Reactive Oxygen Species Free Radicals Research Articles

Oxygen vacancy-mediated activation of Zn-O bonds at the S-scheme heterostructure interface for efficient uranium collection and resistance to biological contamination

Efficient reduction of U(VI) to U(IV) during seawater uranium extraction remains a challenge. Here, cerium dioxide quantum dots were bonded to the surface of indium zinc sulfide (ZIS) to form ZIS composite cerium dioxide quantum dots (ZIS/QDs-Ce). The oxygen vacancies are able to activate the Zn-O bonds at the ZIS and QDs-Ce interfaces, thus enabling the constructed S-scheme heterojunction to show great potential in facilitating the separation and transfer of photogenerated carriers. ZIS/QDs-Ce exhibited high anti-bio-pollution activity by generating biotoxic free radical reactive oxygen species (ROS). The photo-induced reduction of uranium by ZIS/QDs-Ce in 10 ppm uranium spiked simulated seawater reached 99.6 %. Oxygen vacancies cause distortions in the crystal field, and the Zn-O bond activation process triggers the movement of ZIS/QDs-Ce from the singlet low-spin state to the stable triplet state resulting in free-carrier trapping centers and optimized electronic energy band structures. ZIS/QD-Ce has superior uranium extraction capabilities and is highly recommended for uranium extraction from seawater.

Defect-Rich Metastable MoS2 Promotes Macrophage Reprogramming in Breast Cancer: A Clinical Perspective.

Tumor-associated macrophages (TAMs) play a crucial function in solid tumor antigen clearance and immune suppression. Notably, 2D transitional metal dichalcogenides (i.e., molybdenum disulfide (MoS2) nanozymes) with enzyme-like activity are demonstrated in animal models for cancer immunotherapy. However, in situ engineering of TAMs polarization through sufficient accumulation of free radical reactive oxygen species for immunotherapy in clinical samples remains a significant challenge. In this study, defect-rich metastable MoS2 nanozymes, i.e., 1T2H-MoS2, are designed via reduction and phase transformation in molten sodium as a guided treatment for human breast cancer. The as-prepared 1T2H-MoS2 exhibited enhanced peroxidase-like activity (≈12-fold enhancement) than that of commercial MoS2, which is attributed to the charge redistribution and electronic state induced by the abundance of S vacancies. The 1T2H-MoS2 nanozyme can function as an extracellular hydroxyl radical generator, efficiently repolarizing TAMs into the M1-like phenotype and directly killing cancer cells. Moreover, the clinical feasibility of 1T2H-MoS2 is demonstrated via ex vivo therapeutic responses in human breast cancer samples. The apoptosis rate of cancer cells is 3.4 times greater than that of cells treated with chemotherapeutic drugs (i.e., doxorubicin).

Chirality‐Dependent Reprogramming of Macrophages by Chiral Nanozymes

AbstractIt is known that extracellular free radical reactive oxygen species (ROS) rather than intracellular ROS plays a non‐substitutable role in regulation of tumor‐suppressing (M1) tumor‐associated macrophages (TAMs) polarization. However, most therapeutic nanoplatforms mainly provide intracellular ROS and exhibit insufficient accumulation near TAMs, which strongly limits the macrophage‐based immunotherapeutic effects. Here we design and synthesize chiral MoS2/CoS2 nanozymes with peroxidase (POD)‐like and catalase (CAT)‐like activities to efficiently modulate TAMs polarization and reverse tumor immunosuppression by harnessing their chirality‐specific interactions with biological systems. MoS2/CoS2 nanoparticles coordinated with d‐chirality (d‐NPs, right‐handed) show improved pharmacokinetics with longer circulating half‐life and higher tumor accumulation compared with their l (left‐handed)‐ and dl (racemate)‐counterparts. Further, d‐NPs can escape from macrophage uptake in the tumor microenvironment (TME) with the aid of cell‐unpreferred opposite chirality and act as extracellular hydroxyl radicals (⋅OH) and oxygen (O2) generators to efficiently repolarize TAMs into M1 phenotype. On the contrary, l‐NPs showed high cellular uptake due to chirality‐driven homologous adhesion between l‐NPs and macrophage membrane, leading to limited M1 polarization performance. As the first example for developing chiral nanozymes as extracellular‐localized ROS generators to reprogram TAMs for cancer immunotherapy, this study opens an avenue for applications of chiral nanozymes in immunomodulation.

Chirality-Dependent Reprogramming of Macrophages by Chiral Nanozymes.

It is known that extracellular free radical reactive oxygen species (ROS) rather than intracellular ROS plays a non-substitutable role in regulation of tumor-suppressing (M1) tumor-associated macrophages (TAMs) polarization. However, most therapeutic nanoplatforms mainly provide intracellular ROS and exhibit insufficient accumulation near TAMs, which strongly limits the macrophage-based immunotherapeutic effects. Here we design and synthesize chiral MoS2 /CoS2 nanozymes with peroxidase (POD)-like and catalase (CAT)-like activities to efficiently modulate TAMs polarization and reverse tumor immunosuppression by harnessing their chirality-specific interactions with biological systems. MoS2 /CoS2 nanoparticles coordinated with d-chirality (d-NPs, right-handed) show improved pharmacokinetics with longer circulating half-life and higher tumor accumulation compared with their l (left-handed)- and dl (racemate)-counterparts. Further, d-NPs can escape from macrophage uptake in the tumor microenvironment (TME) with the aid of cell-unpreferred opposite chirality and act as extracellular hydroxyl radicals (⋅OH) and oxygen (O2 ) generators to efficiently repolarize TAMs into M1 phenotype. On the contrary, l-NPs showed high cellular uptake due to chirality-driven homologous adhesion between l-NPs and macrophage membrane, leading to limited M1 polarization performance. As the first example for developing chiral nanozymes as extracellular-localized ROS generators to reprogram TAMs for cancer immunotherapy, this study opens an avenue for applications of chiral nanozymes in immunomodulation.

Benefits of Natural Antioxidants on Oral Health.

In recent years, special attention has been paid to the correlation between oxidation-reduction mechanisms and human health. The free radicals produced via physiological cellular biochemical processes are major contributors to oxidation phenomena. Their instability is the major cause of cellular damage. Free radical reactive oxygen species containing oxygen are the best-known ones. The body neutralises the harmful effects of free radicals via the production of endogenous antioxidants (superoxide dismutase, catalase, glutathione, and melatonin). The field of study of nutraucetics has found antioxidant capacity in substances such as vitamins A, B, C, E, coenzyme Q-10, selenium, flavonoids, lipoic acid, carotenoids, and lycopene contained in some foods. There are several areas of investigation that aim to research the interaction between reactive oxygen species, exogenous antioxidants, and the microbiota to promote increased protection via the peroxidation of macromolecules (proteins, and lipids) by maintaining a dynamic balance among the species that make up the microbiota. In this scoping review, we aim to map the scientific literature on oxidative stress related to the oral microbiota, and the use of natural antioxidants to counteract it, to assess the volume, nature, characteristics, and type of studies available to date, and to suggest the possible gaps that will emerge from the analysis.

A multifunctional hydrogel loaded with two nanoagents improves the pathological microenvironment associated with radiation combined with skin wounds.

Persistent oxidative stress and recurring waves of inflammation with excessive reactive oxygen species (ROS) and free radical accumulation could be generated by radiation. Exposure to radiation in combination with physical injuries such as wound trauma would produce a more harmful set of medical complications, which was known as radiation combined with skin wounds (RCSWs). However, little attention has been given to RCSW research despite the unsatisfactory therapeutic outcomes. In this study, a dual-nanoagent-loaded multifunctional hydrogel was fabricated to ameliorate the pathological microenvironment associated with RCSWs. The injectable, adhesive, and self-healing hydrogel was prepared by crosslinking carbohydrazide-modified gelatin (Gel-CDH) and oxidized hyaluronic acid (OHA) through the Schiff-base reaction under mild condition. Polydopamine nanoparticles (PDA-NPs) and mesenchymal stem cell-secreted small extracellular vesicles (MSC-sEV) were loaded to relieve radiation-produced tissue inflammation and oxidation impairment and enhance cell vitality and angiogenesis individually or jointly. The proposed PDA-NPs@MSC-sEV hydrogel enhanced cell vitality, as shown by cell proliferation, migration, colony formation, and cell cycle and apoptosis assays in vitro, and promoted reepithelization by attenuating microenvironment pathology in vivo. Notably, a gene set enrichment analysis of proteomic data revealed significant enrichment with adipogenic and hypoxic pathways, which play prominent roles in wound repair. Specifically, target genes were predicted based on differential transcription factor expression. The results suggested that MSC-sEV- and PDA-NP-loaded multifunctional hydrogels may be promising nanotherapies for RCSWs. STATEMENT OF SIGNIFICANCE: The small extracellular vesicle (sEV) has distinct advantages compared with MSCs, and polydopamine nanoparticles (PDA-NPs), known as the biological materials with good cell affinity and histocompatibility which have been reported to scavenge ROS free radicals. In this study, an adhesive, injectable, self-healing, antibacterial, ROS scavenging and amelioration of the radiation related microenvironment hydrogel encapsulating nanoscale particles of MSC-sEV and PDA-NPs (PDA-NPs@MSC-sEV hydrogel) was synthesized for promoting radiation combined with skin wounds (RCSWs). GSEA analysis profiled by proteomics data revealed significant enrichments in the regulations of adipogenic and hypoxic pathways with this multi-functional hydrogel. This is the first report of combining this two promising nanoscale agents for the special skin wounds associated with radiation.

Assessing Free Radical Scavenging Activity of Various Cerium Materials for Proton Exchange Membrane Fuel Cells Using Fluorescence Spectroscopy Presentation Format

Proton-exchange membrane fuel cells (PEMFCs) are an electrochemical energy conversion device that only has water vapor as an emission. During fuel cell operation, the PEM undergoes mechanical, thermal, and chemical degradation. The chemical degradation is attributed to reactive oxygen species (ROS) that are generated in situ through both chemical and electrochemical pathways during fuel cell operation. Hydrogen peroxide (H2O2) is a reactive oxygen species (ROS) and is often an intermediate formed in the presence of transition metal ion like Fe2+ or Fe3+. The free radical ROS mainly hydroxyl and hydroperoxyl radicals initiate oxidative degradation of both the PEM backbone and the side chains that contain ionic groups that are essential for ion conduction. In this study, various types of free radical scavenger (FRS) additives’ free radical scavenging activity are assessed using ex-situ and in-situ fluorescence spectroscopy(1, 2). Some of FRS materials studied are cerium oxide and doped ceria salts. The scavenging ability of the FRS materials were related to their physio-chemical properties – which were assessed by XPS, SEM, and dynamic light scattering (zetasizer). V. Prabhakaran, C. G. Arges and V. Ramani, Proceedings of the National Academy of Sciences of the United States of America, 109, 1029 (2012).V. Prabhakaran, C. G. Arges and V. Ramani, Phys Chem Chem Phys, 15, 18965 (2013).

2020 Research Grant. Mitochondrial targeted protection following incomplete spinal cord injury with noninvasive technology

BACKGROUND CONTEXT Most of the traumatic spinal cord injury (SCI) are treatable, but despite advances in rehabilitation strategies continued impairment in sensorimotor function persists and does not return to pre-injury levels. Following the initial trauma there is a secondary cascade of events characterized by damage to the vasculature of the spinal cord and, therefore, reducing local oxygen delivery to the mitochondria. The main source of ROS (reactive oxygen species; free radicals) production is the mitochondrial electron transport chain. During tissue injury, calcium is released, which activates mitochondrial proteins. The hyperactivate electron transport chain now generates a mitochondrial membrane potential that is above the optimal range. This, in turn, exponentially increases ROS production, which then initiates cellular death cascades causing further damage to the spinal cord, such as inhibiting neuronal differentiation. PURPOSE The purpose of this study was to use a noninvasive infrared red-light therapy (IRL) which reduces the mitochondrial hyperactivity show immediately after SCI. We hypothesized that IRL will reduce mitochondrial hyperactivity which will result in lower ROS production at the epicenter of SCI. METHODS A between-subjects design was used where male Sprague-Dawley rats (3 months old) were randomized into three groups (sham, SCI and SCI + IRL). A balloon catheter model of spinal cord compression was used to induce SCI. The IRL treatment was for 2 hours under anesthesia. RESULTS We found that IRL therapy significantly (p < 0.03) reduced ROS production at the epicenter of SCI. In addition, we found that IL-8 and IL-12 mRNA expression were significantly lower in the SCI + IRL relative to the SCI group, respectively. CONCLUSIONS The results of this pilot study indicated that IRL treatment reduced mitochondrial hyperactivity associated with the initial 24 hours following SCI. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. Most of the traumatic spinal cord injury (SCI) are treatable, but despite advances in rehabilitation strategies continued impairment in sensorimotor function persists and does not return to pre-injury levels. Following the initial trauma there is a secondary cascade of events characterized by damage to the vasculature of the spinal cord and, therefore, reducing local oxygen delivery to the mitochondria. The main source of ROS (reactive oxygen species; free radicals) production is the mitochondrial electron transport chain. During tissue injury, calcium is released, which activates mitochondrial proteins. The hyperactivate electron transport chain now generates a mitochondrial membrane potential that is above the optimal range. This, in turn, exponentially increases ROS production, which then initiates cellular death cascades causing further damage to the spinal cord, such as inhibiting neuronal differentiation. The purpose of this study was to use a noninvasive infrared red-light therapy (IRL) which reduces the mitochondrial hyperactivity show immediately after SCI. We hypothesized that IRL will reduce mitochondrial hyperactivity which will result in lower ROS production at the epicenter of SCI. A between-subjects design was used where male Sprague-Dawley rats (3 months old) were randomized into three groups (sham, SCI and SCI + IRL). A balloon catheter model of spinal cord compression was used to induce SCI. The IRL treatment was for 2 hours under anesthesia. We found that IRL therapy significantly (p < 0.03) reduced ROS production at the epicenter of SCI. In addition, we found that IL-8 and IL-12 mRNA expression were significantly lower in the SCI + IRL relative to the SCI group, respectively. The results of this pilot study indicated that IRL treatment reduced mitochondrial hyperactivity associated with the initial 24 hours following SCI.

Histopathological study of the effect of glutathione in decreasing pathological changes induced by estrogen in internal organs of albino mice

In recent years, there has been a great deal of attention toward the field of free radical chemistry. Free radicals reactive oxygen species and reactive nitrogen species are generated by our body by various endogenous systems, exposure to different physiochemical conditions or pathological states. A balance between free radicals and antioxidants is necessary for proper physiological function. If free radicals overwhelm the body’s ability to regulate them, a condition known as oxidative stress ensues. Free radicals thus adversely alter lipids, proteins, and DNA and trigger a number of human diseases. This study was designed to determine the influence of Glutathione to reduce the pathological changes induced by estrogen. In this study 40 female and male mice are taken at age of 21days with groups of control (10 mouse in each group).The group of experimental animals was treated with estrogen and glutathione diluted with distilled water, as a vehicle, and injected intraperitonially for 12 weeks, once weekly. Each control group was injected with the vehicle of it in the same manner of injection and for the same period.

Hemin with Peroxidase Activity Can Inhibit the Oxidative Damage Induced by Ultraviolet A.

Excessive reactive oxygen species (ROS), a highly reactive substance that contains oxygen, induced by ultraviolet A (UVA) cause oxidative damage to skin. We confirmed that hemin can catalyze the reaction of tyrosine (Tyr) and hydrogen peroxide (H2O2). Catalysis was found to effectively reduce or eliminate oxidative damage to cells induced by H2O2 or UVA. The scavenging effects of hemin for other free-radical ROS were also evaluated through pyrogallol autoxidation, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·)-scavenging assays, and phenanthroline–Fe2+ assays. The results show that a mixture of hemin and tyrosine exhibits strong scavenging activities for H2O2, superoxide anion (O2−·), DPPH·, and the hydroxyl radical (·OH). Furthermore, the inhibition of oxidative damage to human skin keratinocyte (HaCaT) cells induced by H2O2 or UVA was evaluated. The results show that catalysis can significantly reduce the ratio of cell apoptosis and death and inhibit the release of lactate dehydrogenase (LDH), as well as accumulation of malondialdehyde (MDA). Furthermore, the resistance to apoptosis was found to be enhanced. These results show that the mixture of hemin and tyrosine has a significantly protective effect against oxidative damage to HaCaT cells caused by UVA, suggesting it as a protective agent for combating UVA damage.

Electron localization of ZnO/Znln2S4 interface induced lattice relaxation for triggering photocatalytic uranium evolution

Designing a material that efficiently extracts uranium (U) from natural seawater and resists biofouling remains a critical challenge. Here, flake Znln2S4 grew in situ on the surface of black porous zinc oxide (B-ZnO), and finally a binary composite material (B-ZnO/ZnIn2S4) is synthesized. Based on the reduction process of U(VI), the chemical reaction of the U(VI) → U(IV) process occurred on the surface and interface of the composite material. The S-scheme heterojunction system constructed of ZnO and Znln2S4 with a matching band structure showed great potential for promoting the separation and transfer of photogenerated carriers and obtaining powerful photoredox capabilities. By generating biologically toxic free radical reactive oxygen species and Zn2+, the adsorbent had high antibiological fouling activity. After 120 min of extraction in simulated seawater, the light-induced reduction ability of B-ZnO/ZnIn2S4-45% (mass ratio) on U(VI) reached 99%, which was 6.2 times higher than that under dark conditions. The conversion path of U(VI) was calculated by density functional theory (DFT). In addition, ZnIn2S4 (007) exhibited the ability to localize to the surface of ZnO (002) and promote electron transfer. These results indicate that interface atomic structure engineering is crucial for the synthesis of efficient and durable seawater U(VI) extraction catalysts.

An overview of free Radicals &amp; antioxidants and its Deletenous actions.

In modern years, there has been a large dealing of work toward the area of free radical chemistry. Free radicals reactive oxygen species and reactive nitrogen species are create by our body by various endogenic systems, influence to different physio chemical conditions or unhealthy states. A balance between free radicals and antioxidants is necessary for proper physiological function. If free radicals overwhelm the body's ability to modulate them, a condition known as oxidative stress ensues. Free radicals thus unfavorable alter lipids, proteins, and DNA and activate a number of human diseases. Hence application of external source of antioxidants can assist in coping this oxidative stress. Synthetic antioxidants such as butylated hydroxytoluene and butylated hydroxyanisole have recently been reported to be dangerous for human health. The present review provides a brief overview on oxidative stress mediate cellular damages and role of dietary antioxidants as functional foods in the organization of human diseases. We need to take balance diet which provide much more antioxidants to lower risks of health and run to life longer.The purpose of this review is that we want awareness related to sources of antioxidants from plants and highlight the studies of antioxidants and free radicals which provide prove for maintaining healthy aging.&#x0D; Key words: antioxidant, free radicals, aging, oxidative stress.&#x0D; Graphically Abstract;&#x0D;

Emerging Designs of Aggregation-Induced Emission Agents for Enhanced Phototherapy Applications

Emerging Designs of Aggregation-Induced Emission Agents for Enhanced Phototherapy Applications

Novel niobium-doped titanium oxide towards electrochemical destruction of forever chemicals

Electrochemical advanced oxidative processes (EAOP) are a promising route to destroy recalcitrant organic contaminants such as per- and polyfluoroalkyl substances (PFAS) in drinking water. Central to EAOP are catalysis-induced reactive free radicals for breaking the carbon fluorine bonds in PFAS. Generating these reactive species electrochemically at electrodes provides an advantage over other oxidation processes that rely on chemicals or other harsh conditions. Herein, we report on the performance of niobium (Nb) doped rutile titanium oxide (TiO2) as a novel EAOP catalytic material, combining theoretical modeling with experimental synthesis and characterization. Calculations based on density functional theory are used to predict the overpotential for oxygen evolution at these candidate electrodes, which must be high in order to oxidize PFAS. The results indicate a non-monotonic trend in which Nb doping below 6.25 at.% is expected to reduce performance relative to TiO2, while higher concentrations up to 12.5 at.% lead to increased performance, approaching that of state-of-the-art Magnéli Ti4O7. TiO2 samples were synthesized with Nb doping concentration at 10 at.%, heat treated at temperatures from 800 to 1100 °C, and found to exhibit high oxidative stability and high generation of reactive oxygen free radical species. The capability of Nb-doped TiO2 to destroy two common species of PFAS in challenge water was tested, and moderate reduction by ~ 30% was observed, comparable to that of Ti4O7 using a simple three-electrode configuration. We conclude that Nb-doped TiO2 is a promising alternative EAOP catalytic material with increased activity towards generating reactive oxygen species and warrants further development for electrochemically destroying PFAS contaminants.

A feasible molecular engineering for bright Π-conjugation free radical photosensitizers with aggregation-induced emission

Fluorescence imaging-guided tumor photodynamic therapy (PDT) has received increasing attention due to its higher resolution of fluorescence imaging and noninvasive treatment of PDT. Two problems of fluorescence aggregation-caused quenching (ACQ) and tumor microenvironment hypoxia are urgently resolved in traditional PDT with fluorescence imaging function, but there is still a lack of effective molecular engineering to design delicate photosensitizers (PSs) to overcome fluorescence ACQ and tumor hypoxia, simultaneously. Herein, we develop a feasible molecular engineering to design aggregation-induced emission (AIE)-active PSs with unique free radical (type I) reactive oxygen species (ROS) by researching molecular structure-property relationship, which possesses bright fluorescence at aggregation and low O2-dependent under the process of generating free radical ROS. The intersystem crossing (ISC) channel is activated when frequently enhance intramolecular charge transfer (ICT) effect in electron-rich AIEgens with typical heavy atoms, which ensure enough triplet energy generation to induce superoxide anion free radical (O2−·) generation. In vitro fluorescence imaging and photo triggering biotoxicity evaluation both revealed that new AIE-active photogenerator is a promising candidate for fluorescence imaging-guided PDT.

Cisplatin-induced neurotoxicity in cerebellar cortex of male mice involves oxidative stress and histopathology

BackgroundDespite evidence of neurotoxicity, cisplatin is still considered the most potent drug prescribed in human chemotherapy for a broad spectrum of malignancies. The objective was to evaluate the cerebellar cortex damage including oxidative stress biomarkers and histopathology aspects in male mice. One saline control group and two cisplatin groups were intraperitoneally injected with 0, 5, and 10 mg/kg body weight (bw) cisplatin, twice per week for four successive weeks, respectively.ResultsCisplatin decreased the body weights of treated mice. Serum levels of superoxide dismutase and glutathione peroxidase were significantly reduced in the 5 and 10 mg/kg dose, twice weekly for 4 weeks treatment; in contrast, there was a significant increase of lipid peroxidation. 5 and 10 mg/kg bw of cisplatin caused histopathological damage in the cerebellum tissue characterized by disruption, disorganization, and degeneration with dense pyknotic nuclei of the granular cells. Ultrastructurally, in the cortical region of the cerebellum, the Purkinje cells showed irregular pyknotic nuclei with indistinct nucleoli, cytoplasmic vacuolation, marked indentation of the nuclear membrane, dilatation of the endoplasmic reticulum, and breakdown and disappearance of mitochondrial cristae. Moreover, the molecular layer showed cellular necrosis and an increased number of lysosomal particles. The myelinated nerve fibers showed degenerative areas distinct by splitting, disruption, and loss of the lamellar pattern of the myelin sheath.ConclusionThese findings provide a confirmed foresight that the in vivo potential treatment of mice with cisplatin induces cerebellum deficits and impairment in neuronal histology. The identified mechanism which evokes neurotoxicity is oxidative stress-dependent status. This mechanism is pharmacologically boosted by great production of free radical reactive oxygen species.

Fe-MOGs-based enzyme mimetic and its mediated electrochemiluminescence for in situ detection of H2O2 released from Hela cells

Enzyme mimetics have attracted wide interest due to their inherent enzyme-like activity and unique physicochemical properties, as well as promising applications in disease diagnosis, treatment and monitoring. Inspired by the attributes of nonheme iron enzymes, synthetic models were designed to mimic their capability and investigate the catalytic mechanisms. Herein, metal-organic gels (Fe-MOGs) with horseradish peroxidase (HRP) like Fe-NX structure were successfully synthesized though the coordination between iron and 1,10-phenanthroline-2,9-dicarboxylic acid (PDA) and exhibited excellent peroxidase-like activity. Its structure-activity relationship and the in-situ electrochemiluminescence (ECL) detection of H2O2 secreted by Hela cells were further investigated. The highly dispersed Fe-NX active sites inside Fe-MOGs were able to catalyze the decomposition of H2O2 into large amounts of reactive oxygen species (ROS) via a Fenton-like reaction under a low overpotential. Due to the accumulation of ROS free radicals, the luminol ECL emission was significantly amplified. A proof-of-concept biosensor was constructed with a detection limit as low as 2.2 nM and a wide linear range from 0.01 to 40 μM. As a novel metal organic gels based enzyme mimetic, Fe-MOGs show great promises in early cancer detection and pathological process monitoring.

Moringa Leaf (Moringa oleifera Lam) Nanoparticle Supplementation on Zygote Cleavage in Goat Embryo Culture In Vitro

One of the causes of failure of zygote development is oxidative stress in the culture medium. Where oxidative stress can damage the structure and function of zygotes due to free radicals Reactive Oxygen Species (ROS). Moringa oleifera Lam contains antioxidant polyphenol compounds, flavonoid flavanols namely quercetin which is the most antioxidant content in Moringa leaves which is expected to fight excess ROS. The purpose of this study was to prove that the supplementation of Moringa oleifera Lam leaf nanoparticles to increase zygote cleavage in goat embryo culture in vitro. The research subjects used goat oocytes which were divided into 4 groups consisting of 1 control group and 3 treatment groups. Each group consisted of 31 samples. Control group K1 without Moringa leaf nanoparticle supplementation, treatment group I P1 Moringa leaf nanoparticle supplementation with a dose of 0.5 µM, treatment group II P2 supplementation of Moringa leaf nanoparticles with a dose of 1.0 µM, Treatment group III P3 supplementation with Moringa leaf 2.0 µM. Embryo culture was carried out in a 5% CO2 incubator, temperature 38.5oC for 48 hours, then observed under an inverted microscope. The results show that there are significant differences with the value of p = 0.041 which means p <0.05. Supplementation of moringa leaf nanoparticles (Moringa oleifera Lam) can significantly increase zygote cleavage at embryo culture stage in vitro.

Antioxidants: a brief review

The field of free radical chemistry has gained a great deal of attention in recent years. Free radicals reactive oxygen species generated by our body by various endogenous systems leads to various pathological conditions. A balance between free radicals and antioxidants is prerequisite for proper physiological function. Oxidative stress caused by generation of free radicals adversely alters lipids, proteins, and DNA and provokes a number of human ailments. Oxidative stress can be managed by using external sources of antioxidants. Synthetic antioxidants such as butylated hydroxytoluene and butylated hydroxyanisole have recently been reported to be harmful for human health. Thus, the search for effective, nontoxic natural compounds with antioxidant activity has been escalated in recent years. The present review provides a brief overview on antioxidants and natural sources of antioxidants in the management of human diseases.&#x0D; Keywords: free radical, Oxidative stress, antioxidants,

Low Molecular Weight Antioxidant versus Flavonoids in Combating Oxidative Stress: Which One is Superior?

According to the free radical theory of aging, firstly proposed by Denham Harman, the most prominent cause of aging and degenerative diseases (DD) is continuously chemical reaction in cells and tissues. In this context aging and or DD is manifested as chemical composition, whilst aging process is reflected by chemical reaction affected by environment (Harman, 1981). Thus, both aging and DD have similar process, predisposed with oxidative stress and characterized by the progressive cellular alteration accumulation in line with time and account for increase in susceptibility to diseases and death. The most prevalent chemical reaction is between free radical reactive oxygen species (ROS) and reactive nitrogen species (RNS) with cellular biomolecules such as lipids, protein, carbohydrate, and DNA (Lamichhane et al., 2013). In order to prevent the deleterious effect of that chemical reaction, human’s body provides an antioxidant defense system to counterbalance the free radical dangerous effect. However, owing to inappropriate life style, eating style, physical activity, and poor environment, production of ROS and RNS may be increased and induce cellular damages. Numerous publications indicated that oxidative stress and cellular damages can be reduced even prevented by exogenous antioxidant, thus intake antioxidant from external sources is necessary. There are two type of exogenous antioxidant consisting of low molecular weight antioxidant (LMWA) and flavonoids. Unfortunately, the effect of LMWA on delaying aging and ameliorating DD remain inconsistent. On the other hand, numerous data indicate that flavonoids a botanical antioxidant was capable of improving oxidative stress and emerging as an alternative promising antioxidant (Sudhakaran et al., 2019). However, the effect of LMWA and flavonoids in combating oxidative stress remain unknown which one is better.