Hyaluronate ◽  
Water Soluble ◽  
Aqueous Environment ◽  
Ethylcarbodiimide Hydrochloride ◽  
Swelling Capacity ◽  
Thawing Process ◽  
Interconnected Pores

Abstract Novel bio-inspired conductive scaffolds composed of sodium hyaluronate containing water soluble polyaniline or polypyrrole colloidal particles (concentrations 0.108, 0.054 and 0.036 % w/w) were manufactured. For this purpose, either crosslinking with N-(3-dimethylaminopropyl-N-ethylcarbodiimide hydrochloride and N-hydroxysuccinimid or a freeze-thawing process in the presence of poly(vinylalcohol) were used. The scaffolds comprised interconnected pores with prevailing porosity values of ~30 % and pore sizes enabling the accommodation of cells. Good swelling capacity (92 – 97 %) without any sign of disintegration was typical for all samples. The elasticity modulus depended on the composition of the scaffolds, with the highest value of ~50 000 Pa obtained for the sample containing the highest content of polypyrrole particles. The scaffolds did not possess cytotoxicity and allowed cell adhesion and growth on the surface. Using the in vivo-mimicking conditions in a bioreactor, cells were also able to grow into the structure of the scaffolds. The technique of scaffold preparation used here thus overcomes the limitations of conducting polymers (e.g. poor solubility in an aqueous environment, and limited miscibility with other hydrophilic polymer matrices) and moreover leads to the preparation of cytocompatible scaffolds with potentially cell-instructive properties, which may be of advantage in the healing of damaged electro-sensitive tissues.

scholarly journals Spectroscopic and electrochemical study of interactions between DNA and different salts of 1,4-dihydropyridine AV-153

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10061
Author(s):  
Elina Leonova ◽  
Karlis Shvirksts ◽  
Vitalijs Borisovs ◽  
Edgars Smelovs ◽  
Jelizaveta Sokolovska ◽  
...  
Keyword(s):  
Dna Binding ◽  
Conformational Changes ◽  
Biological Activities ◽  
Binding Mode ◽  
Water Soluble ◽  
Dna Bases ◽  
Spectroscopy Data ◽  
Vis Spectroscopy ◽  
Intercalation Binding ◽  
Phosphate Groups

1,4-dihydropyridines (1,4-DHP) possess important biochemical and pharmacological properties, including antimutagenic and DNA-binding activity. The latter activity was first described for water-soluble 1,4-DHP with carboxylic group in position 4, the sodium salt of the 1,4-DHP derivative AV-153 among others. Some data show the modification of physicochemical properties and biological activities of organic compounds by metal ions that form the salts. We demonstrated the different affinity to DNA and DNA-protecting capacity of AV-153 salts, depending on the salt-forming ion (Na, K, Li, Rb, Ca, Mg). This study aimed to use different approaches to collate data on the DNA-binding mode of AV-153-Na and five other AV-153 salts. All the AV-153 salts in this study quenched the ethidium bromide and DNA complex fluorescence, which points to an intercalation binding mode. For some of them, the intercalation binding was confirmed using cyclic voltammetry and circular dichroism spectroscopy. It was shown that in vitro all AV-153 salts can interact with four DNA bases. The FTIR spectroscopy data showed the interaction of AV-153 salts with both DNA bases and phosphate groups. A preference for base interaction was observed as the AV-153 salts interacted mostly with G and C bases. However, the highest differences were detected in the spectral region assigned to phosphate groups, which might indicate either conformational changes of DNA molecule (B form to A or H form) or partial denaturation of the molecule. According to the UV/VIS spectroscopy data, the salts also interact with the human telomere repeat, both in guanine quadruplex (G4) and single-stranded form; Na and K salts manifested higher affinity to G4, Li and Rb –to single-stranded DNA.

Pharmacologically potentials of different substituted coumarin derivatives

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Benzene Ring ◽  
Bioactive Compounds ◽  
Biological Activities ◽  
Pharmacological Properties ◽  
Coumarin Derivatives ◽  
Wide Range ◽  
Anti Oxidant ◽  
Anti Inflammatory ◽  
Coumarin Compounds

Coumarin and its derivatives are widely spread in nature. Coumarin goes to agroup as benzopyrones, which consists of a benzene ring connected to a pyronemoiety. Coumarins displayed a broad range of pharmacologically useful profile.Coumarins are considered as a promising group of bioactive compounds thatexhibited a wide range of biological activities like anti-microbial, anti-viral,antiparasitic, anti-helmintic, analgesic, anti-inflammatory, anti-diabetic, anticancer,anti-oxidant, anti-proliferative, anti-convulsant, and antihypertensiveactivities etc. The coumarin compounds have immense interest due to theirdiverse pharmacological properties. In particular, these biological activities makecoumarin compounds more attractive and testing as novel therapeuticcompounds.

α-Glucosidase Inhibition, Antioxidant and Docking Studies of Hydroxycoumarins and their Mono and Bis O-alkylated/acetylated Analogs

2018 ◽  
Vol 15 (2) ◽  
pp. 127-135 ◽  
Author(s):  
Parvesh Singh ◽  
Nomandla Ngcoya ◽  
Ramgopal Mopuri ◽  
Nagaraju Kerru ◽  
Neha Manhas ◽  
...  
Keyword(s):  
In Silico ◽  
Biological Activities ◽  
Wide Spectrum ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Catalytic Site ◽  
Docking Simulations ◽  
In Silico Docking ◽  
Anti Oxidant

Background: Diabetes Mellitus (DM) is a complex metabolic disease illustrated by abnormally high levels of plasma glucose or hyperglycaemia. Accordingly, several α-glucosidase inhibitors have been developed for the treatment of diabetes and other degenerative disorders. While, a coumarin ring has the privilege to represent numerous natural and synthetic compounds with a wide spectrum of biological activities e.g. anti-cancer, anti-HIV, anti-viral, anti-malarial, anti-microbial, anti-convulsant, anti-hypertensive properties. Besides this, coumarins have also shown potential to inhibit α-glucosidase leading to a generation of new promising antidiabetic agents. However, the testing of O-substituted coumarins for α-glucosidase inhibition has evaded the attention of medicinal chemists. Methods: For O-alkylation/acetylation reactions, the hydroxyl coumarins (A-B) initially activated by K2CO3 in dry DMF were reacted with variedly substituted haloalkanes at room temperature under nitrogen. The synthesized compounds were tested for their α-glucosidase (from Saccharomyces cerevisiae) inhibitory activity and anti-oxidant activity using DPPH radical scavenging activity. In silico docking simulations were conducted using CDocker module in DS (Accelrys) to explore the binding modes of the representative compounds in the catalytic site of α-glucosidase. Results: All the coumarin analogues (A1, B1, A2-A10, B2-B8) including their precursors (A-B) were evaluated for their in vitro α-glucosidase inhibition using acarbose as a standard inhibitor. All the mono O-alkylated coumarins (except A1) showed significant (p <0.05) α-glucosidase inhibition relative to the hydroxyl coumarin (A) with IC50 values ranging between 11.084±0.117 to 145.24± 29.22 µg/mL. Compound 7-(benzyloxy)-4, 5-dimethyl-2H-chromen-2-one (A9) bearing a benzyl group (Ph-CH2-) at position 7 showed a remarkable (p <0.05) increase in the activity (IC50 = 11.084±0.117 µg/mL), almost four-fold more than acarbose (IC50 = 40.578±5.999 µg/mL). The introduction of –NO2 group dramatically improved the anti-oxidant activity of coumarin, while the O-alkylation/acetylation decreased the activity. Conclusion: The present study describes the synthesis of functionalized coumarins and their evaluation for α-glucosidase inhibition and antioxidant activity under in vitro conditions. Based on IC50 data, the mono O-alkylated coumarins were observed to be stronger inhibitors of α-glucosidase with respect to their bis O-alkylated analogues. Coumarin (A9) bearing O-benzyloxy group displayed the strongest α-glucosidase inhibition, even higher than the standard inhibitor acarbose. The coumarin (A10) bearing –NO2 group showed the highest anti-oxidant activity amongst the synthesized compounds, almost comparable to the ascorbic acid. Finally, in silico docking simulations revealed the role of hydrogen bonding and hydrophobic forces in locking the compounds in catalytic site of α-glucosidase.

scholarly journals The Effect of Extraction Conditions on the Barrier and Mechanical Properties of Kefiran Films

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 602
Author(s):  
Carmen Rodica Pop ◽  
Teodora Emilia Coldea ◽  
Liana Claudia Salanţă ◽  
Alina Lăcrămioara Nistor ◽  
Andrei Borşa ◽  
...  
Keyword(s):  
Water Vapor ◽  
Conformational Changes ◽  
Water Vapor Permeability ◽  
Edible Films ◽  
Film Structure ◽  
Water Soluble ◽  
Vapor Permeability ◽  
Water Molecules ◽  
Compact Structure ◽  
Technology Applications

Kefiran is an exopolysaccharide classified as a heteropolysaccharide comprising glucose and galactose in equimolar quantities, and it is classified as a water-soluble glucogalactan. This work aimed to investigate the effect of different extraction conditions of kefiran on the structural and physical properties of the edible films obtained. Fourier-transform infrared spectroscopy and scanning electron microscopy were performed, together with a determinations of moisture content, solubility, water vapor permeability and degree of swelling. The kefiran films presented values of the water vapor permeability between 0.93 and 4.38 × 10−11 g/m.s.Pa. These results can be attributed to the development of a more compact structure, where glycerol had no power to increase the free volume and the water vapor diffusion through their structure. The possible conformational changes in the kefiran film structure, due to the interspersing of the plasticizers and water molecules that they absorb, could be the reason for producing flexible kefiran films in the case of using glycerol as a plasticizer at 7.5% w/w. Moreover, it was observed that the extraction conditions are a significant factor in the properties of these films and their food technology applications.

scholarly journals Self-Healing Polymer-Clay Hybrids by Facile Complexation of a Waterborne Polymer with a Clay

2021 ◽  
Author(s):  
Aranee Pleng Teepakakorn ◽  
Makoto Ogawa
Keyword(s):  
Vinyl Alcohol ◽  
Aqueous Media ◽  
Water Soluble ◽  
Poly Vinyl Alcohol ◽  
Self Healing ◽  
Soluble Polymer ◽  
Water Soluble Polymer ◽  
Smectite Clay

Water-induced self-healing materials were prepared by the hybridization of a water-soluble polymer, poly(vinyl alcohol), with a smectite clay by mixing in an aqueous media and subsequent casting. Without using chemical...

scholarly journals Analyzing the Carotenoid Composition of Melilot (Melilotus officinalis (L.) Pall.) Extracts and the Effects of Isolated (All-E)-lutein-5,6-epoxide on Primary Sensory Neurons and Macrophages

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 503
Author(s):  
Györgyi Horváth ◽  
Eszter Csikós ◽  
Eichertné Violetta Andres ◽  
Tímea Bencsik ◽  
Anikó Takátsy ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Sensory Neurons ◽  
Biological Activities ◽  
Water Soluble ◽  
Soluble Form ◽  
Primary Sensory Neurons ◽  
Isolation And Identification ◽  
Melilotus Officinalis ◽  
Carotenoid Composition ◽  
Anti Inflammatory

Melilotus officinalis is known to contain several types of secondary metabolites. In contrast, the carotenoid composition of this medicinal plant has not been investigated, although it may also contribute to the biological activities of the drug, such as anti-inflammatory effects. Therefore, this study focuses on the isolation and identification of carotenoids from Meliloti herba and on the effect of isolated (all-E)-lutein 5,6-epoxide on primary sensory neurons and macrophages involved in nociception, as well as neurogenic and non-neurogenic inflammatory processes. The composition of the plant extracts was analyzed by high performance liquid chromatography (HPLC). The main carotenoid was isolated by column liquid chromatography (CLC) and identified by MS and NMR. The effect of water-soluble lutein 5,6-epoxide-RAMEB (randomly methylated-β-cyclodextrin) was investigated on Ca2+-influx in rat primary sensory neurons induced by the activation of the transient receptor potential ankyrin 1 receptor agonist to mustard-oil and on endotoxin-induced IL-1β release from isolated mouse peritoneal macrophages. (all-E)-Lutein 5,6-epoxide significantly decreased the percent of responsive primary sensory neurons compared to the vehicle-treated stimulated control. Furthermore, endotoxin-evoked IL-1β release from macrophages was significantly decreased by 100 µM lutein 5,6-epoxide compared to the vehicle-treated control. The water-soluble form of lutein 5,6-epoxide-RAMEB decreases the activation of primary sensory neurons and macrophages, which opens perspectives for its analgesic and anti-inflammatory applications.

scholarly journals Design of Mucoadhesive Strips for Buccal Fast Release of Tramadol

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1187
Author(s):  
Nayla Francine Garcia Pastório ◽  
Camila Felix Vecchi ◽  
Rafaela Said dos Santos ◽  
Marcos Luciano Bruschi
Keyword(s):  
Ex Vivo ◽  
Polymer Concentration ◽  
Peroral Administration ◽  
Patient Acceptance ◽  
Poly Vinyl Alcohol ◽  
Synthetic Analogue ◽  
Drug Release Profile ◽  
Opioid Agonist ◽  
In Vivo Evaluation ◽  
Tramadol Hydrochloride

Tramadol hydrochloride is a synthetic analogue of codeine and shows activity on the central nervous system as an opioid agonist and inhibitor of serotonin and norepinephrine reuptake. It has been used for controlling moderate to severe pain. Mucoadhesive fast-dissolving films can present greater drug availability and patient acceptance when compared to the systems of peroral administration. The films were prepared using the solvent casting method with ethylcellulose, polyvinylpyrrolidone and poly(vinyl alcohol). The effect of each polymer concentration was investigated using a 2³ factorial design with repetition at the central point. The formulations were subjected to physicochemical, mechanical, ex vivo mucoadhesive and in vitro drug release profile analysis. These properties were dependent on the polymeric composition (independent factors) of each system. The optimized formulations showed good macroscopic characteristics, improved resistance to bending, rigidity, rapid swelling up to 60 s, improved mechanical and mucoadhesive characteristics, and also fast dissolving and tramadol release. The optimized formulations constitute platforms and strategies to improve the therapy of tramadol with regard to availability at the site of application, considering the necessity of rapid pain relief, and show potential for in vivo evaluation.

Effect of Cobalt Stearate and Vegetable Oil on Uv and Biodegradation of Linear Low-Density Poly(Ethylene)-Poly(Vinyl Alcohol) Blends

2011 ◽  
Vol 2 (4) ◽  
pp. 131-148 ◽  
Author(s):  
Francis Vidya ◽  
Subin S. Raghul ◽  
Sarita G Bhat ◽  
Eby Thomas Thachil
Keyword(s):  
Vegetable Oil ◽  
Vinyl Alcohol ◽  
Water Soluble ◽  
Poly Vinyl Alcohol ◽  
Low Density ◽  
Compression Moulding ◽  
Melt Mixing ◽  
Degradation Behaviour ◽  
Moulding Process ◽  
Poly Ethylene

The main objective of this study was to enhance the rate of UV and biodegradation of polyethylene by incorporating biodegradable materials and prooxidants. Prooxidants such as transition metal complexes are capable of initiating photooxidation and polymer chain cleavage, rendering the product more susceptible to biodegradation. In this work, the effect of (1) a metallic photoinitiator, cobalt stearate, and (2) different combinations of cobalt stearate and vegetable oil on the photooxidative degradation of linear low-density poly(ethylene)-poly(vinyl alcohol) (LLDPE/PVA) blend films has been investigated. For this, film-grade LLDPE was blended with different proportions of PVA. PVA is widely used in the industrial field, and recently it has attracted increasing attention as a water-soluble biodegradable polymer. Cobalt stearate and vegetable oil were added to the blends as prooxidants. The blends were prepared by melt mixing in a Thermo HAAKE Polylab system. Thin films containing these additives were prepared by a subsequent compression moulding process. The effect of UV exposure on LLDPE/PVA films in the presence as well as absence of these additives was investigated. Tensile properties, FTIR spectra, and scanning electron microscopy (SEM) were employed to investigate the degradation behaviour. It was found

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