Generation Of Oxidative Radicals Research Articles

Photocatalytic degradation evaluation using ternary structures of titanium dioxide, silver and carbon quantum dots

The catalytic photodegradation of organic pollutants offers an eco-friendly alternative to improving water quality by reducing the use of strong oxidants. This method is particularly promising in dealing with emerging pollutants that are not completely removed using only the traditional methodologies. However, limitations of the main photocatalysts used such as high bandgap value and electronic recombination are a challenge to face when trying to upscale applications. In this study, photocatalytic heterostructures were synthesized using TiO2 P25, carbon quantum dots (CQDs), and silver (Ag) to enhance photocatalytic performance and overcome these challenges. The results demonstrated significant improvements in photodegradation efficiency, with an 827% increase for the catalyst containing only CQDs and a 400% increase for the heterostructures containing both CQDs and Ag. These enhancements are attributed to the synergy of the ballistic electronic transferer properties and the diminished availability of recombination sites of the semiconductor which enables the generation of oxidative radicals.

Regulating iron center by defective MoS2 for superior Fenton-like catalysis in water purification: The key role of surface interaction and superoxide radical in accelerating metal redox-cycling

Transition metals exhibit high reactivity for Fenton-like catalysis in environmental remediation, but how to save consumption and reduce pollution is of great interest. In this study, rationally designed defect-engineered Fe@MoS2 (Fe@D-MoS2) was prepared by incorporating reactive iron onto structural defects generated from the chemical acid-etching, aiming to improve the energetic consumption of the catalyst in Fenton-like applications. Morphological and structural properties were elucidated in details, the Fenton-like reactivity was evaluated with five phenolic contaminants for oxidant activation, radical generation and environmental remediation. Compared to Fe@MoS2, Fe@D-MoS2 exhibited a 18.9-fold increase in phenol degradation (0.09 versus 1.79 min−1). Quenching experiments, electron paramagnetic resonance tests and electrochemical measurements revealed the dominant sulfate and superoxide radicals. Rendered by strong metal-substrate surface and electronic interactions from regulated chemical environment and coordination structure, the inert ≡ Fe(III) was reduced to the reactive ≡ Fe(II) accompanied by the ≡ Mo(IV) oxidation to ≡ Mo(V) in MoS2 lattice, with adjacent sulfur serving as the key electron transfer bridge. Therefore, this work shows that the incorporation of reactive centers is able to boost two-dimensional sulfide materials for environmental catalysis applications.

In situ enhanced chlorine oxide radical generation on a novel space-confined photoanode and its application for ammonia oxidation: Structure, performance, and mechanism

Oxidizing ammonia to nitrogen is a challenge in wastewater treatment. For this challenge ammonia oxidation via chlorine oxide radicals has been proved to be a potential method. In this study, a space-confined photoanode was designed and prepared by loading RuO2 nanoparticles on TiO2/WO3 nanowires for in situ enhancing the generation of chlorine oxide radical. Scanning electron microscopy characterization confirmed that RuO2 nanoparticles were uniformly deposited on TiO2/WO3 nanowires. The generation of chlorine oxide radical was markedly boosted, and its steady-state concentration reached 2.76 × 10−12 M. This value was 3 times that of the traditional bifacial electrode (a type of electrode that has been widely used for chlorine oxide radical-related research). As a result, ammonia oxidation was greatly enhanced. In 90 min, 31.9 mg/L ammonia nitrogen could be degraded, yet only 0.94 mg/L nitrate was accumulated. In addition, the space-confined photoanode exhibited good performance for real wastewater treatment, and 41.0 mg/L ammonia nitrogen could be oxidized in 135 min. During photoelectrocatalysis, a synergistic index (47.7 %) was obtained. Besides the synergistic effect between photocatalysis and electrocatalysis, the unique morphology and structural design (TiO2/WO3 and RuO2 were mainly responsible to hydroxyl radical generation and free chlorine production, respectively) also synergistically promoted the generation of chlorine oxide radical, thereby improving ammonia oxidation. The mechanism for ammonia oxidation via chlorine oxide radicals over the space-confined photoanode was proposed based on experimental results and theoretical calculations.

Probing the design principles of photosynthetic systems through fluorescence noise measurement

Elucidating the energetic processes which govern photosynthesis, the engine of life on earth, are an essential goal both for fundamental research and for cutting-edge biotechnological applications. Fluorescent signal of photosynthetic markers has long been utilised in this endeavour. In this research we demonstrate the use of fluorescent noise analysis to reveal further layers of intricacy in photosynthetic energy transfer. While noise is a common tool analysing dynamics in physics and engineering, its application in biology has thus far been limited. Here, a distinct behaviour in photosynthetic pigments across various chemical and biological environments is measured. These changes seem to elucidate quantum effects governing the generation of oxidative radicals. Although our method offers insights, it is important to note that the interpretation should be further validated expertly to support as conclusive theory. This innovative method is simple, non-invasive, and immediate, making it a promising tool to uncover further, more complex energetic events in photosynthesis, with potential uses in environmental monitoring, agriculture, and food-tech.

Tailoring the selective generation of oxidative organic radicals for toxic-by-product-free water decontamination

Peracetic acid (PAA) is emerging as a versatile agent for generating long-lived and selectively oxidative organic radicals (R-O•). Currently, the conventional transition metal-based activation strategies still suffer from metal ion leaching, undesirable by-products formation, and uncontrolled reactive species production. To address these challenges, we present a method employing BiOI with a unique electron structure as a PAA activator, thereby predominantly generating CH3C(O)O• radicals. The specificity of CH3C(O)O• generation ensured the superior performance of the BiOI/PAA system across a wide pH range (2.0 to 11.0), even in the presence of complex interfering substances such as humic acids, chloride ions, bicarbonate ions, and real-world water matrices. Unlike conventional catalytic oxidative methods, the BiOI/PAA system degrades sulfonamides without producing any toxic by-products. Our findings demonstrate the advantages of CH3C(O)O• in water decontamination and pave the way for the development of eco-friendly water decontaminations based on organic peroxides.

Antidiabetic effectiveness of Phyllanthus niruri bioactive compounds via targeting DPP-IV.

Phyllanthus niruri Linn. (Euphorbiaceae) is a small herb and is categorised as one of the rich medicinal plants throughout the world. This study aimed to evaluate the P. niruri L. whole plant extract (PNE) for secondary metabolite assay (total phenolic and terpenoid content) followed by the potential antioxidant activity (ABTS diammonium salt radical assay, DPPH· activity, superoxide anion (O2-) radicals' assay, and nitric oxide (NO) radical generation) and antidiabetic activity in vivo and in vitro in streptozotocin (STZ) induced albino mice. PNE showed good scavenging activity with a value of 286.45 ± 6.55 mg TE/g and 194.54 ± 4.64 mg TE/g in ABTS and DPPH assays respectively. In the superoxide anion assay, the PNE caused a dose-dependent inhibition at the lowest IC25 value of 0.17 ± 0.00 mg/mL compared to ascorbic acid (IC25 of 0.25 ± 0.02 mg/mL). The scavenging ability of PNE against nitric oxide showed an IC25 of 1.13 ± 0.04 mg/mL compared to ascorbic acid (IC25 4.78 ± 0.09 mg/mL). Unlike diabetic control mice, the PNE-treated diabetic mice presented significant amelioration of glycaemia and lipid dysmetabolism. Phytochemicals like Astragalin, Gallocatechin, Ellagic acid, Gallic acid, Brevifolin carboxylic acid, Phyllnirurin, and Hypophyllanthin showed significant docking score (> -4) of inhibitory potential with DPP-IV protein. Results indicated that PNE phytochemicals could be a promising antidiabetic agent by targeting DPP-IV.

Effects of pH on the triplet state dissolved organic matter induced free available chlorine decay and radical formation

Triplet state dissolved organic matter (3DOM*) plays a significant role in inducing oxidant decay and radical generation in light-based advanced oxidation processes. However, the effects of pH still need investigation. This work quantitatively analyzed the pH-dependent free available chlorine (FAC) decay and radical formation (i.e., HO• and Cl•) induced by 3DOM* or triplet state photosensitizer (3PS*). Upon UV irradiation at 254 nm, the decay rate of FAC by 3DOM* or 3PS* was the highest at neutral pH, while those by dark reaction of DOM and the direct photolysis of FAC were the highest at acidic conditions. This is attributed to the variation of FAC species, 3DOM* or 3PS* formation, and the reaction rate constants of FAC with 3DOM* or 3PS* at pH 5.0–10.0. 3DOM* and 3PS* formed increasingly with pH varying from 5.0 to 10.0, while their reactivity with FAC decreased due to the speciation from HOCl to OCl–. Radical formation (i.e., HO• and Cl•) from FAC reaction with 3DOM* or 3PS* occurred at all the testing pH range (5.0–10.0). This work highlighted the pH-dependent role of 3DOM* in oxidant decay and radical formation in treating DOM containing waters through oxidant photolysis. Environmental implicationsTriplet state dissolved organic matter (3DOM*) plays a significant role in inducing oxidant decay and radical generation in light-based AOPs. This study revealed the effects of pH in 3DOM* induced free available chlorine (FAC) decay and radical formation (i.e., HO• and Cl•). With DOM at 3 mgC L−1, FAC decayed fastest under neutral conditions and radical formation (i.e., HO• and Cl•) was enhanced at 5.0–10.0 due to 3DOM* reaction with FAC. These results highlighted the pH-dependent role of 3DOM* in oxidant transformation and radical formation in treating DOM containing waters by AOPs based on oxidant photolysis.

The regulation of Lewis acid/basic sites in NaFe bimetal MOXs for the controllable photocatalytic degradation of electron-rich/deficient VOCs

The performance of metal-organic xerogels (MOXs) in the photocatalytic oxidative degradation (PCO) of volatile organic compounds (VOCs) relies on their Lewis acid-base interaction and the generation of oxidative radicals. Herein, by engineering the local charge imbalance of carboxyl ligands through synthesizing NaFe bimetal MOXs, the Lewis acidity of MIL-100(Fe) MOX was well tuned for the adsorption-degradation of electron-rich (aromatic hydrocarbons) and electron-deficient (aldehydes) VOCs. Benefiting from the implanted Lewis basic sites, NaFe-MOXs showed increased adsorption-PCO capacity for single acetaldehyde, while Fe-MOX with abundant Lewis acid sites could capture and degrade more o-xylene. The Lewis basic sites promoted the mineralization of single o-xylene and acetaldehyde by altering their interactions with the photocatalysts and improving the generation of oxidative radicals, which extended the lifetime of photocatalysts. By regulating the Lewis acid/basic sites within MOXs, this work provides an effective way for optimizing photocatalysts to enable the photocatalytic degradation of both electron-rich/deficient VOCs.

Generation of oxidative radicals by advanced oxidation processes (AOPs) in wastewater treatment: a mechanistic, environmental and economic review

Generation of oxidative radicals by advanced oxidation processes (AOPs) in wastewater treatment: a mechanistic, environmental and economic review

Quasi-In Situ Synthesis of Ag NPs@m-MIL-100(Fe) for the Enhanced Photocatalytic Elimination of Flowing Xylenes

The implantation of metal nanoparticles (MNPs) into metal-organic framework (MOF) hosts is a promising means to prepare high-performance photocatalysts for the degradation of gas pollutants. However, the uniform encapsulation of MNPs in MOFs is still challenging. Herein, a facile "quasi-in situ" encapsulation method is proposed by utilizing the spatial confinement effect of the colloidal network formed during the synthesis of the MIL-100(Fe) monolith [noted as m-MIL-100(Fe)]. Highly dispersed Ag NPs with an average diameter of ∼2 nm are encapsulated in the MIL-100(Fe) monolith to form a unique "watermelon-seed" structure, which ensures the large contact area between the two components and protects Ag NPs from being oxidized. The fast charge transfer between m-MIL-100(Fe) and Ag NPs enables the spatial separation of electron-hole pairs and promotes the generation of oxidative radicals. Compared with pristine m-MIL-100(Fe), the 0.2 wt % Ag@m-MIL-100(Fe) composite shows obviously enhanced photodegradation efficiencies for flowing o-xylene under both xenon (∼97%) and visible light (∼80.0%) with high stability. This work not only provides a promising Ag@m-MIL-100(Fe) material for eliminating air pollutants but also gives a versatile means for the design and synthesis of nanoparticles@MOFs composites with desired performance.

A novel approach to interpret quasi-collimated beam results to support design and scale-up of vacuum UV based AOPs

UV-C at 254 nm and vacuum UV (VUV) at 185 nm are the two major emission lines of a low-pressure mercury lamp. Upon absorption of VUV photons, water molecules and selected inorganic anions generate hydroxyl (HO.) and other redox radicals, both capable of degrading organic micropollutants (OMPs), thereby offering the opportunity to reduce H2O2 and energy consumption in UV-based advanced oxidation process (AOP). To be successfully scaled-up, the dual-wavelength VUV+UV/H2O2 AOP requires laboratory-scale experiments to establish design criteria. The figures of merit typically used for reporting and interpreting quasi-collimated beam results for UV-based AOPs (time, dose, absorbed energy and EEO) are insufficient and inaccurate when employed for dual-wavelength AOP such as the VUV+UV/H2O2 AOP, and do not support system scale-up. In this study, we introduce a novel figure of merit, useful absorbed energy (uAE), defined as fraction of absorbed energy that results in the generation of oxidative radicals. Here, results of quasi-collimated beam VUV+UV/H2O2 AOP experiments on four different water matrices are used to introduce 2D plots that employ both uAEUV and uAEVUV as a novel method to represent laboratory-scale experiments of VUV+UV/H2O2 AOP and demonstrate how the 2D plots sufficiently support scale-up of the AOP.

High selective conversion of fructose to lactic acid by photocatalytic reforming of BiOBr/Znx@SnO2-n in alkaline condition

Herein, a novel p-n type BiOBr/Znx@SnO2-n photocatalyst was designed by using BiOBr coupling with large specific surface area Zn doped SnO2 through a facile in situ approach. The composite possesses proper redox potential as well as high efficiency interfacial charge transfer capability. Coupling BiOBr with Zn doped SnO2 is proved efficiency to form a facile bandgap regulation mechanism and could adjust the absorption capacity of visible light, thus enhances the photocatalytic performance effectively. The photocatalyst exhibits high efficiency in photo-reforming of fructose to lactic acid under alkaline conditions, achieving a maximum yield of 79.6% and still achieving a lactic acid yield of 70.7% even after five cycles of recycling. Possible pathways of the lactic acid production were proposed based on the generation of active oxidative radicals and the products detected during the reaction. Therefore, this work provides an effective approach for biomass conversion through rational photocatalyst design.

Oxidative potential and hydroxyl radical generation capacity of ambient PM2.5 over a high-altitude site in northeastern Himalaya: Role of long-range transport

This study investigates the dithiothreitol (DTT)-based oxidative potential (OP) and corresponding hydroxyl radical (•OH) generations capacity of PM2.5 (particulate matter with aerodynamic diameter ≤ 2.5 μm) over a high-altitude site, Shillong (25.7 °N, 91.9 °E; 1064 m above mean sea level), located in the northeastern Himalaya. Measured OP and •OH are reported in two units: per m3 of filtered air (OPV and OHV) or per unit mass of PM2.5 in μg (OPM and OHM). Based on the characteristic ratios of chemical species in different sources, PM2.5 were classified into three source categories: Biomass Burning (BB) (N = 10), Secondary Organic Aerosols (SOA) (N = 12), and Mixed (N = 12). Consistently higher OP and •OH generation per m3 of air (OPV: 6.2 ± 1.0 (average ± SD, 1σ) nmol DTT min−1 m−3, and OHV: 1.2 ± 0.31 nmol •OH m−3) in all BB-dominated PM2.5 samples indicate relatively hazardous exposure dose from BB emissions among all sources. Characteristic OC/EC, WSOC/OC, and nss-K+/EC ratios evoked that SOA from biogenic precursors was a significant source for the observed OP and •OH in SOA-categorized samples. Distinctly different chemical composition of PM2.5 over Shillong (about 55% composed of organic matter) makes it relatively more (2–4 times) intrinsically redox-active compare to a reported study over another high-altitude site in a semi-arid region of India. Despite ∼1.7 times lower PM2.5 mass over Shillong (characterized by more aged PM2.5) compare to Patiala (30.3°N, 76.4°E; 250m amsl, a semi-urban city, characterized by fresher PM2.5 from mixed sources), the observed OPV over Shillong was about 1.2 times higher, and the OPM was about 2 times higher. It is attributed to the effect of atmospheric processing on particle's redox-activity. While examining the relationship of OPV and OHV with chemical species, it was observed that •OH generation capacity was more influenced by WSOC species' origin (primary or secondary) compare to DTT consumption. Such an observation restricts the practicality of particle-induced OP to be considered as the only metric for aerosol particle toxicity, and suggests also to consider simultaneous measurements of •OH generations. For the BB-dominated category, OC-normalized OP (OPOC) was correlated strongly with the fractions of N-containing water-soluble organic aerosols (i.e., a fraction of WSON and a fraction of familyCHO1N). Corresponding OC/EC, nss-K+/EC and nss-SO42−/EC ratios hint that coal combustion, in addition to BB, could be a significant source of redox-active WSON species in these samples. Such studies are important for identifying redox-active aerosol species and developing appropriate mitigation policies for healthy air.

Vitamin C and its therapeutic potential in the management of COVID19.

COVID19 has emerged as one of the worst pandemics in the history of mankind. Several vaccines have been approved by different government agencies worldwide, but data on their efficacy and safety are limited, and distribution remains a massive challenge. As per WHO, personal immunity is vital for protection against COVID19. Earlier, Vitamin C-mediated pathways have been shown to play critical role in boosting immunity attributed to its antioxidant properties. Recently, the involvement of such pathways in protection against COVID19 has been suggested. The controlled doses of Vitamin C administered through intravenous (IV) injections are being studied for determining its role in the prognosis of COVID19. In this article, we have discussed the potential role of Vitamin C in the management in COVID19 patients and presented recent clinical trials data. Additionally, we have elaborated the possibility of administering Vitamin C through inhalers in order to achieve local high concentration and the challenges of such approach.

Trigonal Bipyramidal Rhodium(I) Methyl and Phenyl Complexes: Precursors of Oxidative Methyl and Phenyl Radical Generation

The new complexes [Rh(Me)(trop3P)] (2) and [Rh(Ph)(trop3P)] (3) (trop = 5H-dibenzo[a,d]cyclohepten-5-yl) were synthesised by addition of organolithium reagents (MeLi and PhLi) to the parent pentacoordinated chloride complex [RhCl(trop3P)]. The compounds have a trigonal bipyramidal structure with olefin-only ligands in the equatorial position and the methyl or phenyl substituent in the axial position. Oxidation of complexes 2 and 3 leads to the liberation of methyl and phenyl radicals, which were indirectly detected by reaction with common spin trapping reagents.

Hierarchical porous zeolitic imidazolate frameworks (ZIF-8) and ZnO@N-doped carbon for selective adsorption and photocatalytic degradation of organic pollutants.

Removing organic contaminants such as dyes from water is essential to purify wastewater. Herein, zeolitic imidazolate framework-8 (ZIF-8) and ZnO@N-doped C are reported as effective adsorbents and photocatalysts for the adsorption and degradation of organic dyes. The materials showed effective and selective adsorption toward anionic dyes such as methyl blue (MeB) dye in the presence of fluorescein (FLU) dye. The adsorption capacities of ZnO@N-doped C for MeB and FLU dyes are 900 mg g−1 and 100 mg g−1, respectively. According to UV-Vis diffuse reflectance spectroscopy (DRS) data, ZnO@N-doped C has a lower bandgap (2.07 eV) than ZIF-8 (4.34 eV) and ZnO (3.12 eV). Thus, ZnO@N-doped C serves as an effective photocatalyst for the degradation of both dyes under UV exposure. The degradation efficiency capacity of the dye (50 mg L−1) is >90% using 200 mg L−1 of the photocatalyst. The mechanism of adsorption and photocatalysis is investigated. The photodegradation pathway of the dye involved the generation of oxidative hydroxy radicals (OH˙), which can degrade the dyes. The degradation products of FLU were recorded using mass spectrometry.

On-site generation of reactive oxidative radicals from dithionite treated oxic soil slurry

ABSTRACT Whereas dithionite has been extensively used as a reducing agent in soil and sediment remediation, here, we demonstrate that it can be used as a potential source of oxidizing radical in oxic soils with potential application in organic pollutant remediation. Benzoic acid was used as a probe compound and the generation of its oxidative product para-hydroxybenzoic acid (p-HBA) was detected to quantify the production of oxidative radicals (ROS). By increasing the dithionite concentration from 2.5–10 Mm, the accumulated P-HBA concentration in 120 min increased from 15.0–27 µM. Whereas, above 10 mM, the p-HBA concentration decreased due to radical scavenging. Increasing soil dosage from 2.5–15 g/100 mL the accumulated p-HBA amount increased from 22.8–33.7 µM. Temperature 25–35 oC and pH 6.2–7.5 were favoured for p-HBA generation. Furthermore, we investigated the roles of different active intermediates in the reaction system and proposed the mechanism behind the ROS genearation. This study suggested that dithionite can be used as an active reagent for advanced oxidation remediation in oxic soil medium.

Strengthened photocatalytic removal of bisphenol a by robust 3D hierarchical n-p heterojunctions Bi4O5Br2-MnO2via boosting oxidative radicals generation

Design and creation of photocatalytic systems with favorable microstructural and morphological merits are quite crucial to heighten removal of environmental hormones. For such purpose, in the current study n-type Bi4O5Br2 and p-type MnO2 were specially selected to construct three-dimensional (3D) hierarchical composites Bi4O5Br2-MnO2 (MB) via a facile one-pot procedure. Through thorough and systematical analyses, the existence of both expected components was confirmed in composites and these heterojunction MB composites showed significantly improved photocatalytic degradation of bisphenol A (BPA) under visible light. Particularly, the best candidate 0.5 MB owned the largest Kapp value 11.03 × 10−3 min−1 that was about 3.89 and 1.81 times those of bare Bi4O5Br2 and mechanical mixture 0.5 MB, which primarily attributed to strengthened visible-light absorption, effective integration of favorable morphologies, proper chemical composition, and efficient spatial separation of induced charge carriers through n-p heterojunction domains and thus boosted generation of oxidative radicals in a Z-Scheme model. In addition, other parameters possibly influenced photocatalytic degradation performance such as catalyst dosages, initial concentrations of BPA, pH values, and involvement of inorganic anions were also explored. Moreover, some intermediates were detected by GC-MS analysis to provide a plausible degradation path of these robust 3D hierarchical heterojunctions with satisfactory reusability and structural stability.

Simultaneously Enhanced Activity and Selectivity for C(sp3)\u2013H Bond Oxidation Under Visible Light by Nitrogen Doping

Selective oxidation of saturated C(sp3)–H bonds in hydrocarbon to target chemicals under mild conditions remains a significant but challenging task because of the chemical inertness and high dissociation energy of C(sp3)–H bonds. Semiconductor photocatalysis can induce the generation of holes and oxidative radicals, offering an alternative way toward selective oxidation of hydrocarbons under ambient conditions. Herein, we constructed N-doped TiO2 nanotubes (N-TNTs) that exhibited remarkable activity and selectivity for toluene oxidation under visible light, delivering the conversion of toluene and selectivity of benzaldehyde of 32% and > 99%, respectively. Further mechanistic studies demonstrated that the incorporation of nitrogen induced the generation of N-doping level above the O 2p valance band, directly contributing to the visible-light response of TiO2. Furthermore, hydroxyl radicals generated by photogenerated holes at the orbit of O 2p were found to be unselective for the oxidation of toluene, affording both benzaldehyde and benzoic acid. The incorporation of nitrogen was able to inhibit the generation of hydroxyl radicals, terminating the formation of benzoic acid.

Isolation and neuronal apoptosis inhibitory property of bacoside-A3 via downregulation of β-amyloid induced inflammatory response.

Alzheimer's disease is one of the neurodegenerative disorders caused by neuronal degeneration and apoptosis in brain. Bacoside A and B isolated from the Bacopa monniera plant are responsible for cognitive effects. These compounds repair damaged neurons by promoting activity of kinases, synaptic activity restoration, and improvement of nerve transmission. The present study explored the effect of bacoside-A3 on β-amyloid-induced reduction of U87MG cell viability, generation of oxidative radicals, and activation of nuclear factor-κB. The U87MG cells were stimulated with β-amyloid (10 μM) after 24 h of bacoside-A3 pretreatment or without pretreatment to induce characteristics of Alzheimer disease in vitro. Sulforhodamine B (SRB) assay was used to count viable cells and ELISA kit for analysis of PGE2 secretion. The pretreatment with bacoside-A3 prevented β-amyloid-mediated suppression of U87MG cell proliferation. Pretreatment of U87MG cells with bacoside-A3 prior to β-amyloid stimulation suppressed generation of ROS in a concentration-based manner. The β-amyloid-mediated formation of iNOS in U87MG cells was suppressed by bacoside-A3 in a dose-based manner. The β-amyloid-mediated PGE2 secretion was suppressed by bacoside-A3 pretreatment in U87MG cells in the dose-based manner. The overexpression of COX-2 by β-amyloid stimulation was suppressed in bacoside-A pretreated cells in the dose-based manner. The bacoside-A3 pretreatment prevented nuclear translocation of NF-κB in U87MG cells in the dose-based manner. In summary, bacoside-A3 prevented β-amyloid-mediated suppression of U87MG cell viability, inhibited generation of oxidative radicals, PGE2, and synthesis of iNOS. Therefore, bacoside-A3 has therapeutic potential for Alzheimer disease and further in vivo studies need to be performed.