The present review paper focuses on the chemistry of oxidative stress mitigation by antioxidants. Oxidative stress is understood as a lack of balance between the pro-oxidant and the antioxidant ...species. Reactive oxygen species in limited amounts are necessary for cell homeostasis and redox signaling. Excessive reactive oxygenated/nitrogenated species production, which counteracts the organism’s defense systems, is known as oxidative stress. Sustained attack of endogenous and exogenous ROS results in conformational and oxidative alterations in key biomolecules. Chronic oxidative stress is associated with oxidative modifications occurring in key biomolecules: lipid peroxidation, protein carbonylation, carbonyl (aldehyde/ketone) adduct formation, nitration, sulfoxidation, DNA impairment such strand breaks or nucleobase oxidation. Oxidative stress is tightly linked to the development of cancer, diabetes, neurodegeneration, cardiovascular diseases, rheumatoid arthritis, kidney disease, eye disease. The deleterious action of reactive oxygenated species and their role in the onset and progression of pathologies are discussed. The results of oxidative attack become themselves sources of oxidative stress, becoming part of a vicious cycle that amplifies oxidative impairment. The term antioxidant refers to a compound that is able to impede or retard oxidation, acting at a lower concentration compared to that of the protected substrate. Antioxidant intervention against the radicalic lipid peroxidation can involve different mechanisms. Chain breaking antioxidants are called primary antioxidants, acting by scavenging radical species, converting them into more stable radicals or non-radical species. Secondary antioxidants quench singlet oxygen, decompose peroxides, chelate prooxidative metal ions, inhibit oxidative enzymes. Moreover, four reactivity-based lines of defense have been identified: preventative antioxidants, radical scavengers, repair antioxidants, and those relying on adaptation mechanisms. The specific mechanism of a series of endogenous and exogenous antioxidants in particular aspects of oxidative stress, is detailed. The final section resumes critical conclusions regarding antioxidant supplementation.
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•Pro-oxidant/antioxidant imbalance results in oxidative stress.•Oxidative stress implies deleterious alterations in biomolecules and disease occurrence.•The results of oxidative insults become themselves sources of oxidative stress.•Endogenous and exogenous antioxidants neutralize ROS and oxidative enzymes.•Supplements are recommended when oxidative stress surpasses the endogenous defense.
The levels of phytochemicals (total phenols, proanthocyanidins, gallic acid + gallotannins, ellagic acid + ellagitannins, flavonoids, phenolic acids, stilbenes and phytates), fat-soluble bioactives ...(lipid, tocols, phytosterols, sphingolipids, carotenoids, chlorophylls and alkyl phenols) as well as natural antioxidants (nutrient and non-nutrient) present in commonly consumed twelve nuts (almond, Brazil nut, cashew, chestnut, hazelnut, heartnut, macadamia, peanut, pecan, pine nut, pistachio and walnut) are compared and reported. Recent studies adding new evidence for the health benefits of nuts are also discussed. Research findings from over 112 references, many of which have been published within last 10 years, have been compiled and reported.
Chia (
L.) is a small seed that comes from an annual herbaceous plant,
L. In recent years, usage of Chia seeds has tremendously grown due to their high nutritional and medicinal values. Chia was ...cultivated by Mesopotamian cultures, but then disappeared for centuries until the middle of the 20th century, when it was rediscovered. Chia seeds contain healthy ω-3 fatty acids, polyunsaturated fatty acids, dietary fiber, proteins, vitamins, and some minerals. Besides this, the seeds are an excellent source of polyphenols and antioxidants, such as caffeic acid, rosmarinic acid, myricetin, quercetin, and others. Today, chia has been analyzed in different areas of research. Researches around the world have been investigating the benefits of chia seeds in the medicinal, pharmaceutical, and food industry. Chia oil is today one of the most valuable oils on the market. Different extraction methods have been used to produce the oil. In the present study, an extensive overview of the chemical composition, nutritional properties, and antioxidant and antimicrobial activities, along with extraction methods used to produce chia oil, will be discussed.
Natural antioxidants are widely distributed in food and medicinal plants. These natural antioxidants, especially polyphenols and carotenoids, exhibit a wide range of biological effects, including ...anti-inflammatory, anti-aging, anti-atherosclerosis and anticancer. The effective extraction and proper assessment of antioxidants from food and medicinal plants are crucial to explore the potential antioxidant sources and promote the application in functional foods, pharmaceuticals and food additives. The present paper provides comprehensive information on the green extraction technologies of natural antioxidants, assessment of antioxidant activity at chemical and cellular based levels and their main resources from food and medicinal plants.
A marked decrease in human cancers, including breast cancer, bone cancer, and cervical cancer, has been linked to the consumption of vegetable and fruit, and the corresponding chemoprotective effect ...has been associated with the presence of several active molecules, such as kaempferol. Kaempferol is a major flavonoid aglycone found in many natural products, such as beans, bee pollen, broccoli, cabbage, capers, cauliflower, chia seeds, chives, cumin, moringa leaves, endive, fennel, and garlic. Kaempferol displays several pharmacological properties, among them antimicrobial, anti-inflammatory, antioxidant, antitumor, cardioprotective, neuroprotective, and antidiabetic activities, and is being applied in cancer chemotherapy. Specifically, kaempferol-rich food has been linked to a decrease in the risk of developing some types of cancers, including skin, liver, and colon. The mechanisms of action include apoptosis, cell cycle arrest at the G2/M phase, downregulation of epithelial-mesenchymal transition (EMT)-related markers, and phosphoinositide 3-kinase/protein kinase B signaling pathways. In this sense, this article reviews data from experimental studies that investigated the links between kaempferol and kaempferol-rich food intake and cancer prevention. Even though growing evidence supports the use of kaempferol for cancer prevention, further preclinical and clinical investigations using kaempferol or kaempferol-rich foods are of pivotal importance before any public health recommendation or formulation using kaempferol.
The effect of microwave-assisted extraction (MAE) process on the antioxidant capacity/activity of three medicinal herbs from Turkey was investigated by electrochemical differential pulse voltammetric ...(DPV)- CUPric Reducing Antioxidant Capacity ( CUPRAC) assay. The optimal extraction time, temperature and solvent type were 6 min, 80 °C and 80% (v/v) methanol (MeOH), respectively. Microwave-assisted extracts of herbs (Hypericum scabrum L., Papaver fugax Poiret var. platydiscus Cullen , and Achillea vermicularis Trin.) were screened for total antioxidant capacity (TAC), total phenolic content (TPC) and ROS scavenging activities by employing different in vitro spectrophotometric assays. A positive correlation was observed between TAC-CUPRAC and TPC ( R 2 = 0.972). Similarly, a positive correlation was observed between TAC-CUPRAC and free radical scavenging (FRS) activity ( R 2 = 0.977). The order of FRS activities of tested samples was as follows: Hypericum scabrum L. > Achillea vermicularis Trin. > Papaver fugax Poiret var. platydiscus Cullen . These results suggest that these medicinal herbs provide promising antioxidant potentials as potential natural preservative agents in pharmaceutical industries.
2-Dodecylthiomethyl-5-hydroxy-2,3-dihydrobenzofurans, new sulfur-containing analogs of tocopherols, were synthesized based on methylphenols through the intermediate preparation of ...4-alkoxy-2-allylphenols and then 5-alkoxy-2-iodomethyl-2,3-dihydrobenzofurans.
In this study, the effect of limited hydrolysis of soy I2-conglycinin (7S) on the oxidative stability of 7S hydrolysate (7SH)-stabilized emulsions was investigated under different conditions of pH, ...ionic strength, degrees of hydrolysis (DH), and protein concentration in the continuous phase. The hydrolysis was performed using trypsinization and acid hydrolysis. Interfacial protein conformations were studied by thioflavin T fluorescence, scanning and transmission electron microscopy techniques, and Raman spectroscopy at oil-mimicking, functionalized silver surfaces. The antioxidant property was tested by the Trolox equivalent antioxidant capacity (TEAC) assay. At DH 0.7%, trypsinization improved emulsion oxidative stability at pH 7 under low ionic strength, as a result of an increase in protein antioxidant property and enhanced interfacial barrier property due to substantial increment of intermolecular I2-sheets. The loose coil/helix to intermolecular I2-sheet transition was deemed essential in the building of an effective interfacial barrier. At pH 3, however, the tryptic 7SH turned pro-oxidant, and interfacial coverage by the protein became uneven. As such, the emulsion oxidative stability was not better than that based on the native 7S at pH 7. The modification of the surface charge of the oil from non-polar to anionic led to increased formation of intermolecular I2-sheet, but it did not improve the emulsion oxidative stability. Lastly, acid hydrolysis of 7S at a similar DH led to flocculation-induced destabilization of the emulsion at pH 3, which exacerbated the intrinsic oxidation of the encapsulated oil even further. Depletion flocculation and bridging were a result of fibril formation during acid hydrolysis.
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