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Bioproducts Derived from Lignin Obtained from Micro- and Nanocrystalline Cellulose Preparation
Published in Jorge M.T.B. Varejão, Biomass, Bioproducts and Biofuels, 2022
The quantification of the antioxidant activity of soluble polyphenolic substances obtained from the degradation of wheat straw lignin, under conditions that allow obtaining MCC, was studied in detail and some results are provided in Table 4. The test selected to verify its antioxidant activity was the classic oxidation of 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic) or ABTS, to the colored cation ABTS+·, using as oxygen donor the H2O2, catalyzed by horseradish peroxidase (Putter and Becker 1985). Some versions use the colored radical ABTS+· preformed with persulfate oxidation, but there is some instability in the radical solutions (Boligon et al. 2014). The similarity of the results in both test trials and their conversion to antioxidant capacity equivalent to Trolox (TEAC) is used in the present evaluation (Re et al. 1999, Lingua et al. 2016). The activity of the diluted hydrolysates was compared with diluted red wine solutions and standard Trolox solutions using a spectrophotometric method, with ABTS+· radical ion monitoring at 660 nm.
Purification of polysaccharides from Phellinus linteus by using an aqueous two-phase system and evaluation of the physicochemical and antioxidant properties of polysaccharides in vitro
Published in Preparative Biochemistry & Biotechnology, 2022
Yan Wu, Hong Liu, Zhihua Li, Dongye Huang, Lizheng Nong, Zhenxing Ning, Zhizhong Hu, Chunping Xu, Jing-Kun Yan
TEAC and FRAP methods are commonly used to determine the total antioxidant capacity of potential antioxidants and can be used as an important indicator to evaluate the antioxidant potential of the measured samples.[37]Figure 5C shows that PLPS presented more excellent antioxidant capacities (TEAC = 61.33 µmol Trolox per g sample, FRAP = 79.77 µmol Fe2+ per g sample) than C-PLPS, indicating that the antioxidant activity of PLPS after ATPS extraction showed moderate improvement due to decreased molecular weight in PLPS molecules.[16] Likewise, Yan et al. reported that Hericium erinaceus PS (HEP-C) obtained via citric acid solution extraction has lower MW and more pronounced antioxidant capacity with high TEAC and FRAP values than HEP-W and HEP-S extracted with hot water and 0.9% NaCl solutions, respectively.[38] Besides, the antioxidant potential of the PS might be determined by the monosaccharide constituents, structural characteristics, and space conformation.[20,37,38]
Serum cortisol but not oxidative stress biomarkers are related to frailty: results of a cross-sectional study in Spanish older adults
Published in Journal of Toxicology and Environmental Health, Part A, 2019
Diego Marcos-Pérez, María Sánchez-Flores, Ana Maseda, Laura Lorenzo-López, José C. Millán-Calenti, Eduardo Pásaro, Blanca Laffon, Vanessa Valdiglesias
Total antioxidant capacity was measured in plasma samples by using the Antioxidant assay kit (Sigma Aldrich), following manufacturer´s guidelines. The principle of the assay is the formation of a radical cation, a soluble chromogen that is green in color and determined spectrophotometrically. Antioxidants present in the plasma samples suppress the production of the radical cation in a concentration-dependent manner, and the color intensity decreases proportionately. TroloxTM, a water-soluble vitamin E analog, serves as a standard or control antioxidant. Absorbance at 405 nm was measured with a Spectrostar Nano microplate reader (BMG Labtech) equipped with kinetic analysis software (Spectrostar Nano Control, BMG Labtech). Results were expressed as TroloxTM equivalent antioxidant capacity (TEAC). The sensitivity of this method was 0.015 mM TEAC.
Blood oxidative stress and post-exercise recovery are unaffected byhypobaric and hypoxic environments
Published in Journal of Sports Sciences, 2021
Cassie M. Williamson-Reisdorph, Tiffany S. Quindry, Kathryn G. Tiemessen, John Cuddy, Walter Hailes, Dustin Slivka, Brent C. Ruby, John C. Quindry
Antioxidant status was assessed through the quantification of antioxidant capacity (TEAC) and antioxidant potential (FRAP). Within the current investigation, both TEAC and FRAP were unaffected by recovery under both hypobaric and hypoxic conditions. Our findings are in conflict with prior work, in which Ballmann et al. demonstrated that recovery in a hypoxic environment mitigated the exercise-dependent increase of FRAP and TEAC that typically occurs in a normoxic environment (Ballmann et al., 2014). The exercise bout selected within the aforementioned study was longer in duration (90-minutes) and consisted of intervals that peaked at a much higher exercise intensity (80% VO2max). In further support, Peters et al. examined the effects of hypoxia on recovery of blood oxidative stress following one-hour of cycling at 70% VO2max (Peters et al., 2016). An exercise-induced elevation of TEAC and FRAP was observed, but there were no differences between recovery in a hypoxic environment (1667 m, 3333 m, or 5000 m) when compared to normoxia (Peters et al., 2016). Although an exercise-induced increase in TEAC and FRAP was present within the current study, the magnitude of the oxidative stress response was modest and may not have been sufficient to observe changes among the environmental conditions. Importantly, previous research has demonstrated a post-exercise drop in FRAP, with no observed changes in TEAC, following one-hour of moderate-intensity cycling exercise (60% VO2peak) under normoxic and hypoxic conditions; thus, biomarkers of antioxidant status are not always elevated in response to a bout of exercise (McGinnis et al., 2014).