Free Radical Synthesis Research Articles

Investigation of the Effect of Nano-melatonin on Oxidative Stress in Sera of Patients with Polycystic Syndrome

Background: The association between polycystic ovary syndrome (PCOS) and oxidative stress in women, the possible causes of PCOS, insulin resistance (IR), obesity, and oxidative stress. Oxidants are chemical elements that tend to gain electrons, losing positive charge. The Oxidative Stress (OS) is defined as an imbalance between the formation and synthesis of free radicals and the antioxidant defense system, which results in oxidative damage. Objective: The purpose of this research is to investigate the effect of nano-melatonin on oxidative stress in the sera of patients with polycystic syndrome. Methods: The study includes 120 Iraqi women, divided into two groups: 60 PCOS patients and 60 healthy control patients. Sample Analysis Biochemistry analyses the hormonal profile and determines the hormonal levels (LH, FSH, Testosterone, and Prolactin) that were identified for all controls and patients. Hormones analysis was performed using the enzyme-linked fluorescent assay (ELFA) technique. Synthesized ML nanoparticles by ultrasonic sonication. Results: The results indicate that the mean of serum LH significantly increased (P<0.02) in PCOS BMI ≥ 25 patients G1 (6.19±3.13) mIU/mL compared with controls C1 (4.504±1.591) mIU/mL, while a nonsignificant difference (P>0.05) when compared the BMI<25 kg/m2 for G2 (5.55±1.93) with control group C2 (6.31±2.58) of luteinizing hormone in G1 and G2. Conclusions: An increased ratio of LH to FSH was shown to be characteristic of PCOS. For PCOS, high LH values are crucial. For the purpose of diagnosing PCOS, high LH values are crucial release of gonadotropin hormones (LH, FSH) from the pituitary. To higher the production of androgen in ovarian theca cells, The LH receptor is activated by the luteinizing hormone (LH). The nano Mel was higher in the inhibition of Oxidative stress two causes nano-melatonin high surface area and small size.

Solvent-based synthesis, structural elucidation and thermal characterisation of free radical grafted PHBV

This study investigates the solvent-based free-radical graft copolymerization of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with C11 (undecenoic acid, UDA), C12 (dodecene, DD), and C18 (octadecene, OD) alkene substrates using dicumyl peroxide as an initiator. Comprehensive Nuclear Magnetic Resonance (NMR) spectroscopy was employed to confirm and quantify grafting, which was achieved at up to 5.8 mol% of monomer units. Thermal analysis revealed a significant reduction in melting temperature for all modified PHBVs, ranging from 10-20°C decrease in comparison to virgin PHBV. A decrease in crystallisation temperature and a reduction in glass transition temperature was measured for the UDA and DD grafted PHBV. Additionally, molecular weight analysis showed a marked decrease in weight average molecular weight (M¯w) and number average molecular weight (M¯n) for PHBV grafted with UDA, which was attributed to the presence of carboxylic acid functionality, which accelerates chain scission. The molecular weight profiles of the dodecene and octadecene grafted PHBV were only marginally reduced (32% and 18% reductions in M¯w, respectively), which is a much less severe reduction than has been previously observed for similar chemistries. Overall, this work demonstrates that solvent-based free-radical graft copolymerization can reduce the melting temperature and disrupt the crystallinity of PHBV, hence improving its processability and progressing the field of PHA modification and application.

Effect of interval hypoxytherapy on the immune status of hypertensive patients

In recent years, the role of sluggish nonspecific inflammation in the pathogenesis of hypertension has been proven. Oxidative stress that develops in hypertension leads to damage of endothelial glycocalyx with impaired barrier and adaptive functions of endothelium. Activation of transcription factor NF-kB leads to increased synthesis of free oxygen radicals, adhesion molecules (VCAM-1, ICAM-1, P-selectin, E-selectin) and proinflammatory cytokines (TNFα, IL-1, IL-6), triggering the inflammatory process in the endothelium. Modern antihypertensive drugs, affecting various pathogenetic mechanisms of arterial hypertension development, do not fully affect the immune component of arterial hypertension. Therefore, the search for various methods affecting the immunologic reactivity of hypertensive patients remains relevant in our time. The aim of the study was to reveal the effect of interval hypoxytherapy on the state of immunologic reactivity of patients with hypertension stage I. One hundred seventy male patients of 30-45 years old (mean age 38.36±1.64 years) with hypertension stage I (n = 170) who underwent combined treatment including drug therapy and normobaric interval hypoxic therapy in hypoxia-normoxia mode (oxygen content in hypoxic gas mixture was 20.9%) were examined. Indices of redox status and immunologic reactivity before and after interval hypoxytherapy were studied. Having a significant antioxidant effect, interval hypoxytherapy led to the subsidence of oxidative stress, which was indicated by an increase in the activity of superoxide dismutase and glutathione peroxidase in blood erythrocytes and a decrease in the content of malonic dialdehyde in blood as a result of a decrease in the generation of free oxygen radicals and suppression of lipid peroxidation processes. Interval hypoxytherapy resulted in a statistically significant increase in the initially decreased content of CD3+T lymphocytes (p 0.05), CD3+CD4+T lymphocytes (p 0.02), CD3+CD8+T lymphocytes (p 0.02). Initially increased number of B-lymphocytes CD19+, CD16+ lymphocytes, CD95+ lymphocytes significantly decreased. An important result of interval hypoxytherapy was a pronounced anti-inflammatory effect: statistically significant decrease in the content of pro-inflammatory interleukins IL-1β (p 0.02), IL-6 (p 0.01) and increase in the content of anti-inflammatory cytokines IL-4 (p 0.005) and IL-10 (p 0.005), which led to the subsidence of sluggish nonspecific inflammation. Suppression of oxidative stress and normalization of immunological reactivity of hypertensive patients after interval hypoxytherapy led to the subsidence of sluggish nonspecific inflammation, reduction of endothelial dysfunction and restoration of the structure and tone of the vascular wall with a decrease in blood pressure and improvement of the clinical course of hypertension.

Orchestrating Stress Responses in Multiple Sclerosis: A Role for Astrocytic IFNγ Signaling.

Multiple sclerosis (MS) is an inflammatory and neurodegenerative disease that is characterized by the infiltration of peripheral immune cells into the central nervous system (CNS), secretion of inflammatory factors, demyelination, and axonal degeneration. Inflammatory mediators such as cytokines alter cellular function and activate resident CNS cells, including astrocytes. Notably, interferon (IFN)γ is a prominent pleiotropic cytokine involved in MS that contributes to disease pathogenesis. Astrocytes are dynamic cells that respond to changes in the cellular microenvironment and are highly responsive to many cytokines, including IFNγ. Throughout the course of MS, intrinsic cell stress is initiated in response to inflammation, which can impact the pathology. It is known that cell stress is pronounced during MS; however, the specific mechanisms relating IFNγ signaling to cell stress responses in astrocytes are still under investigation. This review will highlight the current literature regarding the impact of IFNγ signaling alone and in combination with other immune mediators on astrocyte synthesis of free oxygen radicals and cell death, and cover what is understood regarding astrocytic mitochondrial dysfunction and endoplasmic reticulum stress.

Nephroprotective Potentials of Ethanol Leaf Extract of Balakat Tree (Ziziphus Talanai) (Blanco) Merrill. Against Gentamicin- Induced Nephrotoxicity in Male Icr Mice (Mus Musculus L.)

Renal dysfunction can be caused by antibiotic drugs like Gentamicin, which can induce lipid peroxidation, increase free radical synthesis, and decrease antioxidant activity, leading to kidney failure. In the antiques, Philippines, an endemic species of Ziziphus, Ziziphus talanai (Balakat tree), is used as a traditional medicine to treat kidney problems. Phytochemical screening of the ethanol leaf extract of the Balakat tree revealed its potential as a nephroprotective agent. Twelve 6- to 8-week-old male ICR mice were divided into four groups, and treatments were administered for 18 days. Gentamicin was administered intraperitoneally, whereas water, leaf extract, and garlic supplement were administered via oral gavage. The ethanolic leaf extract of the Balakat tree exhibited little potential as a nephroprotective agent at the single dosage used (0.3ml/20g bw), and further studies involving higher doses are recommended. These findings suggest that the ethanolic leaf extract of the balakat tree has potential as a nephroprotective agent. Further studies with higher doses are recommended.

An Isolable One-Coordinate Lead(I) Radical with Strong g-Factor Anisotropy.

Lead-based radicals in the oxidation state of +1 are elusive species and are highly challenging to isolate in the condensed phase. In this study, we present the synthesis and characterization of the first isolable free plumbylyne radical 2 bearing a one-coordinate Pb(I) atom. It reacts with an N-heterocyclic carbene (NHC) to afford a two-coordinate NHC-ligated Pb(I) radical 3. 2 and 3 represent the first isolable Pb(I)-based radicals. Theoretical calculations and electron paramagnetic resonance analysis revealed that the unpaired electron mainly resides at the Pb 6p orbital in both radicals. Owing to the unique one-coordinate nature of the Pb atom in 2, it possesses two-fold orbital pseudo-degeneracy and substantial unquenched orbital angular momentum, and exhibits hitherto strongest g-factor anisotropy (gx,y,z=1.496, 1.166, 0.683) amongst main group radicals. Preliminary investigations into the reactivity of 2 unveiled its Pb-centered radical nature, and plumbylenes were isolated as products.

An Isolable One‐Coordinate Lead(I) Radical with Strong g‐Factor Anisotropy

AbstractLead‐based radicals in the oxidation state of +1 are elusive species and are highly challenging to isolate in the condensed phase. In this study, we present the synthesis and characterization of the first isolable free plumbylyne radical 2 bearing a one‐coordinate Pb(I) atom. It reacts with an N‐heterocyclic carbene (NHC) to afford a two‐coordinate NHC‐ligated Pb(I) radical 3. 2 and 3 represent the first isolable Pb(I)‐based radicals. Theoretical calculations and electron paramagnetic resonance analysis revealed that the unpaired electron mainly resides at the Pb 6p orbital in both radicals. Owing to the unique one‐coordinate nature of the Pb atom in 2, it possesses two‐fold orbital pseudo‐degeneracy and substantial unquenched orbital angular momentum, and exhibits hitherto strongest g‐factor anisotropy (gx,y,z=1.496, 1.166, 0.683) amongst main group radicals. Preliminary investigations into the reactivity of 2 unveiled its Pb‐centered radical nature, and plumbylenes were isolated as products.

The Association of Dietary Glycemic Index with the Prevention and Treatment of COVID-19: A Narrative Review

In 2019, a new coronavirus causing a flu-like syndrome was discovered in Chinese province of Hubei and there was a subsequent outbreak in Wuhan in December 2019. The severity and mortality of COVID-19 are affected by several preexisting comorbidities such as type 2 diabetes mellitus (T2DM). A more severe complication of COVID-19 in patients with diabetes could be due to the fact that hyperglycemia and insulin resistance, as important features of diabetes mellitus, are associated with a higher expression rate of angiotensin-converting enzyme-2 (ACE-2). ACE-2 can act as the entry site for SARS-CoV-2 to lung cells. Furthermore, in diabetes mellitus, increased inflammatory responses and impaired immune function are often present. Glycemic index (GI) and glycemic load (GL) are the characteristics of the diet that can affect glycemic control and insulin resistance. These two characteristics could possibly affect infections through their effect on gut microbiota composition, free radical synthesis, and mitochondrial loading. Therefore, it can be proposed that dietary GI and GL might be important factors in the development of COVID-19.

Comment on "Determination of Orellanine in Human Biological Matrices Using Liquid Chromatography with High-Resolution Mass Spectrometry Detection: A Validated Method Applied to Suspected Poisoning Cases".

To the Editor, Following our recent published article presenting an analytical method to detect orellanine in human fluids (i.e., urine, plasma and whole blood) (1), we would like to provide additional information regarding the detection of orellanine in kidney biopsies. Indeed, renal biopsy analysis in order to demonstrate orellanine intoxication was proposed decades ago (2, 3), but the elements presented here make us consider this approach likely to be questionable. Some Cortinarius mushrooms contain a nephrotoxic mycotoxin called orellanine. Known since a massive poisoning in Poland in 1957, orellanus syndrome after a consumption of Cortinarius mushrooms is characterized by the long latency period (2–14 days) between intake and first symptoms (4). Renal damage observed from biopsies has shown acute tubular necrosis, interstitial nephritis and fibrosis (5). The mechanism of orellanine toxicity is not clearly understood. Proposed mechanisms include inhibition of different cellular enzymes, inhibition of RNA and DNA synthesis and production of oxygen free radicals generated via oxidated orellanine. It is also unclear whether it is orellanine that is toxic to kidney cells or a degradation product such as orellinine or an unidentified metabolite (1, 4, 5). Diagnosis of orellanine poisoning is based on a suspicion of ingestion of Cortinarius mushrooms and acute kidney injury. Therefore, the clinical diagnosis is difficult and deserves analytical confirmation. Some have proposed kidney biopsy to detect orellanine on the belief that orellanine or its metabolites persist in renal cells (2, 3). This was based on the postulate that the release of orellanine and its metabolites from renal cells was very slow, allowing for a greater detection window range.

Novel eco-friendly initiation system based on vitamin C for energy efficient synthesis of PMAA hydrogel used for delivery of phenolic compounds

This study reports successful free radical synthesis of pH-sensitive hydrogels based on poly(methacrylic acid) (PMAA) by using new green initiation system based on vitamin C and hydrogen peroxide (VC/H2O2). The application of proposed initiation system provides many advantages, above all cost effective and eco-friendly synthesis which can be carried out under ambient conditions. The obtained PMAA hydrogels are analyzed by various technics: Differential Scanning Calorimetry, Fourier Transform Infrared spectroscopy, Scanning Electron Microscopy and by using single compression tests. In line with the intended application, PMAA hydrogels are further investigated in terms of their potential to be used for encapsulation and controlled release of active substances such as antioxidant phenolic compounds. To keep it green, the total phenolic compounds (TPC) were obtained from orange peels waste by applying ultrasonic-assisted extraction and deep eutectic solvent (DES) based on glycerol:urea:water. The TPC were successfully encapsulated into the PMAA hydrogels which were previously estimated to have the optimal mechanical and swelling properties with respect to the final application. The swelling behavior of the PMAA hydrogels and controlled release of the TPC were tested as a function of the various synthesis parameters in several media with different pH values. It was shown that TPC can be released in control manner in medium which simulates the environment in human intestines, finally resulting in enhanced bioavailability of TPC, reduced side effects and improved therapeutic effects.

In Vitro Analysis of Biological Activity of Circulating Cell-Free DNA Isolated from Blood Plasma of Schizophrenic Patients and Healthy Controls-Part 2: Adaptive Response.

Oxidized in vitro genomic DNA (gDNA) is known to launch an adaptive response in human cell cultures. The cfDNA extracted from the plasma of schizophrenic patients (sz-cfDNA) and healthy controls (hc-cfDNA) contains increased amounts of 8-oxodG, a DNA-oxidation marker. The aim of the research was answering a question: can the human cfDNA isolated from blood plasma stimulate the adaptive response in human cells? In vitro responses of ten human skin fibroblasts (HSFs) and four peripheral blood mononuclear cell (PBMC) lines after 1-24 h of incubation with sz-cfDNA, gDNA and hc-cfDNA containing different amounts of 8-oxodG were examined. Expressions of RNA of eight genes (NOX4, NFE2L2, SOD1, HIF1A, BRCA1, BRCA2, BAX and BCL2), six proteins (NOX4, NRF2, SOD1, HIF1A, γH2AX and BRCA1) and DNA-oxidation marker 8-oxodG were analyzed by RT-qPCR and flow cytometry (when analyzing the data, a subpopulation of lymphocytes (PBL) was identified). Adding hc-cfDNA or sz-cfDNA to HSFs or PBMC media in equal amounts (50 ng/mL, 1-3 h) stimulated transient synthesis of free radicals (ROS), which correlated with an increase in the expressions of NOX4 and SOD1 genes and with an increase in the levels of the markers of DNA damage γH2AX and 8-oxodG. ROS and DNA damage induced an antioxidant response (expression of NFE2L2 and HIF1A), DNA damage response (BRCA1 and BRCA2 gene expression) and anti-apoptotic response (changes in BAX and BCL2 genes expression). Heterogeneity of cells of the same HSFs or PBL population was found with respect to the type of response to (sz,hc)-cfDNA. Most cells responded to oxidative stress with an increase in the amount of NRF2 and BRCA1 proteins along with a moderate increase in the amount of NOX4 protein and a low amount of 8-oxodG oxidation marker. However, upon the exposure to (sz,hc)-cfDNA, the size of the subpopulation with apoptosis signs (high DNA damage degree, high NOX4 and low NRF2 and BRCA1 levels) also increased. No significant difference between the responses to sz-cfDNA and hc-cfDNA was observed. Sz-cfDNA and hc-cfDNA showed similarly high bioactivity towards fibroblasts and lymphocytes. Conclusion: In cultured human cells, hc-cfDNA and sz-cfDNA equally stimulated an adaptive response aimed at launching the antioxidant, repair, and anti-apoptotic processes. The mediator of the development of the adaptive response are ROS produced by, among others, NOX4 and SOD1 enzymes.

Performance of a novel, eco‐friendly, cellulose‐based superabsorbent polymer (Cellulo‐SAP): Absorbency, stability, reusability, and biodegradability

AbstractSuperabsorbent polymers (SAPs) have attracted tremendous attention recently, with researchers noting that their high water absorbability is valuable for various applications, especially in agricultural contexts. Two types of materials can be used to produce SAPs: Fossil‐based (which are harmful to the environment) and bio‐based (which are significantly more environmentally friendly, given their biodegradability and minimal toxic side effects). Although bio‐based SAPs are preferable for environmental reasons, their synthesis tends to be time consuming and labour intensive, while their absorption capacity (AC) can be far below expectations. To address these problems, a novel, eco‐friendly, cellulose‐based superabsorbent polymer (Cellulo‐SAP) was developed in this study through facile preparation via free radical synthesis using modified cellulose. Then, the absorbency, thermal/pH stability, reusability, and biodegradability of Cellulo‐SAP were evaluated. This new polymer demonstrated reusability as a water reservoir, in addition to high thermal and pH stability. More importantly, Cellulo‐SAP achieved an AC of 475 g/g and exhibited superior biodegradability compared to a commercial, fossil‐based SAP. Accordingly, these results prove that Cellulo‐SAP can be used in agriculture as an effective alternative to fossil‐based SAPs.

Importance of Iron Metabolism

Iron is a vital micronutrient that is mandatory for fundamental processes in both humans and bacteria. Iron is an essential trace element which promotes cell proliferation and growth. It also has the potential to initiate redox cycling and free radical synthesis. Hence, it is engaged in initiating tumorigenesis, its microenvironment and metastasis. Acquisition of iron, efflux, storage and regulation pathways are disturbed in carcinogenesis which suggests a reprogramming role of iron metabolism in tumor cell survival. Targeting iron metabolic pathways may give a new insight for prognosis and therapy [1].
 Globally many people suffer from iron overload toxicity diseases e.g. trans fusional iron overload in thalassemia and hereditary haemochromatosis. Accumulated toxic iron deposits can cause tissue damage and identified in neurological disorders as well such as Alzheimer’s and Parkinson’s [2]. Regulation of iron is an essential defense mechanism against microbial infections. Individuals with toxic iron overload are more prone to bacterial infections as it is up taken by bacteria for their growth and survival [3]. These bacteria release iron binding molecules and then resorb them to recover iron deficiency. They also get rid of extra iron from transportation and hemoglobin. Microbes face more metabolic pressure when they have to strive hard to acquire it. Hence, the microbes with iron deficiency have a slower rate of reproduction as compared to others [5]. A small amount of iron is lost by sweating and shedding of cell from skin as well as mucosal lining of the digestive tract. However, most of it is restored and recycled by the reticuloendothelial system, which also breaks down the red blood cells [6].
 Iron homeostasis is perturbed in inflammation and sepsis, causing raised iron transportation, influx into cells and reduction in iron efflux. Iron may be used as a predictive and diagnostic marker to evaluate the severity of diseases related to iron metabolism, sepsis and inflammation. Further studies are required to explore the drugs targeting specifically to iron metabolic pathways and providing an optimal therapeutic opportunity [7].

Comet Parameters and Plasma 8-Iso-Prostaglandins F2α

Background: Major depression can be characterized by isolated episodes of disturbance in psychosomatic functions for a duration of at least two weeks along with intermediate non-symptomatic periods. The factors playing important role in the etiology of major depression were family history, genetic factors, decreased levels of serotonin and norepinephrine; increased levels of interleukins or any other medical illness having an increased cytokine production. The pathogenesis of major depression involves oxidative stress, which consists of synthesis of free radicals causing damage to nucleic acids, lipids, carbohydrates, and proteins present in the cells. Oxidative stress – induced DNA damage consists of numerous types of lesions which can be assessed by the comet assay method. Prostaglandin F2-alpha is produced because of oxidative stress-induced peroxidation of cell membrane lipids and has elevated plasma levels in patients with major depression. Fluoxetine is the drug of choice for major depression and found to have antioxidant properties. The present study was done to assess the correlation between plasma 8-iso-PGF2α levels and the comet parameters, namely comet length (CL), head diameter (HD), % of DNA in head (%DNA Head), tail length (TL) and % of DNA in tail (%DNA Tail), before starting and after finishing the eight-week fluoxetine therapy. Methodology: The prospective clinical study was conducted in the Department of Anatomy in collaboration at, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry. The study group consisted of drug naïve, newly diagnosed major depression patients belonging to age-group of ≥ 18 to 50 years and followed up after eight weeks of fluoxetine therapy. Results: The correlation was found to be positive between the levels of 8-iso-PGF2α in the plasma and all the comet parameters except %DNA Tail, which showed a negative (inverse) relationship with the levels of 8-iso-PGF2α in the plasma. Conclusion: The current study suggested the role of oxidative stress in causing DNA damage and lipid peroxidation in major depression patients and the antioxidant role of fluoxetine in causing decrease in the levels of parameters of oxidative stress and subsequent DNA repair.

Preparation and characterization of microwave irradiated pH-sensitive polyacrylamide grafted flax seed mucilage graft copolymeric hydrogel (PFLSM-g-PAM-cl-MBA) and its evaluation as effective polymeric scaffold

Microwave irradiated free radical synthesis of polyacrylamide-flax seed mucilage graft copolymeric hydrogel (PFLSM-g-PAM-cl-MBA) was evaluated for pH sensitivity at pH 2, 8 with maximum swellability at pH 7.4.The analytical characterizations of the optimized grade G6 was done using FTIR spectroscopy, 13C-NMR, TGA, XRD which indicated that grafting of acrylamide was successfully done on flax seed mucilage (PFLSM). The elemental composition also indicated successful grafting of acrylamide on flax seed mucilage. The electrokinetic potential of the G6 indicated it to be a good colloid stabilizer when compared to PFLSM. The surface morphology of G6 as observed by scanning electron microscope (SEM) and field emission scanning electron microscope (FESEM) indicated porous surface, whereas PFLSM as observed by SEM showed smooth topography. The inserted G6 in mice model showed satisfactory tissue growth with evidence of tissue compatibility as observed under Field emission scanning electron microscopy (FESEM).Histopathology studies of local tissue showed sufficient fibroblast and collagen growth indicating PFLSM-g-PAM-cl-MBA to be a promising pH-sensitive novel material for tissue proliferation as polymeric scaffold.

Meiofaunal Adaptation to Environmental Variability and Human Trampling of Tropical Sandy Beaches at Goa, India

Coenzyme Q10 (CoQ10) is one of the most commonly used dietary and nutritional supplements and is known to be a potent antioxidant. There are two forms of CoQ10 including ubiquinone (oxidized form) and ubiquinol (reduced form) that are produced in the mitochondria [1-2]. CoQ10 is an essential component in the mitochondrial electron transport chain that plays a role in synthesis of Adenosine Triphosphate (ATP) and scavenging free radicals. A deficiency in CoQ10 can cause cellular energetic impairment and decreased antioxidant defensive mechanisms. Patients with heart failure with preserved ejection fraction (HFpEF) often have a reduction in CoQ10 and are prone to oxidative stress.

Synthesis and characterization of a new hydrazyl free radical, a formyl-derivative of DPPH

Starting from 2,2-diphenyl-1-(2,4,6-trinitropheyl)hydrazine and urotropine in the presence of trifluoracetic acid it was obtained a formyl derivative as a yellow solid, that can form under oxidative condition the persistent hydrazyl free radical 2-(p-formyl-phenyl)-2-phenyl-1-(2,4,6-trinitrophenyl)hydrazyl having a violet colour. The same formyl hydrazine derivative in the presence of a base forms the corresponding anion with a red-brown colour. The new compounds were characterized by appropriate means, like NMR, IR, UV-VIS, ESR.

Recent advances in synthesis of organosilicons via radical strategies

Organosilicon compounds play an important role in the fields of materials science, pharmacy, and organic synthesis. The development of effective approaches for the preparation of these compounds have also become a research focus in organic synthesis. In recent years, free radical synthesis of organosilicons has been vigorously developed, which generally has the advantages of milder synthesis conditions, higher yields and selectivity, and free of precious metal catalysts compared with traditional strategies. This article reviews research progresses in the synthesis of organosilicon compounds by free radical pathways since 2016. In most cases, the radical silylation is achieved based on the reaction of silyl radicals, which are triggered by four routes including peroxide, transition-metal-induced peroxide decomposition, alkali, photocatalysis. The alkyl radicals can also initiate the radical silylation for the generation of C(sp3)Si bonds.

Role of Free Radicals, Glutamate Toxicity, Glutathione Depletion in Apoptosis of Cochlear Hair Cells, Neuronal Cells among Patients with Sensorineural Hearing Loss

Abstract Introduction Hearing loss may lead to depression, decreased quality of life, reduced functional status and social isolation. The glutathione-S transferase (GSTS) is an antioxidant scavenging enzyme. Decreased glutathione and GSTS activity levels lead to an increase in susceptibility of hair-cell damage leading to sensorineural hearing loss. The cumulative effect of oxidative stress and mitochondrial damage by free radicals results in the mutation/deletion of deoxyribonucleic acid, leading to decline in mitochondrial function, which in turn plays an important role in inducing apoptosis of the cochlear cells. Other risk factors also include noise exposure, genetic predisposition, health comorbidities, ototoxic drugs, infections, and immune-mediated inflammation of auditory cells. Study Design Prospective, non-comparative, metacentric clinical study. Materials and Methods The study was carried out in 30 patients from 6/5/2016 to 10/1/2018. Total of 30 patients of sensorineural hearing loss were enrolled (17 males, 13 females). Clinical history, ENT examination, and audiogram were done, treatment duration of 8 weeks for each patient and followed up to 3 outpatient visits. The patient was administered rebamipide 100 mg, alpha lipoic acid 100 mg, and acetylcysteine 100 mg capsules twice a day for a total period of 8 weeks. Wherever giddiness was an added symptom, Cinnarizine 20mg with Diaminehydrate 40 mg combination twice a day was added up to complete relief of symptoms, thereafter once a day as maintenance dose over a period of 8 weeks. Wherever tinnitus was an added symptom, deflazacort 6 mg twice a day was added and tapered up to 1 month. If the symptom of tinnitus persisted, intratympanic steroid injection was given. During every visit, clinical assessment and audiogram were repeated. Results Our study demonstrated greater improvement in hearing at higher frequencies with 8 weeks of rebamipide 100 mg + alpha lipoic acid 100 mg + acetylcysteine 100 mg administration in 30 patients with twice-daily dosing. Conclusion Synthesis of free radicals in the inner ear may play an important part in the pathogenesis of sensory hearing loss. The combination of rebamipide 100 mg + alpha lipoic acid 100 mg + acetylcysteine 100 mg is effective prophylaxis in sensorineural hearing loss that addresses both factors of inhibiting the cochlear cell damage and enhancing cochlear cell preservation.

Mechanistic study of visible light-driven CdS or g-C3N4-catalyzed C[sbnd]H direct trifluoromethylation of (hetero)arenes using CF3SO2Na as the trifluoromethyl source

The mild and sustainable methods for CH direct trifluoromethylation of (hetero)arenes without any base or strong oxidants are in extremely high demand. Here, we report that the photo-generated electron-hole pairs of classical semiconductors (CdS or g-C3N4) under visible light excitation are effective to drive CH trifluoromethylation of (hetero)arenes with stable and inexpensive CF3SO2Na as the trifluoromethyl (TFM) source via radical pathway. Either CdS or g-C3N4 propagated reaction can efficiently transform CF3SO2Na to CF3 radical and further afford the desired benzotrifluoride derivatives in moderate to good yields. After visible light initiated photocatalytic process, the key elements (such as F, S and C) derived from the starting TFM source of CF3SO2Na exhibited differential chemical forms as compared to those in other oxidative reactions. The photogenerated electron was trapped by chemisorbed O2 on photocatalysts to form superoxide radical anion (O2−) which will further attack CF3 radical with the generation of inorganic product F− and CO2. This resulted in a low utilization efficiency of CF3 (<50%). When nitro aromatic compounds and CF3SO2Na served as the starting materials in inert atmosphere, the photoexcited electrons can be directed to reduce the nitro group to amino group rather than being trapped by O2. Meanwhile, the photogenerated holes oxidize SO2CF3− into CF3. Both the photogenerated electrons and holes were engaged in reductive and oxidative paths, respectively. The desired product, trifluoromethylated aniline, was obtained successfully via one-pot free-radical synthesis.