Search Results (28)

The development of ceria (CeO_2−x)-based nanoantioxidants requires fine-tuning of structural and surface properties for enhancing antioxidant behavior in biological environments. In this contest, here ultrasmall water-dispersible CeO_2−x nanoparticles (NPs), characterized by a high Ce³⁺/Ce⁴⁺ ratio, were synthesized in a non-polar solvent and phase-transfer to an aqueous environment through ligand-exchange reactions using citric acid (CeO_2−x@Cit) and post-treatment with dopamine hydrochloride (CeO_2−x@Dopa). The concept behind this work is to enhance via surface engineering the intrinsic antioxidant properties of CeO_2−x NPs. For this purpose, thanks to electron transfer reactions between dopamine and CeO_2−x, the CeO_2−x@Dopa was obtained, characterized by increased surface Ce³⁺ sites and surface functionalized with polydopamine bearing o-quinone structures as demonstrated by complementary spectroscopic (UV–vis, FT-IR, and XPS) characterizations. To test the antioxidant properties of CeO_2−x NPs, the scavenging activity before and after dopamine treatment against artificial radical 1,1-diphenyl-2-picrylhydrazyl (DPPH^·) and the ability to reduce the reactive oxygen species in Diencephalic Immortalized Type Neural Cell line 1 were evaluated. CeO_2−x@Dopa demonstrated less efficiency in DPPH^· scavenging (%radical scavenging activity 13% versus 42% for CeO_2−x@Cit before dopamine treatment at 33 μM DPPH^· and 0.13 mg/mL loading of NPs), while it markedly reduced intracellular ROS levels (ROS production 35% compared to 66% of CeO_2−x@Cit before dopamine treatment with respect to control—p < 0.001 and p < 0.01, respectively). While steric hindrance from the dopamine-derived polymer layer limited direct electron transfer from CeO_2−x NP surface to DPPH^·, within cells the presence of o-quinone groups contributed with CeO_2−x NPs to break the autoxidation chain of organic substrates, enhancing the antioxidant activity. The functionalization of NPs with o-quinone structures represents a valuable approach to increase the inherent antioxidant properties of CeO_2−x NPs, enhancing their effectiveness in biological systems by promoting additional redox pathways. Full article

In this study, microwave-assisted extraction (MAE) was performed to recover antioxidant hemp seed oil (HSO) with the purpose of developing polybutylene succinate (PBS)/HSO-based films for active packaging to improve food shelf-life. It was found that MAE achieved comparable yields, structural characteristics, and antioxidant activity to Soxhlet extraction, but in significantly less time (2.5 min vs. 6 h). PBS-based films with 0.5 and 1 wt% HSO were prepared by compression molding. Morphological investigation of the PBS-HSO films highlighted uniform oil droplet dispersion and good compatibility. HSO reduced PBS crystallinity but did not affect the α-form of PBS. Thermal analysis showed reductions in T_m and T_c, whereas T_g remained unchanged at −17 °C. PBS containing 1 wt% HSO exhibited a 42% decrease in Young’s modulus, 47% reduction in elongation at break, and 47% decrease in tensile strength due to the plasticizing effect of the oil and, which reduced the intermolecular forces and facilitated polymer chain disentanglement, in agreement with the FTIR analysis, which showed a distinct broadening of the carbonyl stretching region associated with the amorphous phase (1720–1730 cm⁻¹) in the PBS-HSO films compared to neat PBS. Migration tests showed that the films are unsuitable for fatty foods but safe for aqueous, acidic, and alcoholic foods. Full article

Increasing interest is being devoted to innovative food products enriched with fruits and vegetables to enhance the nutritional and bioactive properties from the perspective of sustainable management. The addition (10, 15, and 20%) of blueberry fruits derived from two spontaneous flora varieties from the Rarău (G) and Ciocănești (C) mountains (Romania) into ‘French’ bread resulted in increased maximum breaking strength and mechanical work in spherical dough up to 10 and 15% in variety G, and deformation strength up to 20% integration; the untreated control displayed the highest values in the strips of dough. The 20% incorporation of both blueberry varieties in bread enhanced total, open, and closed porosity, maximum strength, gummosity, and chewiness, as well as titratable acidity, total soluble solids, vitamin C, flavonoids, anthocyanins, and antioxidant activity. Resilience and pH showed the highest levels in the untreated bread, which also exhibited the highest values of the color components ‘L’, ‘a’, and ‘b’ in both the bread crust and crumb. The untreated control showed the highest scores for some sensory features, and in most cases, an increasing trend with the fruit integration rising from 10 to 20% was recorded. The addition of blueberries represents an interesting strategy for creating bread as an innovative functional food under sustainable supply chain management. Full article

This study focuses on developing an active and biodegradable packaging using electrospinning, with polylactic acid (PLA) as the matrix and bamboo leaf extract (BLE) as the antioxidant compound. The research systematically evaluates the relationship among process parameters, material properties, and structure. The electrospun membranes were produced using different BLE contents (10 wt%, 20 wt%, 30 wt%, and 40 wt%) and characterized by their morphology, mechanical properties, wettability, and antioxidant activity. Scanning electron microscopy (SEM) revealed BLE’s influence on fiber morphology, with a slight increase in diameter in PLA/BLE at 10% and 20%, attributed to higher viscosity. Conversely, PLA/BLE 30% and 40% showed a mild reduction in fiber diameter likely due to polyphenols’ capacity to enhance PLA chain mobility. Mechanical tests indicated proportional reductions in modulus, maximum stress, and strain at break, upon increasing the BLE concentration, although these parameters are still suitable for packaging applications. The decrease in modulus is attributed to polyphenol capacity to increase PLA chain mobility, while increased fragility results from embedded particles acting as local defects. Wettability tests demonstrated increased hydrophilicity with higher BLE content. Total polyphenol content, estimated through FOLIN assay, increased proportionally with incorporated BLE, impacting antioxidant properties assessed via FRAP assay. Full article

The incorporation of biopolymers and natural colorants in smart packaging has garnered significant attention in the food packaging industry. This study investigates the design and characterization of novel fibrous films incorporating betalain extract (BE) from Stenocereus thurberi in poly (lactic acid) (PLA). An electrospinning technique was developed with varying PLA concentrations (2%–12% w/v) and BE concentrations (8%–12% w/v) to create a colorimetric freshness indicator. BE was characterized by quantifying its phytochemical content and assessing its antioxidant capacity. Morphological and structural analyses included scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), polydispersity index (PI), mechanical properties, and functional characteristics such as ammonia sensitivity and total antioxidant activity. The results indicated that the incorporation of BE significantly influenced the average diameter of the nanofibers, ranging from 313 ± 74 nm to 657 ± 99 nm. SEM micrographs showed that PLA12-BE12 films exhibited smooth surfaces without bead formation. The FTIR analysis confirmed effective BE incorporation, revealing intermolecular interactions between the betalain molecules and the PLA matrix, which contributed to enhanced structural and functional stability. The mechanical properties analysis revealed that moderate BE additions (8%–10% w/v) enhanced the Young’s modulus and tensile strength, while higher BE concentrations (12% w/v) disrupted the polymer network, reducing these properties. Additionally, the strain at break decreased significantly with BE incorporation, reflecting limited molecular chain mobility. Increasing BE concentration notably improved antioxidant activity, with the BE concentration of 12% (w/v), the ABTS•+, DPPH•, and FRAP radical scavenging activities at the highest values of 84.28 ± 1.59%, 29.95 ± 0.34%, and 710.57 ± 28.90 µM ET/g, respectively. Ammonia sensitivity tests demonstrated a significant halochromic transition from reddish-pink to yellow, indicating high sensitivity to low ammonia concentrations. The possible mechanism is alkaline pH induces aldimine bond hydrolysis and generates betalamic acid (yellow) and cyclo-DOPA-5-O-ß-glucoside (colorless) The fibrous films also exhibited reversible color changes and maintained good color stability over 30 days, emphasizing their potential for use in smart packaging applications for real-time freshness monitoring and food quality assessment. Full article

Nowadays, incorporating quaternary ammonium groups into polymers is one of the most promising strategies for preparing antimicrobial biomaterials for general applications. The main objective of this work was to evaluate the effect of different concentrations of antimicrobial quaternary polymers in gelatin- and starch-based films for the development of active materials intended for applications in food packaging and medical fields. Two antimicrobial biobased polymers, called MeFPIAx (MeFPIA1 and MeFPIA2), were previously synthesized through the radical polymerization of itaconic acid (IA), followed by their subsequent functionalization and modification. Both polymers were incorporated into a new blend of gelatin and starch (15% w/w, 4:1 mass ratio), using glycerol (30% w/w) as a plasticizer. Films were prepared using the casting technique from aqueous dispersions of the polymers and their structure was characterized by Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR). The findings of this study showed the addition of MeFPIAx had a significant effect (p < 0.05), resulting in films with higher tensile strength (TS) and a higher Young’s modulus (YM), with values close to 20 MPa and exceeding 250 MPa, respectively. On the other hand, elongation at break (EB) values lower than 80% were obtained. Additionally, the swelling was reduced from ~400% to 100% and a reduction in water vapor permeability (P_w) was observed, thanks to the increased interaction between the polymeric chains. Differential scanning calorimetry (DSC) scans showed that the addition of MeFPIAx increased the glass transition temperatures (T_g) from 29 °C to 65 °C. Furthermore, thermogravimetry analysis (TGA) indicated an increase in the initial degradation temperatures, suggesting that the films were more thermally resistant. Finally, the films exhibited slight antioxidant activity but significant antimicrobial activity, achieving bacterial reduction values greater than 70% with the incorporation of MeFPIAx polymers against Gram-positive Staphylococcus aureus. Full article

The residues from selenium-enriched Cardamine violifolia after the extraction of protein were still rich in polysaccharides. Thus, the recovery of selenium polysaccharides (SePSs) was compared using hot water extraction and ultrasonic-assisted extraction techniques. The yield, extraction rate, purity, specific energy consumption, and content of total and organic selenium from different SePS extracts were determined. The results indicated that at conditions of 250 W (ultrasonic power), 30 °C, and a liquid-to-material ratio of 30:1 extracted for 60 min, the yield of SePSs was 3.97 $\pm$ 0.07%, the extraction rate was 22.76 $\pm$ 0.40%, and the purity was 65.56 $\pm$ 0.35%, while the total and organic selenium content was 749.16 $\pm$ 6.91 mg/kg and 628.37 $\pm$ 5.93 mg/kg, respectively. Compared to traditional hot water extraction, ultrasonic-assisted extraction significantly improves efficiency, reduces energy use, and boosts both total and organic selenium content in the extract. Measurements of particle size, molecular weight, and monosaccharide composition, along with infrared and ultraviolet spectroscopy, revealed that ultrasonic-assisted extraction breaks down long-chain structures, decreases particle size, and changes monosaccharide composition in SePSs, leading to lower molecular weight and reduced dispersity. The unique structure of SePSs, which integrates selenium with polysaccharide groups, results in markedly improved antioxidant activity and reducing power, even at low concentrations, due to the synergistic effects of selenium and polysaccharides. This study establishes a basis for using SePSs in functional foods. Full article

Enhancing the productivity and bioactivity of high-functional foods holds great significance. Carbon nanoparticles (CNPs) have a recognized capacity for boosting both plant growth and the efficacy of primary and secondary metabolites. Furthermore, while salinity diminishes plant growth, it concurrently amplifies the production of phytomolecules. To ensure the robust and sustainable production of nutritious food, it becomes essential to elevate biomolecule yield without compromising plant growth. Here, we assessed the CNPs priming on plant performance and metabolites of the glycophyte amaranth (Amaranthus hypochondriacus) sprouts at the threshold salinity (25 mM NaCl; i.e., salinity that does not reduce growth but enhances the metabolites of that plant). We measured growth parameters, pigment levels, and primary (carbohydrates, amino acids, organic acids, fatty acids) and secondary metabolites (phenolics, flavonoids, tocopherols). CNP priming significantly improved biomass accumulation (fresh and dry weight) and primary and secondary metabolites of amaranth sprouts. Increased photosynthetic pigments can explain these increases in photosynthesis. Enhanced photosynthesis induced carbohydrate production, providing a C source for producing bioactive primary and secondary metabolites. The priming effect of CNPs further enhanced the accumulation of essential amino acids, organic acids, unsaturated fatty acids, tocopherols, and phenolics at threshold salinity. The increase in bioactive metabolites under threshold salinity can explain the CNP priming impact on boosting the antioxidant activities (FRAP, DPPH, anti-lipid peroxidation, superoxide-anion-scavenger, hydroxyl-radical-scavenger, Fe-chelating and chain-breaking activity in aqueous and lipid phases) and antimicrobial activities against Gram-positive and Gram-negative bacteria and fungi. Overall, this study suggested that threshold salinity and CNP priming could be useful for enhancing amaranth sprouts’ growth and nutritional quality. Full article

Butein (BU) and homobutein (HB) are bioactive polyhydroxylated chalcones widespread in dietary plants, whose antioxidant properties require mechanistic definition. They were investigated by inhibited autoxidation kinetic studies of methyl linoleate in Triton™ X-100 micelles at pH 7.4, 37 °C. Butein had k_inh = (3.0 ± 0.9) × 10⁴ M⁻¹s⁻¹ showing a chain-breaking mechanism with higher antioxidant activity than reference α-tocopherol (k_inh = (2.2 ± 0.6) × 10⁴ M⁻¹s⁻¹), particularly concerning the stoichiometry or peroxyl radical trapping n = 3.7 ± 1.1 vs. 2.0 for tocopherol. Homobutein had k_inh = (2.8 ± 0.9) × 10³ M⁻¹s⁻¹, pairing the relative BDE_OH measured by radical equilibration EPR as 78.4 ± 0.2 kcal/mol for BU and estimated as 82.6 kcal/mol for HB. The inhibition of mushroom tyrosinase (mTYR) by HB and BU was also investigated. BU gives a reversible uncompetitive inhibition of monophenolase reaction with K_I′ = 9.95 ± 2.69 µM and mixed-type diphenolase inhibition with K_I = 3.30 ± 0.75 µM and K_I′ = 18.75 ± 5.15 µM, while HB was nearly competitive toward both mono- and diphenolase with respective K_I of 2.76 ± 0.70 µM and 2.50 ± 1.56 µM. IC₅₀ values (monophenolase/diphenolase at 1 mM substrate) were 10.88 ± 2.19 µM/15.20 ± 1.25 µM, 14.78 ± 1.05 µM/12.36 ± 2.00 µM, and 33.14 ± 5.03 µM/18.27 ± 3.42 µM, respectively, for BU, HB, and reference kojic acid. Molecular docking studies confirmed the mechanism. Results indicate very potent antioxidant activity for BU and potent anti-tyrosinase activity for both chalcones, which is discussed in relation to bioactivity toward protection from skin disorders and food oxidative spoilage. Full article

The quality of surimi gel can be improved using protein cross-linkers, especially from plant extracts. Apart from the presence of phenolic compounds, Duea ching fruit is rich in calcium, which can activate indigenous transglutaminase or form the salt bridge between protein chains. Its extract can serve as a potential additive for surimi. The effect of different media for the extraction of Duea ching was studied and the use of the extract in sardine surimi gel was also investigated. The Duea ching fruit extract (DCE) was prepared using distilled water and ethanol (EtOH) at varying concentrations. The DCE prepared using 60% EtOH (DCE-60) had the highest antioxidant activity and total phenolic content. When DCE-60 (0–0.125%; w/w) was added to the sardine surimi gel, the breaking force (BF), deformation (DF) and water holding capacity (WHC) of the gel upsurged and the highest values were attained with the 0.05% DCE-60 addition (p < 0.05). However, the whiteness of the gel decreased when DCE-60 levels were augmented. The gel containing 0.05% DCE-60, namely D60-0.05, showed a denser network and had a higher overall likeness score than the control. When the D60-0.05 gel was packed in air, under vacuum or modified atmospheric packaging and stored at 4 °C, BF, DF, WHC and whiteness gradually decreased throughout 12 days of storage. However, the D60-0.05 gel sample showed lower deterioration than the control, regardless of the packaging. Moreover, the gel packaged under vacuum conditions showed the lowest reduction in properties throughout the storage than those packaged with another two conditions. Thus, the incorporation of 0.05% DCE-60 could improve the properties of sardine surimi gel and the deterioration of the resulting gel was retarded when stored at 4 °C under vacuum packaging conditions. Full article

Blends based on polylactic acid (PLA), chitosan, and grape seed extract (GE) were prepared by extrusion and injection molding. The effect of chitosan (5% and 15% on PLA basis) and natural extract (1% on PLA basis) incorporated into the PLA host matrix was explored regarding the thermal and mechanical properties. GE showed antioxidant activity, as determined by the DPPH assay method. Chitosan and GE affect the degree of crystallinity up to 30% as the polysaccharide acts as a nucleating agent, while the extract reduces the mobility of PLA chains. The decomposition temperature was mainly affected by adding chitosan, with a reduction of up to 25 °C. The color of the blends was specially modified after the incorporation of both components, obtaining high values of b* and L* after the addition of chitosan, while GE switched to high values of a*. The elongation at break (EB) exhibited that the polysaccharide is mainly responsible for its reduction of around 50%. Slight differences were accessed in tensile strength and Young’s modulus, which were not statistically significant. Blends showed increased irregularities in their surface appearance, as observed by SEM analysis, corresponding to the partial miscibility of both polymers. Full article

Honokiol is a natural bisphenol neolignan present in the bark of Magnolia officinalis, whose extracts have been employed in oriental medicine to treat several disorders, showing a variety of biological properties, including antitumor activity, potentially related to radical scavenging. Six bisphenol neolignans with structural motifs related to the natural bioactive honokiol were synthesized. Their chain-breaking antioxidant activity was evaluated in the presence of peroxyl (ROO•) and hydroperoxyl (HOO•) radicals by both experimental and computational methods. Depending on the number and position of the hydroxyl and alkyl groups present on the molecules, these derivatives are more or less effective than the reference natural compound. The rate constant of the reaction with ROO• radicals for compound 7 is two orders of magnitude greater than that of honokiol. Moreover, for compounds displaying quinonic oxidized forms, we demonstrate that the addition of 1,4 cyclohexadiene, able to generate HOO• radicals, restores their antioxidant activity, because of the reducing capability of the HOO• radicals. The antioxidant activity of the oxidized compounds in combination with 1,4-cyclohexadiene is, in some cases, greater than that found for the starting compounds towards the peroxyl radicals. This synergy can be applied to maximize the performances of these new bisphenol neolignans. Full article

Superparamagnetic iron oxide nanoparticles (SPION) are important materials for biomedical applications, and phenol capping is a common procedure to passivate their surface. As phenol capped SPION have been reported to behave as antioxidants, herein, we investigate the mechanism underlying this activity by studying the reaction with alkyl peroxyl (ROO^•) radicals. SPION were prepared by coprecipitation of Fe(II) and Fe(III), using phenolic antioxidants (gallic acid, Trolox and nordihydroguaiaretic acid) as post-synthesis capping agents and by different purification procedures. The reactivity of ROO^• was investigated by inhibited autoxidation studies, using styrene as an oxidizable substrate (solvent MeCN, 30 °C) and azo-bis(isobutyronitrile) as a radical initiator. While unprotected, bare SPION behaved as prooxidant, accelerating the O₂ consumption of styrene autoxidation, phenol capping provided a variable antioxidant effect that was dependent upon the purification degree of the material. Thoroughly washed SPION, containing from 7% to 14% (w/w) of phenols, had a low reactivity toward peroxyl radicals, while SPION with a higher phenol content (46% to 55%) showed a strong radical trapping activity. Our results indicate that the antioxidant activity of phenol-capped SPION can be caused by its release in a solution of weakly bound phenols, and that purification plays a major role in determining the properties of these materials. Full article

The activity of natural phenols is primarily associated to their antioxidant potential, but is ultimately expressed in a variety of biological effects. Molecular scaffold manipulation of this large variety of compounds is a currently pursued approach to boost or modulate their properties. Insertion of S/Se/Te containing substituents on phenols may increase/decrease their H-donor/acceptor ability by electronic and stereo-electronic effects related to the site of substitution and geometrical constrains. Oxygen to sulphur/selenium isosteric replacement in resveratrol or ferulic acid leads to an increase in the radical scavenging activity with respect to the parent phenol. Several chalcogen-substituted phenols inspired by Vitamin E and flavonoids have been prepared, which in some cases prove to be chain-breaking antioxidants, far better than the natural counterparts. Conjugation of catechols with biological thiols (cysteine, glutathione, dihydrolipoic acid) is easily achieved by addition to the corresponding ortho-quinones. Noticeable examples of compounds with potentiated antioxidant activities are the human metabolite 5-S-cysteinyldopa, with high iron-induced lipid peroxidation inhibitory activity, due to strong iron (III) binding, 5-S-glutathionylpiceatannol a most effective inhibitor of nitrosation processes, and 5-S-lipoylhydroxytyrosol, and its polysulfides that proved valuable oxidative-stress protective agents in various cellular models. Different methodologies have been used for evaluation of the antioxidant power of these compounds against the parent compounds. These include kinetics of inhibition of lipid peroxidation alkylperoxyl radicals, common chemical assays of radical scavenging, inhibition of the OH• mediated hydroxylation/oxidation of model systems, ferric- or copper-reducing power, scavenging of nitrosating species. In addition, computational methods allowed researchers to determine the Bond Dissociation Enthalpy values of the OH groups of chalcogen modified phenolics and predict the best performing derivative. Finally, the activity of Se and Te containing compounds as mimic of glutathione peroxidase has been evaluated, together with other biological activities including anticancer action and (neuro)protective effects in various cellular models. These and other achievements are discussed and rationalized to guide future development in the field. Full article

In the minireview presented here, the authors discuss the evaluation of inhibitory effect of substances in the phases of initiation and propagation of high-molar-mass hyaluronan oxidative degradation. The experimental approach should be considered as original since on using a simple experimental assay it is possible to prove both the so-called “preventive” and “chain-breaking” antioxidant activity of investigated water-soluble endo- or exogenous substances. Full article