Efficient Radical Scavenger Research Articles

Chlorogenic acid-chitosan copolymers: Synthesis, characterization and application in O/W emulsions for enhanced β-carotene stability

In this study, chlorogenic acid-chitosan (CA-CS) copolymers were prepared with varying Chitosan (CS): chlorogenic acid (CA)ratios and characterized for their water solubility, antioxidant capacity, and emulsions stability. Results showed that CA-CS samples exhibited up to 90.5 % increase in DPPH scavenging efficiency and 20 % increase in hydroxyl radical scavenging efficiency compared to CS alone. CA-CS copolymers used to stabilize oil in water (O/W) emulsions, which were evaluated for their potential in encapsulating and protecting β-carotene. Microscopic observations revealed homogeneous spherical droplets in stable emulsions, suggesting effective interfacial structures. The selected CA-CS-stabilized O/W emulsions demonstrated encapsulation efficiencies of 74.8 % and 75.26 % for β-carotene. The CA-CS stabilized O/W emulsions provided the most effective protection against β-carotene degradation under UV exposure, retaining over 80 % of β-carotene content after 12 h of testing. These findings indicate that CA-CS-based O/W emulsions show promise as carriers and protectors for bioactive compounds, due to their improved antioxidant capacity, emulsions stability, and protection against degradation.

Development of Novel Multifunctional Electroactive, Self-Healing, and Tissue Adhesive Scaffold To Accelerate Cutaneous Wound Healing and Hemostatic Materials.

Designing a multifunctional conducting hydrogel wound dressing of suitable mechanical properties, adhesiveness, self-healing, autolytic debridement, antibacterial properties, and radical scavenging ability, as well as retaining an appropriate level of moisture around the wound is highly desirable in clinical application for treating cutaneous wounds healing. Here, we designed a novel class of electroactive hydrogel based on thiol-functionalized silver-graphene oxide nanoparticles (GO/Ag/TGA) core polyaniline (PANI) shell GO/Ag/TGA/PANI nanocomposites. Thus, a series of physically cross-linked hydrogel based on GO/Ag/TGA/PANI and poly(vinyl alcohol) (PVA) was prepared by freeze-thawing method. The hydrogel was characterized by XRD, UV, FTIR, TGA, TEM, SEM, Raman spectroscopy, cyclic voltammetry (CV), and four probes test. The hydrogel showed favorable properties such as excellent tensile strength, suitable gelation time (30-56 s), tunable rheological properties (G' ∼ 1 kPa), adhesiveness, and interconnected porous structure (freeze-dried). Besides this, the hydrogel also exhibits excellent exudate uptake capacity (10.4-0.2 g/g), high swelling ratio (72.4 to 93.5%), long-term antibacterial activity against multidrug-resistant (MDR) bacterial isolates, promising antioxidant (radical scavenging) efficiency, keeping the wound moisturized, prominent hemostatic efficiency, and fast self-healing ability to bear deformation. Interestingly, in vivo experiments indicated that electroactive hydrogels can significantly promote the healing rate of artificial wounds in rats, and histological analysis by H&E reveals higher granulation tissue thickness, collagen deposition, hair follicles, dermal papillary, keratinocytes, and marked increase (P < 0.05) in hydroxyproline at the wound site during 15 days of healing of impaired wounds. On the basis of vivo and vitro assay results, it is concluded that electroactive-hydrogel-attributed multifunctional properties may serve as suitable scaffold for treating chronic wound healing and skin regeneration.

Enhancement of the Cytotoxicity of Quinazolinone Schiff Base Derivatives with Copper Coordination

Two copper(II) complexes (Cu-L1, Cu-L2) derived from 2,3-substituted quinazolinone Schiff base ligands (L1, L2) were prepared to examine their anticancer activity. Compounds were characterized using various spectroscopic methods (FTIR, NMR, UV-vis) and quantum-chemical calculations. The biological effects of Cu(II) complexes bearing quinazolinone scaffolds were evaluated on two cancers’ cell lines (breast—MCF-7 and lung—A549), as well as on untransformed cells (keratinocytes—HaCaT). Copper complexes were highly cytotoxic, with IC50 in the low micromolar range, while the quinazoline ligands L1 and L2 remained inactive in inhibiting cell proliferation. Antioxidant activity was investigated in the model systems using DPPH and FRAP assays. The Cu-L1 and Cu-L2 complexes exhibited enhanced DPPH free radical scavenging efficiency compared to the L1 and L2 ligands, but their reducing ability was comparable to that of the free ligands. Evaluation of oxidative stress in vitro carried out by staining cells with various ROS-specific indicators showed reduced production of superoxide anion radical and hydrogen peroxide after treatment of cells with copper complexes. Such a negative impact on ROS formation in cells can lead to cellular redox imbalance and consequent cell death, among others, by inducing apoptosis and/or necrosis, depending on the copper complex used. We hypothesize that the high cytotoxic activity of the investigated copper complexes is apparently the result of multiple mechanisms of action, and the imbalance in the cellular antioxidant system partly contributes to the overall cytotoxic effect.

Bioinspired poly(aspartic acid) based hydrogel with ROS scavenging ability as mEGF carrier for wound repairing applications.

Poly(amino acid) based self-healing hydrogels have important application in biomedications. In this research, the catechol pendant groups were imported to poly(aspartic acid) based self-healing hydrogel to improved skin adhesion and ROS scavenging performance. The poly(succinimide) (PSI) was reacted with 3,4-dihydroxyphenylalanine (DA) and then hydraziolyzed to import catechol group and hydrazide group respectively, which are responsible for mussel inspired tissue adhesion and dynamic coupling reactivity. The dopamine modified poly(aspartic hydrazide) (PDAH) was reacted with PEO90 dialdehyde (PEO90 DA) to prepare hydrogels, and the resultant hydrogel showed good biocompatibility both in vitro and in vivo. The skin adhesion strength of the mussel inspired hydrogel increased notably with enhanced radical scavenging efficiency fit for in vivo wound repairing applications. The PDAH/PEO90 DA hydrogel also showed sustained albumin release profile and the in vivo wound repairing experiment proved the mouse Epidermal Growth Factor (mEGF) loaded hydrogel as wound dressing material accelerated the wound repairing rate.

Fabrication andin vitroevaluation of photo cross-linkable silk fibroin - epsilon-poly-L-lysine hydrogel for wound repair.

An optimal wound-healing hydrogel requires effective antibacterial properties and a favorable cell adhesion and proliferation environment. AlthoughBombyx morisilk fibroin (SF) possesses inherent wound-healing properties, it lacks these essential qualities. This study aimed to fabricate a novel photo-polymerizable hydrogel by utilizing SF's wound-healing efficiency and the epsilon-poly-L-lysine (EPL) antimicrobial activity. The SF was modified with three different concentrations of glycidyl methacrylate (GMA) to obtain SF-GMA(L), SF-GMA(M), and SF-GMA(H). A methacrylated EPL (EPL-GMA) was also produced. Then, SF-GMA was mixed with EPL-GMA to produce photo-crosslinkable SF-GMA-EPL hydrogels. The SF-GMA(L)-EPL, SF-GMA(M)-EPL, and SF-GMA(H)-EPL hydrogels, fabricated with 20% EPL-GMA, demonstrated maximum antimicrobial activity and mammalian cell adhesion ability. The hydroxyl radical (•OH) scavenging efficiency of the hydrogels was tested and shown to be between 69% and 74%. These hydrogels also exhibited 60% efficiency in removing bacterial lipopolysaccharides. The water absorption ability of the hydrogels was consistent with the size of their internal pores. The hydrogels exhibited a slow degradation fashion, and their degradation products appeared cytocompatible. Finally, the elastomeric properties of the hydrogels were determined, and a storage modulus (G') of 300-600 Pa was demonstrated. In conclusion, the hydrogels created in this study possess excellent biological and physical properties to support wound healing.

DNA condensation by cysteine containing tetra-arginine ligands as a model for ionizing radiation damage to chromatin

We examined DNA binding and condensation by AcCR4NH2 and CR4NH2 ligands. By this approach, we can model physical DNA damage by ionizing radiation. The binding constant was 1 × 106 L mol−1 at low ionic strength (ca. 10 mmol L−1 sodium ions) and the resulting condensate size was ca. 1 μm. Given the similar base pair concentrations of ca. 250 mmol L−1 in condensed DNA and chromatin, DNA damage yields by ionizing irradiation in condensates with related oligoarginine ligands are comparable to those in eukaryotic nuclei. Therefore, with the benefit of these results, we can envisage an experimental system suitable for modeling DNA damage by ionizing radiation because it reproduces well the essential conditions in cell nuclei that affect this damage, particularly the high concentrations of DNA and protein in chromatin and the resulting highly efficient radical scavenging environment.

Cynaropicrin- and chlorogenic acid-rich extracts easily prepared from Cynara cardunculus var. scolymus: Antioxidant and antigenotoxic properties

Cynara cardunculus L. var. scolymus, commonly known as globe artichoke, is known for its medicinal and culinary properties since ancient times. Nowadays, with the increasing demand for healthier foods artichoke has been valorized and worldwide production has increased to meet the increasing demand in consumption of the flower and infusion from leaves. The aim of this work was to characterize the main bioactive compounds obtained from artichoke leaf extracts using simple and sustainable techniques. Among different extraction procedures tested, decoction in water gave extracts particularly rich in chlorogenic acid (1) and cynaropicrin (2) as demonstrated by the NMR spectroscopy analysis. Compounds 1 and 2 were efficiently separated by liquid-liquid extraction, as 1 was only found in the aqueous (Aq) fraction and 2 was selectively isolated in the organic (O) fraction. While both fractions showed in vitro antioxidant activity by scavenging activity, only the O fraction was able to protect Saccharomyces cerevisiae cells from oxidative stress. Interestingly, the O fraction was much more antigenotoxic than Aq fraction, suggesting a highly efficient hydroxyl radical scavenging activity. Besides being simple and avoiding organic solvents, decoction in water provides maximal extraction of 1 and 2 and, presumably, maximal bioactivities.

Antioxidant Chimeric Molecules: Are Chemical Motifs Additive? The Case of a Selenium-Based Ligand.

We set up an in silico experiment and designed a chimeric compound integrating molecular features from different efficient ROS (Reactive Oxygen Species) scavengers, with the purpose of investigating potential relationships between molecular structure and antioxidant activity. Furthermore, a selenium centre was inserted due to its known capacity to reduce hydroperoxides, acting as a molecular mimic of glutathione peroxidase; finally, since this organoselenide is a precursor of a N-heterocyclic carbene ligand, its Au(I) carbene complex was designed and examined. A validated protocol based on DFT (Density Functional Theory) was employed to investigate the radical scavenging activity of available sites on the organoselenide precursor ((SMD)-M06-2X/6-311+G(d,p)//M06-2X/6-31G(d)), as well as on the organometallic complex ((SMD)-M06-2X/SDD (Au), 6-311+G(d,p)//ZORA-BLYP-D3(BJ)/TZ2P), considering HAT (Hydrogen Atom Transfer) and RAF (Radical Adduct Formation) regarding five different radicals. The results of this case study suggest that the antioxidant potential of chemical motifs should not be considered as an additive property when designing a chimeric compound, but rather that the relevance of a molecular topology is derived from a chemical motif combined with an opportune chemical space of the molecule. Thus, the direct contributions of single functional groups which are generally thought of as antioxidants per se do not guarantee the efficient radical scavenging potential of a molecular species.

Porous lanthanum titanium oxide nanostructure composite membrane to enhance the power output and chemical durability of low-humidifying polymer electrolyte fuel cells: impact of additive morphology

Tuning the morphologies for improving the properties of the additive materials receives immense attention during the fabrication of proton-exchange membranes for fuel cells. This study reports the synthesis of lanthanum titanium oxide (LTO) nanostructures with different morphologies (cube, spherical, and tubular) via the pyrolysis of nanofibers containing metal precursors. A mixed matrix membrane is fabricated by incorporating LTO cubes (LTO-C), LTO spheres (LTO-S), or LTO tubes (LTO-T) into a Nafion matrix, with improved physicochemical, thermomechanical, and electrochemical properties compared to those of the unmodified Nafion and Nafion-212 membranes. We investigate the effect of LTO morphology on the performance of the Nafion membranes in low-humidity polymer electrolyte fuel cells (LH-PEFCs). The water retention and diffusion behavior of LTO-T nanostructures improve the proton conductivity and LH-PEFC performance of the Nafion composite membranes. The coexistence of La3+ and Ti4+ affords efficient radical scavenging during long-term LH-PEFC operation, which realizes higher durability for the composite membranes compared to Nafion. Accordingly, this study proposes a novel strategy to resolve the major challenges associated with the operation of LH-PEFCs with Nafion membranes: dehumidification and oxidative degradation.

Injectable, pro-osteogenic and antioxidant composite microspheres composed of cerium-containing mesoporous bioactive glass and chitosan for bone regeneration applications

Repair of bone defects caused by excess reactive oxygen species (ROS) remains a clinical challenge. It is essential to inhibit the overaccumulation of ROS to accelerate the bone healing process. Herein, we developed an injectable composite phenylboronic acid-modified chitosan microspheres (CSP@BG) containing cerium-doped mesoporous bioactive glass nanoparticles (Ce-MBGNs) using a W/O emulsification method and investigated the structure, antioxidant, and osteogenic activity of microspheres. We systematically evaluated the microscopic morphology and chemical structure of the microspheres using FT-IR, XRD, SEM and TGA. When the content of incorporated Ce-MBGNs ranged from 0.83 to 14.37 wt%, the microspheres retained their morphology and their particle size varied from ∼10 to ∼23 μm. In vitro tests indicated that the CSP@BG microspheres exhibited desirable antioxidant activity, scavenged a variety of ROS such as H2O2 and ·OH, and demonstrated significant DPPH radical scavenging efficiency with up to 72.8% DPPH was scavenged. In addition, the results of CCK8 assay, ALP and ARS staining, and RT-PCR assay demonstrated that the CSP@BG microspheres could significantly promote the proliferation and osteogenic differentiation of human bone marrow stromal cells by tuning the amount of Ce-MBGNs added. In conclusion, this study systematically investigated the effects of Ce-MBGNs content on the morphological characteristic, antioxidant properties, and osteogenic activity of CSP@BG microspheres. Our results demonstrate the potential of pro-osteogenic and antioxidant composite microspheres composed of Ce-MBGNs and chitosan for bone regeneration applications.

Obtaining non-digestible polysaccharides from distillers' grains of Chinese baijiu after extrusion with enhanced antioxidation capability

Distillers' grains of Chinese Baijiu (DGS) presents a significant challenge to the environmentally-friendly production of the brewing industry. This study utilized screw extrusion to modify the morphological and crystalline characteristics of DGS, resulting in a 316 % increase in the yield of non-digestible polysaccharides extraction. Physiochemical characteristics of extracted polysaccharides were variated, including infrared spectrum, monosaccharide composition, and molecular weight. Polysaccharides extracted from extruded DGS exhibited enhanced inhibitory capacity on α-amylase activity and starch hydrolyzation, as compared to those extracted from unextruded DGS. Additionally, the ABTS, DPPH, and OH radical scavenging efficiencies took a maximum increase of 1.20, 1.38, and 1.02-fold, correspondingly. Extrusion is a novel approach for the recycling non-digestible polysaccharides from DGS, augmenting the bioactivity of extracts and their potential application in functional food.

Improving antioxidant scavenging effect of fruit peel waste extracts and their applicability in biodiesel stability enhancement

The increasing popularity of fruit peel extracts as effective sources of natural antioxidants is primarily attributed to their affordability, easy availability, and high phenolic contents that readily dissolve in solutions. However, most natural antioxidants demonstrate a lesser free radical scavenging effect when applied in mono blends compared to their synthetic counterparts. To address this problem, this work aims to improve the antioxidant capacities of palm fruit, banana, and mango peel liquid extracts recovered using supercritical fluid extraction (SFE). Firstly, a reverse-phase high-performance liquid chromatography (RP-HPLC) was used to isolate three (3) target bioactive compounds from the extracts, whose estimated quantities ranged between 1.2983–4.6841, 1.1469–3.6987, and 0.0254–0.0489 mg/g for quercetin, beta-carotene, and gallic acid respectively. Subsequently, blends of the recovered extracts were formulated in mono, binary, and ternary dosage ratios (S.1–S.10) to assess their free radical scavenging efficiency (RSE) in terms of inhibitory concentration at 50% (IC50) using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, total phenolic content (TPC), total flavonoid content (TFC), and total carotenoid content (TCC). Based on the results obtained, the highest RSE was exhibited by the ternary blend (S.9), with an IC50 value of 76.21 ± 032 µg/mL and a TPC value of 242.38 ± 0.26 mg gallic acid equivalent (GAE/g). The fastest kinetics for the extracts’ reaction with DPPH corresponding to a rate constant (K) of 1.2351 M−1.min−1 and activation energy (Ea) of 0.55 KJ/mol were presented by the same sample blend (S.9), indicating the ease of hydrogen atom release for radical scavenging. Finally, the peel extracts demonstrate an improved antioxidative performance by prolonging the biodiesel’s induction period of the extracts-blended samples as obtained from Rancimat analysis.

Study on extraction and characterization of new antibiotics violacein from engineered Escherichia coli VioABCDE-SD.

To better understand the characteristic properties of violacein biosynthesized by engineered Escherichia coli VioABCDE-SD, a convenient and simplified method was designed to extract violacein and its stability, antimicrobial activity, and antioxidant capacity were analyzed. Different fromthetraditional extraction methods, ournew method is easierandlesstime consuming and can directly obtain violacein dry powder product with a higher extraction rate. Low temperature, darkcondition, neutral pH, reducing agents, Ba2+ , Mn2+ , Ni2+ , Co2+ , and some food additives of sucrose, xylose, and glucose were conducive tomaintainingitsstability. The violacein also exhibited surprisingly high bacteriostatic action against Gram-positive Bacillus subtilis, Deinococcus radiodurans R1, and Staphylococcus aureus and Gram-negative Pseudomonasaeruginosa, but no effect on E. coli. The violacein of VioABCDE-SD exhibited strong antioxidant activity, with the scavenging rate of 1,1-diphenyl-2-picrylhydrazyl free radicals reaching 60.33%, the scavenging efficiency of hydroxyl radical scavenging reaching 56.34%, and the total antioxidant capacity reaching 0.63U/mL. Violacein from VioABCDE-SD can be synthesized directionally with better stability, antibacterial, and antioxidant properties compared with that from the original strain Janthinobacterium sp. B9-8. Therefore, our study indicated that violacein from engineered E. coli VioABCDE-SD was a kind of new antibiotic with potential biological activities, which may havepotentialutilityinmultiple areas such as pharmacological, cosmetics, and healthy food industries.

Employing Supervised Algorithms for the Prediction of Nanomaterial's Antioxidant Efficiency.

Reactive oxygen species (ROS) are compounds that readily transform into free radicals. Excessive exposure to ROS depletes antioxidant enzymes that protect cells, leading to oxidative stress and cellular damage. Nanomaterials (NMs) exhibit free radical scavenging efficiency representing a potential solution for oxidative stress-induced disorders. This study aims to demonstrate the application of machine learning (ML) algorithms for predicting the antioxidant efficiency of NMs. We manually compiled a comprehensive dataset based on a literature review of 62 in vitro studies. We extracted NMs' physico-chemical (P-chem) properties, the NMs' synthesis technique and various experimental conditions as input features to predict the antioxidant efficiency measured by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Following data pre-processing, various regression models were trained and validated. The random forest model showed the highest predictive performance reaching an R2 = 0.83. The attribute importance analysis revealed that the NM's type, core-size and dosage are the most important attributes influencing the prediction. Our findings corroborate with those of the prior research landscape regarding the importance of P-chem characteristics. This study expands the application of ML in the nano-domain beyond safety-related outcomes by capturing the functional performance. Accordingly, this study has two objectives: (1) to develop a model to forecast the antioxidant efficiency of NMs to complement conventional in vitro assays and (2) to underline the lack of a comprehensive database and the scarcity of relevant data and/or data management practices in the nanotechnology field, especially with regards to functionality assessments.

Scavenging of DPPH by Persistent Free Radicals in Carbonized Particles

AbstractPersistent free radicals (PFR) in carbonized particles may play a role in degradation of environmental compounds. The influence of PFR is evaluated in various carbonized particles on their radical scavenging efficiency upon the common radical indicator 2‐2‐diphenyl‐1‐picrylhydrazyl (DPPH). Carbonized particles are derived by hydrothermal carbonization of glucose (C‐W) or glucose and urea (NC‐W) and ionothermal carbonization of glucose and urea ionic liquid (IL) (NC‐IL). The carbonized materials contain OH/COOH, C=C, and C‐O functionalities. The addition of urea introduces NH/NH2 functionalities. The content of polar surface groups is lower in IL‐processed NC‐IL. The scavenging ability, measured as DPPH UV–vis absorption decline, increases with concentration and time for all particles, while the efficiency changes are in the order of C‐W &gt; NC‐W &gt; NC‐IL. Electron paramagnetic resonance analysis reveals similar radical concentration in all carbonized materials studied. The difference in efficiency is, thus, not directly related to the PFR concentration but rather to the type of PFR, surface functionalities and/or scavenging mechanism. According to the g‐values, radicals in these particles are carbon‐centered. The minor variation in g‐values suggests interactions between the radicals and their environmental functional groups. This provides insights into the influence of PFR in carbonized materials on their radical scavenging efficiency.

Polyphenol-assisted albumin-based biomineralization nanocarriers with NIR-II-targeted photothermal performance towards broad-spectrum radical scavenging.

The oxidative stress is a state of imbalance in the body's oxidative balance, which can cause or worsen many diseases. Several studies have focused on the direct scavenging of free radicals, however, the strategy of precisely controlling antioxidant activities remotely and spatiotemporally has rarely been reported. Herein, we report a method inspired by the albumin-triggered biomineralization process with polyphenol-assisted strategy to prepare nanoparticles (TA-BSA@CuS) with NIR-II-targeted photo-enhanced antioxidant capacity. Systematic characterization demonstrated that the introduction of polyphenol (tannic acid (TA)) induced the formation of a CuO-doped heterogeneous structure and CuS nanoparticles. Compared with the TA-free CuS nanoparticles, TA-BSA@CuS exhibited excellent photothermal property in the NIR-II region, which is ascribed to the TA-induced Cu defects and doped CuO. Moreover, the photothermal property of CuS improved the broad-spectrum free radical scavenging efficiency of TA-BSA@CuS, and its H2O2 clearance rate increased by 47.3% under NIR-II irradiation. Meanwhile, TA-BSA@CuS exhibited low biological toxicity and intracellular free radical scavenging ability. Moreover, the excellent photothermal property of TA-BSA@CuS endowed it with good antibacterial ability. Therefore, we expect that this work will pave the way for the synthesis of polyphenolic compounds and the improvement in their antioxidant capacity.

Antioxidant, Cytotoxic, and DNA Damage Protection Activities of Endophytic Fungus Pestalotiopsis neglecta Isolated from Ziziphus spina-christi Medicinal Plant

Fungal endophytes are friendly microorganisms that colonize plants and are important in the interactions between plants and their environment. They generate valuable secondary metabolites that are valuable to both plants and humans. Endophytic fungi with bioactivities were isolated from the leaves of the medicinal plant Ziziphus spina-christi. An efficient isolate was selected and identified as Pestalotiopsis neglecta based on nucleotide sequencing of the internal transcribed spacer region (ITS 1-5.8S-ITS 2) of the 18S rRNA gene (NCBI accession number OP529850); the 564 bp had 99 to 100% similarity with P. neglecta MH860161.1, AY682935.1, KP689121.1, and MG572407.1, according to the BLASTn analysis, following preliminary phytochemical and antifungal screening. The biological activities of this fungus' crude ethyl acetate (EtOAc) extract were assessed. With an efficient radical scavenging activity against 2,2'-diphenyl-1-picrylhydrazyl and an IC50 value of 36.6 µg mL-1, P. neglecta extract has shown its potential as an antioxidant. Moreover, it displayed notable cytotoxic effects against MCF-7 (breast carcinoma, IC50 = 22.4 µg mL-1), HeLa (cervical carcinoma, IC50 = 28.9 µg mL-1) and HepG-2 (liver carcinoma, IC50 = 28.9 µg mL-1). At 10 µg mL-1, EtOAc demonstrated significant DNA protection against hydroxyl radical-induced damage. Based on FT-IR and GC-MS spectral analysis, it was detected that the EtOAc of P. neglecta product contains multiple bioactive functional groups. Subsequently, this validated the features of major different potent compounds; tolycaine, 1H-pyrazol, 1,3,5-trimethyl-, eugenol, 2,5-cyclohexadiene-1,4-dione, 2,6-bis(1,1-dimethyl), and bis(2-ethylhexyl) phthalate. Since these compounds are biologically relevant in various aspects, and distinct biological activities of fungal extract were acceptable in vitro, this suggests that endophytic fungus P. neglecta may be a viable source of bioactive natural products. This could be a good starting point for pharmaceutical applications.

Synthesis and Antioxidant Properties of Novel 1,2,3-Triazole-Containing Nitrones.

Herein, we report the synthesis and antioxidant capacity of twelve novel 1,2,3-triazole-containing nitrones such as N-(2-(4-aryl-1H-1,2,3-triazol-1-yl)ethylidene)methanamine oxides 8a-f and N-(2-(4-aryl)-1H-1,2,3-triazol-1-yl)ethylidene)-2-methylpropan-2-amine oxides 9a-f, bearing an N-methyl, and an N-t-butyl substituent, respectively, at the nitrogen of the nitrone motif. Nitrones 8 and 9 were studied with regard to their antioxidant ability, as well as their ability to inhibit soybean lypoxygenase (LOX), and their in vitro antioxidant activity. For this, we used three different antioxidant assays, such as that featuring the interaction with the water-soluble azo compound AAPH for the inhibition of lipid peroxidation (LP), the competition with the DMSO for scavenging hydroxyl radicals, and the ABTS•+-decolorization assay. t-Butyl nitrone 9e, bearing the 2,4-difluorophenyl motif, showed a strong LP inhibitory effect (100%), close to the reference compound Trolox (93%), being the most potent LP inhibitor (LPi) of the whole series of tested nitrones. Nitrones 9d, 9e and 9f, bearing the 4-fluorophenyl, 2,4-difluorophenyl, and 4-fluoro-3-methylphenyl motif, respectively, were almost equipotent, and the most potent hydroxyl radical scavengers (~100%), more potent than Trolox (88%), were used as a reference compound. Regarding the LOX inhibition, the most potent inhibitor was the t-butyl substituted nitrone 9f (27 μM), bearing the 4-fluoro-3-methylphenyl motif, being 60-fold less potent than NDGA (0.45 μM), which was used as the standard in this test. The results from the antioxidant determination in the ABTS radical cation (ABTS•+) decolorization assay were not significant. N-Methyl nitrone 8f, bearing the 4-fluoro-3-methylphenyl motif, was the only promising representative, with a value of 34.3%, followed by nitrone 9f (16%). From the antioxidant analyses, we have identified N-(2-(4-(4-fluoro-3-methylphenyl)-1H-1,2,3-triazol-1-yl)ethylidene)-2-methylpropan-2-amine oxide (9f), bearing t-butyl and 4-fluoro-3-methylphenyl motifs in its structure, as the most balanced and potent antioxidant agent among the tested nitrones, as it was the most potent LOX inhibitor (27 μM), an extremely efficient and potent hydroxyl radical scavenger (99.9%), as well as one of the most potent LPi (87%) and ABTS•+ scavengers (16%).

Structurally characterized copper complexes of flavonoid naringenin with enhanced radical scavenging activity

Naringenin is a well-known flavanone with well-established radical scavenging and antioxidant properties. Its biological potency is strongly related to its potential to chelate with biologically active transition metal ions generating novel metal-based drugs with optimized pharmacological properties and biochemical activity. In this work, the thorough physico-chemical characterization and structural determination of two newly synthesized heteroleptic complexes of Cu(II) ion with naringenin and the ancillary aromatic chelators 2,2′-bipyridine and 1,10-phenanthroline is presented. The new complex assemblies were evaluated for their in vitro antioxidant capacity via the 2,2-diphenyl-1‑picrylhydrazyl assay, both displaying significant radical scavenging efficiency and setting the base for further examination of their pharmacological effects.

Ce (III)-terephthalic acid metal-organic frameworks as highly efficient ·OH radical scavengers for fuel cells and investigation of its antioxidation mechanism

Herein, in order to relieve the chemical degradation of perfluorosulfonic acid (PFSA) membranes without decreasing their proton conductivity, Ce (III)-terephthalic acid metal-organic frameworks (Ce-TPA MOFs) with efficient ·OH radical scavenging efficiency are designed via coordinating the organic antioxidant ligand (TPA) with inorganic radical scavenger (Ce ions). Ce-TPA MOFs with a different weight ratio of 0.5, 1.0, or 2.0% was introduced in PFSA matrix to produce composite membranes. On the one hand, the hydrophilic groups of Ce-TPA MOFs caused better water absorption, which promoted the proton conduction to some extent. Also, the presence of the redox Ce3+/Ce4+ couple, oxygen vacancy, and TPA molecules in Ce-TPA MOFs scavenging ·OH radical together via synergy effect. The optimum peak power density of the PFSA/Ce-TPA1.0 composite membrane at 75 °C under 80% relative humidity was 1086 mW/cm that of pristine PFSA membrane was only 1032 mW/cm. Furthermore, PFSA/Ce-TPA1.0 composite membrane experienced the decay of only 0.31 mV/h during 96 h operation under the same conditions, whereas that of pristine PFSA membrane was 2.20 mV/h. Thus, the PFSA/Ce-TPA membrane was a potential candidate for proton exchange membrane fuel cells.