scholarly journals Physico-chemical characterization of bilirubin-10-sulfonate and comparison of its acid–base behavior with unconjugated bilirubin

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adam Čepa ◽  
Veronika Dejmková ◽  
Ladislav Lešetický ◽  
Ivan Jelínek ◽  
Stanislav Smrček ◽  
...  

AbstractUnconjugated bilirubin (UCB) is the end-product of heme catabolism in the intravascular compartment. Although beneficial for human health when mildly elevated in the body, when present at greater than a critical threshold concentration, UCB exerts toxic effects that are related to its physico-chemical properties, particularly affecting the central nervous system. The aim of the present study was to characterize bilirubin-10-sulfonate (ranarubin), a naturally occurring bile pigment, including determination of its mixed acidity constants (pKa*). Thanks to the presence of the sulfonic acid moiety, this compound is more polar compared to UCB, which might theoretically solve the problem with an accurate determination of the UCB pKa* values of its propionic acid carboxylic groups. Bilirubin-10-sulfonate was synthesized by modification of a previously described procedure; and its properties were studied by mass spectrometry (MS), nuclear magnetic resonance (NMR), infrared (IR), and circular dichroism (CD) spectroscopy. Determination of pKa* values of bilirubin-10-sulfonate and UCB was performed by capillary electrophoresis with low pigment concentrations in polar buffers. The identity of the synthesized bilirubin-10-sulfonate was confirmed by MS, and the pigment was further characterized by NMR, IR, and CD spectroscopy. The pKa values of carboxylic acid moieties of bilirubin-10-sulfonate were determined to be 5.02, whereas those of UCB were determined to be 9.01. The physico-chemical properties of bilirubin-10-sulfonate were partially characterized with low pKa* values compared to those of UCB, indicating that bilirubin-10-sulfonate cannot be used as a surrogate pigment for UCB chemical studies. In addition, using a different methodological approach, the pKa* values of UCB were found to be in a mildly alkaline region, confirming the conclusions of a recent critical re-evaluation of this specific issue.

2018 ◽  
Vol 122 ◽  
pp. 702-708 ◽  
Author(s):  
S. Sani ◽  
M.U. Kaisan ◽  
D.M. Kulla ◽  
A.I. Obi ◽  
A. Jibrin ◽  
...  

2013 ◽  
Vol 59 (No. 8) ◽  
pp. 372-377 ◽  
Author(s):  
W. Szulc ◽  
B. Rutkowska

The determination of a range of boron concentration in the soil solution, evaluation of the effect of physico-chemical soil properties on boron concentration in the soil solution as well verification whether boron quantity in the soil solution is sufficient for nutritional needs of selected plants cultivated in Poland were comprised. Average boron concentration in the soil solution of Poland&rsquo;s cultivated soils ranges from 0.59 to 5.07 &micro;mol/L and is differentiated by physico-chemical properties of soil. Taking into account decreasing effects of soil properties on the increase of boron concentration in the soil solution, the soil properties can be arranged as follows: organic C &gt;<br />soil abundance in available boron &gt; soil texture &gt; soil pH. The minimum boron quantity observed in the soil solution of Poland&rsquo;s cultivated soils was not sufficient to fulfil nutritional needs of the plants. The maximum boron quantity observed secured nutritional needs of cereals and potatoes but not those of rape plants and sugar beets. Based on the study it can be concluded that the measurement of the concentration of boron in the soil solution can be used in the diagnosis of deficiency of this element for crops.


2020 ◽  
Vol 20 (sup3) ◽  
pp. S1579-S1589
Author(s):  
Dinesh Chandra Naithani ◽  
J.M.S. Rawat ◽  
Bhupendra Singh ◽  
Vinod Prasad Khanduri ◽  
Manoj Kumar Riyal

1997 ◽  
Vol 500 ◽  
Author(s):  
M. L. Pereira Da Silva ◽  
A. Romanelli Cardoso ◽  
J. J. Santiago-Aviles

ABSTRACTThis work presents the analysis performed on a SiO2 film deposited from organometallic precursors with the aim of correlating their physico-chemical properties including electrical characteristics with processing variables. The characterization tools used in this study included SEM for film homogeneity; SIMS for the determination of total carbon content; FT-MS and Raman scattering spectroscopy for surface characterization. GC-MS was used to understand the electrochemical reactions taking place while performing I-V characteristics measurements.The use of these multiple characterization techniques pointed out to deposited films with reasonable deposition characteristics but poor electrical ones. Phase segregated heterogeneity's rich in carbonatious residues influenced the degradation of the electrical characteristics.


Geoderma ◽  
2014 ◽  
Vol 232-234 ◽  
pp. 381-393 ◽  
Author(s):  
Rong-Jiang Yao ◽  
Jing-Song Yang ◽  
Tong-Juan Zhang ◽  
Peng Gao ◽  
Xiang-Ping Wang ◽  
...  

2016 ◽  
Vol 57 (4) ◽  
pp. 523-532
Author(s):  
Danijela Rajic ◽  
Dragan Toskovic ◽  
Ljubica Vasiljevic ◽  
Zeljko Ostojic

2020 ◽  
Vol 71 (2) ◽  
pp. 121-127
Author(s):  
Antonina Gritco-Todirascu ◽  
Dorina Emilia Creanga ◽  
Liliana Mihaela Ivan ◽  
Dana Ortansa Dorohoi ◽  
Anamaria Ciubara

The present paper is focused on determination of the main parameters of Chlortetracycline. Chlortetracycline belongs to one of the most used family of antibiotics worldwide, Tetracyclines. Because of the large spectrum of infections which can be treated with this category of antibiotics there are attempts to find new derivatives from this class. The compounds derived from the same basic structure exhibit same chemical properties, that is why knowing in detail the main physico-chemical properties of Chlortetracycline could be a real help in synthesize new efficient derivatives. In order to evaluate the reactivity and biological activity HyperChem was used to establish the optimized structure, the electro-optical, the energetic and QSAR parameters. The solvatochromic methods allowed determining the intermolecular interactions types and their contribution to the spectral shifts of measured electronic absorption bands. Based on computational and solvatochromic results, the excited state dipole moment of Chlortetracycline was established by variation method.


Author(s):  
Adelina Ion ◽  
Mirela Praisler ◽  
Steluta Gosav

Molecular descriptors play a fundamental role in chemistry and pharmaceutical sciences, being defined as a way to transform molecules into a set of numbers, allowing the mathematical assessment of the chemical information characterizing a molecule. This study presents the usefulness of molecular descriptors for the determination of physico-chemical properties of a series of new hallucinogenic amphetamines. Molecular descriptors of these compounds was performed with the Dragon 5.5 software. The chemometric processing of the information allowed the determination of structural correlations (similarities) between this class of designer drugs and an unknown compound.


2014 ◽  
Vol 13 (1) ◽  
pp. 135-144
Author(s):  
I. V. Mitrofanova ◽  
I. V. Milto ◽  
I. V. Suhodolo ◽  
G. Yu. Vasyukov

Nanomaterials  –  materials,  whouse  structure  elements  has  proportions  doesn’t  exceed  100  nm.  In superdispersed state matter acquire new properties. In the last decade, carbon nanotubes become the most popular nanomaterials, that cause attention of representatives of various scientific field. The сarbon nanotubes offer new opportunities for biological and medical applications: imaging at the molecular, cellular and tissue levels, biosensors and electrodes based on carbon nanotubes, target delivery of various substances, radiation and photothermal therapy. The most promising of carbon nanotubes in the context of biomedical applications is their ability to penetrate the various tissues of the body and carry large doses of agents, providing diagnostic and therapeutic effects. Functionalized nanotubes are biodegradable. Other current direction of using carbon nanotubes in medicine and biology is to visualize objects on the molecular, cellular and tissue level. Associated with carbon nanotubes contrasting substances improve the visualization of cells and tissues, which can detected new patterns of development of the pathological process. Due to the vagueness of the question of biocompatibility and cytotoxicity of carbon nanotubes possibility of their practical application is hampered. Before the introduction of carbon nanotubes into practical health care is necessary to provide all the possible consequences of using nanotubes. High rates of properties and development of new nanostructures based on carbon nanotubes in the near future will lead to new advances related to the application and development of new parameters that will determine their properties and effects. In these review attention is paid to the structure, physico-chemical properties of nanotubes, their functionalization, pharmacokinetics and pharmacodynamics and all aspects of using of carbon nanotubes.


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