Free Radical Formation Research Articles

Oxygen, the Paradox of Life and the Eye

Oxidative stress, caused by the formation of free radicals, such as reactive oxygen species (ROS), leads to cell and tissue degradation, contributing to various diseases and aging. While oxygen is essential for aerobic organisms, it inevitably causes oxidative stress. Antioxidants protect against damage from free radicals, and oxidative stress arises when an imbalance occurs between free radical production and antioxidant defenses. However, when investigating whether an excess of antioxidants, almost eliminating oxidative stress, could benefit aging and disease susceptibility, it was observed that a basic level of oxidative stress appears necessary to maintain the correct homeostasis of tissues and organs and life in general. Therefore, this review aimed to compile the most significant and recent papers characterizing and describing the dual role of oxygen as a molecule essential for life and as a precursor of oxidative stress, which can be detrimental to life. We conducted targeted searches in PubMed and Google browsers to gather all relevant papers. We then focused on the eye, an organ particularly vulnerable due to its high metabolic activity combined with direct exposure to light and environmental pollutants, which produces a substantial number of free radicals (mainly ROS). We present a curated selection of relevant literature describing the main ocular pathologies of the posterior and anterior segments of the eye, highlighting oxidative stress as a significant contributing factor. Additionally, we report how endogenous and exogenous antioxidants can mitigate the development and progression of these diseases. Finally, we consider a frequently overlooked aspect: the balance between oxidants and antioxidants in maintaining the homeostatic equilibrium of tissues and organs. It is widely recognized that when oxidants overwhelm antioxidants, oxidative stress occurs, leading to negative consequences for the organism's homeostasis. However, we emphasize that a similarly dangerous situation can arise when the presence of antioxidants overwhelms the production of free radicals, drastically reducing their amount and adversely affecting aging and longevity. Unfortunately, no specific studies have addressed this particular situation in the eye.

Novel Methods for the Formation of Free Carbyne Radicals in Solution.

Carbyne free radicals RC⋮ (RC) are usually associated with high-energy processes, thus research on their preparation, chemical reactivity, and prevalence under mild conditions is scarce. Recently, it was reported that metallo-complexes containing CR ligands may undergo spontaneous degradation in aqueous solutions to produce free RC radicals. These highly reactive species may react with each other to form the corresponding alkyne and other products. The reaction of 1,1,1 halo-carbo-hydrates with Cr(II) ions also forms RC radicals under mild conditions. Herein, we report two additional synthetic routes that produce free RC radicals under mild conditions. First, the reaction between metallic zinc and acetic anhydride produces 2-butyne and several other C2, C3, and C4 compounds. Isotopic-labeling experiments indicate that the formation of 2-butyne results from an inter-molecular reaction in which two RC moieties from two acetic anhydride molecules combine in solution. In addition, the degradation of the tri-molybdenum complex [Mo3(H3CC≡CCH3)(OAc)(H2O)2Br7], in which a 2-butyne ligand is coordinated to the Mo3 framework in a μ3-η2 (⊥) binding mode in aqueous solution produces several C2, C3, C4 and C5 molecules. This indicates the formation of free CH3C radicals by a homolytic cleavage of the carbon-carbon triple bond.

Engineering atomic Rb-N configurations to tune radical pathways for highly selective photocatalytic H2O2 synthesis coupled with biomass valorization

Photocatalytic oxygen reduction for hydrogen peroxide (H₂O₂) synthesis presents a green and cost-effective production method. However, achieving highly selective H₂O₂ synthesis remains challenging, necessitating precise control over free radical reaction pathways and minimizing undesirable oxidative by-products. Herein, we report for the visible light-driven simultaneous co-photocatalytic reduction of O2 to H2O2 and oxidation of biomass using the atomic rubidium-nitride modified carbon nitride (CNRb). The optimized CNRb catalyst demonstrates a record photoreduction rate of 8.01 mM h−1 for H2O2 generation and photooxidation rate of 3.75 mM h−1 for furfuryl alcohol to furoic acid, achieving a remarkable solar-to-chemical conversion (SCC) efficiency of up to 2.27%. Experimental characterizations and DFT calculation disclosed that the introducing atomic Rb–N configurations allows for the high-selective generation of superoxide radicals while suppressing hydroxyl free radical formation. This is because the Rb–N serves as the new alternative site to perceive a stronger connection position for O2 adsorption and reinforce the capability to extract protons, thereby triggering a high selective redox product formation. This study holds great potential in precisely regulating reactive radical processes at the atomic level, thereby paving the way for efficient synthesis of H2O2 coupled with biomass valorization.

The Effect of Prawns Shell Carotenoprotein Insertion on the Quality and Oxidative Stability of Tuna Eye Oil

The oxidation of polyunsaturated fatty acids (PUFAs) reduces the nutritional value of fish oil supplements and poses health risks due to the formation of free radicals and oxidative compounds. Consequently, preventing or minimizing oxidation in these supplements is a critical concern in the production industry. Tuna eye (TE) oil, similar to other fish oils, is highly prone to oxidation, leading to the need for antioxidant enhancement. Carotenoprotein, rich in astaxanthin from shrimp shells, is a powerful natural antioxidant that can potentially stabilize PUFAs in TE oil, but the application to TE oil has not been previously explored. Therefore, this study aimed to evaluate the effect of shrimp shell-derived carotenoprotein on the quality and oxidative stability of TE oil during storage. The proximate composition of tuna eye and shrimp by-products was analyzed during the investigation process. Initial TE oil and TE oil with added carotenoprotein were assessed for free fatty acid content, acid value, peroxide value, p-anisidine value, total oxidation value, and heavy metal content. Carotenoprotein was evaluated for its color and antioxidant activity. The TE oil was combined with 0.4%, 0.6%, and 0.8% (v/v) concentrations of carotenoprotein and examined for stability using the Schaal oven test method at 40°C. The variations in these concentrations were systematically selected to determine potential concentration-dependent effects on TE oil oxidative stability. The results showed that on day 60 of TE oil storage at room temperature, oxidative degradation was significantly influenced by carotenoprotein concentration. Free fatty acids increased to 1.39%, while the values of acid, peroxide, anisidine, and total oxidation identified at the 0.4, 0.6, and 0.8% concentrations were 1.61, 1.50, and 1.24 mg KOH/kg, 18.87, 15.98, and 13.29 meq/kg, 10.80, 11.40, and 9.70 meq/kg, as well as 48.54, 43.36, and 36.28 meq/kg, respectively. Moreover, 0.8% carotenoprotein addition was found to effectively prevent TE oil deterioration compared to the control group.

The role of doxorubicin in the formation of cardiotoxicity is a consensus statement. Part II. Cardiotoxicity of doxorubicin unrelated to myocytes and cardioprotection strategy (review)

Introduction. The use of doxorubicin in clinical practice has shown cumulative and dose-dependent toxic effects on cardiomyocytes, leading to an increase of mortality risk among patients with cancer and as a resulting to restrictions in the indications for its use.Text. A dangerous adverse reaction of doxorubicin is cardiomyopathy, leading to congestive heart failure. Cardiotoxicity is based on at least several pathophysiological mechanisms (described in more detail in the first part of the review), leading to damage to cardiomyocytes as a result of oxidative stress with the formation of free radicals, dysfunction of mitochondria, autophagy, release of nitric oxide and inflammatory mediators, as well as changes in gene expression and proteins leading to apoptosis. The current (second) part of the review provides detailed information on the actual understanding of the pathophysiological mechanisms underlying the described cardiotoxicity, the effect of doxorubicin on other heart cells. The use of cardioprotective strategies will reduce the severity and likelihood of developing cardiotoxicity. This article describes strategies based on reducing the maximum cumulative dose, changing the speed of doxorubicin administration, using pegylated liposomal formulations and cardioprotective agents, as well as exercise.Conclusion. Despite the huge number of scientific papers devoted to various aspects of cardiotoxicity of doxorubicin, its prevention and treatment, this issue requires more careful study and development of more advanced methods of early diagnosis, prevention and more effective therapy the complication.

A step to microplastic formation: Microcracking and associated surface transformations of recycled LDPE, LLDPE, HDPE, and PP plastics exposed to UV radiation

Plastics when exposed to UV radiation start to degrade via photooxidative aging including free radical formation, oxidation, chain scission and/or crosslinking reactions. These chemical changes can cause loss in mechanical strength, surface embrittlement, and eventually surface erosion. The eroded particles are microplastics (MPs), which have been identified as a potentially serious threat to the environment and its inhabitants. In general, photodegradation of virgin plastics has been studied extensively, but there is not much literature on the degradation of recycled plastics. The goal of the study was to investigate the changes caused by photodegradation in recycled plastics and assess the potential risks of MPs formation. And eventually, knowing the chemical and physical transformations occurring on the surface understand the mechanism behind surface microcracking, which is the first step of MPs formation. Pellets of five industrially recycled plastics (low-density polyethylene (rLDPE), linear low-density polyethylene (rLLDPE), high-density polyethylene (rHDPE), and two polypropylenes (rPP)) from different waste sources were analysed. UV irradiation was performed in an accelerated weathering chamber for milled (< 400 µm) plastic powder to ensure homogeneous changes throughout the sample. The properties were investigated by ATR-FTIR, HT-SEC, XPS and DSC. Formation of microcracks was studied on plastic pellets by SEM. The results showed that the degradation significantly differed between the recycled plastics, and the waste source was more important than the plastic type. rLDPE and one of the rPP samples showed a significant increase in carbonyl index as well as decrease in molar mass during the first 500 h of UV exposure. The other rPP and rHDPE samples showed first considerable signs of degradation only after 1000 h of UV exposure. Minor changes were observed for the rLLDPE sample during the whole test. The SEM revealed microcracking on the surface of all samples, which also had noticeable degradation identified by other methods. These recycled plastics can be considered the ones with the highest potential of MPs formation. From the chemical and physical transformations identified on the surface, the mechanism leading to microcracking, which is the first step in the formation of MPs, is proposed.

Effect of sonoprocessing on the quality of plant-based analog foods: Compatibility to sustainable development goals, drawbacks and limitations

Sonoprocessing (US), as one of the most well-known and widely used green processing techniques, has tremendous benefits to be used in the food industry. The urgent call for global sustainable food production encourages the usage of such techniques more often and effectively. Using ultrasound as a hurdle technology synergistically with other green methods is crucial to improving the efficiency of the protein shift as well as the number of plant-based analog foods (PBAFs) against conventional products. It was revealed that the US has a significant impact when used as an assistant tool with other green technologies rather than being used alone. It increases the protein extraction efficiencies from plant biomasses, improves the techno-functional properties of food compounds, and makes them more applicable for industrial-scale alternative food production in the circular economy. The US aligns well with the objectives outlined in the UN’s Sustainable Development Goals (SDGs), and Planetary Boundaries (PBs) framework, demonstrating promising outcomes in life cycle assessment. However, several challenges such as uncontrolled complex matrix effect, free radical formation, uncontrolled microbial growth/germination or off-flavor formation, removal of aromatic compounds, and Maillard reaction, are revealed in an increased number of studies, all of which need to be considered. In addition to a variety of advantages, this review also discusses the drawbacks and limitations of US focusing on PBAF production.

Photochromism, Thermochromism, and Electrochromism in Solid-State Host-Guest Inclusion Complexes of β-Cyclodextrin with Dialkylcarboxyl-Substituted Viologens.

Multi-stimuli-responsive chromic materials have immense potential for utilization. Herein, two supramolecular inclusion complexes were prepared by self-assembly of β-cyclodextrin (β-CD) with dialkylcarboxyl-substituted viologens, N,N'-di(3-carboxy-propyl)-4,4'-bipyridinium dichloride (CPV·Cl2) and N,N'-di(6-carboxy-hexyl)-4,4'-bipyridinium dibromide (CHV·Br2). The self-assembled inclusion complexes CPV2+@β-CD and CHV2+@β-CD2 in the solid-state exhibited naked-eye photochromism, thermochromism, and electrochromism in response to multiple external stimuli including light, temperature, and electric field, respectively. Solid-state UV-vis diffuse reflectance and electron spin resonance (ESR) spectroscopy revealed that the observed photochromism, thermochromism and electrochromism are attributed to the formation of viologen free radicals induced by electron transfer under external stimuli. The excellent stimuli-response chromic properties of the title inclusion complexes support their practical utility in visual display, multiple anticounterfeiting, and multilevel information encryption.

The Use of Photodynamic Therapy in the Treatment of Endometrial Cancer-A Review of the Literature.

Endometrial cancer is the most common malignant tumor of the female reproductive system. It develops in the mucous membrane lining the inside of the uterine body-the endometrium, through the abnormal and continuous growth of cancer cells originating from the uterine mucosa. In recent years, there has been a significant increase in the number of cases in European countries. Photodynamic therapy (PDT) is an innovative and dynamically developing medical procedure, useful in the treatment of cancer and non-cancer tissue conditions. The PDT reaction involves the activation of a photosensitizing substance with visible light, which in turn leads to the formation of free oxygen radicals, which contribute to the destruction of the cell. PDT is minimally invasive, has few side effects, and preserves organ anatomy and function. Both diagnostics and photodynamic therapy as modern methods of treatment are becoming more and more popular in many research units around the world. They are most often practiced and tested in in vitro experimental conditions. In clinical practice, the use of PDT is rare. Comprehensive cooperation between scientists contributes to taking steps towards obtaining new, synthetic photosensitizers, directing their physicochemical properties, and showing the impact on a given organism. This review examines the evidence for the potential and usefulness of PDT in the treatment of endometrial cancer. This review highlights that PDT is gaining popularity and is becoming a promising field of medical research.

Physicochemical, thermal, and functional properties of edible red algae (Gracilaria corticata).

In the present research, physicochemical, functional, and antioxidant properties of Gracilaria corticata (GC) powder were evaluated. The seaweed was found rich in protein (21%) carbohydrate (53.03%) and fat (7.8%). The inductively coupled plasma-optical emission spectrometry showed among the mineral's calcium (13.987mg/g) and magnesium (7.48mg/g) were found to be in higher percent. Three transition peaks were observed as the samples were subjected to DSC (-5.27°C for fat, 82.25°C for carbohydrates, and 98.79°C for proteins). The CHNS analysis demonstrated sulfur content (2.23%) depicts presence of sulfate polysaccharide confirmed by Fourier transform infrared spectroscopy spectra band at 1235cm-1. A significant increase in the swelling capacity (14.26-21mL/g) and water holding capacity (8.21-9.09g/g) was observed as the temperature was increased from 25 to 80°C. On the contrary, oil holding capacity decreased significantly from 3.98 to 2.11g/g with an increase in temperature. Nowadays, the sedentary lifestyle leads to chronic disease; however, the antioxidants derived from plants provide the biochemical defense from free radical formation. The marine-derived algal are good sources of nutrition and antioxidants, being natural sources of GC, the antioxidant activity exhibited by total phenolic content and α-diphenyl-β-picrylhydrazyl were found to be (11mg GAE/g and 18%) inhibition, respectively. The principal phytochemicals profile was quantified by liquid chromatography-mass spectrometry as catechin, coumaric acid, phloroglucinol, and luteolin.

Localized in vivo prodrug activation using radionuclides.

We screened the ability of radionuclides to chemically activate a model radiation-activated prodrug consisting of the microtubule destabilizing monomethyl auristatin E caged by a radiation-responsive phenyl azide ("caged-MMAE") and interpreted experimental results using the radiobiology computational simulation suite TOPAS-nBio. RAiDER was evaluated in syngeneic mouse models of cancer using fibroblast activation protein inhibitor (FAPI) agents 99m Tc-FAPI-34 and 177 Lu-FAPI-04, the prostate-specific membrane antigen (PSMA) agent 177 Lu-PSMA-617, combined with caged-MMAE or caged-exatecan. Biodistribution in mice, combined with clinical dosimetry, estimated the relationship between radiopharmaceutical uptake in patients and anticipated concentrations of activated prodrug using RAiDER. RAiDER efficiency varied by 250-fold across radionuclides ( 99m Tc> 177 Lu> 64 Cu> 68 Ga> 223 Ra> 18 F), yielding up to 1.22µM prodrug activation per Gy of exposure from 99m Tc. Computational simulations implicated low-energy electron-mediated free radical formation as driving prodrug activation. Clinically relevant radionuclide concentrations chemically activated caged-MMAE restored its ability to destabilize microtubules and increased its cytotoxicity by up to 600-fold compared to non-irradiated prodrug. Mice treated with 99m Tc-FAPI-34 and caged-MMAE accumulated up to 3000× greater concentrations of activated MMAE in tumors compared to other tissues. RAiDER with 99m Tc-FAPI-34 or 177 Lu-FAPI-04 delayed tumor growth, while monotherapies did not ( P <0.03). Clinically-guided dosimetry suggests sufficient radiation doses can be delivered to activate therapeutically meaningful levels of prodrug. This proof-of-concept study shows that RAiDER is compatible with multiple radionuclides commonly used in nuclear medicine and has the potential to improve the efficacy of radiopharmaceutical therapies to treat cancer safely. RAiDER thus shows promise as an effective strategy to treat disseminated malignancies and broadens the capability of radiopharmaceuticals to trigger diverse biological and therapeutic responses.

Protective Role of Polyethylene Glycol Towards the Damaging Effects of Cadmium.

This study aimed to evaluate the role of drought-induced changes in the effects of cadmium (Cd) in plants. Cd is the most hazardous and important environmental pollutant. Water deficit is the most common environmental stress encountered by plants and affects most of the plant functions. The present study assessed the effect of Cd and water deficit on Capsicum frutescens seedlings in single and combined treatments. The seedlings of Capsicum were grown in a hydroponic solution and treated with Cd. The seedlings were subjected to water deficit with the help of polyethylene glycol (PEG). The other set of seedlings was treated with combined Cd + PEG. In the absence of PEG, maximum Cd accumulation was observed. The root and shoot growth of the seedlings were affected under all treatments with maximum inhibition in Cd. Pigment, protein and sugar contents and nitrate reductase activity decreased significantly in all treatments, while proline content increased. Induction of oxidative damage occurred through the formation of free radicals which caused alteration in electrolyte leakage, lipid peroxidation and activities of antioxidant enzymes, viz. superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase and non-enzymatic non-protein thiol content and ascorbic acid in the stressed seedlings. Water deficit buttressed the toxic effect of Cd on chilli seedlings.

Estimation of the Salivary Copper Levels in Oral Submucous Fibrosis Condition: An In Vivo Study.

The aim of the present study was to estimate the salivary copper levels in oral submucous fibrosis (OSMF) condition. A total of 60 individuals of which an equal number of 30 each in normal healthy control group as well as in clinically and histopathologically (the biopsy was done once after the clinical confirmation of OSMF in the patient) confirmed patients of OSMF were included in the study group. Total of 51 males and 9 females were considered for the present study and the age distribution of these groups ranged from a minimum of 21 years to a maximum of 74 years. Unstimulated whole saliva was collected from the patient followed by the conventional biopsy practice. The collected saliva was then subjected for the analysis of copper levels. Trace element copper was estimated by using Digital Semiautomatic Analyzer with the help of copper kit. The clinical mouth opening of OSMF was estimated. Analysis of variance (ANOVA) and Tukey HSD post hoc test was used analyze the data wherein the participants were grouped into age ranges of 20-30, 31-40, 41-50, and >60 years. The mean salivary copper level among OSMF and control groups with respect to age in 20-30 years was 55.98 ± 15.50 and 30.87 ± 7.70, in 31-40 years was 63.96 ± 21.13 and 32.95 ± 4.56, in 41-50 years was 50.11 ± 6.83 and 30.46 ± 3.28, and >60 years was 45.65 and 13.67 µg/dL, respectively. The mean salivary copper levels among OSMF and Control groups with respect to males were 55.60 ± 15.27 and 31.18 ± 6.97 and among females were 67.0 ± 24.25 and 30.06 ± 5.77 µg/dL, respectively. The mean salivary copper levels with histopathological grades in very early stage was 47.18 ± 5.73, in early stage was 49.22 ± 7.65, in moderately advanced was 73.53 ± 10.62 and in OSMF with mild dysplasia was 79.98 ± 16.27 µg/dL, respectively. The mean salivary copper levels in individuals with clinical mouth opening more than 35 mm was 45.65 ± 6.57, in 25-35 mm was 48.94 ± 21.60, in 15-25 mm was 70.54 ± 3.52 and in less than 15 mm was 81.50 ± 16.66, respectively. The present study concluded that salivary trace element levels could be used as potential diagnostic and prognostic markers in patients with OSMF. Trace elements are involved in many different physiological and metabolic processes in humans, either directly or indirectly. Copper is involved in vital biochemical activities like different redox and free radical formation and in maintaining cellular proton homeostasis. It is also associated with the processing of oxygen and a component of arecanut in all forms, which is implicated in the etiology of OSMF. How to cite this article: Gupta R, Jayanti I, Das A, et al. Estimation of the Salivary Copper Levels in Oral Submucous Fibrosis Condition: An In Vivo Study. J Contemp Dent Pract 2024;25(5):498-502.

Activating Fenton-like reaction by hydrochars containing persistent free radicals derived from various pomelo peel components

To reveal the influence of the diversity of precursors on the formation of environmental persistent free radicals (EPFRs), pomelo peel (PP) and its physically divided portion, pomelo cuticle (PC), and white fiber (WF) were used as precursors to prepare six hydrochars: PPH-Fe, PCH-Fe, WFH-Fe, PPH, PCH, and WFH with and without Fe(III) addition during hydrothermal carbonization (HTC). PPH-Fe and WFH-Fe had higher EPFRs content (9.11 × 1018 and 8.25 × 1018 spins·g−1) compared to PPH and WFH (3.33 × 1018 and 2.96 × 1018 spins·g−1), indicating that iron-doping favored EPFRs formation. However, PCH-Fe had lower EPFRs content (2.78 × 1018 spins·g−1) than PCH (7.95 × 1018 spins·g−1), possibly due to excessive iron leading to the consumption of the generated EPFRs. For another reason, the required Fe(III) amount for EPFRs formation might vary among different precursors. PC has a lower concentration of phenolic compounds but 68–97% fatty acids, while WF and PP are rich in cellulose and lignin. In the Fenton-like reaction, oxygen-centered radicals of hydrochar played a significant role in activating H2O2 and efficiently degrading bisphenol A (BPA). Mechanisms of reactive oxygen species (ROS) generation in hydrochar/H2O2 system were proposed. EPFRs on hydrochar activate H2O2 via electron transfer, creating ·OH and 1O2, leading to BPA degradation. More importantly, the embedded EPFRs on the hydrochar's inner surface contributed to the prolonged Fenton-like reactivity of PPH-Fe stored for 45 days. This study demonstrates that by optimizing precursor selection and iron doping, hydrochars can be engineered to maximize their EPFRs content and reactivity, providing a cost-effective solution for the degradation of hazardous pollutants.Graphical abstract

Native and TMT Chestnut Extractives as Hydrophobic and Photostabylizing Additives for Wood Surfaces

Wood extractives have proven strong anti-oxidative properties which may be used to mitigate surface deterioration caused by photolytic effects and free radical formations. An interesting challenge regarding wood extractives is understanding how they behave in terms of treating natural wood surfaces to reduce anti-oxidative processes that arise from exposure to the main environmental factors. In this study, the possible efficacy of chestnut (Castanea sativa Mill.) extractives derived from native (CH) and thermally modified wood (TMT CH), as a means of protecting against UV exposure in poplar (Populus spp.) and spruce (Picea abies Karst.) wood, was evaluated. Chestnut wood was first thermally modified at 180 °C for 3 h, and the extractives were obtained by the accelerated solvent extraction technique (ASE) and subsequently used to treat wood surfaces. Samples were immersed in extractive solutions and exposed to artificial UV-weathering exposure, then contact angle and colour stability were monitored during the process. An FTIR analysis of the photo-degradation process of poplar and spruce surfaces was also executed. Extractives of TMT chestnut changed the total colour variation in both poplar and spruce wood. A much darker colour compared to the extractives of native wood was observed and an increase in ∆E* from 9.75 to 30.76 and 6.24 to 22.97 in poplar and spruce was calculated. The stability of the colour depended both on the surface wood and the type of extractive. The initial contact angle remained almost unchanged in the poplar wood surface and only slightly increased in spruce regardless of whether they were treated with extractives from native or TMT chestnut wood. A strong reduction in contact angle after the accelerated UV exposure test was observed, especially in spruce treated with CH extractives. FTIR analysis confirmed the lower levels of chemical degradation of surfaces observed by colorimetry, where TMT CH extractives formed more stable chemical bonds than native extractives. The comparative analysis in this study clarified the complex relationships between the effects of high-temperature modification of wood and the potential protective role of TMT extractives on some wood surfaces.

Qualitative Analysis and Anti-oxidant Potential of Ethanolic Extract ofManilkara zapota (L.) P. Royen Leaves

Background: The normal metabolic functioning of aerobic cells is related to free radical formation. The oxygen utilized in the cell growth gives rise to a number of oxygen free radicals. Further, these oxygen free radicals interact with lipidic molecules to produce hydroxyperoxides and various other peroxides also, radicals like superoxide, hydroxyls, and lipoid peroxides, which lead to cytotoxicity due to their interaction with biological systems. The uncontrolled generation of free radicals may lead to various diseases and disorders like prostate cancer, coronary heart disease and also ageing. The therapeutic potential of the plant M. zapota has been demonstrated in various diseases, such as cancers (e.g., breast, prostate, cervical, and hepatocellular cancer), diabetes mellitus, arthritis, bacterial infections, and gastrointestinal disorders (e.g., diarrhea and ulcers) and many medical conditions. The main phytocomponents of this plant are polyphenols, alkaloids, glycosides, flavonoids, saponins, triterpenoids, carbohydrates, tannins, and sterols. Objective: The objective of this study is to investigate qualitative analysis and anti-oxidant potential of ethanolic extract of Manilkara zapota (L.) P. Royen Leaves. In demand to minimize the damage caused by free radicals. It is very essential to develop such antioxidants which protect the body from the effect of free radicals and also do not cause much harm to the human body. The main phytocomponents of the plant are polyphenols, alkaloids, glycosides, flavonoids, saponins, triterpenoids, carbohydrates, tannins and sterols which are responsible for antioxidant activity. Materials and Methods: Phytochemical screening methods, Gas chromatography–mass spectrometry (GC-MS), Fourier transform infrared (FTIR), and Hydrogen Peroxide scavenging assay for analysis of an ethanolic extract of plant leaves. Results and Discussion: Antioxidant activity was determined by a hydrogen peroxide assay. Plant extract was examined using phytochemical screening, GC-MS analysis, and FTIR spectra. The plant extract showed hydrogen peroxide scavenging activity (IC50 = 16.45 μg/ml) compared to the IC50 values of standard ascorbic acid (IC50 = 9.079 μg/ml). Conclusion: The present study concluded the antioxidant and phytochemical assessment of the ethanolic extract of the leaves of Manilkara zapota. The results of the present research study demonstrated that the antioxidant activity of the plant extract was strong as compared to ascorbic acid.

Weak magnetic effect and free radical reaction mechanism on the dissolution of lightweight magnesia in CaO–Al2O3–SiO2 melts

Lightweight magnesia-based refractories play a crucial role in achieving energy savings and carbon reduction in steelmaking furnaces. The primary requirement is to make lightweight magnesia refractories with high corrosion resistance. The introduction of a weak static magnetic field is also a promising way to improve the slag resistance of lightweight refractories in addition to optimizing the composition and structure of the refractories. In this paper, the dissolution behavior of the lightweight magnesia in CaO–Al2O3–SiO2 molten slags at and above 1600 °C under weak static magnetic field is presented. The influence of the weak static magnetic field on the dissolution rate was analyzed, the behavior from the perspective of free radical and kinetics was discussed, and the influence of different calcia–silica weight ratios (C/S) on slag, magnetic flux density and the reaction mechanism are revealed. The results show that the dissolution rate of the lightweight magnesia in the molten slag presents a significantly weak magnetic effect, with a reaction inhibition interval of 2–4 mT in the range of 0–16 mT magnetic field intensity, and the key inhibition threshold surpasses that of alumina. The mechanism of the free radical formation and reaction during magnesia dissolution in high-temperature slag is explained and illustrated. The relationship between the magnetic flux density, superoxide radical content, and dissolution rate is presented, providing theoretical guidance for developing magnetic combined magnesia refractories.

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.

Targeted HER2-positive cancer therapy using ADAPT6 fused to horseradish peroxidase

Targeted cancer therapy is a promising alternative to the currently established cancer treatments, aiming to selectively kill cancer cells while sparing healthy tissues. Hereby, molecular targeting agents, such as monoclonal antibodies, are used to bind to cancer cell surface markers specifically. Although these agents have shown great clinical success, limitations still remain such as low tumor penetration and off-target effects. To overcome this limitation, novel fusion proteins comprised of the two proteins ADAPT6 and Horseradish Peroxidase (HRP) were engineered. Cancer cell targeting is hereby enabled by the small scaffold protein ADAPT6, engineered to specifically bind to human epidermal growth factor receptor 2 (HER2), a cell surface marker overexpressed in various cancer types, while the enzyme HRP oxidizes the nontoxic prodrug indole-3-acetic acid (IAA) which leads to the formation of free radicals and thereby to cytotoxic effects on cancer cells. The high affinity to HER2, as well as the enzymatic activity of HRP, were still present for the ADAPT6-HRP fusion proteins. Further, in vitro cytotoxicity assay using HER2-positive SKOV-3 cells revealed a clear advantage of the fusion proteins over free HRP by association of the fusion proteins directly to the cancer cells and therefore sustained cell killing. This novel strategy of combining ADAPT6 and HRP represents a promising approach and a viable alternative to antibody conjugation for targeted cancer therapy.

Differential Incidence of Contrast-Associated Acute Kidney Injury: Comparing Intravenous and Intraarterial Contrast Administration.

Contrast-associated acute kidney injury (CA-AKI) remains a significant concern in diagnostic and invasive procedures, particularly in the context of iodinated contrast material administration. The traditional definition of CA-AKI, based on serum creatinine elevation following contrast exposure, may not accurately capture its multifactorial nature. Studies have provided new insights into the differential incidence of CA-AKI between intravenous and intraarterial contrast administration, emphasizing the importance of tailored preventative strategies for high-risk procedures. This higher risk may arise from two proposed mechanisms: one implicating free radical formation leading to cytotoxicity and apoptosis in renal cells and another suggesting that contrast media alter renal hemodynamics, particularly in the outer medulla, by constricting the vasa recta and reducing medullary flow. Advances in technology and patient care, including contemporary use of low-osmolar contrast agents and hydration protocols, mitigate CA-AKI risk. Diagnostic and invasive procedures should not be avoided solely due to concerns about renal dysfunction if the patient is likely to benefit clinically.