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From Designer Food Formulation to Oxidative Stress Mitigation: Health-Boosting Constituents of Cabbage
Published in Megh R. Goyal, Hafiz Ansar Rasul Suleria, Ramasamy Harikrishnan, The Role of Phytoconstitutents in Health Care, 2020
Faiza Ashfaq, Masood Sadiq Butt, Ahmad Bilal, Kanza Aziz Awan, Hafiz Ansar Rasul Suleria
Numerous tests have acknowledged the assessment of antioxidant potential [99]. Commonly, radical trapping capacity is measured by ABTS and DPPH (free radical producing) reagents because polyphenols can react with these free radicals, ensuring stability [86]. Additionally, FRAP assay is a reducing assay by which reductional potential (ability to donate electron or hydrogen) is estimated, also known as total antioxidant capacity [7]. Earlier research on fifty popular fruits and vegetables and beverages showed that antioxidant assessment of pigmented and hydrophilic phenolics is better represented via ABTS assay than that of DPPH reagent [52].
Antioxidant assays
Published in Roger L. McMullen, Antioxidants and the Skin, 2018
Similar to the TRAP assay, the original FRAP assay was designed to measure the ferric reducing ability of plasma (FRAP).36 However, the assay has undergone revisions and is now commonly employed to measure the antioxidant capacity of substances other than plasma, especially extracts that can easily be dissolved in a suitable solvent.37–43 The assay is carried out using a complex of 2,4,6-tripyridyl-s-triazine (TPTZ) and the ferric (Fe3+) form of iron. Figure 6.12 contains the structure of the organic ligand, TPTZ, in which case two moles of TPTZ complex with one Fe3+ atom. At low pH, the ferric iron present in this complex may be reduced to ferrous iron (Fe2+) in the presence of antioxidants, as shown in Equation 6.5:
In Vitro Plant Regeneration, Comparative Biochemical and Antioxidant Potential of Calli and Seeds of Sesbania grandiflora (L.) Poiret
Published in Parimelazhagan Thangaraj, Medicinal Plants, 2018
Krishnamoorthy Vinothini, Masilamani Sri Devi, Sudharshan Sekar, Blassan P. George, Heidi Abrahamse, Bettine van Vuuren, Arjun Pandian
The modified method of Xu and Chang (2007) was used to find out the ferric reducing ability of samples. Briefly, acetate buffer (300 mM, pH 3.6) and weigh sodium acetate trihydrate (3.1 g) were added into the glacial acetic acid (16 mL) and made up to 1 L with distilled water. TPTZ (2,4,6-tripyridyl-s-triazine; M.W. 312.34), TPTZ (10 mM) dissolved in HCl (40 mM: M.W. 36.46) and FeCl3.6H2O (20 mM; M.W. 270.30) were used to make the FRAP reagent. The working FRAP reagent was prepared by mixing a, b and c (10:1:1). The FRAP reagent (150 μL) was read at 600 nm and the samples were added (20 μL). They were incubated at room temperature under dark condition for eight min and read at 600 nm. The results were expressed in mM Fe (II)/g fresh and dry mass.
Tight junctions: from molecules to gastrointestinal diseases
Published in Tissue Barriers, 2023
Aekkacha Moonwiriyakit, Nutthapoom Pathomthongtaweechai, Peter R. Steinhagen, Papasara Chantawichitwong, Wilasinee Satianrapapong, Pawin Pongkorpsakol
As proteins related to the structure of the cell, the integrity of tight junctions was thought to provide a static, impermeable barrier at the site of apical intercellular space complexes. However, this hypothesis was proven to be almost entirely incorrect. In fact, the concept of tight junction dynamics has a long history of over 30 years.126 In the last decade, fluorescence recovery after photobleaching (FRAP) revealed different mobile characteristics of fluorescent protein-tagged tight junctions during a steady state.127–129 Although claudin-1 stably localized at the tight junction region, ZO-1 and occludin are differentially exchangeable at subcellular levels. Notably, tight junction-to-cytoplasm switching of ZO-1 was found to occur in an energy-dependent manner, which required activity of the actin-binding region (ABR) and MLCK. Indeed, ZO-1 switching could occur via either MLCK-dependent or MLCK-independent mechanisms, which are slow and fast kinetics, respectively.23 Meanwhile, occludin passively diffuses between apical and lateral membrane.23 Therefore, it is widely accepted that tight junction remodeling can spontaneously occur.127 These kinetic behaviors of three representative tight junction proteins refute the theory of tight junctions having a static architecture (Figure 3a).
Effect of pesticide exposure on total antioxidant capacity and biochemical parameters in Brazilian soybean farmers
Published in Drug and Chemical Toxicology, 2021
Tanandra Bernieri, Dabiana Rodrigues, Isadora Randon Barbosa, Magda Susana Perassolo, Patrícia Grolli Ardenghi, Luciano Basso da Silva
Ferric-reducing ability of plasma was used to compare the effects of pesticide exposure on the farmers’ antioxidant potential during different periods of the same crop season. The capacity of antioxidant defense may be determined by the contributions of certain vitamins and antioxidant enzymes, and the variations in antioxidant capacity might affect the susceptibility to the deleterious effects of oxidative stress (Zepeda-Arce et al.2017). FRAP is a non-enzymatic assay able to measure the antioxidant defense system (Benzie and Strain 1996). Studies with farmers have showed lower level of FRAP in populations exposed to pesticides (Arnal et al.2011, Sharma et al.2013). An increased level of FRAP in the high exposure period observed in the present study might result from an adaptive or compensatory mechanism to overcome the intensive pesticide exposure in that period (Zepeda-Arce et al.2017).
Metformin protects red blood cells against rotenone induced oxidative stress and cytotoxicity
Published in Archives of Physiology and Biochemistry, 2021
Shambhoo Sharan Tripathi, Abhishek Kumar Singh, Farhan Akhtar, Ankita Chaudhary, Syed Ibrahim Rizvi
PMRS is ubiquitously present in all cell types and acts as an electron transporter. Erythrocytes membrane also contain PMRS (de Grey 2005). It has been reported that the intracellular ascorbate (ASC) donates electrons to extracellular ascorbate free radical (AFR) via the PMRS which recruits an AFR reductase; this redox system empowers the cells to effectively neutralise oxidative processes, thus preventing the depletion of extracellular ASC (Van Duijn et al.1998). This is the first time, we have seen that PMRS level is increasing in erythrocytes membrane after rotenone exposure. However, we found an elevated level of ROS following rotenone exposure. We speculate that after rotenone exposure, ROS is the cause of oxidative stress which leads to the activation of PMRS. PMRS has been suggested to play a vital role in reducing oxidative stress; this property has been hypothesised to control pathological conditions associated with increased oxidative stress (Rizvi and Srivastava 2010, Rizvi et al.2011). FRAP, being a marker of antioxidant capacity of plasma, is a reliable and primary measure for the evaluation of oxidative damage (Benzie and Strain 1996). A significant deterioration in the reducing power/antioxidant capacity of plasma was observed as anticipated in rotenone-treated group. A significant restoration of FRAP after metformin supplementation to rotenone-treated rats strongly suggests the protective role of metformin, it may be an independent mechanism of glycemic control that is characteristic of diabetic patients (Benzie and Strain 1996).