Search Results (157)

Caffeoyl hexapeptide-9 (CH-9) is a novel cosmetic peptide designed by conjugating hexapeptide-9 (H-9), a known collagen-mimetic peptide with established skin anti-aging activity, with caffeic acid (CA) via an amide bond, leveraging peptide-drug conjugate (PDC) design principles. In ultraviolet (UV)-irradiated cellular and skin models, CH-9 outperformed H-9 in preserving cell viability, restoring collagen types I, III, and IV, and suppressing interleukin-6 and -8 secretion. Additionally, its direct antioxidant activity, absent in H-9, was demonstrated in vitro by scavenging of hydroxyl and peroxyl radicals. Molecular docking indicated CH-9 interacted with the catalytic domain of matrix metalloproteinase 2 (MMP2), a key enzyme in collagen degradation during photoaging, suggesting a potential inhibition of its activity. Molecular dynamics (MD) simulations revealed an improved insertion of CH-9 into a stratum corneum (SC) lipid bilayer compared to H-9, consistent with enhanced skin permeation in vivo. Moreover, CH-9 exhibited improved aqueous and cosmetic serum stability over CA. In a 28-day clinical study, topical application of CH-9 significantly improved skin elasticity and firmness compared to H-9. This work demonstrates that the PDC-based conjugate CH-9 combines enhanced anti-photoaging efficacy with improved transdermal permeation and stability, highlighting a promising strategy for the development of advanced cosmetic ingredients. Full article

Wine is a rich source of biologically active compounds, particularly polyphenols, which exhibit antioxidant and antiradical properties. The objective of this study was to optimize the vinification procedures of Polish wines from the hybrid white grape cv. ‘Johanniter’ and red grape cv. ‘Regent’, grown in the temperate climate of central Europe, by applying different skin maceration times: 4, 8, 12, 16, and 20 days. The wines were compared for their basic oenological characteristics and polyphenolic (UHPLC–MS) content as well as their antioxidant (FRAP test) and antiradical (DPPH test, ORAC-fl and EPR spectroscopy) capacities. Both wines demonstrated a substantial increase in their total phenolic content and antioxidant and antiradical capacities after a 4-day maceration; further treatment did not lead to considerable enrichment in bioactive compounds. Scavenging activities against nitroxyl radicals and DPPH were divergent for the tested wines and depended on the analytical method applied, which indicated distinct molecular mechanisms. In turn, the activity of peroxyl radical scavengers, antioxidant capacity, and the total content of phenolics were higher in all the red wine samples. The antioxidant and antiradical properties of the examined wines were comparable or even exceeded those determined for most wines produced in regions with a rich winemaking tradition. Full article

Diseases caused by oxidative stress can present different susceptibilities depending on blood typing according to the ABO system and RhD factor, which turn out to be of great clinical importance. The use of antioxidants such as C-phycocyanin (a phycobiliprotein) could be an alternative to mitigate oxidative stress in the blood. Therefore, the objective of this study is to evaluate the antioxidant and erythroprotective activity of C-phycocyanin (C-PC) from Spirulina sp. against oxidative stress caused by peroxyl radicals, before and after in vitro digestion, comparing susceptibilities between blood groups. C-phycocyanin from Spirulina sp. was obtained commercially. The antioxidant capacity by ABTS+•, DPPH•, and FRAP assays of the bioaccessible fraction of C-PC increased compared to baseline in all assays. Samples appear to have high hydrogen atom transfer. C-PC is not cytotoxic in most blood groups. The AAPH hemolysis assays showed differences between blood groups, yielding results of 27.90, 22.60, 26.94, 27.66, 28.16, 28.34, and 24.91% hemolysis for O+, O−, A+, A−, B+, AB+, and AB−, respectively. Furthermore, in vitro digestion increased the erythroprotective effect in the bioavailable fraction in most blood groups, showing 37.12, 80.13, 5.48, 92.38, 67.93, 80.30, and 76.49% inhibition of hemolysis in O+, O−, A+, A−, B+, AB+, and AB−, respectively. These results demonstrate the biotechnological and biomedical potential of phycobiliproteins as safe candidates for the development of nutraceuticals and functional foods aimed at preventing oxidative damage. Full article

Essential oils (EOs) are complex volatile mixtures that exhibit antioxidant activity through both chemical and biological pathways. Phenolic constituents act as efficient chain-breaking radical-trapping antioxidants, whereas some non-phenolic terpenes operate through distinct mechanisms. Notably, γ-terpinene functions via a “radical export” pathway, generating hydroperoxyl radicals that intercept lipid peroxyl radicals and accelerate chain termination. Recent methodological advances, such as inhibited autoxidation kinetics, oxygen-consumption assays, and fluorescence-based lipid peroxidation probes, have enabled more quantitative evaluation of these activities. Beyond direct radical chemistry, EOs also regulate redox homeostasis by modulating signaling networks such as Nrf2/Keap1, thereby activating antioxidant response element–driven enzymatic defenses in cell and animal models. Phenolic constituents and electrophilic compounds bearing an α,β-unsaturated carbonyl structure may directly activate Nrf2 by modifying Keap1 cysteine residues, whereas non-phenolic terpenes likely depend on oxidative metabolism to form active electrophilic species. Despite broad evidence of antioxidant efficacy, molecular characterization of EO–protein interactions remains limited. This review integrates radical-chain dynamics with redox signaling biology to clarify the mechanistic basis of EO antioxidant activity and to provide a framework for future research. Full article

Chia seed oil, valued for its health-promoting omega-3 and omega-6 fatty acids, is highly susceptible to oxidation. This study employed a multi-technique approach based on electron spin resonance (ESR), low-field nuclear magnetic resonance (LF-NMR), and small-angle X-ray scattering (SAXS) to monitor its oxidative process. ESR identified alkyl (DMPO-•R) and peroxyl (DMPO-•OOR) radicals as primary species derived from unsaturated fatty acids. This was accompanied by a decrease in relaxation time of peak T₂₁, T₂₂, and T₂₃, and the peak area of S₂₁ gradually increased as the heating time increased. The SAXS intensity of chia seed oil at q = 3.4 nm⁻¹ increased markedly after heating for 20 h, and the peak shifted to the low q-region with Δq = 0.6 nm⁻¹, confirming the significant formation of nanoscale aggregates, which correlated with observed increases in oil turbidity. Our findings demonstrate the value of an integrated analytical strategy for a comprehensive understanding of oxidation in chia seed oil. Full article

The ability of ultrasound/peracetic acid (US/PAA) to degrade the azo dye Sunset Yellow FCF (SSY) was evaluated considering the impacts of power, pH, inorganic carbon, common salts, radical scavengers, and real water matrices. Pseudo-first-order rate constants revealed synergy indices of 2.90, 3.28, 2.22, and 2.03 at electrical powers of 40, 60, 80, and 100 W, respectively. Selective scavenger assays revealed a mixed radical regime. ^•OH radical involvement was confirmed by inhibition with alcohols (tert-butanol, 2-propanol), benzoic acid, nitrobenzene, sodium azide, and phenol, while suppression by TEMPO highlighted the key role of PAA-derived acyl and peroxyl radicals. Nitrobenzene caused pronounced inhibition at elevated doses, while nitrite acted as a decisive quencher by converting ^•OH and other oxidants into less reactive species. Carbonate alkalinity exerted dual effects: at acidic pH (3.7–4.4) it diverted ^•OH radicals to carbonate radicals and reduced cavitation through dissolved CO₂, whereas at near-neutral pH it buffered conditions toward the optimum (pH 9) and enhanced degradation. Common anions (chloride, sulfate, nitrate) at ≤10 mM produced minor effects. Tests in environmental waters revealed the following reactivity order: seawater > ultrapure water > tap water ≈ Zamzam water > tertiary effluent. Enhanced performance in seawater was attributed to halide-mediated formation of reactive chlorine and bromine species, while inhibition in effluent was linked to organic matter scavenging. Overall, US/PAA emerges as a robust and adaptable advanced oxidation process for azo dye abatement across diverse water matrices. Full article

With the development of the new energy industry in high-altitude regions, epoxy resin insulating materials in electrical equipment face severe challenges from prolonged exposure to strong radiation environments. Strong ultraviolet irradiation induces the generation of free radicals such as alkyl (CH₂), alkoxy (CH₂O), and peroxyl (CH₂OO), which continuously attack the cross-linking structure of epoxy resin, leading to its degradation. This study employs molecular dynamics simulations to evaluate the enhancing effect of graphene quantum dots (GQDs) on the radiation resistance of epoxy resin (EP), proposing cross-linking structural integrity as an evaluation criterion. It compares and analyses pure EP (EP/neat), hydrogen-terminated GQDs (EP/GQD_C₅₄H₁₈), and carboxyl-terminated GQDs (EP/GQD_COOH) under three types of free radicals. The results indicate that the unique sp² hybrid structure and hydrogen-donating ability of GQDs can effectively inhibit the activity of free radicals, and improve the integrity of the cross-linked structure by 8% to 16% compared to EP/neat. While both types of GQDs demonstrate comparable behavior in response to alkyl free radicals, EP/GQD_COOH exhibits superior performance under the influence of oxygen-containing free radicals. This enhanced performance can be attributed to its augmented hydrogen-donating capacity and an increased number of active sites. This study investigates the extent to which GQDs with different structures enhance the radiation resistance of epoxy resins, providing an important theoretical basis for the modification of epoxy resins for applications in high-radiation environments. Full article

Polyphenolic compounds, commonly found in Greek medicinal plants, exhibit promising antiviral and antioxidant properties, making them potential candidates for therapeutic purposes. This study aims to evaluate the antiviral activity of nine selected polyphenols against Dengue virus (DENV) and Yellow Fever virus (YFV) life cycles, alongside their antioxidant capacity determined by the DPPH method and the ABTS assay, and their ability to inhibit DNA strand scission induced by peroxyl radicals. Kaempferol and caffeic acid demonstrated the most potent inhibitory effects on DENV genome replication, while coumaric acid blocked viral entry more effectively. Notably, among the nine compounds, kaempferol exhibited the strongest anti-DENV effect, especially at the level of virus-released infectivity, showing the lowest EC₅₀ (3.55 μΜ) and the highest selectivity index (SI = 25.45). In contrast, none of the compounds showed significant antiviral activity against YFV genome replication. Concomitantly, caffeic acid and kaempferol had the highest radical scavenging activity (DPPH and ABTS assays), highlighting their dual properties. Moreover, DNA scission inhibition assays confirmed the strong antioxidant potential of all tested compounds, with caffeic acid and kaempferol achieving the highest inhibition rate of 98.98% and 97.34% respectively. These findings underscore the potential of specific polyphenols, particularly kaempferol and caffeic acid, as antiviral and antioxidant agents targeting DENV and oxidative stress-related damage. Full article

In this paper, we aimed to evaluate whether simple, low molecular mass benzoquinone derivatives, featuring different substituents in para- and meta-position relative to the tert-butyl group, possess biological activities against major targets associated with Alzheimer’s disease. The 1,4-benzoquinone derivatives studied herein inhibited both cholinesterases in the micromolar concentration range, generally showing a preference for butyrylcholinesterase over acetylcholinesterase; formed complexes with biometal ions Fe²⁺, Cu²⁺ and Zn²⁺; and displayed a certain BACE1 inhibition. Moreover, the tested compounds displayed certain antioxidant activity via either electron transfer or hydrogen atom transfer mechanisms. The antioxidant capacity of the unsubstituted tert-butyl-1,4-benzoquinone (compound 1) was three times lower than that of the standard antioxidant BHT, while 2,6-disubstituted derivatives (compounds 15 and 7) exhibited peroxyl radical scavenging activity comparable to that of Trolox. Taken together with in silico-predicted low toxicity, good intestinal absorption and favorable oral bioavailability, the presented 1,4-benzoquinone derivatives are promising scaffolds for the design of more complex molecules with enhanced cholinesterase and BACE1 inhibitory activity. Furthermore, they could serve as functional substituents in other structural scaffolds to combine and enhance their biological activities. Full article

Olive mill wastewater (OMW), a byproduct of the olive oil industry, is a potential source of natural bioactive phenolic polymers. In this work, a column chromatography technique was used for the isolation of a new complex polymer (named OMW-2000XAD) from OMW via fractionation on Amberlite^® XAD16 resin. The developed procedure was simple and proved to be reproducible using OMW from two different sources. OMW-2000XAD was further characterized by elemental, glycosidic, and amino acid composition analysis, as well as spectroscopic techniques. The polymer’s molecular size, which was estimated via gel filtration chromatography, was 1960 kDa, which is significantly larger than other high-molecular weight fractions previously isolated from OMW or other agro-industrial wastes. OMW-2000XAD was mainly composed of phenolic compounds (89.8%). It also contained polysaccharides (16.1%) and proteins (10.3%), with glucose (12.25%) and cysteine (1.71%) being the most abundant sugar and amino acid, respectively, as well as metals (1.29%, primarily potassium). However, due to its low solubility, complexity, and heterogeneous composition, it was not possible to identify all phenolic compounds or elucidate a definitive structure via MS, FTIR, and NMR. OMW-2000XAD exhibited strong radical scavenging antioxidant capacity (ABTS^•+, DPPH^• and peroxyl radicals), with results up to 7415 µmol Trolox equivalent/mol (ORAC method), but showed no antiproliferative effects, highlighting the need for further research. Full article

In the present study, we characterized and investigated the effect of the araçá-boi extract on antioxidant activity, cell viability, and the regulation of genes related to tumor suppression and epigenetic mechanisms in ovarian cancer cells. The results showed that araçá-boi extract revealed a remarkable diversity of phytochemicals (organic acids, phenolic acids, and flavonoids), significant antioxidant potential, and efficient scavenging of reactive oxygen species, particularly hydroxyl and peroxyl radicals. Gallic acid, one of the phenolic acids present in the extract, was used alone to verify its contribution to cytotoxic activities. Exposure of human ovarian cancer cells (NCI/ADR-RES and OVCAR3) to the extract (0.15–150 μg/mL) and gallic acid (6–48 μg/mL) resulted in a significant reduction in cell viability, particularly after 48 h of treatment. Both treatments modulated genes involved in DNA repair, tumor suppression, and epigenetic regulation. However, no changes were observed in the methylation status of the BRCA1 gene promoter region with either araçá-boi extract or gallic acid. These findings reinforce the therapeutic potential of araçá-boi extract and its phenolic compounds against ovarian cancer and point to the need for further studies to better elucidate the molecular pathways involved and validate these effects in vivo. Full article

Competitive reactions between additives and probes towards peroxyl radicals (ROO^•) are usually employed to determine the antioxidant activity (AC) of bioactive peptides. In this work, we investigated the AC of free and peptide Trp and Tyr residues, employing pyranine (PYR) as the probe and AAPH (2,2′-azobis(2-methylpropionamidine) dihydrochloride) as the ROO^• source. Solutions containing PYR and 10 mM AAPH were incubated at 37 °C in the absence and presence of additives. The initial consumption rates (R₀) of PYR (5 µM) were affected by the type of peptide, with free Trp showing a higher effect than short peptides (R₀ = Gly-Trp > Gly-Trp-Gly > Trp-Gly > free Trp), while the order of R₀ of Tyr residues was as follows: free Tyr ~ Tyr-Tyr-Tyr > Gly-Tyr. Experiments carried out at 1 µM PYR, and employing larger peptides showed that the AC of Trp and Tyr cannot be explained by a simple mechanism. While the generation of lag times in the kinetics would not be necessarily associated with PYR repairing, their absence would not exclusively reflect competition for ROO^•. These results demonstrate that the AC of Trp and Tyr follows complex mechanisms, implying that particular care should be taken when amino acids and peptides are proposed as antioxidants. Full article

FLASH radiotherapy is a novel irradiation modality that employs ultra-high mean dose rates exceeding 40–150 Gy/s, far surpassing the typical ~0.03 Gy/s used in conventional radiotherapy. This advanced technology delivers high doses of radiation within milliseconds, effectively targeting tumors while minimizing damage to the surrounding healthy tissues. However, the precise mechanism that differentiates responses between tumor and normal tissues is not yet understood. This study primarily examines the ROD hypothesis, which posits that oxygen undergoes transient radiolytic depletion following a radiation pulse. We developed a computational model to investigate the effects of dose rate on radiolysis in an aqueous environment that mimics a confined cellular space subjected to instantaneous pulses of energetic protons. This study employed the multi-track chemistry Monte Carlo simulation code, IONLYS-IRT, which has been optimized to model this radiolysis in a homogeneous and aerated medium. This medium is composed primarily of water, alongside carbon-based biological molecules (RH), radiation-induced bio-radicals (R^●), glutathione (GSH), ascorbate (AH⁻), nitric oxide (^●NO), and α-tocopherol (TOH). Our model closely monitors the temporal variations in these components, specifically focusing on oxygen consumption, from the initial picoseconds to one second after exposure. Simulations reveal that cellular oxygen is transiently depleted primarily through its reaction with R^● radicals, consistent with prior research, but also with glutathione disulfide radical anions (GSSG^●−) in roughly equal proportions. Notably, we show that, contrary to some reports, the peroxyl radicals (ROO^●) formed are not neutralized by recombination reactions. Instead, these radicals are rapidly neutralized by antioxidants present in irradiated cells, with AH⁻ and ^●NO proving to be the most effective in preventing the propagation of harmful peroxidation chain reactions. Moreover, our model identifies a critical dose rate threshold below which the FLASH effect, as predicted by the ROD hypothesis, cannot fully manifest. By comparing our findings with existing experimental data, we determine that the ROD hypothesis alone cannot entirely explain the observed FLASH effect. Our findings indicate that antioxidants might significantly contribute to the FLASH effect by mitigating radiation-induced cellular damage and, in turn, enhancing cellular radioprotection. Additionally, our model lends support to the hypothesis that transient oxygen depletion may partially contribute to the FLASH effect observed in radiotherapy. However, our findings indicate that this mechanism alone is insufficient to fully explain the phenomenon, suggesting the involvement of additional mechanisms or factors and warranting further investigation. Full article

Background: Within the solar ultraviolet (UV) spectrum, ultraviolet A rays (UVA, 320–400 nm), although less energetic than ultraviolet B rays (UVB, 280–320 nm), constitute at least 95% of solar UV radiation that penetrates deep into the skin The UV rays are associated with both epidermal and dermal damage resulting from the generation of reactive oxygen species (ROS). Among them, the longest UVA wavelengths (UVA1, 340–400 nm) can represent up to 75% of the total UV energy. Therefore, UVA radiation is linked to various acute and chronic conditions, including increased skin pigmentation and photoaging. Despite many advances in the skin photoprotection category, there is still a growing demand for natural daily photoprotection active ingredients that offer broad protection against skin damage caused by UVA exposure. In our quest to discover new, disruptive, next generation of photoprotective ingredients, we were drawn to pomegranate, based on its diverse polyphenolic profile. We investigated the pericarp of the fruit, so far considered as byproducts of the pomegranate supply chain, to design a novel patented extract “POMAOX” with a desired spectrum of phenolic components comprising of αβ-punicalagins, αβ-punicalins and ellagic acid. Methods: Antioxidant properties of POMAOX were measured using in-tubo standard tests capable of revealing a battery of radical oxygen species (ROS): peroxyl radical (ORAC), singlet oxygen (SOAC), superoxide anion (SORAC), peroxynitrite (NORAC), and hydroxyl radical (HORAC). In vitro, confirmation of antioxidant properties was first performed by evaluating protection against UVA-induced lipid peroxidation in human dermal fibroblasts (HDF), via the release of 8 iso-prostanes. The protection offered by POMAOX was further validated in a 3D in vitro reconstructed T-Skin^TM model, by analyzing tissue viability/morphology and measuring the release of Matrix Metallopeptidase 1 (MMP-1) & pro-inflammatory mediators (IL-1α, IL-1ra, IL-6, IL-8, GM-CSF, and TNF-α) after UVA1 exposure. Results: POMAOX displayed strong antioxidant activity against peroxynitrite (NORAC) at 1.0–3.0 ppm, comparable to the reference vitaminC, as well as singlet oxygen (SOAC) at 220 ppm, and superoxide radicals with a SORAC value of 500 ppm. Additionally, POMAOX demonstrated strong photoprotection benefit at 0.001% concentration, offering up to 74% protection against UVA-induced lipid peroxidation on HDF, in a similar range as the positive reference, Vitamin E at 0.002% (50 µM), and with higher efficacy than ellagic acid alone at 5 µM. Moreover, our pomegranate-derived extract delivered photoprotection at 0.001%, mitigating dermal damages induced by UVA1, through inhibition of MMP-1 and significant inhibition of pro-inflammatory mediators release (including IL-1α, IL-1ra, IL-6, IL-8, GM-CSF, and TNFα) on an in vitro reconstructed full-thickness human skin model with a similar level of protection to that of Vitamin C tested at 0.035% (200 µM). Conclusions: Overall, the novel pomegranate-derived extract “POMAOX” significantly reduced the impact of UVA on human skin, due to its broad-spectrum antioxidant profile. These findings suggest that POMAOX could offer enhanced protection against the detrimental effects of UV exposure, addressing the growing consumer demand for strong photoprotection with skincare benefits. Full article

In this study, the antioxidant and prooxidant potency of protocatechuic aldehyde (PCA) was evaluated using density functional theory (DFT). The potency of direct scavenging of hydroperoxyl (HOO^•) and lipid peroxyl radicals (modeled by vinyl peroxyl, H₂C=CHOO^•) involved in lipid peroxidation was estimated. The repair of oxidative damage in biomolecules (lipids, proteins and nucleic acids) and the prooxidant ability of PCA phenoxyl radicals were considered. The repairing potency of PCA was investigated for damaged tryptophan, cysteine, leucine, DNA base guanine and linolenic acid. The thermodynamics and kinetics of the single electron transfer (SET) and formal hydrogen atom transfer (fHAT) mechanisms underlying the studied processes were investigated under physiological conditions in aqueous and lipid environments using the SMD/M06-2X/6-311++G(d,p) level of theory. Sequestration of catalytic Fe²⁺ and Fe³⁺ ions by PCA, which prevents HO^• production via Fenton-like reactions, was modeled. Molecular docking was used to study the inhibitory capability of PCA against xanthine oxidase (XO), one of the enzymes producing reactive oxygen species. The attained results show that PCA has the capability to scavenge lipid peroxyl radicals, repair damaged tryptophan, leucine and guanine, chelate catalytic iron ions and inhibit XO. Thus, PCA could be considered a possible multifunctional antioxidant. Full article