Propranolol degradation through processes based on the generation of hydroxyl free radical

Pharmaceutical substances such as propranolol (PRO) are an emerging class of aquatic contaminants that have increasingly been detected in ground and surface water. For this reason, the aim of this study was to evaluate the efficiency of advanced oxidation systems for the PRO degradation. The tests started with anodic oxidation (AO), using 0.01, 0.05, and 0.1 M Na2SO4 as the supporting electrolyte and 16, 32, 48, and 64 mA cm−2 as current density. Under the best conditions obtained in AO, the electro-Fenton (EF) process was reviewed, where the effect of Fe2+ was analyzed with 5, 10, 15, and 20 mg Fe2+ L−1. The Fenton reaction (FR) was studied using the Fe2+ concentration that promoted the highest percentage of PRO removal and initial concentration of 16 mg L−1 of H2O2, in addition to these conditions, in the photo-Fenton (PF) system, the effect of UV light with wavelengths 254 and 365 nm were evaluated. The results obtained showed that the degradation efficiency of the EF > AO > PF > FR system along with a percent removal of 94.52, 90.4, 25.97, and 4.4%, respectively. The results showed that PRO can be removed through the studied systems, with the EF system being the most efficient.

Antioxidants into Nopal (Opuntia ficus-indica), Important Inhibitors of Free Radicals’ Formation

Nopal (Opuntia ficus indica) belonging to the Cactacea family has many nutritional benefits attributed to a wide variety of phenolic and flavonoid compounds. Coumaric acid (COA), ferulic acid (FLA), protocatechuic acid (PRA), and gallic acid (GAA) are the phenolic acids (PhAs) present in nopal. In this study, the role of these PhAs in copper-induced oxidative stress was investigated using the density functional theory (DFT). The PhAs form 5 thermodynamically favorable complexes with Cu(II), their conditional Gibbs free energies of reaction (ΔG’, at pH = 7.4, in kcal/mol) are from −23 kcal/mol to −18 kcal/mol. All of them are bi-dentate complexes. The complexes of PRA and GAA are capable of inhibiting the Cu(II) reduction by both O2•− and Asc−, their reactions with the chelated metal are endergonic having rate constants about ~10−5–102 M−1 s−1, PhAs can prevent the formation of hydroxyl free radicals by chelating the copper ions. Once the hydroxyl radicals are formed by Fenton reactions, the complexes of PhAs with Cu(II) can immediately react with them, thus inhibiting the damage that they can cause to molecules of biological interest. The reactions between PhAs-Cu(II) complexes and hydroxyl free radical were estimated to be diffusion-limited (~108 M−1s−1). Thus, these chelates can reduce the harmful effects caused by the most reactive free radical existent immediately after it is formed by Fenton reactions.

Synthesis of a Carbon-Loaded Bi2O2CO3/TiO2 Photocatalyst with Improved Photocatalytic Degradation of Methyl Orange Dye

A microflower-like C/Bi2O2CO3/TiO2 nanocomposite was prepared via a two-step method. Scanning electron microscopy (SEM) showed the sample to have a layered petal-like microstructure consisting of many nanosheets with an average diameter of 2–5 μm, along with activated carbon (AC) or carbon nanotubes (CNTs) and TiO2 nanoparticles deposited on the surface. Compared with pure Bi2O2CO3, Bi2O2CO3/TiO2 photocatalyst loaded with microflower-like carbon has a good degradation rate of methyl orange (MO) under visible light (0.019 min−1). The highest photodegradation efficiency of MO by AC or CNT-loaded Bi2O2CO3/TiO2 microflowers reached a maximum of 95% degradation after 180 minutes of reaction. The results show that the photocatalytic reaction of the hole and the hydroxyl free radical groups were important for the process of the photocatalytic degradation, and the effect of the hole was slightly greater than that of the hydroxyl free radical. After comparing the different photocatalysts, it showed that C and TiO2 could improve the photocatalytic activity of Bi2O2CO3-based photocatalysts.

Structure, Antioxidant and Anti-inflammatory Activities of the (4R)- and (4S)-epimers of S-Carboxymethyl-L-cysteine Sulfoxide

S-Carboxymethyl-L-cysteine (CMC) is an antioxidant and mucolytic commonly prescribed to patients with chronic obstructive pulmonary disease. In humans, CMC is rapidly metabolized to S-carboxymethyl-L-cysteine sulfoxide (CMCO). In this study, we assessed structural and functional similarities between CMC and CMCO. X-Ray diffraction analysis provided detailed structural information about CMCO, which exists as a 1:1 mixture of epimers, due to the emergence of a new chiral center at the sulfur atom. Both CMC and CMCO epimers protected model DNA from copper-mediated hydroxyl free radical damage. Using an insulated transposable construct for reporting activity of the cellular stress-responsive transcription factors Nrf2, p53, NF-κB, and AP-1, we demonstrate that CMCO, especially its (4R)-epimer, is comparable to CMC in their ability to mitigate the effects of oxidative stress and pro-inflammatory stimuli in human alveolar (A549) and bronchial epithelial (BEAS-2B) cells. The results of these in vitro studies suggest that CMCO retains, at least partially, the antioxidant potential of CMC and may inform pharmacodynamics considerations of CMC use in clinics.

Synthesis of Superior Visible-Light-Driven Nanophotocatalyst Using High Surface Area TiO2 Nanoparticles Decorated with CuxO Particles

This work provides an alternate unique simple methodology to design and synthesize chemically modified nanophotocatalyst based on high surface area TiO2 nanoparticles that can be used efficiently for the photodegradation of organic pollutants under normal visible light rather than complicated UV irradiation. In this study, dual visible light and UV-driven nanophotocatalysts were synthesized via wet chemistry procedures using high surface area TiO2 nanoparticles functionalized with (3-Aminopropyl) trimethoxysilane and attached chemically to the CuXO to improve the charge separation and maintain the non-charge recombination. The successful modification of the TiO2 nanoparticles and the formation of the TiO2-NH2-CuxO nanophotocatalyst were confirmed using different characterization techniques, and the results revealed the synthesis of high surface area TiO2 nanoparticles, and their chemical modification with an amino group and further decoration with copper to produce TiO2-NH2-CuxO nanophotocatalyst. The photocatalytic activity of TiO2 and TiO2-NH2-CuxO nanophotocatalyst were evaluated using methylene blue (MB) dye; as an example of organic pollutants. The resulting TiO2-NH2-CuxO nanophotocatalyst exhibited superior photocatalytic activity for the degradation of MB dye under visible light irradiation, due to the reduction in the energy bandgap. The degradation of the MB dye using the TiO2-NH2-CuxO nanophotocatalyst was investigated using LC-MS, and the results revealed that the hydroxyl free radical is mainly responsible for the cleavage and the degradation of the MB dye.

Effect of Quercetin on Dexamethasone-Induced C2C12 Skeletal Muscle Cell Injury

Glucocorticoids are widely used anti-inflammatory drugs in clinical settings. However, they can induce skeletal muscle atrophy by reducing fiber cross-sectional area and myofibrillar protein content. Studies have proven that antioxidants can improve glucocorticoid-induced skeletal muscle atrophy. Quercetin is a potent antioxidant flavonoid widely distributed in fruits and vegetables and has shown protective effects against dexamethasone-induced skeletal muscle atrophy. In this study, we demonstrated that dexamethasone significantly inhibited cell growth and induced cell apoptosis by stimulating hydroxyl free radical production in C2C12 skeletal muscle cells. Our results evidenced that quercetin increased C2C12 skeletal cell viability and exerted antiapoptotic effects on dexamethasone-treated C2C12 cells by regulating mitochondrial membrane potential (ΔΨm) and reducing oxidative species. Quercetin can protect against dexamethasone-induced muscle atrophy by regulating the Bax/Bcl-2 ratio at the protein level and abnormal ΔΨm, which leads to the suppression of apoptosis.

The Astaxanthin Aggregation Pattern Greatly Influences Its Antioxidant Activity: A Comparative Study in Caco-2 Cells

Astaxanthin is an excellent antioxidant that can form unstable aggregates in biological or artificial systems. The changes of astaxanthin properties caused by molecular aggregation have gained much attention recently. Here, water-dispersible astaxanthin H- and J-aggregates were fabricated and stabilized by a natural DNA/chitosan nanocomplex (respectively noted as H-ADC and J-ADC), as evidenced by ultraviolet and visible spectrophotometry, Fourier transform infrared spectroscopy, and Raman spectroscopy. Compared with J-ADC, H-ADC with equivalent astaxanthin loading capacity and encapsulation efficiency showed smaller particle size and similar zeta potential. To explore the antioxidant differences between astaxanthin H- and J-aggregates, H-ADC and J-ADC were subjected to H2O2-pretreated Caco-2 cells. Compared with astaxanthin monomers and J-aggregates, H-aggregates showed a better cytoprotective effect by promoting scavenging of intracellular reactive oxygen species. Furthermore, in vitro 1,1-diphenyl-2-picrylhydrazyl and hydroxyl free radical scavenging studies confirmed a higher efficiency of H-aggregates than J-aggregates or astaxanthin monomers. These findings give inspiration to the precise design of carotenoid aggregates for efficient utilization.

Oxidative Stress: A Key Modulator in Neurodegenerative Diseases

Oxidative stress is proposed as a regulatory element in ageing and various neurological disorders. The excess of oxidants causes a reduction of antioxidants, which in turn produce an oxidation–reduction imbalance in organisms. Paucity of the antioxidant system generates oxidative-stress, characterized by elevated levels of reactive species (oxygen, hydroxyl free radical, and so on). Mitochondria play a key role in ATP supply to cells via oxidative phosphorylation, as well as synthesis of essential biological molecules. Various redox reactions catalyzed by enzymes take place in the oxidative phosphorylation process. An inefficient oxidative phosphorylation may generate reactive oxygen species (ROS), leading to mitochondrial dysfunction. Mitochondrial redox metabolism, phospholipid metabolism, and proteolytic pathways are found to be the major and potential source of free radicals. A lower concentration of ROS is essential for normal cellular signaling, whereas the higher concentration and long-time exposure of ROS cause damage to cellular macromolecules such as DNA, lipids and proteins, ultimately resulting in necrosis and apoptotic cell death. Normal and proper functioning of the central nervous system (CNS) is entirely dependent on the chemical integrity of brain. It is well established that the brain consumes a large amount of oxygen and is highly rich in lipid content, becoming prone to oxidative stress. A high consumption of oxygen leads to excessive production of ROS. Apart from this, the neuronal membranes are found to be rich in polyunsaturated fatty acids, which are highly susceptible to ROS. Various neurodegenerative diseases such as Parkinson’s disease (PD), Alzheimer’s disease (AD), Huntington’s disease (HD), and amyotrophic lateral sclerosis (ALS), among others, can be the result of biochemical alteration (due to oxidative stress) in bimolecular components. There is a need to understand the processes and role of oxidative stress in neurodegenerative diseases. This review is an effort towards improving our understanding of the pivotal role played by OS in neurodegenerative disorders.

Study of DNA-Binding Activity and Antibacterial Effect of Escitalopram Oxalate, an Extensively Prescribed Antidepressant

Escitalopram oxalate (EO) is considered as one of the extensively prescribed antidepressant drug in Turkey and some other countries, therefore this research was aimed to study the interaction of the drug with DNA and study of the substance effect on bacterial growth. The absorption value of the drug solution at 238 nm was increased when DNA was added gradually to it and it showed hyperchromism effect. The value obtained for DNA binding constant (Kb) was 0.035 M −1. When we added the CuCl2 2H2O to the mixture, any breakage was not shown in double strand DNA in comparison with control DNA. In addition low concentration of EO couldn’t protect DNA (0.5273 µmole bp) against Hydroxyl free radical (0.12 µmole) although it could protect the DNA when it was at the same or higher concentrations (0.5273, 5.273 and 252.73 µmole) than the DNA concentration. In addition, MIC of the drug for E.coli and Bacillus subtilis was almost 0.185 mM and 0.55 mM respectively. The E.coli strain was killed at concentrations 45, 15, 5 mM while the Bacillus subtilis was stable against all of the concentrations.