The present article is devoted to searching for biologically active agents among novel thio‐containing pteridines. Synthetic protocols based on the condensation of ...5,6‐diamino‐2‐thioxo‐2,3‐dihydropyrimidin‐4(1H)‐ones with dicarbonyl compounds were elaborated and used for the synthesis of target products. The directions for further modification of the obtained thio‐containing pteridines were substantiated and realized. The spectral properties of the obtained compounds were studied and described. The results of the in silico study revealed that the predicted affinity of the obtained compounds to the dihydrofolate reductase (DHFR) active site is comparable with the affinity of methotrexate, despite the differences in the nature of the ligand–enzyme interactions. The in vitro study of DHFR‐inhibiting activity revealed that the most active compounds 3.9 and 4.2 have lg IC50 values of −5.889 and −5.233, respectively, significantly inferior to methotrexate (lg IC50 = −7.605). Additionally, the synthesized compounds were studied for their antiradical activity as a possible mechanism of pharmacological effects. Among the obtained pteridines, compounds 5.1 (lg EC50 = −4.82) and 5.3 (lg EC50= −4.92) have antiradical activity higher than the reference compound ascorbic acid (lg EC50= −4.81). The conducted structure–activity relationship analysis provided valuable data for the further search for biologically active agents among thio‐containing pteridines and related compounds.
Novel thio‐containing pteridines were obtained and assessed for their dihydrofolate reductase (DHFR)‐inhibitory activity. The affinity of the obtained compounds to the DHFR active site is comparable to that of methotrexate. Some of the obtained compounds exhibited moderate DHFR‐inhibiting activity. Compounds 5.1 and 5.3 have antiradical activity higher than the reference compound ascorbic acid.
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Photothermal therapy (PTT) has gained widespread attention due to its significant advantages, such as noninvasiveness and ability to perform laser localization. However, PTT usually ...reaches temperatures exceeding 50 °C, which causes tumor coagulation necrosis and unfavorable inflammatory reactions, ultimately decreasing its efficacy. In this study, multifunctional two-dimensional Bi2Se3 nanodisks were synthesized as noninflammatory photothermal agents for glioma therapy. The Bi2Se3 nanodisks showed high photothermal stability and biocompatibility and no apparent toxicology. In addition, in vitro and in vivo studies revealed that the Bi2Se3 nanodisks effectively ablated gliomas at relatively low concentrations and inhibited tumor proliferation and migration. Moreover, the multienzymatic activity of the Bi2Se3 nanodisks inhibited the PTT-induced inflammatory response through their high ability to scavenge reactive oxygen species. Finally, the Bi2Se3 nanodisks demonstrated computed tomography capabilities for integrating diagnosis and treatment. These findings suggest that multifunctional Bi2Se3 nanodisk nanozymes can enable more effective cancer therapy and noninflammatory PTT.
AbstractThere is considerable interest in identifying new antioxidants from plant materials. Several studies have emphasized the antioxidant activity of species belonging to the Myrtaceae family. ...However, there are few reports on these species from the Cerrado (Brazilian savanna). In this study, the antioxidant activity and phenolic content of 12 native Myrtaceae species from the Cerrado were evaluated (Blepharocalyx salicifolius, Eugenia bimarginata, Eugenia dysenterica, Eugenia klotzschiana, Hexachlamys edulis, Myrcia bella, Myrcia lingua, Myrcia splendens, Myrcia tomentosa, Psidium australe, Psidium cinereum, and Psidium laruotteanum). Antioxidant potential was assessed using the antioxidant activity index (AAI) by the DPPH method and total phenolic content (TPC) by the Folin-Ciocalteu assay. There was a high correlation between TPC and AAI values. Psidium laruotteanum showed the highest TPC (576.56 mg GAE/g extract) and was the most potent antioxidant (AAI = 7.97, IC50 = 3.86 µg·mL-1), with activity close to that of pure quercetin (IC50 = 2.99 µg·mL-1). The extracts of nine species showed IC50 of 6.24-8.75 µg·mL-1. Most species showed TPC and AAI values similar to or higher than those for Camellia sinensis, a commonly consumed tea with strong antioxidant properties. The results reveal that the analyzed Myrtaceae species from the Cerrado possess high phenolic contents and antioxidant activities. Thus, they are a potential source of new natural antioxidants.
Melanins are ancient biological pigments found in all kingdoms of life. In fungi, their role in microbial pathogenesis is well established; however, these complex biomolecules also confer upon fungal ...microorganisms the faculty to tolerate extreme environments such as the Earth's poles, the International Space Station and places contaminated by toxic metals and ionizing radiation. A remarkable property of melanin is its capacity to interact with a wide range of electromagnetic radiation frequencies, functioning as a protecting and energy harvesting pigment. Other roles of fungal melanin include scavenging of free radical, thermo-tolerance, metal ion sequestration, cell development, and mechanical-chemical cellular strength. In this review, we explore the various functions ascribed to this biological pigment in fungi and its remarkable physicochemical properties.
Functions of fungal melanin. Fungal melanins play multiple biological functions including photoprotection, energy harvest and thermoregulation by readily absorbing and transducing electromagnetic radiation. Fungal melanins also function in free radical and metal binding; protection against dehydration, chemical and mechanical stressors; and fungal development and conidiation. Display omitted
•Melanins play multiple ecological and biochemical functions in living organisms.•Black fungi are polyextremophiles.•Fungal melanins protect against many physical and chemical environmental stressors.•The physicochemical properties of fungal melanins many differ among species.
•A novel peptide ATVY demonstrating high scavenging activity to ABTS was purified.•The crucial amino acid as key action site in ATVY was Tyr in N-terminal.•The scavenging kinetics of ATVY on ABTS ...demonstrated a two-phase reaction process.•ABTS+-Peptide was formed by covalently bonding through phenol group of ATVY to ABTS.•ATVY can be used as a natural agent in controlling food oxidation in food industry.
Marine byproducts have become popular research themes due to their biological significance. The black sharkskin protein hydrolysate-based antioxidant peptides were firstly investigated in this study. The black sharkskin-derived novel antioxidant peptide demonstrating 81.05% free radical scavenging activity to ABTS at 500 μg/mL, was identified to be Ala-Thr-Val-Tyr (ATVY). The crucially antioxidant interaction site of ATVY action on ABTS was determined to be Tyr in the N-terminal. ATVY reacted with ABTS to generate polyphenol-derived adducts which subsequently degraded into a purple compound. The MS/MS showed it was formed by covalently bonding through the phenol group of ATVY to the N group of ABTS. The free radical scavenging kinetics of ATVY on ABTS demonstrated a two-phase reaction process. These findings reveal the action mechanism of ATVY on ABTS, implying ATVY can be incorporated in the production of antioxidant food additives.
Unsaturated lipids undergo radical-initiated oxidative deterioration during lipid oxidation, which is one of the most significant food quality and waste issues. Lipid oxidation results in ...off-flavors, toxic aldehydes, and the co-oxidation of proteins and color compounds. Various antioxidant strategies are utilized by the food industry to reduce lipid oxidation and increase shelf-life. Combining antioxidants to achieve synergistic interactions has been practiced for decades to improve oxidative stability. Nevertheless, underlying mechanisms of synergistic interactions between antioxidants are poorly understood and rarely studied.
This review examines the main hypothesized mechanisms of antioxidant synergism, which include: 1) Regeneration of an oxidized antioxidant by another compound, 2) Differences in antioxidant partitioning in homogeneous and heterogeneous systems, 3) Combination of free radical scavenging and metal chelating activities to provide two distinct protection pathways, and 4) Formation of additional antioxidant compounds, such as phenolics, dimers, or adducts, upon oxidation which can further inhibit lipid oxidation.
In complex food systems, it is often difficult to predict which antioxidant combinations will work synergistically. Understanding the mechanisms of synergism will aid the food industry in the production of effective antioxidant mixtures to improve oxidative stability and shelf-life, as well as in the development of simple, rapid, and reliable methods for determining and evaluating synergism.
•Discussion of the mechanisms behind synergistic antioxidant interactions in foods.•Free radical scavengers can regenerate each other due to redox cycling.•The physical structures influence the partitioning and activity of antioxidants.•Free radical scavengers and metal chelators can be combined for synergistic effect.•Main antioxidants can generate additional antioxidants upon decomposition.
•Twenty-four accessions of Damask rose has been studied.•Based on essential oil HCA and PCA were classified accessions into seven chemotypes.•Two chemotypes of geraniol with 55 and 49% have been ...introduced.•Damask rose petals had a high content of total phenol, flavonoid, and antioxidant activity.•IC50 of methanolic extracts from DPPH of petals samples was lower than ascorbic acid.
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In the present study, the percentage, and compositions of essential oil, total phenol, flavonoids, anthocyanins, carotenoids and antioxidant capacity of 24 accessions of cultivated Damask rose have been investigated. These accessions had a 0.010–0.055 (v/w) percentage of essential oil. GC/MS analysis revealed forty-nine constituents that formed more than 90% of detected compounds. Geraniol, citral, methyl linoleate, n-heneicosane, and n-octane were the major components of essential oils. Acc.1 had the highest total phenol (165 mg Gallic acid/g DW) and flavonoid content (81 mg Quercetin/g DW). Total anthocyanin ranged from 0.5 to 3.5 (mg cyanidin-3-glucoside/g DW). Carotenoid content ranged from 0.002 to 0.055 mg/g DW, the highest being observed in Acc.18. Based on cluster analysis and, the accessions were categorized into seven groups. The antioxidant activities of the samples were determined using DPPH free radical scavenging activity and ferric reducing antioxidant power (FRAP) assay. All the accessions (4–12 µg/ml) had lower IC50 than ascorbic acid (18 µg/ml). In FRAP assay, they had high antioxidant activity in a range of 10–25 µmol Fe+2/g DW. Based on the high and valuable source of bioactive compounds of Damask rose the elite accessions can be recommended for boosting cultivation and food applications.
Small molecule, dietary antioxidants exert a remarkably broad range of bioactivities, and many of these can be explained by the influence of antioxidants on the redox homeostasis. Such compounds help ...to modulate the levels of harmful reactive oxygen/nitrogen species, and therefore participate in the regulation of various redox signaling pathways. However, upon ingestion, antioxidants usually undergo extensive metabolism that can generate a wide range of bioactive metabolites. This makes it difficult, but otherwise a need, to identify the ones responsible for the different activities of antioxidants. By better understanding their ways of action, the use of antioxidants in therapy can be improved.
This review provides a summary on the role of the in vivo metabolic changes and the oxidized metabolites on the mechanisms behind the bioactivity of antioxidants. A special attention is given to metabolites described as products of biomimetic oxidative chemical reactions, which can be considered as models of free radical scavenging. During such reactions a wide variety of metabolites are formed, and they can exert completely different specific bioactivities as compared to their parent antioxidants. This implies that exploring the free radical scavenging‐related metabolite fingerprint of each antioxidant molecule, collectively defined here as the scavengome, will lead to a deeper understanding of the bioactivity of these compounds.
Furthermore, this paper aims to be a working tool for systematic studies on oxidized metabolic fingerprints of antioxidants, which will certainly reveal an often‐neglected segment of chemical space that is a treasury of bioactive compounds.
The use of
might be beneficial in inflammatory illnesses and can be used for a variety of health conditions. In this article, we studied the identification of antioxidants using (DPPH) ...2,2-Diphenyl-1-picrylhydrazylradical scavenging activity in
, as
is an important herbal plant, and every part of it has various medicinal properties such as antibacterial properties that can be used by the researchers in the development and design of various new drugs. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) is a popular, quick, easy, and affordable approach for the measurement of antioxidant properties that includes the use of the free radicals used for assessing the potential of substances to serve as hydrogen providers or free-radical scavengers (FRS). The technique of DPPH testing is associated with the elimination of DPPH, which would be a stabilized free radical. The free-radical DPPH interacts with an odd electron to yield a strong absorbance at 517 nm, i.e., a purple hue. An FRS antioxidant, for example, reacts to DPPH to form DPPHH, which has a lower absorbance than DPPH because of the lower amount of hydrogen. It is radical in comparison to the DPPH-H form, because it causes decolorization, or a yellow hue, as the number of electrons absorbed increases. Decolorization affects the lowering capacity significantly. As soon as the DPPH solutions are combined with the hydrogen atom source, the lower state of diphenylpicrylhydrazine is formed, shedding its violet color. To explain the processes behind the DPPH tests, as well as their applicability to
(
) in the manufacture of metal oxide nanoparticles, in particular MgO, and their influence on antioxidants, a specimen from the test was chosen for further study. According to our findings,
has antioxidant qualities and may be useful in the treatment of disorders caused by free radicals.
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