scholarly journals N-Acetyl-Cysteine Regenerates Albumin Cys34 by a Thiol-Disulfide Breaking Mechanism: An Explanation of Its Extracellular Antioxidant Activity

Antioxidants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 367 ◽  
Author(s):  
Alessandra Altomare ◽  
Giovanna Baron ◽  
Maura Brioschi ◽  
Martina Longoni ◽  
Riccardo Butti ◽  
...  

In the present paper, the extracellular antioxidant activity of N-acetyl-cysteine (NAC) is explained by considering its ability to regenerate the free form of albumin Cys34 by breaking the disulfide bond of the cysteinylated form (HSA-Cys). NAC’s capability to regenerate albumin Cys34 (HSA-SH) was studied by MS intact protein analysis in human plasma and in a concentration range of NAC easily achievable after oral and i.v. administration (5–50 µg/mL). NAC dose-dependently broke the HSA-Cys bond to form the dimer NAC-Cys thus regenerating Cys34, whose reduced state was maintained for at least 120 min. Cys was faster in restoring Cys34, according to the reaction constant determined with the glutathione disulfide (GSSG) reaction, but after 60 min the mixed disulfide HSA-Cys turned back due to the reaction of the dimer Cys-Cys with Cys34. The explanation for the different rate exchanges between Cys-Cys and Cys-NAC with Cys34 was given by molecular modeling studies. Finally, the Cys34 regenerating effect of NAC was related to its ability to improve the total antioxidant capacity of plasma (TRAP assay). The results well indicate that NAC greatly increases the plasma antioxidant activity and this effect is not reached by a direct effect but through the regenerating effect of Cys34.


Author(s):  
N. N. Malyutina ◽  
A. F. Bolotova ◽  
R. B. Eremeev ◽  
A. Zh. Gilmanov ◽  
D. Yu. Sosnin

Introduction. The overwhelming number of publications contains only data on the content of individual antioxidants, but not on the overall antioxidant activity of the blood in patients with vibration disease.The aim of the study was to determine the total antioxidant activity of blood serum in patients with vibration disease.Materials and methods. Th e main group consisted of 30 people diagnosed with “Vibration disease” of 1 degree (n=21) and 2 degrees (n=9). Th e control group consisted of 30 clinically healthy men, comparable in age with the main group (p=0.66). Th e total activity of antioxidant systems of blood plasma was evaluated photometrically using the test system “Total antioxidant status-Novo” (“Vector-best”, Russia).Results. The indicator of the total antioxidant status (TAS) was 1,038±0.232 mmol/l in the examined main group, against 1,456±0.225 mmol/l in the examined control group (p<0.000001). Th e coefficient of variation (CV) in patients with vibration disease was 22.35%, 1.45 times higher than in the control group (15.45%). In the main group there was a positive correlation between age and TAS (R=0.525), in the control group there was no such relationship (R=0.095). Th e degree of decrease depended on the severity of vibration disease.Conclusions. 1. The development of vibration disease is accompanied by a decrease in the antioxidant status of blood serum. 2. Th e degree of decrease in the antioxidant status of blood serum correlates with the severity of vibration disease. 3. Reduction of TAS can serve as a pathogenetic justification of the need to include drugs and/or biologically active additives with antioxidant activity in therapy



2019 ◽  
pp. 49-59
Author(s):  
Nu Linh Giang Ton ◽  
Thi Hoai Nguyen ◽  
Quoc Hung Vo

Avocado peel has been considered as a potential source of natural antioxidants in which phenolics are among the most important compounds. Therefore, this study aims to optimize the extraction process of phenolics using response surface methodology and evaluate the corresponding antioxidant activity. From the quadratic model, the optimal condition was determined including the ethanol concentration 54.55% (v/v), the solvent/solute ratio 71.82/1 (mL/g), temperature 53.03 oC and extraction time 99.09 min. The total phenolic content and the total antioxidant capacity at this condition with minor modifications were 26,74 ± 0,04 (mg GAE/g DW) and 188.06 ± 1.41 (mg AAE/g DW), respectively. The significant correlation between total phenolic content and total antioxidant capacity was also confirmed. Key words: response surface methodology, central composite rotatable design, total phenolic content, total antioxidant capacity, avocado peel





2007 ◽  
Vol 33 (3) ◽  
pp. 375-376 ◽  
Author(s):  
M. F. Borisenkov ◽  
L. A. Erunova ◽  
E. M. Lyuseva ◽  
N. V. Pozdeeva


1970 ◽  
Vol 3 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Afia Ferdous ◽  
Mohammad Zafar Imam ◽  
Tajnin Ahmed

In the present investigation the n-hexane, carbon tetrachloride and choloroform soluble fractions of crude methanolic extract of Samanea saman bark were tested for antioxidant, antimicrobial and cytotoxic potential. Antioxidant activity of the extracts was evaluated by DPPH radical scavenging assay and total antioxidant activity test. Antimicrobial activity was tested using disc diffusion method against thirteen bacteria and three fungi and cytotoxicity was tested by brine shrimp lethality bioassay. Chloroform and hexane soluble fraction showed IC50 value of 12μg/ml and 14μg/ml respectively in scavenging DPPH radical while the reference Butylated hydroxytoluene showed an IC50 value of 10μg/ml. The carbon tetrachloride fraction showed the highest total antioxidant capacity. The carbon tetrachloride fraction was also found to possess mild to moderate microbial growth inhibitory capacity. In the brine shrimp lethality bioassay, the n-hexane, carbon tetrachloride, chloroform soluble fractions showed LC50 value of 14.94μg/ml, 0.831μg/ml and 3.288μg/ml respectively. The results suggest good antioxidant and cytotoxic potential of chloroform and hexane soluble fractions and antimicrobial activity of carbon tetrachloride fraction of Samanea saman bark extract. Key Words: Samanea saman; Leguminoseae; Cytotoxicity; Antimicrobial; Antioxidant; Total antioxidant capacity. DOI: 10.3329/sjps.v3i1.6792S. J. Pharm. Sci. 3(1): 11-17



Author(s):  
Pozdnyakovа Т.А. ◽  
Kuleshovа Е.S. ◽  
Bubenchikov R.A.

The predominance of synthetic and genetically modified foods in the diet of a modern person often leads to disruption of natural metabolic processes and the accumulation of toxic free radicals in the body, which provokes the development of various diseases. Natural antioxidants from medicinal plants can help maintain health and stop the processes of peroxidation. In our opinion, Аstragalus onobrychis can become a promising source of natural antioxidants. The aim of this study was to establish the antioxidant activity in extracts from the herb Astragalus onobrychis. In order to obtain objective and reliable results during our research, we used two methods: the method of titrimetry and spectrophotometry of free radicals. The titrimetric method is based on the chemical interaction between an oxidizing agent (potassium permanganate) and natural antioxidants present in extracts from plant raw materials, since they exhibit the properties of reducing agents. The spectrophotometric method makes it possible to assess the value of antioxidant activity and the duration of the reaction by assessing the interaction of 2,2-diphenyl-1-picrylhydrazil with plant antioxidants. To establish the relationship between the antioxidant activity and the presence of phenolic compounds in the plant, the content of flavonoids and hydroxycinnamic acids in the herb Astragalus onobrychis was determined. As a result of the studies, the total antioxidant activity of extracts from the herb Astragalus onobrychis was established and it was revealed that its value depends on the type of extractant used, since this factor is associated with the content of various groups of natural antioxidants in the extraction. The data obtained indicate the prospects of using the herb Astragalus onobrychis as a source of natural antioxidants.



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