Excellent Free Radical Scavenging Research Articles

Elucidating the Binding Interaction of a Highly Efficient Phytochemical-Sinapic Acid with Human Serum Albumin: A Spectroscopic and Calorimetric Approach

Polyphenolic compounds have received much attention due to their major function as antioxidants. Sinapic acid (SA) is an orally bioavailable phytochemical with excellent free radical scavenging property transported in the blood by human serum albumin (HSA) which is the chief carrier protein found abundantly in human plasma. SA contains a single phenolic group. This study investigates the binding and interaction mechanism between SA and HSA by multiple spectroscopic and calorimetric techniques, such as UV/visible absorption spectroscopy, intrinsic fluorescence studies, Fourier transform infrared (FTIR) spectroscopy and isothermal titration calorimetry (ITC). UV/visible absorption spectroscopy showed hyperchromicity in the absorption spectra, suggestive of structural change due to complex formation between HSA and SA. Intrinsic fluorescence measurements, performed at three different temperatures, showed quenching of the fluorescence spectra and the mechanism of quenching was static in nature which occurred due to ground state complex formation. The FTIR results demonstrated a 16% decrease in α-helical content of the secondary structure of HSA in the presence of SA. Hydrogen bonds and hydrophobic forces were the main forces of interaction, according to the thermodynamic characteristics found through ITC. Moreover, the data obtained through ITC indicated strong binding affinity between HSA and SA and supported the exothermic and spontaneous nature of the interaction.

Preparation of chitosan-based macromolecular antioxidant with high-efficiency free radical scavenging ability to improve the antioxidative properties of styrene-butadiene rubber/silica composites

To address the disadvantages of traditional rubber antioxidants with low molecular weight such as easy migration, poor extraction resistance, low thermal stability and antioxidant efficiency, in this work, we first prepared an antioxidant containing primary and secondary antioxidant groups (MC-MPA) through thiol-ene click reaction between N-(4-aminophenyl)maleimide (MC) and 3-mercaptopropionic acid (MPA). Then, we synthesized a chitosan-based macromolecular antioxidant with long-chain alkene, aromatic secondary amine, and thioether groups (COS-UC-MC-MPA) by sequentially grafting functional compounds 10-undecanonyl chloride (UC) and antioxidant MC-MPA onto natural macromolecular polymer chitosan (COS). The free radical scavenging ability of COS-UC-MC-MPA was assessed by using 2,2-Diphenyl-1-picrylhydrazyl (DPPH), and the results demonstrated that COS-OC-MC-MPA has high scavenging rate of 76.5% for DPPH free radicals after 1 min of contact with DPPH dimethyl sulfoxide solution, showing excellent free radical scavenging ability. In addition, the results of accelerated thermo-oxidative aging test, thermogravimetric (TG) test, kinetic analysis of thermal-oxidative degradation, extraction resistance test, and volatilization resistance test indicated that COS-UC-MC-MPA with superior migration resistance and volatilization resistance could effectively enhance the antioxidative properties, thermal stability and thermal-oxidative stability of rubber composites. Moreover, the results of rubber processibility analysis (RPA) test and scanning electron microscopy (SEM) implied that the addition of COS-UC-MC-MPA is also conductive to improving the dispersibility of silica in rubber matrix. This study supplies a new perspective for the preparation of environmentally friendly and highly efficient macromolecular antioxidants for rubber composites.

LCMS and FTIR profiling of microalga Chlorella sp. for cosmetics and skin care applications

People are exposed to extreme levels of UV radiation from the sun which gives a harmful effect on the skin. A prevention step should be taken such as applying a protective layer that able to protect the skin from UV rays. Hence, the protective layer should contain the antioxidant components that are able to prevent the formation of free radicals. Microalgae and the bioactive components that can be derived from them are thought to be viable raw material replacements in the cosmetics and pharmaceutical industries. In this study, carotenoid compounds with antioxidant characteristics such as neoxanthin and cryptoxanthin were successfully identified in Chlorella sp. by LC‑QTOF and the compounds have been reported to give a shield from skin aging. Meanwhile, the phenolic compounds were successfully identified through LC‑QTOF in Chlorella sp. that also been reported to be an active compound in sunscreen products. Besides, the identification of polysaccharide compounds was done by FTIR analysis, and the presence of the functional group was successfully identified. Polysaccharides have been reported to be an excellent anti-wrinkles characteristic. The alginate compound was analyses from the identification of a functional group based on the peaks formed. The alginate compound has been an excellent free radical scavenging. Therefore, Chlorella sp. can be applicable for cosmetics and skincare products as the antioxidant compounds such as phenolics compound, carotenoids, and polysaccharides have been identified.

Triazole-benzenesulfonamide hybrids: Synthesis, biological evaluation, and molecular docking study as non-toxic antimicrobial and antioxidant agents

We have synthesized a library of twenty novel heterocyclic compounds having benzenesulfonamide and triazole moieties in their skeleton. Synthesized target compounds were tested for their inhibition potential against the growth of seven bacterial and one fungal pathogens. Free radical scavenging activities were also determined for the synthesized series of compounds using DPPH method. Furthermore, cytotoxicity studies of the target compounds were performed against mouse fibroblast animal cell lines and plant seed germination cell lines. To identify the binding modes, molecular docking of the most active antibacterial compound 3e and the most active antifungal compound 3g was performed in the active sites of target enzymes. All the tested compounds were found to be good antibacterial (MIC values = 4.9 – 37.8 µM) and antifungal (MIC values = 5.4 – 37.8 µM) agents. Results of antioxidant study showed that all the tested compounds are moderate to excellent free radical scavengers (% RSA values = 75.45 – 95.34). Furthermore, all were found safe against both the tested cell lines during cytotoxicity studies.

Pyrolytic oil from Muli bamboo (Melocanna baccifera, Roxb.): Biological potential and possible functional attributes

Bamboos with over 160 different species are important sources of food and other value-added products especially among the tribal communities of Northeast India. In the study, bio-oil was extracted from Melocanna baccifera through pyrolysis process and was evaluated for their biological properties. The characterization of the functional attributes responsible for the activities was achieved using advance techniques. The extracted bio-oil was found to be smoky dark brown in colour with a pH of 2.46 ± 0.2. Bio-assays showed that the bio-oil was efficient in inhibiting the growth of pathogenic fungal and bacterial strains such as Fusarium udum, F. proliferatum, Micrococcus luteus, and Salmonella typhimurium in a concentration dependent manner. The bio-oil also exhibit excellent free radical scavenging properties even at concentration of 1% and tend to increase with the concentration of the extract. Similar to previous reports, the antimicrobial and antioxidant properties of the bio-oil were attributed to bioactive compounds like Guaiacol, Catechins, Catechol, Quinol, 2-Methoxy-4-methylphenol, etc. which were further validated by gas chromatography, ICP-MS and FTIR characterization techniques. While the extract did not show any significant phytotoxicity effect either on the seed germination rate or root elongation, they were found to promote the development of secondary roots in Vigna radiate. The present findings offer valuable insights for the further exploration and evaluation of bamboo biomass as possible sources of novel bioactive compounds and also extraction of other high-value added products.

Neuroprotective potential of traditionally used medicinal plants of Manipur against rotenone-induced neurotoxicity in SH-SY5Y neuroblastoma cells

Ethnopharmacological relevanceAlternanthera sessilis (L.) R. Br. ex DC., Eryngium foetidum L., and Stephania japonica (Thunb.) Miers plants are traditionally used to treat various central nervous system disorders like paralysis, epilepsy, seizure, convulsion, chronic pain, headache, sleep disturbances, sprain, and mental disorders. However, their possible neuroprotective effects have not been evaluated experimentally so far. Aim of the studyThe study aims to examine the neuroprotective potential of the three plants against cytotoxicity induced by rotenone in SH-SY5Y neuroblastoma cells and assess its plausible mechanisms of neuroprotection. Materials and methodsThe antioxidant properties of the plant extracts were determined chemically by DPPH and ABTS assay methods. The cytotoxicity of rotenone and the cytoprotective activities of the extracts were evaluated using MTT assays. Microtubule-associated protein 2 (MAP2) expression studies in cells were performed to assess neuronal survival after rotenone and extract treatments. Mitochondrial membrane potential and intracellular levels of reactive oxygen species were evaluated using Rhodamine 123 and DCF-DA dye, respectively. Catalase, glutathione peroxidase, and superoxide dismutase activities were also measured. Apoptotic nuclei were examined using DAPI staining. Liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (LC-QTOF-MS) analysis of the plant extracts was also performed. ResultsThe methanol extracts of A. sessilis, S. japonica, and E. foetidum showed excellent free radical scavenging activities. MAP2 expression studies show that A. sessilis and S. japonica have higher neuroprotective effects against rotenone-induced neurotoxicity in SH-SY5Y cells than E. foetidum. Pre-treating cells with the plant extracts reverses the rotenone-induced increase in intracellular ROS. The plant extracts could also restore the reduced mitochondrial membrane potential induced by rotenone treatment and reinstate rotenone-induced increases in catalase, glutathione peroxidase, and superoxide dismutase activities. All the extracts inhibited rotenone-induced changes in nuclear morphology and DNA condensation, an early event of cellular apoptosis. LC-QTOF-MS analysis of the plant extracts shows the presence of neuroprotective compounds. ConclusionsThe plant extracts showed neuroprotective activities against rotenone-treated SH-SY5Y cells through antioxidant and anti-apoptotic mechanisms. These findings support the ethnopharmacological uses of these plants in treating neurological disorders. They probably are a good source of neuroprotective compounds that could be further explored to develop treatment strategies for neurodegenerative diseases like Parkinson's disease.

Synthesis,Antidiabetic and Antitubercular Evaluation of Quinoline-pyrazolopyrimidine hybrids and Quinoline-4-Arylamines.

Two libraries of quinoline-based hybrids 1-(7-chloroquinolin-4-yl)-1H-pyrazolo[3,4-d]pyrimidin-4-amine and 7-chloro-N-phenylquinolin-4-amine were synthesized and evaluated for their α-glucosidase inhibitory and antioxidant properties. Compounds with 4-methylpiperidine and para-trifluoromethoxy groups, respectively, showed the most promising α-glucosidase inhibition activity with IC50 =46.70 and 40.84 μM, compared to the reference inhibitor, acarbose (IC50 =51.73 μM). Structure-activity relationship analysis suggested that the cyclic secondary amine pendants and para-phenyl substituents account for the variable enzyme inhibition. Antioxidant profiling further revealed that compounds with an N-methylpiperazine and N-ethylpiperazine ring, respectively, have good DPPH scavenging abilities with IC50 =0.18, 0.58 and 0.93 mM, as compared to ascorbic acid (IC50 =0.05 mM), while the best DPPH scavenger is NO2 -substituted compound (IC50 =0.08 mM). Also, compound with N-(2-hydroxyethyl)piperazine moiety emerged as the best NO radical scavenger with IC50 =0.28 mM. Molecular docking studies showed that the present compounds are orthosteric inhibitors with their quinoline, pyrimidine, and 4-amino units as crucial pharmacophores furnishing α-glucosidase binding at the catalytic site. Taken together, these compounds exhibit dual potentials; i. e., potent α-glucosidase inhibitors and excellent free radical scavengers. Hence, they may serve as structural templates in the search for agents to manage Type 2 diabetes mellitus. Finally, in preliminary assays investigating the anti-tubercular potential of these compounds, two pyrazolopyrimidine series compounds and a 7-chloro-N-phenylquinolin-4-amine hybrid showed sub-10 μM whole-cell activities against Mycobacterium tuberculosis.

Hybrids of selective COX-2 inhibitors and active derivatives of edaravone as COX-2 selective NSAIDs with free radical scavenging activity: Design, synthesis and biological activities

Novel hybrids of selective COX-2 inhibitors (coxibs) and active derivatives of free radical scavenger edaravone were designed to overcome the risk of cardiovascular events and stroke increased by NSAIDs (nonsteroidal anti-inflammatory drugs) in this study. All the hybrids were assayed for the COX-2 inhibitory and DPPH (2, 2-diphenyl-1-picrylhydrazyl) free radical scavenging activities in vitro. Finally, we found a series of hybrids with good inhibitory activity and selectivity of COX-2 and excellent free radical scavenging activity in vitro. The most promising compound 6a (WYZ90) exhibited very potent COX-2 inhibitory activity (COX-2, IC50 = 75 nM), weak COX-1 inhibitory activity (COX-1, IC50 = 5734 nM), better free radical scavenging activity (DPPH, IC50 = 19.9 μM) than edaravone, moderate drug-likeness and ADME properties in silico, acceptable pharmacokinetic properties (T1/2 = 4.16 h, 10 mg/kg, o.p.) and oral bioavailability (F% = 36.03 %) in mice. In addition, compound WYZ90 showed similar analgesic activity to the selective COX-2 inhibitor celecoxib in acetic acid-induced mice and better antioxidant activity in Fe2+-induced lipid peroxidation in mouse liver tissue homogenate than edaravone. In conclusion, this study provided a novel class of coxibs containing edaravone moiety as COX-2 selective NSAIDs with free radical scavenging activity and the candidate compound WYZ90 showed not only similar selective COX-2 inhibitory and analgesic activity to celecoxib but also better free radical scavenging and antioxidant activity than edaravone.

Heteroatom co-doping (N, NS, NB) on carbon dots and their antibacterial and antioxidant properties

The development of new nanoparticle-based antibiotics with biocompatible properties is an emerging advance in nanotechnology. This study advocated the development of carbon dots (CDs) doped with nitrogen, nitrogen with sulfur, and nitrogen with boron (N, NS, and NB-CDs). This led to changes in the properties of the CDs, both chemically and biologically. A facile hydrothermal technique was used to synthesize CDs and the formation of CDs was confirmed through various analytical techniques. The CDs had sizes ranging from 3.2–4.8 nm and ζ-potential values of +13 to 27 mV. The doped CDs exhibited moderate changes in fluorescence behaviors depending on the excitation wavelength (λex). The N- and NB-doped CDs were effective at eliminating gram-negative pathogens (E. coli and K. pneumoniae), with minimum inhibitory concentrations (MIC) of 300 µg/mL and 400 µg/mL, respectively. The bactericidal effect of these CDs was attributed to the positive surface charge of the doped CDs and the production of ROS, which caused damage to the bacterial membrane and led to cell death. N- and NS-CDs also showed excellent free radical scavenging activities (<90 %) for DPPH and ABTS. The biocompatibility of doped CDs was examined by a human leukemia monocytic cell line (THP1 cell) and hemolysis test, which found that N, NB-CDs showed over 80 % viable cells at equivalent bactericidal (MBC) concentrations compared with NS-doped CDs. Our findings suggest that doping CDs with various dopants could be a new approach for selectively eliminating bacterial pathogens in hospital and biomedical environments.

Untargeted metabolomics-based molecular networking for chemical characterization of selected Apiaceae fruit extracts in relation to their antioxidant and anti-cellulite potentials

Stress, obesity, hormonal changes, and aging have been connected to cellulite aggravation resulting in skin dimpled appearance, a very common painless skin disorder with a female preponderance. Several Apiaceae plants have been traditionally used for cosmetic applications. However, their screening for anti-cellulite potential has not been deeply investigated. In this work, UPLC-HRMS/MS coupled with molecular networking was employed to glean a holistic overview of the chemodiversity of the metabolome of nine Apiaceae fruits. Additionally, the extracts were screened for in vitro antioxidant and anti-cellulite activities. Apium graveolens and Petroselinum crispum revealed excellent free radical scavenging activity, remarkably increased lipolysis, and decreased adipogenesis. Furthermore, apigenin and its glycosides were identified to be the major components in both extracts, which might be responsible for the antioxidant activity and anti-cellulite potential. Conclusively, these results signify the potent antioxidant and anti-cellulite properties of A. graveolens and P. crispum fruit extracts, holding potential for the development of plant derived products for cellulite management.

Nano Self-Assemblies of Caffeic Acid-Fibronectin Mimic a Peptide Conjugate for the Treatment of Corneal Epithelial Injury.

Rapid corneal re-epithelialization is important for corneal wound healing. Corneal epithelial cell motility and oxidative stress are important targets for therapeutic intervention. In this study, we covalently conjugated the antioxidant caffeic acid (CA) with a bioactive peptide sequence (PHSRN) to generate a CA-PHSRN amphiphile, which was formulated into nanoparticular eye drops with an average size of 43.21 ± 16 nm. CA-PHSRN caused minimal cytotoxicity against human corneal epithelial cells (HCECs) and RAW264.7 cells, exhibited an excellent free radical scavenging ability, and remarkably attenuated reactive oxygen species (ROS) levels in H2O2-stimulated HCECs. The antioxidant and anti-inflammatory activities of CA-PHSRN were assessed in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The results show that CA-PHSRN treatment effectively prevented LPS-induced DNA damage and significantly reduced the levels of LPS-induced pro-inflammatory cytochemokines (i.e., iNOS, NO, TNF-α, IL-6, and COX-2) in a dose-dependent manner. Moreover, using a rabbit corneal epithelial ex vivo migration assay, we demonstrated that the proposed CA-PHSRN accelerated corneal epithelial cell migration and exhibited high ocular tolerance and ocular bioavailability after topical instillation. Taken together, the proposed CA-PHSRN nanoparticular eye drops are a promising therapeutic formulation for the treatment of corneal epithelial injury.

Water extract from Ligusticum chuanxiong delays the aging of Saccharomyces cerevisiae via improving antioxidant activity

Ligusticum chuanxiong is a common traditional edible-medicinal herb that has various pharmacological activities. However, its effects on Saccharomyces cerevisiae (S. cerevisiae) remains unknown. In this study, we found that water extract of Ligusticum chuanxiong (abbreviated as WEL) exhibited excellent free radical scavenging ability in-vitro. Moreover, WEL treatment could delay the aging of S. cerevisiae, an important food microorganism sensitive to reactive oxygen species (ROS) stress. Biochemical analyses revealed that WEL significantly increased the activity of antioxidant enzymes in S. cerevisiae, including superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR), as well as their gene expression. As a result, ROS level was significantly decreased and accompanied with the decline of malondialdehyde (MDA), which represented a state of low oxidative stress. The reduction of oxidative stress could elevate S. cerevisiae's ethanol fermentation efficiency. Taken together, WEL plays a protective role against S. cerevisiae aging via improving antioxidant activity.

Development of κ-carrageenan-PEG/lecithin bioactive hydrogel membranes for antibacterial adhesion and painless detachment

The issue of wound dressing adherence poses a substantial challenge in the field of wound care, with implications both clinically and economically. Overcoming this challenge requires the development of a hydrogel dressing that enables painless removal without causing any secondary damage. However, addressing this issue still remains a significant challenge that requires attention and further exploration. The present study is focused on the synthesis of hydrogel membranes based on κ-carrageenan (CG), polyethylene glycol (PEG), and soy lecithin (LC), which can provide superior antioxidant and antibacterial attachment properties with a tissue anti adhesion activity for allowing an easy removability without causing secondary damage. The (CG-PEG)/LC mass ratio was varied to fabricate hydrogel membranes via a facile approach of physical blending and solution casting. The physicochemical properties of (CG-PEG)/LC hydrogel membranes were studied by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and mechanical analyses. The membranes showed significantly enhanced mechanical properties with excellent flexibility and had high swelling capacity (˃1000 %), which would provide a moist condition for wound healing. The membranes also exhibited excellent free radical scavenging ability (>60 %). In addition, the (CG-PEG)/LC hydrogel membranes showed reduced peel strength 26.5 N/m as a result of weakening the hydrogel-gelatin interface during an in vitro gelatin peeling test. Moreover, the membrane showed superior antibacterial adhesion activity (>90 %) against both S. aureus and E. coli due to the presence of both PEG and LC. The results also suggested that the hydrogel membranes exhibit NIH3T3 cell antiadhesion property, making them promising material for easy detachment from the healed tissue without causing secondary damage. Thus, this novel combination of (CG-PEG)/LC hydrogel membranes have immense application potential as a biomaterial in the healthcare sector.

Screening the Chemical Composition and Bioactivity of Cerasus serrulata Flower Extracts Using Two Extraction Methods

Background Cerasus serrulata has an excellent antioxidative, antibacterial, and anti-alopecia effect, but its active ingredients and the underlying mechanism are currently unclear, in addition to the fact that the active products vary with the extraction methods. Aim Therefore, this study aims to clarify the active components and antioxidative property of C. serrulata extracted by two different methods (low-temperature vacuum extraction and ethanol extraction) and explore its potential biofunction. Materials and Methods First, the compositions in extracts were characterized by gas chromatographic mass spectrometry (GC-MS) and liquid chromatography-mass spectrography (LC-MS). Then, the antioxidative activity of both extracts was evaluated using free radical scavenging assay (ABTS) and ORAC. Next, the antibacterial activity of both extracts was measured via a bacteriostatic circle experiment. The anti-alopecia effects of both extracts were studied using a mouse model of alopecia. The hematoxylin and eosin (H&amp;E) staining was used to evaluate hair follicles; vascular endothelial-derived growth factor (VEGF) and interleukin-6 (IL-6) expression in mouse skin were evaluated by immunohistochemistry, while β-catenin expression in tissues was used by immunofluorescence. The expression of FGFR and insulin-like growth factor 1 (IGF-1) in the skin was determined to evaluate using real-time quantitative polymerase chain reaction (RT-qPCR). The levels of DHT and 5α-reductase in the experimental mice were determined by ELISA. Results The GC-MS analysis results showed that the extracts were rich in alkanes and aromatic compounds, specifically benzaldehyde, which was the highest component in the cold vacuum extraction, while pipecolic acid was the main component in the ethanol extract. This indicates that C. serrulata has components that exhibit strong inhibitory ability against the growth of five common bacterial strains, expressing excellent free radical scavenging ability. In addition, the active ingredients in C. serrulata were found to significantly deregulate the protein levels in the skin of androgenetic alopecia (AGA) mice, with the levels of IL-6. They were also able to significantly inhibit VEGF reduction. The β-catenin was being significantly upregulated in skin tissue. In addition, FGFR and IGF-1 gene expression also increased. The 5α-reductase and dihydrotestosterone (DHT) can be reduced in the C. serrulata treatment. Conclusion Our data indicate that C. serrulata extract could be beneficial supplements of natural antioxidative, antibacterial, and anti-alopecia agents.

Vanillic acid exhibits potent antiproliferative and free radical scavenging effects under in vitro conditions

Cells endure oxidative stress as a result of an imbalance between the status of body’s reactive oxygen species (ROS) and antioxidants. Higher production of ROS or weak antioxidant defense mechanism in the cell could lead to various pathological disorders, including carcinogenesis. The present study investigated the in vitro free radical scavenging activity and antiproliferative efficacy of vanillic acid using a spectrum of radical scavenging assays and cytotoxic assays, respectively. Vanillic acid’s antioxidant ability was investigated using in vitro antioxidant assays such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), hydroxyl, and superoxide radical scavenging assays. The current study observed an excellent free radical scavenging capacity of vanillic acid, which was comparable to that of ascorbic acid (reference drug). The antiproliferative effect of vanillic acid was assessed in mammary cancer cells (Michigan Cancer Foundation-7 [MCF-7]) by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, ROS generation potential, changes in mitochondrial membrane potential, and by evaluating its apoptotic induction potential. The cell viability of breast cancer cells was drastically decreased by vanillic acid, and its antiproliferative potential in MCF-7 cells could be due to its ability to induce excessive generation of ROS and its apoptotic induction potential. The present investigation thus explores antioxidant and antiproliferative properties of vanillic acid under in vitro conditions.

Preparation of Novel Chitosan Oligosaccharide Quaternary Ammonium Derivatives Bearing Quinoline with Antioxidative and Antibacterial Activities

AbstractIn this study, five new chitosan oligosaccharide quaternary ammonium derivatives bearing quinoline are synthesized by reaction between 6‐O‐chloroacetyl‐2‐N, N, N‐trimethyl quaternary ammonium salt chitosan oligosaccharide (CTCOS, compound 1) and quinoline derivatives. The derivatives are characterized by analytical techniques including Fourier Transform Infrared (FTIR), 1H Nuclear Magnetic Resonance (1H NMR) spectroscopy, and elemental analysis. The obtained results confirm that quinoline groups are successfully introduced into the CTCOS molecule. Meanwhile, the antioxidant activities of the prepared chitosan oligosaccharide derivatives are evaluated in vitro. The experimental results show that the derivatives have excellent free radical scavenging ability. The free radical scavenging abilities are all over 75% at the concentration of 1.6 mg mL−1. Moreover, antibacterial tests show that derivative 2e has the best antibacterial activities. Its minimum inhibitory concentration (MIC) value and minimum bactericidal concentration (MBC) value against Staphylococcus aureus and Escherichia coli are 0.0625 and 0.03125 mg mL−1, respectively. In addition, the cytotoxicity of chitosan oligosaccharide and its derivatives is examined by MTT colorimetric assay in RAW 264.7 macrophages, observing that all derivatives are non‐cytotoxic. Consequently, the findings indicate that the enhanced antioxidant activity, antibacterial activity, and biocompatibility of these chitosan oligosaccharide derivatives can enlarge the scope of the application of chitosan oligosaccharides, particularly as antioxidant and antibacterial agents in food packaging, pharmaceutical, cosmetics industries, and other fields.

Hollow-polydopamine-nanocarrier-based near-infrared-light/pH-responsive drug delivery system for diffuse alveolar hemorrhage treatment.

Introduction: Diffuse alveolar hemorrhage (DAH) is a serious complication caused by systemic lupus erythematosus (SLE). Tissue damage and changes in immune response are all associated with excessive free radical production. Therefore, removing excess reactive oxygen species are considered a feasible scheme for diffuse alveolar hemorrhage treatment. Cyclophosphamide is often used as the main therapeutic drug in clinics. However, CTX carries a high risk of dose-increasing toxicity, treatment intolerance, and high recurrence rate. The combination of therapeutic drugs and functional nanocarriers may provide an effective solution. PDA is rich in phenolic groups, which can remove the reactive oxygen species generated in inflammatory reactions, and can serve as excellent free radical scavengers. Methods: We developed a hollow polydopamine (HPDA) nanocarrier loaded with CTX by ionization to prepare the novel nanoplatform, CTX@HPDA, for DAH treatment. The monodisperse silica nanoparticles were acquired by reference to the typical Stober method. PDA was coated on the surface of SiO2 by oxidation self-polymerization method to obtain SiO2@PDA NPs. Then, HPDA NPs were obtained by HF etching. Then HPDA was loaded with CTX by ionization to prepare CTX@HPDA. Then we tested the photothermal effect, animal model therapeutics effect, and biosafety of CTX@HPDA. Results: Material tests showed that the CTX@ HPDA nanoplatform had a uniform diameter and could release CTX in acidic environments. The vitro experiments demonstrated that CTX@HPDA has good photothermal conversion ability and photothermal stability. Animal experiments demonstrated that the CTX@HPDA nanoplatform had good biocompatibility. The nanoplatform can dissociate in acidic SLE environment and trigger CTX release through photothermal conversion. Combining HPDA, which scavenges oxygen free radicals, and CTX, which has immunosuppressive effect, can treat pulmonary hemorrhage in SLE. Micro-CT can be used to continuously analyze DAH severity and lung changes in mice after treatment. The pulmonary exudation in the various treatment groups improved to varying degrees. Discussion: In this study, we report a photothermal/PH-triggered nanocarrier (CTX@HPDA) for the precise treatment of SLE-DAH. CTX@HPDA is a simple and efficient nanocarrier system for DAH therapy. This work provides valuable insights into SLE treatment.

The antioxidant potential of copper oxide nanoparticles synthesized from a new bacterial strain

Abstract. Alshami HGA, Al-Tamimi WH, Hateet RR. 2023. The antioxidant potential of copper oxide nanoparticles synthesized from a new bacterial strain. Biodiversitas 24: 2666-2673. Copper oxide nanoparticles (CuONPs) have recently gained much attention due to their potential in various fields. The present study aimed to screen nine bacterial strains (Klebsiella quasipneumoniae KP18-31, K. pneumoniae IOB-L, K. quasipneumoniae subsp. similipneumoniae 2437, Bacillus cereus DBA1, B. thuringiensis MSP51, Neobacillus drentensis ROA042, Enterococcus faecalis 2674, Exiguobacterium mexicanum AB201, and Acinetobacter lwoffii K34) isolated from produced water of oil field reservoirs for their ability to biosynthesize CuONPs, as well as characterize and evaluate the antioxidant potential of the manufactured CuONPs. Biosynthesized CuONPs were characterized using XRD, TEM, AFM, and zeta potential analysis. In addition, the DPPH method was used to analyze the antioxidant activity of CuONPs. The results revealed that five of the nine isolates could synthesize CuONPs. B. thuringiensis MSP5 was the best and most productive among them, and it was used for the first time in this present study as an oil field bacteria for the biosynthesis of CuONPs. The results showed that CuONPs have a spherical shape with an average size of 20, 33, and 75 nm based on XRD, TEM, and AFM analysis, respectively. The zeta potential value of the synthesized CuONPs was -12.4 mV. The antioxidant results demonstrated that CuONPs have a remarkable scavenging activity with an IC50 value of 141.68 ?g/mL. This study concluded that CuONPs were excellent free radical scavengers.

A Coumarin‐Derived New Chemosensor for Colorimetric and Turn‐Off Fluorescent Sensing of Cu2+, F− and CN− Ions: Studies on Its Antioxidant Property

AbstractA simple coumarin derived novel chemosensor, (E)‐4‐[(2‐hydroxyphenyl)amino]‐3‐[2‐(4‐nitrophenylhydrazonomethyl)]‐2H‐chromen‐2‐one (HNHC), has been designed and synthesized which displays colorimetric as well as “turn‐off” fluorescence repercussion for Cu2+ in the nano molar level. This procedure approves the selectivity as well as sensitivity of a chemosensor HNHC within an expansive linear range of (4.6–2094)×10−8 M at λmax of 449 nm; with detection limit (LOD) 9.13×10−8 M for Cu2+, 1.17×10−7 M for F− and 5.64×10−7 M for CN−. Moreover, HNHC may be pursued as a potential antioxidant for its excellent free radical scavenging capability.

In-silico Molecular Docking and ADMET predictions of Pyrido[2,3-d]pyrimidine-2,4(1H,3H)-Dione Analogues as promising Antimicrobial, Antioxidant and Anticancer agents

Pyridopyrimidine are heterocyclic molecules enclosing fused pyridine and pyrimidine rings. Owing to its fascinating core structure and pharmacological applications a series of 7-([1,1′-biphenyl]-4-yl)-5-arylpyrido[2,3-d]pyrimidine-2,4(1H,3H)-diones were synthesized and characterized using IR, 1H, 13C NMR and Mass spectral techniques. The antibacterial, antioxidant and anticancer activities were investigated for the synthesized compound 5a-5f. Compounds with electron-donating groups showed excellent free radical scavenging activity. Halogen-substituted compounds showed more potent antimicrobial and anticancer activity than other derivatives in comparison with their respective standards. Based on the IC50 value obtained from anticancer activity, 5c was further analyzed for apoptosis by AO/EB staining method. The findings suggested early apoptosis in the MCF-7 cell line. Molecular Docking studies of the synthesized compounds were performed with Kinase 1 inhibitors (PDB id: 2YEX), 5c exposed good docking results with minimum binding energy. Further, these compounds were acknowledged as orally active drug candidates from in-silico ADMET studies. Computational analysis supports biological findings indicating compound 5c as a promising anticancer agent against the human breast cancer MCF-7 cell line.