Diet and nutrition contribute to both beneficial and harmful aspects of oxidative processes. The harmful processes, termed oxidative stress, occur with many human diseases. Major advances in ...understanding oxidative stress and nutrition have occurred with broad characterization of dietary oxidants and antioxidants, and with mechanistic studies showing antioxidant efficacy. However, randomized controlled trials in humans with free-radical-scavenging antioxidants and the glutathione precursor N-acetylcysteine have provided limited or inconsistent evidence for health benefits. This, combined with emerging redox theory, indicates that holistic models are needed to understand the interplay of nutrition and oxidative stress. The purpose of this article is to highlight how recent advances in redox theory and the development of new omics tools and data-driven approaches provide a framework for future nutrition and oxidative stress research. Here we describe why a holistic approach is needed to understand the impact of nutrition on oxidative stress and how recent advances in omics and data analysis methods are viable tools for systems nutrition approaches. Based on the extensive research on glutathione and related thiol antioxidant systems, we summarize the advancing framework for diet and oxidative stress in which antioxidant systems are a component of a larger redox network that serves as a responsive interface between the environment and an individual. The feasibility for redox network analysis has been established by experimental models in which dietary factors are systematically varied and oxidative stress markers are linked through integrated omics (metabolome, transcriptome, proteome). With this framework, integrated redox network models will support optimization of diet to protect against oxidative stress and disease.
•(±)-Gossypol was isolated from cotton seeds.•Enantioseparation of (±)-gossypol was achieved by diastereomeric crystallization.•Chitosan was modified with (−)-gossypol by the formation of imine ...groups.•Chitosan-gossypol derivatives showed good antioxidant activity.
In this work, two new chitosan-Schiff base derivatives (HCS-GSP and LCS-GSP) were synthesized by the condensation reaction of high molecular weight chitosan (HCS) and low molecular weight chitosan (LCS) with (−)-gossypol (GSP), respectively. For this purpose, racemic gossypol was isolated from cotton seeds and it was further enantiomerically purified by diastereomeric resolution technique using l-tryptophan methyl ester hydrochloride. Then, chitosan polymers were derivatized with (−)-gossypol by the condensation reaction. The isolated and synthesized coumpounds were characterized by physical measurements and spectroscopic methods (elemental analysis C,H,N, Uv–vis, FT-IR, 1H&13C NMR and TG/DTG/DTA). The antioxidant activity of high molecular weight chitosan (HCS), low molecular weight chitosan (LCS) and their gossypol derivatives was evaluated as radical scavengers against 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH). The results showed that both of the chitosan-gossypol derivatives (HCS-GSP and LCS-GSP) had a better ability to scavenging DPPH radical (IC50, 12 μg/mL and 16 μg/mL, respectively) than its unmodified chitosan.
Brown seaweeds are rich source of functional polysaccharides that exhibit various bioactivities. However, Malaysian seaweeds are under-utilised, leading to low revenue throughout the supply chain of ...the seaweed industry. The aims of this study were to extract the functional polysaccharides, namely fucoidan (F), laminaran (L) and alginate (A) from Malaysian brown seaweeds (Sargassum polycystum, Turbinaria ornata and Padina boryana) and subsequently evaluate the properties of the extracted polysaccharides. P. boryana recorded the significantly (p ≤ 0.05) highest carbohydrate content (74.78 ± 1.63%) with highest fucoidan yield (Fpad = 1.59 ± 0.16%) while T. ornata contained significantly (p ≤ 0.05) highest alginate yield (Atur = 105.19 ± 3.45%). Water activities of these extracted polysaccharides varied from 0.63–0.71 with average score of browning indexes (~40). Fourier transform infrared (FTIR) spectroscopy analysis demonstrated that the extracted polysaccharides exhibited similar spectral pattern of spectra with the respective standards. Meanwhile, laminaran extracts showed the significantly highest (p ≤ 0.05) total phenolic contents (Lsar = 43.29 ± 0.43 mgGAE/g) and superoxide anion scavenging activity (Lsig = 21.7 ± 3.6%). On the other hand, the significantly highest (p ≤ 0.05) DPPH scavenging activity was recorded in alginate with Asar at 85.3 ± 0.8%. These findings reported the properties and bioactivities of natural polysaccharides from Malaysian brown seaweeds that revealed the potential to develop high-value functional ingredients from Malaysian brown seaweeds.
•P. boryana recorded the significantly highest carbohydrate content (75.92 ± 0.68%).•The highest fucoidan content (1.59 ± 0.16% dw) was extracted from Padina boryana.•FTIR spectra of the polysaccharides were positively finger-printed at the standard.•Laminaran extract showed the highest total phenolic content (43.29 ± 0.43 mg GAE/g).•Alginate isolated from Sargassum polycystum scavenged DPPH radical (85.3 ± 0.8%).
The purpose of this study was to determine the content of certain phenolic compounds, antioxidant activity, pressing efficiency, extract content, and sugars in celeriac juices obtained from the pulp ...after α-amylase treatment from Aspergillus oryzae. The test material consisted of peeled and unpeeled celery pulp kept at a temperature of 25 °C with and without the enzyme for a period of 30 and 60 min. The juices obtained from them were analyzed for the content of selected phenolic acids and flavonoids using the UPLC-PDA-ESI-MS/MS method, for antioxidant activity measured using the ABTS˙sup.+ and DPPH˙ method, and for the total polyphenol content using the F-C method. Additionally, the juice pressing efficiency, the extract content using the refractometer method, and the sugar content using the HPLC method were checked. Significantly higher antioxidant activity, pressing yield, and average content of caffeic acid glucoside, quinic acid, kaempferol-3,7-di-O-glucoside, and chrysoeriol-7-O-apiosylglucoside were obtained in juices from peeled celery. Maceration of the pulp with amylase resulted in a significant reduction in antioxidant activity compared to control samples. An is-total increase of 17–41% in total flavonoid content was observed in all juices tested after treatment with the enzyme for 30 and 60 min, and the phenolic acid content increased by 4–41% after treatment of the pulp with amylase for 60 min. The 60 min holding of the pulp at 25 °C, including with the enzyme, was shown to decrease the antioxidant activity and the content of quinic acid, ferulic acid, and chrysoriol-7-O-apiose-glucoside in the juices tested compared to the samples held for 30 min, while the content of other phenolic acids and flavonoids increased. In addition, after 60 min of enzymatic maceration, the pressing yield of the juices increased.
Antioxidants play a very critical role in many biological processes in which free radicals are present. The physiological part of these compounds prevents damage to cellular components from arising ...because of chemical reactions involving free radicals. Oxidation mechanisms appear continuously in living metabolism, and reactive oxygen species are taken from outside step-up oxidation events. Many attempts have been made rapid, economical, and user-friendly analytical approaches for detecting and determining antioxidant capacity in recent years. Electrochemical techniques offer an alternative and powerful strategy for determining antioxidant content as they allow simple and inexpensive detection. This review discusses information about antioxidants, their classification, mechanism of action, and the applications of electrochemical nanosensors to analyze non-enzymatic/enzymatic endogenous, exogenous antioxidants, and synthetic antioxidants. The purpose of this review is to highlight the articles describing the mechanism underlying the modulatory effect of natural and synthetic antioxidants on oxidative stress.
•New developments, challenges, frontiers and future prospect on electrochemical nanosensors for the analysis of antioxidants.•Recent and up-to-date studies on various electrochemical nanosensors for the analysis of antioxidants.•Illustrating the usefulness of natural and synthetic antioxidants as novel therapeutic approaches.•Using of different platforms to form electrochemical nanosensors for the analysis of antioxidants.
In order to explore Cassia seed polysaccharides (CSPs) as natural antioxidants for application in the functional-food industry, microwave-assisted extraction (MAE) was optimized for the extraction of ...CSPs by using a response surface methodology. Furthermore, the chemical structures and antioxidant activities of CSPs extracted by MAE and hot water extraction were investigated and compared. The maximum extraction yield of CSPs extracted by MAE (8.02 ± 0.19%) was obtained at the optimized extraction parameters as follows: microwave power (415 W), extraction time (7.0 min), and ratio of water to raw material (51 mL/g). Additionally, the contents of the uronic acids, molecular weight, ratio of constituent monosaccharides, intrinsic viscosities, and degrees of esterification of CSPs were significantly affected by the MAE method. Moreover, CSPs exhibited remarkable 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) ABTS, 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl DPPH, nitric oxide, and hydroxyl radical scavenging activities as well as reducing power. The high antioxidant activities observed in CSPs extracted by MAE could be partially attributed to its low molecular weights and high content of unmethylated galacturonic acid. Results indicate that the MAE method could be an efficient technique for the extraction of CSPs with high antioxidant activity, and CSPs could be further explored as functional food ingredients.
For combating multidrug-resistant microorganisms, exploration of natural compounds from plant endophytes increases the chance of finding novel compounds. An efficient bioactive metabolites producing ...endophytic fungal strain AE1 was isolated from leaves of Azadirachta indica A. Juss. The metabolites were found to be thermostable, non-proteinacious and produced prominent zones of inhibition against numbers of Gram positive and Gram negative bacteria. Based on 28S rDNA (D1/D2) sequence homology the isolate AE1 was identified as Alternaria alternata. Malt extract broth was found effective for the maximum production of bioactive metabolites by the isolate and was subjected for solvent extraction. The Ethyl acetate (EA) fraction of AE1 showed MIC values of 300-400 μg/ml against Gram positive and Gram negative bacteria tested. The cidal mode of action of EA fraction was detected by treating bacterial cultures at mid log phase. Scanning electron microscopic study supported morphological disintegration of bacterial cells. Release of nucleic acid, protein and potassium ions (K+) also suggested lysis of bacterial cells or leakage of cell membrane upon treatment. In addition, reduction of the activity of EMP pathway, TCA cycle and gluconeogenic enzymes in all bacteria suggested the interference of antibacterial principles with central carbohydrate metabolic pathways. Thin layer chromatographic separation followed by GC-MS analysis of EA fraction suggested numbers of antimicrobial compound production by AE1. In addition, DPPH free radical as well as superoxide radical scavenging assay also suggested strong antioxidant potential of AE1 with an IC50 value of 38.0±1.7 μg/ml and 11.38±1.2 μg/ml respectively. On the basis of above facts it can be concluded that the strain AE1 will be a good source of bioactive compounds having medicinal importance.
In this study, ultrasound-assisted extraction conditions were optimized to maximize the yields of sennoside A, sennoside B, aloe-emodin, emodin, and chrysophanol from
(aerial parts). The three UAE ...factors, extraction temperature (
), extraction time (
), and liquid to solid ratio (
), were optimized using response surface methodology (RSM). A Box-Behnken design was used for experimental design and phytoconstituent analysis was performed using high-performance liquid chromatography-UV. The optimal extraction conditions were found to be a 64.2 °C extraction temperature, 52.1 min extraction time, and 25.2 mL/g liquid to solid ratio. The experimental values of sennoside A, sennoside B, aloe-emodin, emodin, and chrysophanol (2.237, 12.792, 2.457, 0.261, and 1.529%, respectively) agreed with those predicted (2.152, 12.031, 2.331, 0.214, and 1.411%, respectively) by RSM models, thus demonstrating the appropriateness of the model used and the accomplishment of RSM in optimizing the extraction conditions. Excellent antioxidant properties were exhibited by
methanol extract obtained using the optimized extraction conditions with a DPPH assay (IC50 = 59.7 ± 1.93, µg/mL) and ABTS method (47.2 ± 1.40, µg/mL) compared to standard ascorbic acid.
Vicia faba L. pods are a by-product generated from the industrial processing of beans for human and animal consumption. As phenolic compounds may play important roles in health, the present work ...envisaged the phenolic characterization of seven European varieties and cultivars of V. faba (major and minor) pods and the assessment of their antioxidant activity. The V. faba methanolic extracts were characterized by HPLC-DAD-MS/MS for identification of polyphenolic compounds. The total phenolic content and antioxidant capacity of the extracts were evaluated by colorimetric methods (Folin-Ciocalteu, DPPH scavenging capacity assay, and FRAP assay). Main compounds identified by HPLC-DAD-MS/MS were derivatives of caffeic acid, coumaric acid and kaempferol. The broad bean Jögeva variety presented the highest content of free and esterified phenolics (26.3 and 26.7 mg 100 g−1 dry weight, respectively), followed by the horse bean varieties Bauska and Lielplatones. These results were corroborated by the analysis of total phenolic content, DPPH scavenging capacity and FRAP. This study confirmed the rich phenolic content of V. faba pods suggesting to be an interesting novel source for animal nutrition, promoting product quality and consumers' health.
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•Pods are the main by-product of Vicia faba L industrial processing.•Seven European varieties and cultivars of V. faba pods were evaluated in this work.•Characterization of the phenolic profile and antioxidant activity was performed.•Main compounds were derivatives of caffeic and coumaric acids, and kaempferol.•The rich phenolic content of V. faba pods was confirmed.
Quercetin is a unique dietary polyphenol because it can exert biphasic dose‐responses on cells depending on its concentration. Cancer preventative effects of quercetin are observed at concentrations ...of approximately 1–40 µM and are likely mediated by quercetin's antioxidant properties. Pro‐oxidant effects are present at cellular concentrations of 40–100 µM. However, at higher concentrations, many novel pathways in addition to ROS contribute to its effects. The potent bioactivity of quercetin has led to vigorous study of this compound and revealed numerous pathways that could interact synergistically to prevent or treat cancer. The effect of intake and concentration on emerging pathways and how they may interact are discussed in this review.
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