Deprotonation routes of anthocyanidins in aqueous solution, pKavalues, and speciation under physiological conditions

RSC Advances ◽  
2016 ◽  
Vol 6 (58) ◽  
pp. 53421-53429 ◽  
Author(s):  
Jorge Rafael León-Carmona ◽  
Annia Galano ◽  
Juan Raúl Alvarez-Idaboy

The most likely deprotonation route of 12 anthocyanidins was elucidated, their pKas are calculated and used to estimate the populations of the different species depending on the pH.

2020 ◽  
Vol 27 (24) ◽  
pp. 4109-4117 ◽  
Author(s):  
Penprapa Chanphai ◽  
Philippe Bourassa ◽  
Heidar Ali Tajmir-Riahi

In this review, the loading efficacies of helper and Cationic Lipids Cholesterol (CHOL), 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), Dioctadecyl Dimethyl- Ammonium Bromide (DDAB) and Dioleoyl Phosphatidylethanolamine (DOPE) with milk β- lactoglobulin, α-casein and β-casein were compared in aqueous solution at physiological conditions. Structural analysis showed that lipids bind milk proteins via hydrophilic, hydrophobic and H-bonding contacts with DOTAP and DDAB forming more stable protein conjugates. Loading efficacy was 30-50% and enhanced with cationic lipids. Lipid conjugation altered protein conformation, causing a partial protein structural destabilization. Milk proteins are capable of transporting lipids in vitro.


Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 925
Author(s):  
Vernon Tebong Mbah ◽  
Vincent Pertici ◽  
Céline Lacroix ◽  
Bernard Verrier ◽  
Pierluigi Stipa ◽  
...  

Thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm)-based injectable hydrogels represent highly attractive materials in tissue engineering and drug/vaccine delivery but face the problem of long-term bioaccumulation due to non-degradability. In this context, we developed an amphiphilic poly(D,L-lactide)-b-poly(NIPAAm-co-polyethylene glycol methacrylate) (PLA-b-P(NIPAAm-co-PEGMA)) copolymer architecture, through a combination of ring-opening and nitroxide-mediated polymerizations, undergoing gelation in aqueous solution near 30 °C. Complete hydrogel mass loss was observed under physiological conditions after few days upon PLA hydrolysis. This was due to the inability of the resulting P(NIPAAm-co-PEGMA) segment, that contains sufficiently high PEG content, to gel. The copolymer was shown to be non-toxic on dendritic cells. These results thus provide a new way to engineer safe PNIPAAm-based injectable hydrogels with PNIPAAm-reduced content and a degradable feature.


2015 ◽  
Vol 6 (48) ◽  
pp. 8240-8243 ◽  
Author(s):  
Lilong Gao ◽  
Guangyu Zha ◽  
Ying Wang ◽  
Qiaojie Luo ◽  
Weipu Zhu ◽  
...  

A PCL-POEGM-PCL amphiphilic triblock copolymer was facilely synthesized in “one pot”, which can disperse hydrophobic drugs in aqueous solution and be crosslinked by poly[oligo(ethylene glycol)mercaptosuccinate] (POEGMS) under physiological conditions.


2011 ◽  
Vol 50 (9) ◽  
pp. 4162-4170 ◽  
Author(s):  
Prasenjit Mahato ◽  
Amrita Ghosh ◽  
Sanjiv K. Mishra ◽  
Anupama Shrivastav ◽  
Sandhya Mishra ◽  
...  

2020 ◽  
Vol 16 (10) ◽  
pp. 1495-1503
Author(s):  
Alaa F. Nahhas ◽  
Alrayan F. Nahhas ◽  
Thomas J. Webster

The fast-growing use of supramolecular hydrogelators as biomaterials for a variety of applications, ranging from wound healing to drug delivery to tissue engineering, has highlighted the importance of synthetic design over recent years. Here, we report a new class of nanosheet stereocomplexes in aqueous solution and at physiological conditions (i. e., pH7.4), which are formed by physically mixing right- and left-handed tripeptide supramolecular hydrogelators without any external stimulus. Such tripeptides were obtained by incorporating either α-aminoisobutyric acid (Aib, U) or alanine (Ala, A) at the C-terminus or middle position of known peptide hydrogelators containing naphthalene and two phenylalanine residues. For hydrogels of these peptides, our results show that their morphologies and physical properties changed upon mixing with the L- and D-forms of the peptides forming suspension stereocomplexes. These interactions reduced molecular mobility by forming new structures with new properties and, therefore, increased the thermal stability of the compound promising for numerous medical applications.


2020 ◽  
Vol 44 (3) ◽  
pp. 719-743 ◽  
Author(s):  
Hikaru Fujita ◽  
Jinghuai Dou ◽  
Nobuyuki Matsumoto ◽  
Zhiyuan Wu ◽  
Jonathan S. Lindsey

Oxidative dimerization of an indoxyl moiety, released by glycosidase action in aqueous solution, yields an indigoid dye in formats that enable bioconjugation and molecular cross-linking.


1980 ◽  
Vol 33 (10) ◽  
pp. 2207 ◽  
Author(s):  
H Stunzi ◽  
LN Harris ◽  
DD Perrin ◽  
T Teitei

Stability constants for the Mg2+, Ca2+, Cu2+ and Zn2+ complexes of two isomers (2) and (3) of the defleecing agent mimosine (1) have been sought from potentiometric titrations in aqueous solution, 0.15 M KNO3, at 37°. For the interpretation of the results, complex formation of the simpler ligands 3-hydroxypyridin-4(1H)-one (4), its 2-oxo isomer (5) and DL-α-amino-β-(6-oxo-1,6-dihydropyridin-2-yl)propanoic acid (6) was studied. The results with ligand (2) are very similar to those with mimosine, for which a computer blood-plasma model indicates metal chelation under physiological conditions. Ligand (3) is a much weaker complexing agent.


2020 ◽  
Vol 44 (10) ◽  
pp. 3856-3867 ◽  
Author(s):  
Hikaru Fujita ◽  
Yunlong Zhang ◽  
Zhiyuan Wu ◽  
Jonathan S. Lindsey

A molecular architecture designed for bioconjugation and internal absorption ratiometry undergoes enzymatically triggered cleavage of glucosyl groups and subsequent oxidative dimerization in aqueous solution to yield indigoid-containing scaffolds.


2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Brahim HACHT

This paper describes an experimental investigation in aqueous solution of the equilibria between gallium (III) metal ions and acetate ions as a model of low-molecular-weight ligand using potentiometric techniques under physiological conditions of temperature 37 °C and ionic strength 0.15 mol.dm-3 NaCl. Potentiometric measurements were monitored with the help of a glass electrode calibrated daily in hydrogen ions concentrations. Several metal to ligand ratios were used and the respective titrations data obtained in the pH range of 2.3-5.3 were treated using the SUPERQUAD computer program to determine global stability constants. Different species were considered during the calculation procedure and the following hydroxides have been characterized: ,  and coexist with one mononuclear complex Ga(CH3COO)+2. Speciation calculations based on the determined constants were then used to simulate the species distribution as a function of pH.


Author(s):  
Å. Thureson-Klein

Giant mitochondria of various shapes and with different internal structures and matrix density have been observed in a great number of tissues including nerves. In most instances, the presence of giant mitochondria has been associated with a known disease or with abnormal physiological conditions such as anoxia or exposure to cytotoxic compounds. In these cases degenerative changes occurred in other cell organelles and, therefore the giant mitochondria also were believed to be induced structural abnormalities.Schwann cells ensheating unmyelinated axons of bovine splenic nerve regularly contain giant mitochondria in addition to the conventional smaller type (Fig. 1). These nerves come from healthy inspected animals presumed not to have been exposed to noxious agents. As there are no drastic changes in the small mitochondria and because other cell components also appear reasonably well preserved, it is believed that the giant mitochondria are normally present jin vivo and have not formed as a post-mortem artifact.


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