The role of free radicals in toxicity and disease

AOP report: Development of an adverse outcome pathway for deposition of energy leading to cataracts

Cataracts are one of the leading causes of blindness, with an estimated 95 million people affected worldwide. A hallmark of cataract development is lens opacification, typically associated not only with aging but also radiation exposure as encountered by interventional radiologists and astronauts during the long-term space mission. To better understand radiation-induced cataracts, the adverse outcome pathway (AOP) framework was used to structure and evaluate knowledge across biological levels of organization (e.g., macromolecular, cell, tissue, organ, organism and population). AOPs identify a sequence of key events (KEs) causally connected by key event relationships (KERs) beginning with a molecular initiating event to an adverse outcome (AO) of relevance to regulatory decision-making. To construct the cataract AO and retrieve evidence to support it, a scoping review methodology was used to filter, screen, and review studies based on the modified Bradford Hill criteria. Eight KEs were identified that were moderately supported by empirical evidence (e.g., dose-, time-, incidence-concordance) across the adjacent (directly linked) relationships using well-established endpoints. Over half of the evidence to justify the KER linkages was derived from the evidence stream of biological plausibility. Early KEs of oxidative stress and protein modifications had strong linkages to downstream KEs and could be the focus of countermeasure development. Several identified knowledge gaps and inconsistencies related to the quantitative understanding of KERs which could be the basis of future research, most notably directed to experiments in the range of low or moderate doses and dose-rates, relevant to radiation workers and other occupational exposures.

Electrochemical biosensing platform based on AuNWs/rGO-CMC-PEDOT:PSS composite for the detection of superoxide anion released from living cells

Detection of superoxide anion (O2·-) levels holds significant importance for the diagnosis and even clinical treatments of oxidative stress-related diseases. Herein, we prepared a composite electrode material to encapsulate copper-zinc superoxide dismutase (SOD1) for biosensing of O2·-. The sensing material consists of gold nanowires (AuNWs), reduced graphene oxide (rGO), carboxymethyl cellulose (CMC) and PEDOT:PSS. CMC provides abundant -COOH to bind SOD1, with a high adsorption coverage of 1.499 × 10-9 mol cm-2 on the sensor surface. rGO and PEDOT endow the composite with significant conductivity, whereas PSS has antifouling capability. Moreover, AuNWs exhibit excellent electrical conductivity and a high aspect ratio, which promotes electron transfer, and ultimately enhances the catalytic performance of the enzyme. Meanwhile, SOD1(Cu2+) catalyzes the dismutation of O2·- to O2 and H2O2, and H2O2 is then electrochemically oxidized to generate amperometric signals for determination of O2·-. The sensor demonstrates outstanding detection performance for O2·- with a low detection limit of 2.52 nM, and two dynamic ranges (14.30 nM-1.34 μM and 1.34 μM-42.97 μM) with corresponding sensitivity of 0.479 and 0.052 μA μM-1cm-2, respectively. Additionally, the calculated apparent Michaelis constant (Kmapp) of 1.804 μM for SOD1 demonstrates the outstanding catalytic activity and the surface-immobilized enzyme's substrate affinity. Furthermore, the sensor shows the capability to dynamically detect the level of O2·- released from living HepG2 cells. This study provides an inovative design to obtain a biocompatible electrochemical sensing platform with plenty of immobilization sites for biomolecules, large surface area, high conductivity and flexibility.

Recent Advances in Detection of Hydroxyl Radical by Responsive Fluorescence Nanoprobes

Hydroxyl radical (•OH), a highly reactive oxygen species (ROS), is assumed as one of the most aggressive free radicals. This radical has a detrimental impact on cells as it can react with different biological substrates leading to pathophysiological disorders, including inflammation, mitochondrion dysfunction, and cancer. Quantification of this free radical in-situ plays critical roles in early diagnosis and treatment monitoring of various disorders, like macrophage polarization and tumor cell development. Luminescence analysis using responsive probes has been an emerging and reliable technique for in-situ detection of various cellular ROS, and some recently developed •OH responsive nanoprobes have confirmed the association with cancer development. This paper aims to summarize the recent advances in the characterization of •OH in living organisms using responsive nanoprobes, covering the production, the sources of •OH, and biological function, especially in the development of related diseases followed by the discussion of luminescence nanoprobes for •OH detection.

Argon cold atmospheric plasma eradicates pathogens in vitro that are commonly associated with canine bacterial keratitis

Purpose

To investigate the antimicrobial effect of cold atmospheric plasma (CAP) on pathogens associated with canine bacterial keratitis.

Materials and methods

Pseudomonas aeruginosa, Staphylococcus pseudintermedius, and Streptococcus canis strains, which were obtained from dogs with infectious keratitis, were subjected to testing. For each species, four isolates and a reference strain were cultivated on Columbia sheep blood agar and treated with the kiNPen Vet® plasma pen from Neoplas GmbH, Greifswald, Germany. Various continuous treatment durations (0.5, 2, and 5 min) were applied, along with a 0.5-min treatment repeated four times at short intervals. These treatments were conducted at distances of 3 and 18 mm between the agar surface and the pen.

Results

CAP treatment reduced bacterial growth in all three species. The most effective treatment duration was 5 min at 3 mm distance, resulting in inhibition zones ranging from 19 to 22 mm for P. aeruginosa, 26-45 mm for S. pseudintermedius and an overall reduction of bacterial growth for Str. canis. Inhibition zones were smaller with decreasing treatment duration and larger distance. Treatment times of 30 s repeated four times and 2 min showed comparable results. Treatment with argon alone did not lead to visible reduction of bacterial growth.

Conclusion

Argon cold atmospheric plasma demonstrated a potent in vitro antimicrobial effect on P. aeruginosa, S. pseudintermedius and Str. canis strains with the latter showing the highest sensitivity.

Redox-Mechanisms of Molecular Hydrogen Promote Healthful Longevity

Age-related diseases represent the largest threat to public health. Aging is a degenerative, systemic, multifactorial and progressive process, coupled with progressive loss of function and eventually leading to high mortality rates. Excessive levels of both pro- and anti-oxidant species qualify as oxidative stress (OS) and result in damage to molecules and cells. OS plays a crucial role in the development of age-related diseases. In fact, damage due to oxidation depends strongly on the inherited or acquired defects of the redox-mediated enzymes. Molecular hydrogen (H2) has recently been reported to function as an anti-oxidant and anti-inflammatory agent for the treatment of several oxidative stress and aging-related diseases, including Alzheimer's, Parkinson's, cancer and osteoporosis. Additionally, H2 promotes healthy aging, increases the number of good germs in the intestine that produce more intestinal hydrogen and reduces oxidative stress through its anti-oxidant and anti-inflammatory activities. This review focuses on the therapeutic role of H2 in the treatment of neurological diseases. This review manuscript would be useful in knowing the role of H2 in the redox mechanisms for promoting healthful longevity.

Biological Consequences of Vanadium Effects on Formation of Reactive Oxygen Species and Lipid Peroxidation

Lipid peroxidation (LPO), a process that affects human health, can be induced by exposure to vanadium salts and compounds. LPO is often exacerbated by oxidation stress, with some forms of vanadium providing protective effects. The LPO reaction involves the oxidation of the alkene bonds, primarily in polyunsaturated fatty acids, in a chain reaction to form radical and reactive oxygen species (ROS). LPO reactions typically affect cellular membranes through direct effects on membrane structure and function as well as impacting other cellular functions due to increases in ROS. Although LPO effects on mitochondrial function have been studied in detail, other cellular components and organelles are affected. Because vanadium salts and complexes can induce ROS formation both directly and indirectly, the study of LPO arising from increased ROS should include investigations of both processes. This is made more challenging by the range of vanadium species that exist under physiological conditions and the diverse effects of these species. Thus, complex vanadium chemistry requires speciation studies of vanadium to evaluate the direct and indirect effects of the various species that are present during vanadium exposure. Undoubtedly, speciation is important in assessing how vanadium exerts effects in biological systems and is likely the underlying cause for some of the beneficial effects reported in cancerous, diabetic, neurodegenerative conditions and other diseased tissues impacted by LPO processes. Speciation of vanadium, together with investigations of ROS and LPO, should be considered in future biological studies evaluating vanadium effects on the formation of ROS and on LPO in cells, tissues, and organisms as discussed in this review.

Recent innovation and impacts of nano-based technologies for wastewater treatment on humans: a review

Sustainable wastewater management requires environment-friendly, efficient, and cost-effective methods of water treatment. The ever-growing list of emerging contaminants in municipal wastewater requires advanced, efficient, and cost-effective techniques for its treatment to combat the increasing water demand. The nano-based technologies hold great potential in improving water treatment efficiency and augmenting the water supply. However, the environmental effects of these technologies are still questionable among the public and scientific community. The present review discusses risks to human health due to the use of nano-based technology for the removal of emerging contaminants in water. The discussion will be about the impacts of these technologies on humans. Recommendations about safe and environmentally friendly options for nano-based technology for water treatment have been included. Safest options of nano-based technologies for water treatment and steps to minimize the risk associated with them have also been incorporated in this article. Since all biological systems are different, separate risk analyses should be performed at the environmentally relevant concentration for different durations. There is little/no information on the quantitative impact on humans and requires more understanding. The quantitative measurement of the cellular uptake of nanoparticles is usually difficult. We hope this article will serve its purpose for water researchers, medical researchers, environmentalists, policymakers, and the government.

Hyperglycemia enhances the generation of ROS and RNS that impair antioxidant power and cause oxidative damage in human erythrocytes

Hyperglycemia is a state in which excess glucose circulates in blood. Erythrocytes are in direct contact with this high glucose concentration and are greatly affected by it. We have examined the effect of hyperglycemic condition on isolated human erythrocytes under in vitro conditions. Erythrocytes were incubated with different concentrations of glucose (5, 15, 30, 45 mmol/L) for 24 h, and several biochemical parameters were determined. Treatment with high glucose concentrations increased heme degradation and methemoglobin level, while methemoglobin reductase activity was decreased. A significant increase in protein oxidation and lipid hydroperoxides with a decrease in total sulfhydryl content was seen. This suggested the generation of oxidative stress, which was confirmed by an enhanced production of reactive oxygen and nitrogen species. Hyperglycemia led to a significant decline in the antioxidant power of erythrocytes, lowering their ability to quench free radicals and reduce metal ions to lower oxidation states. The plasma membrane redox system was upregulated, while ascorbate free radical reductase activity was lowered. Glucose exposure inhibited the enzymes of glycolysis and hexose monophosphate shunt. Electron microscopy showed morphological changes resulting in the formation of echinocytes. Thus, the hyperglycemic condition generates reactive species that oxidize proteins, hemoglobin, and lipids; impair the total antioxidant capacity; and alter morphology in human erythrocytes.

Ciguatoxin Detection in Flesh and Liver of Relevant Fish Species from the Canary Islands

The Canary Islands are a ciguatoxin (CTX) hotspot with an established official monitoring for the detection of CTX in fish flesh from the authorised points of first sale. Fish caught by recreational fishermen are not officially tested and the consumption of toxic viscera or flesh could lead to ciguatera poisoning (CP). The objectives of this study were to determine the presence of CTX-like toxicity in relevant species from this archipelago, compare CTX levels in liver and flesh and examine possible factors involved in their toxicity. Sixty amberjack (Seriola spp.), 27 dusky grouper (Epinephelus marginatus), 11 black moray eels (Muraena helena) and 11 common two-banded seabream (Diplodus vulgaris) were analysed by cell-based assay (CBA) and Caribbean ciguatoxin-1 (C-CTX1) was detected by liquid chromatography mass spectrometry (LC-MS/MS) in all these species. Most of the liver displayed higher CTX levels than flesh and even individuals without detectable CTX in flesh exhibited hepatic toxicity. Black moray eels stand out for the large difference between CTX concentration in both tissues. None of the specimens with non-toxic liver showed toxicity in flesh. This is the first evidence of the presence of C-CTX1 in the common two-banded seabream and the first report of toxicity comparison between liver and muscle from relevant fish species captured in the Canary Islands.

Identification of three novel antioxidative peptides from Auxenochlorella pyrenoidosa protein hydrolysates based on a peptidomics strategy

Auxenochlorella pyrenoidosa is recognized as a potential sustainable protein material in food industry, however, its application remains still very limited. Herein, this study aimed to investigate the antioxidative properties of Auxenochlorella pyrenoidosa protein hydrolysates and identify novel antioxidative peptides from protein hydrolysates through a workflow mainly including enzymatic hydrolysis, peptidome quantification, quantitative structure-activity relationship (QSAR) modeling, in silico screening, and validation. Three novel antioxidative peptides including AGWACLVG, IDLAY and YPLDL were identified from protein hydrolysates by papain with the hydrolysis time of 4 h, in which, AGWACLVG showed strong 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity with the IC₅₀ value of 68.88 µM and Trolox equivalent antioxidative capacity of 6.20 ± 0.23 mmol TE/g. This study suggested that Auxenochlorella pyrenoidosa protein hydrolysates could be used as potential antioxidative ingredients in food industry, and the identification of novel antioxidative peptides would contribute to the construction of more robust QSAR models in the future.

In vivo toxicity assessment of 4'-O-methylpyridoxine from Ginkgo biloba seeds: Growth, hematology, metabolism, and oxidative parameters

4'-O-methylpyridoxine (MPN), a recognized antivitamin B₆ compound, is a potentially poisonous substance found in Ginkgo biloba seeds and leaves. In this work, the body weights, histopathological changes, plasma vitamin B₆ (VB₆), biochemical parameters, oxidative stress responses, and amino acids of rats were investigated after intragastric administration of MPN for 15 days. Results showed that intragastric administration of 50 mg/kg BW MPN caused pathological changes in the brain and heart tissues of rats. Administration of 10 mg/kg and 30 mg/kg BW MPN can significantly increase VB₆ analogs in the plasma of rats, such as pyridoxal-5'-phosphate, pyridoxal. Results of biochemical parameters indicated that MPN can damage brains and hearts by changing the enzyme activity of these organs. These results suggest that consumption of Ginkgo biloba seeds for the long term, even in a small quantity, may lead to poisoning.

Biomarkers of Inflammation and Inflammation-Related Indexes upon Emergency Department Admission Are Predictive for the Risk of Intensive Care Unit Hospitalization and Mortality in Acute Poisoning: A 6-Year Prospective Observational Study

Patients poisoned with drugs and nonpharmaceutical substances are frequently admitted from the emergency department (ED) to a medical or ICU department. We hypothesized that biomarkers of inflammation and inflammation-related indexes based on the complete blood cell (CBC) count can identify acutely poisoned patients at increased risk for ICU hospitalization and death. We performed a 6-year prospective cohort study on 1548 adult patients. The demographic data, the levels of hs-CRP (high-sensitivity C-reactive protein), CBC, and inflammation-related indexes based on CBC counts were collected upon admission and compared between survivors and nonsurvivors, based on the poison involved. Both a multivariate logistic regression model with only significant univariate predictors and a model including univariate predictors plus each log-transformed inflammation-related indexes for mortality were constructed. The importance of the variables for mortality was graphically represented using the nomogram. hs-CRP (odds ratio (OR), 1.38; 95% CI, 1.16–1.65, p < 0.001 for log-transformed hs-CRP), red cell distribution width (RDW), neutrophil-lymphocyte ratio (NLR), and platelet-lymphocyte ratio (PLR) were significantly associated with the risk of ICU hospitalization, after multivariable adjustment. Only RDW, NLR, and monocyte-lymphocyte ratio (MLR) were significantly associated with mortality. The predictive accuracy for mortality of the models which included either NLR (AUC 0.917, 95% CI 0.886-0.948) or MLR (AUC 0.916, 95% CI 0.884-0.948) showed a high ability for prognostic detection. The use of hs-CRP, RDW, NLR, and MLR upon ED admission are promising screening tools for predicting the outcomes of patients acutely intoxicated with undifferentiated poisons.

A new skeleton flavonoid and a new lignan from Portulaca oleracea L. and their activities

A new skeleton flavonoid, identified as (5aR)-10-hydroxy-8-methoxy-5aH,11H-chromeno[2,3-b]chromen-11-one (1), named oleracone G, and a new lignan, confirmed as 8-(4-hydroxy-3-methoxyphenyl)-3-methoxynaphthalen-2-ol (2), named oleralignan B, were isolated from Portulaca oleracea L., and the structures of them were determined using spectroscopic methods including UV, IR, 1D NMR, 2D NMR, and UHPLC-ESI-QTOF/MS. In addition, compounds 1-2 were applied to investigate the anti-inflammatory activities on lipopolysaccharide-stimulated macrophages and scavenging effects in 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical. The results showed that the two compounds at 10 μM and 20 μM could dose-dependently decrease the secretion of interleukin 1β in RAW 264.7 cells by enzyme-linked immunosorbent assay, moreover, presented remarkable antioxidant activities with IC₅₀ values of 27.57, 20.12 μM, respectively.

Polymeric Delivery of Therapeutic Nucleic Acids

The advent of genome editing has transformed the therapeutic landscape for several debilitating diseases, and the clinical outlook for gene therapeutics has never been more promising. The therapeutic potential of nucleic acids has been limited by a reliance on engineered viral vectors for delivery. Chemically defined polymers can remediate technological, regulatory, and clinical challenges associated with viral modes of gene delivery. Because of their scalability, versatility, and exquisite tunability, polymers are ideal biomaterial platforms for delivering nucleic acid payloads efficiently while minimizing immune response and cellular toxicity. While polymeric gene delivery has progressed significantly in the past four decades, clinical translation of polymeric vehicles faces several formidable challenges. The aim of our Account is to illustrate diverse concepts in designing polymeric vectors towards meeting therapeutic goals of in vivo and ex vivo gene therapy. Here, we highlight several classes of polymers employed in gene delivery and summarize the recent work on understanding the contributions of chemical and architectural design parameters. We touch upon characterization methods used to visualize and understand events transpiring at the interfaces between polymer, nucleic acids, and the physiological environment. We conclude that interdisciplinary approaches and methodologies motivated by fundamental questions are key to designing high-performing polymeric vehicles for gene therapy.

The role of poly(2-alkyl-2-oxazoline)s in hydrogels and biofabrication

Poly(2-alkyl-2-oxazoline)s (PAOXAs) have been rapidly emerging as starting materials in the design of tissue engineering supports and for the generation of platforms for cell cultures, especially in the form of hydrogels. Thanks to their biocompatibility, chemical versatility and robustness, PAOXAs now represent a valid alternative to poly(ethylene glycol)s (PEGs) and their derivatives in these applications, and in the formulation of bioinks for three-dimensional (3D) bioprinting. In this review, we summarize the recent literature where PAOXAs have been used as main components for hydrogels and biofabrication mixtures, especially highlighting how their easily tunable composition could be exploited to fabricate multifunctional biomaterials with an extremely broad spectrum of properties.

Identification of Maple Anthocyanin and its Antiproliferative Activity against LLC, T47D and C3H10T1/2 Cells

BACKGROUND

The genus Acer contains around 200 species, with more than 400 garden varieties. There is considerable diversity in these species and garden varieties, and each can be characterized by morphology and chemical composition. The red appearance of Acer leaves is due to anthocyanin compounds, including cyanidin glycosides, delphinidin glycosides, and galloylated anthocyanins. Few studies have investigated the diversity of anthocyanin compounds in garden varieties, and no studies have examined the pharmacological effects of these compounds.

OBJECTIVE

The purpose of this study was to identify the anthocyanins of Acer palmatum cv. 'Chishio', a garden variety of A. palmatum and evaluate their antiproliferative and antioxidant activities.

METHODS

A methanol extract of fresh leaves was partitioned with ethyl acetate. The extract was purified by column chromatography and compounds were subsequently identified by 1H and 13C NMR and ESI-HRMS. Antiproliferative activity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4- sulfophenyl)-2H-tetrazolium, inner salt (MTS) colorimetric assay. The antioxidant assay was evaluated by scavenging activity using the stable radical DPPH.

RESULTS

The anthocyanins cyanidin-3-O-(6''-O-α-rhamnopyranosyl- β-glucopyranoside), cyanidin-3-O- β- glucopyranoside, cyanidin-3-O-[2''-O-(galloyl)-6''-O-(rhamnosyl)-β-glucoside], and cyanidin-3-O-[2''-O-(galloyl)- β-glucopyranoside] were isolated from A. palmatum cv. 'Chishio'. All four anthocyanin compounds showed antiproliferative activity against LLC and T47D cells, and galloylated anthocyanin showed antiproliferative activity against C3H10T1/2 cells. All four anthocyanins inhibited the activity of DPPH radicals in a dosedependent manner.

CONCLUSION

Maple anthocyanins could be a new cancer therapeutic agent or prophylactic medicine.

Beneficial and Detrimental Effects of Reactive Oxygen Species on Lifespan: A Comprehensive Review of Comparative and Experimental Studies

Aging is the greatest risk factor for a multitude of diseases including cardiovascular disease, neurodegeneration and cancer. Despite decades of research dedicated to understanding aging, the mechanisms underlying the aging process remain incompletely understood. The widely-accepted free radical theory of aging (FRTA) proposes that the accumulation of oxidative damage caused by reactive oxygen species (ROS) is one of the primary causes of aging. To define the relationship between ROS and aging, there have been two main approaches: comparative studies that measure outcomes related to ROS across species with different lifespans, and experimental studies that modulate ROS levels within a single species using either a genetic or pharmacologic approach. Comparative studies have shown that levels of ROS and oxidative damage are inversely correlated with lifespan. While these studies in general support the FRTA, this type of experiment can only demonstrate correlation, not causation. Experimental studies involving the manipulation of ROS levels in model organisms have generally shown that interventions that increase ROS tend to decrease lifespan, while interventions that decrease ROS tend to increase lifespan. However, there are also multiple examples in which the opposite is observed: increasing ROS levels results in extended longevity, and decreasing ROS levels results in shortened lifespan. While these studies contradict the predictions of the FRTA, these experiments have been performed in a very limited number of species, all of which have a relatively short lifespan. Overall, the data suggest that the relationship between ROS and lifespan is complex, and that ROS can have both beneficial or detrimental effects on longevity depending on the species and conditions. Accordingly, the relationship between ROS and aging is difficult to generalize across the tree of life.

Recent advances on synthesis and biological activities of aurones

Aurones are naturally occurring structural isomerides of flavones that have diverse bioactivities including antiviral, antibacterial, antifungal, anti-inflammatory, antitumor, antimalarial, antioxidant, neuropharmacological activities and so on. They constitute an important class of pharmacologically active scaffolds that exhibit multiple biological activities via diverse mechanisms. This review article provides an update on the recent advances (2013-2020.4) in the synthesis and biological activities of these derivatives. In the cases where sufficient information is available, some important structure-activity relationships (SAR) of their biological activities were presented, and on the strength of our expertise in medicinal chemistry and careful analysis of the recent literature, for the potential of aurones as medicinal drugs is proposed.

Impact of Lactobacillus plantarum 423 fermentation on the antioxidant activity and flavor properties of rice bran and wheat bran

Rice bran (RB) and wheat bran (WB) fermented with L. plantarum 423 had enhanced odor intensity, especially for sulfides and aromatics. The hydroxyl radical-scavenging activity (73.28 ± 3.18%) and oxygen radical-scavenging activity (2.12 ± 0.08 mmol·TE/g) of RB fermentation broth were better than those of WB fermentation broth. Even at 2 μg/ml, the purified antioxidant fractions from the WB fermentation broth showed strong intracellular ROS-scavenging activity in human umbilical vein endothelial cells (HUVECs), and the purified antioxidant fractions (200 μg/ml) from the RB fermentation broth had a good antiaging effect. The dominant antioxidant components in the RB and WB fermentation broths were acids (70.21%) and ketones (10.64%), these components jointly give the RB and WB fermentation broths a variety of antioxidant properties. These results are beneficial for developing RB and WB deep-processing technology and laid the foundation for the preparation of antioxidant fractions with L. plantarum 423.

Lipid and Carotenoid Production by Rhodotorula glutinis with a Combined Cultivation Mode of Nitrogen, Sulfur, and Aluminium Stress

Torulene is a promising pink pigment, produced only by yeasts and fungi, and its production is still in a developing stage due to the low production rate. Accordingly, this study focuses on maximizing torulene production by Rhodotorula glutinis using shaken flask fermentation. The effect of different nitrogen sources, and C/N and C/S ratios on lipid and carotenoid production by R. glutinis was studied using 60 g/L glucose. The largest cells filled with golden fluorescence lipid bodies were observed using fluorescence microscopy when peptone was used as a nitrogen source. The highest total pigment (0.947 mg/L) and carotenoid relative productivity (Car-RP) (89.04 µg/g) were obtained at C/N 146 and C/S 120, and with ammonium sulfate as a nitrogen source, with 62% torulene domination using High Performance Liquid Chromatography (HPLC) for identification. Under a high C/N ratio, regardless of the C/S ratio, the carotenoid synthesis rate decreased after three days while the lipid synthesis rate kept increasing to the sixth day. Interestingly, after adding 0.7 mM Al2(SO4)3 to the optimized medium, the total pigment and Car-RP (2.2 mg/L and 212.9 µg/g) sharply increased, producing around 2.16 mg/L torulene (98%) with around 50% decrease in lipid yield. This is the first report on the role of Al2(SO4)3 for enhancing torulene production under lipogenesis condition, which could be used as a potential tool for torulene production.

Dynamic Nuclear Polarization Nuclear Magnetic Resonance in Human Cells Using Fluorescent Polarizing Agents

Solid state nuclear magnetic resonance (NMR) enables atomic-resolution characterization of the molecular structure and dynamics within complex heterogeneous samples, but it is typically insensitive. Dynamic nuclear polarization (DNP) increases the NMR signal intensity by orders of magnitude and can be performed in combination with magic angle spinning (MAS) for sensitive, high-resolution spectroscopy. Here we report MAS DNP experiments, for the first time, within intact human cells with >40-fold DNP enhancement and a sample temperature of <6 K. In addition to cryogenic MAS results at <6 K, we also show in-cell DNP enhancements of 57-fold at 90 K. In-cell DNP is demonstrated using biradicals and sterically shielded monoradicals as polarizing agents. A novel trimodal polarizing agent is introduced for DNP, which contains a nitroxide biradical, a targeting peptide for cell penetration, and a fluorophore for subcellular localization with confocal microscopy. The fluorescent polarizing agent provides in-cell DNP enhancements of 63-fold at a concentration of 2.7 mM. These experiments pave the way for structural characterization of biomolecules in an endogenous cellular context.

3D-Printed Chips: Compatibility of Additive Manufacturing Photopolymeric Substrata with Biological Applications

Additive manufacturing (AM) is ideal for building adaptable, structurally complex, three-dimensional, monolithic lab-on-chip (LOC) devices from only a computer design file. Consequently, it has potential to advance micro- to milllifluidic LOC design, prototyping, and production and further its application in areas of biomedical and biological research. However, its application in these areas has been hampered due to material biocompatibility concerns. In this review, we summarise commonly used AM techniques: vat polymerisation and material jetting. We discuss factors influencing material biocompatibility as well as methods to mitigate material toxicity and thus promote its application in these research fields.

Enzymatically crosslinked poly(2-alkyl-2-oxazoline) networks for 3D cell culture

Cellularized poly(2-alkyl-2-oxazoline) hydrogels fabricated by sortase-mediated crosslinking feature tunable mechanical properties and enable extremely high cell viability.

Antioxidant and anti-freezing peptides from salmon collagen hydrolysate prepared by bacterial extracellular protease

Extracted salmon skin collagen was hydrolysed with the free or immobilized extracellular protease of Vibrio sp. SQS2-3. The hydrolysate exhibited anti-freezing activity (>3 kDa) and antioxidant activity (<3000 Da) after ultrafiltration. The antioxidant peptide was further purified by size-exclusion chromatography and found to scavenge DPPH (73.29 ± 1.03%), OH (72.73 ± 3.34%,), and intracellular ROS in HUVECs; protect DNA against oxidation-induced damage; and have an ORAC of 2.78 ± 0.28 mmol TE/g. The antioxidant peptide fraction was identified using mass spectrometry, and nineteen salmon collagen-sourced peptides were obtained. Of these, the peptide Pro-Met-Arg-Gly-Gly-Gly-Gly-Tyr-His-Tyr is a novel sequence and was the major component; this peptide was shown to have antioxidant activity via the ORAC assay (2.51 ± 0.14 mmol TE/g). These results suggested that the protease from Vibrio sp. SQS2-3 is suitable for preparation of anti-freezing peptides and antioxidant peptides in a single step and represents a comprehensive use of fish skin collagen.

Preparation of Antioxidant Peptides from Salmon Byproducts with Bacterial Extracellular Proteases

Bacterial extracellular proteases from six strains of marine bacteria and seven strains of terrestrial bacteria were prepared through fermentation. Proteases were analyzed through substrate immersing zymography and used to hydrolyze the collagen and muscle proteins from a salmon skin byproduct, respectively. Collagen could be degraded much more easily than muscle protein, but it commonly showed weaker antioxidant capability. The hydrolysate of muscle proteins was prepared with crude enzymes from Pseudoalteromonas sp. SQN1 displayed the strongest activity of antioxidant in DPPH and hydroxyl radical scavenging assays (74.06% ± 1.14% and 69.71% ± 1.97%), but did not perform well in Fe²⁺ chelating assay. The antioxidant fractions were purified through ultrafiltration, cation exchange chromatography, and size exclusion chromatography gradually, and the final purified fraction U2-S2-I displayed strong activity of antioxidant in DPPH, hydroxyl radical scavenging assays (IC₅₀ = 0.263 ± 0.018 mg/mL and 0.512 ± 0.055 mg/mL), and oxygen radical absorption capability assay (1.960 ± 0.381 mmol·TE/g). The final purified fraction U2-S2-I possessed the capability to protect plasmid DNA against the damage of hydroxyl radical and its effect was similar to that of the original hydrolysis product. It indicated that U2-S2-I might be the major active fraction of the hydrolysate. This study proved that bacterial extracellular proteases could be utilized in hydrolysis of a salmon byproduct. Compared with collagen, muscle proteins was an ideal material used as an enzymatic substrate to prepare antioxidant peptides.

New Approach in Translational Medicine: Effects of Electrolyzed Reduced Water (ERW) on NF-κB/iNOS Pathway in U937 Cell Line under Altered Redox State

It is known that increased levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) can exert harmful effects, altering the cellular redox state. Electrolyzed Reduced Water (ERW) produced near the cathode during water electrolysis exhibits high pH, high concentration of dissolved hydrogen and an extremely negative redox potential. Several findings indicate that ERW had the ability of a scavenger free radical, which results from hydrogen molecules with a high reducing ability and may participate in the redox regulation of cellular function. We investigated the effect of ERW on H₂O₂-induced U937 damage by evaluating the modulation of redox cellular state. Western blotting and spectrophotometrical analysis showed that ERW inhibited oxidative stress by restoring the antioxidant capacity of superoxide dismutase, catalase and glutathione peroxidase. Consequently, ERW restores the ability of the glutathione reductase to supply the cell of an important endogenous antioxidant, such as GSH, reversing the inhibitory effect of H₂O₂ on redox balance of U937 cells. Therefore, this means a reduction of cytotoxicity induced by peroxynitrite via a downregulation of the NF-κB/iNOS pathway and could be used as an antioxidant for preventive and therapeutic application. In conclusion, ERW can protect the cellular redox balance, reducing the risk of several diseases with altered cellular homeostasis such as inflammation.

Multivariate approach to gill pathology in European sea bass after experimental exposure to cadmium and terbuthylazine

The combined use of guided quantitative expert analysis and of multivariate exploratory data analysis is reported as a robust, sensitive and sufficiently specific approach to study European sea bass gill secondary lamellar pathology after exposure to incremental doses of cadmium and terbuthylazine up to 48h. The following elementary pathological findings were considered: "epithelial lifting", "epithelial shrinkage", "epithelial swelling", "pillar cells coarctation", "pillar cells detachment", "channels fusion", "chloride cells swelling", and "chloride cells invasion". The relative spatial extension was determined according to exposure class and data were analyzed by means of canonical correspondence analysis (CCA), linear discriminant analysis (LDA) and canonical variates analysis (CVA). Histologically and ultrastructurally, cellular shrinkage/coarctation prevailed in cadmium exposed lamellae, whereas cellular swelling and epithelial lifting were predominant in terbuthylazine exposed lamellae compared to unexposed fish. Both CCA and CVA permit a good graphical data grouping according to exposure classes by means of the convex hull minimum polygons. This also reveals exposure dose and time gradients in CCA plot. Accordingly, epithelial swelling and epithelial shrinkage were comparatively associated to higher exposure time, whereas epithelial shrinkage and pillar cells coarctation were comparatively associated to higher exposure dose. LDA with only "epithelial shrinkage", "epithelial swelling" and "pillar cells coarctation" in the model classified correctly 87.5% of the cross-validated cases. A possible pathogenetic relationship between the discriminant elementary lesions and the toxic mode of action at the cellular level of both cadmium and terbuthylazine is also discussed.

European sea bass gill pathology after exposure to cadmium and terbuthylazine: expert versus fractal analysis

The objective of this study was to compare expert versus fractal analysis as new methods to evaluate branchial lamellar pathology in European sea bass Dicentrarchus labrax (Linnaeus, 1758) experimentally exposed to cadmium and to terbuthylazine. In particular, guided expert quantitative and fractal analysis were performed on selected images from semithin sections to test possible differences according to exposure class (unexposed, cadmium exposed, or terbuthylazine exposed) and the discrimination power of the two methods. With respect to guided expert quantitative analysis, the following elementary pathological features were assessed according to pre-determined cover classes: 'epithelial lifting', 'epithelial shrinkage', 'epithelial swelling', 'pillar cells coarctation', 'pillar cells detachment', 'channels fusion', 'chloride cells swelling' and 'chloride cells invasion'. Considering fractal analysis, DB (box dimension), DM (mass dimension), Dx (mean fractal dimension) as fractal dimensions and lacunarity from DM and Dx scan types were calculated both from the outlined and skeletonized (one pixel wide lines) images. Despite significant differences among experimental classes, only expert analysis provided good discrimination with correct classification of 91.7 % of the original cases, and of 87.5 % of the cross-validated cases, with a sensitivity of 95.45 % and 91.3 %, respectively, and a specificity of 75 % in both cases. Guided expert quantitative analysis appears to be a reliable method to objectively characterize fish gill pathology and may represent a powerful tool in environmental biomonitoring to ensure proper standardization and reproducibility. Though fractal analysis did not equal the discrimination power of the expert method, it certainly warrants further study to evaluate local variations in complexity or possible multiple scaling rules.

Tea extracts protect normal lymphocytes but not leukemia cells from UV radiation-induced ROS production: An EPR spin trap study

PURPOSE

An ex vivo method for detection of free radicals and their neutralization by aqueous tea in human normal lymphocytes and MEC-1 leukemia cells under ultraviolet (UV) irradiation was investigated.

MATERIALS AND METHODS

This method is based on the electron paramagnetic resonance (EPR) spectroscopy spin-trapping technique. 5-tert-butoxycarbonyl 5-methyl-1-pyrroline N-oxide (BMPO) was used as the spin trap. Normal human lymphocytes and leukemia cells were exposed to UVB radiation (290-315 nm) at 47.7 and 159 mJ/cm(2) and to UVA radiation (315-400 nm) at 53.7 J/cm(2).

RESULTS

No significant radical production at 47.7 mJ/cm(2) UVB dose in both cell lines was observed. In normal cells, free radical production was observed at 159 mJ/cm(2) UVB and 53.7 J/cm(2) UVA doses. However, both UV sources did not significantly produce free radicals in leukemia cells. A radical scavenging property of tea extracts (black, green, sage, rosehip) was observed in normal lymphocytes after both UVB and UVA exposure. In leukemia cells, the intensities of EPR signals produced in BMPO with tea extracts were found to be increased substantially after UVA exposure.

CONCLUSION

These results showed that UV radiation induced free radical formation in normal human lymphocytes and indicated that tea extracts may be useful as photoprotective agents for them. On the other hand, tea extracts facilitated free radical production in leukemia cells.

A Caco-2 cell-based quantitative antioxidant activity assay for antioxidants

A Caco-2 cell-based antioxidant activity (CAA) assay for quantitative evaluation of antioxidants was developed by optimizing seeding density and culture time of Caco-2 cells, incubation time and concentration of fluorescent probe (2',7'-dichlorofluorescin diacetate, DCFH-DA), incubation way and incubation time of antioxidants (pure phytochemicals) and DCFH-DA with cells, and detection time of fluorescence. Results showed that the CAA assay was of good reproducibility and could be used to evaluate the antioxidant activity of antioxidants at the following conditions: seeding density of 5 × 10(4)/well, cell culture time of 24h, co-incubation of 60 μM DCFH-DA and pure phytochemicals with Caco-2 cells for 20 min and fluorescence recorded for 90 min. Additionally, a significant correlation was observed between CAA values and rat plasma ORAC values following the intake of antioxidants for selected pure phytochemicals (R(2) = 0.815, p < 0.01), demonstrating the good biological relevance of CAA assay.

Neutrophil-lymphocyte ratio in patients with pesticide poisoning

BACKGROUND

Pesticides are highly toxic to human beings, and pesticide poisoning is associated with high morbidity and mortality. The identification of powerful prognostic markers is important for the management of patients with pesticide poisoning in emergency settings.

OBJECTIVE

To investigate the prognostic value of the neutrophil-lymphocyte ratio and hematological parameters measured in patients with pesticide poisoning within the first 24 h after admission to the emergency department (ED).

METHODS

All patients (≥15 years old) admitted to the ED from July 2008 through February 2013 due to pesticide poisoning were enrolled in the study. The written and electronic medical charts of patients were reviewed. Neutrophil-lymphocyte ratio and platelet-lymphocyte ratio were calculated for each patient using absolute neutrophil, lymphocyte, and platelet counts. Mechanical ventilation requirement and mortality were used as the primary endpoints.

RESULTS

A total of 189 patients were included in the study. The mechanically ventilated patients had significantly higher leukocyte and neutrophil counts, and neutrophil-lymphocyte and platelet-lymphocyte ratios (p < 0.001, p < 0.001, p < 0.001, p = 0.003, respectively), whereas they had significantly lower lymphocyte counts compared to nonventilated patients (p = 0.011). Survivors had significantly higher leukocyte and neutrophil counts, and neutrophil-lymphocyte ratios (p < 0.001, p < 0.001, p = 0.002, respectively), whereas there was no significant difference between groups in terms of lymphocyte counts (p = 0.463), compared to nonsurvivors.

CONCLUSION

Leukocyte counts, neutrophil counts, and neutrophil-lymphocyte ratios measured within the first 24 h after admission to the ED are useful and easy-to-use parameters for estimating prognosis in the follow-up of patients with pesticide poisoning.

Combined experimental and in silico approaches for exploring antiperoxidative potential of structurally diverse classes of antioxidants on docetaxel-induced lipid peroxidation using 4-HNE as the model marker

The objective of the present work was tantamount to explain the antiperoxidative potential and structural requirements of twenty-eight structurally diverse classes of antioxidants on docetaxel-induced lipid peroxidation. Both experimental and computational approaches were taken to the work. The experiments were performed in vitro and goat liver was used as a source of lipid. 4-hydroxy-2-nonenal was used as model marker for estimation of docetaxel-lipid interaction. The computational portion of the work was limited to QSAR analysis of those antioxidants for better understanding of the structural requirements of antioxidants on docetaxel-lipid interaction. The study was done with freely online available 2D descriptors available on PaDEL (open source). Stepwise regression analysis was used as chemometric tool. The experimental study showed the lipid peroxidation induction capacity of docetaxel. It was also noted that all twenty-eight antioxidants had the ability to suppress the lipid peroxidation. But among them butylated hydroxyl toluene showed the highest potential (-20.5%) and flavone showing lowest potential (-0.8%) to suppress the docetaxel-induced lipid peroxidation. The computational study indicates the importance of topology of the whole molecules, topological distances among atoms within a molecule and specific fragment pattern present in a molecule required for inhibition of lipid peroxidation.

Ultraviolet radiation, aging and the skin: prevention of damage by topical cAMP manipulation

Being the largest and most visible organ of the body and heavily influenced by environmental factors, skin is ideal to study the long-term effects of aging. Throughout our lifetime, we accumulate damage generated by UV radiation. UV causes inflammation, immune changes, physical changes, impaired wound healing and DNA damage that promotes cellular senescence and carcinogenesis. Melanoma is the deadliest form of skin cancer and among the malignancies of highest increasing incidence over the last several decades. Melanoma incidence is directly related to age, with highest rates in individuals over the age of 55 years, making it a clear age-related disease. In this review, we will focus on UV-induced carcinogenesis and photo aging along with natural protective mechanisms that reduce amount of “realized” solar radiation dose and UV-induced injury. We will focus on the theoretical use of forskolin, a plant-derived pharmacologically active compound to protect the skin against UV injury and prevent aging symptoms by up-regulating melanin production. We will discuss its use as a topically-applied root-derived formulation of the Plectranthus barbatus (Coleus forskolii) plant that grows naturally in Asia and that has long been used in various Aryuvedic teas and therapeutic preparations.

Chemical and pharmacological studies of saponins with a focus on American ginseng

Asian ginseng (Panax ginseng) and American ginseng (Panax quinquefolius L.) are the two most recognized ginseng botanicals. It is believed that the ginseng saponins called ginsenosides are the major active constituents in both ginsengs. Although American ginseng is not as extensively studied as Asian ginseng, it is one of the best selling herbs in the U.S., and has garnered increasing attention from scientists in recent years. In this article, after a brief introduction of the distribution and cultivation of American ginseng, we discuss chemical analysis of saponins from these two ginsengs, i.e., their similarities and differences. Subsequently, we review pharmacological effects of the saponins, including the effects on the cardiovascular system, immune system, and central nervous system as well as the antidiabetes and anti-cancer effects. These investigations were mainly derived from American ginseng studies. We also discuss evidence suggesting that chemical modifications of ginseng saponins would be a valuable approach to develop novel compounds in drug discovery.

Short-time exposure to mono-n-butyl phthalate (MBP)-induced oxidative stress associated with DNA damage and the atrophy of the testis in pubertal rats

Phthalates are widely used as plasticizer in various consumer domestic products and are known to disturb the male reproductive function in rodents. This study investigated the involvement of oxidative stress and the atrophy of the testes in pubertal rats exposed to mono-n-butyl phthalate (MBP). Four-week-old pubertal male rats were separated into three groups. In group I, 21 rats were fed rat chow containing 2 % MBP for 3 days. In group II, 21 rats were fed rat chow containing 2 % MBP for 3 days and antioxidant vitamins C (250 mg/kg/day) and E (50 mg/kg/day) were injected daily. In group III, 21 rats were fed standard rat chow and used as controls. After 3 days, each testis was weighed and the germ cell development was evaluated using the Johnsen score. The urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels were measured as a biological marker of oxidative DNA damage. The mean testis weight was significantly lower for group I than groups II or III (p < 0.05). The mean Johnsen score was significantly lower for group I than for groups II or III (p < 0.05). Urinary 8-OHdG concentrations were higher in group I than in groups II or III. Short-time exposure to MBP may therefore induce oxidative DNA damage in rat testes, while antioxidant vitamins administered during exposure may protect against this stress.

Evaluation of the in vitro and in vivo biocompatibility of carrageenan-based hydrogels

Carrageenans are highly sulphated galactans, well-known for their thermogelation properties which have been extensively exploited in food and cosmetics industry but poorly explored in the biomedicine field. In this study, we have assessed the in vitro and in vivo biocompatibility of κ-carrageenan hydrogels that have been explored for regenerative medicine and tissue engineering applications. The in vitro cytotoxicity of the materials using a L929 mouse fibroblast cell line was evaluated, and the effect of κ-carrageenan hydrogels on the activation of human polymorphonuclear neutrophils cells (hPMNs) was also evaluated by the quantification of reactive oxygen species by chemiluminescence. Subsequently, the inflammatory/immune reaction to κ-carrageenan hydrogels on subcutaneous implantation was studied in rats. Explants were retrieved after 1 and 2 weeks of implantation for histological and RT-PCR analysis. The cytotoxicity screening revealed that κ-carrageenan hydrogels did not significantly affect L929 metabolic activity. Moreover, hPMNs contact with κ-carrageenan resulted in a reduced and a neglectable signal regarding the detection of superoxide and hydroxyl anions, respectively. The results from the in vivo experiments indicated that κ-carrageenan induce a low inflammatory response. Overall, the data obtained suggest that κ-carrageenan hydrogels are biocompatible and thus can be further studied for their use in target biomedical applications.

Impact of acute metal stress in Saccharomyces cerevisiae

Although considered as essential cofactors for a variety of enzymatic reactions and for important structural and functional roles in cell metabolism, metals at high concentrations are potent toxic pollutants and pose complex biochemical problems for cells. We report results of single dose acute toxicity testing in the model organism S. cerevisiae. The effects of moderate toxic concentrations of 10 different human health relevant metals, Ag⁺, Al³⁺, As³⁺, Cd²⁺, Co²⁺, Hg²⁺, Mn²⁺, Ni²⁺, V³⁺, and Zn²⁺, following short-term exposure were analyzed by transcription profiling to provide the identification of early-on target genes or pathways. In contrast to common acute toxicity tests where defined endpoints are monitored we focused on the entire genomic response. We provide evidence that the induction of central elements of the oxidative stress response by the majority of investigated metals is the basic detoxification process against short-term metal exposure. General detoxification mechanisms also comprised the induction of genes coding for chaperones and those for chelation of metal ions via siderophores and amino acids. Hierarchical clustering, transcription factor analyses, and gene ontology data further revealed activation of genes involved in metal-specific protein catabolism along with repression of growth-related processes such as protein synthesis. Metal ion group specific differences in the expression responses with shared transcriptional regulators for both, up-regulation and repression were also observed. Additionally, some processes unique for individual metals were evident as well. In view of current concerns regarding environmental pollution our results may support ongoing attempts to develop methods to monitor potentially hazardous areas or liquids and to establish standardized tests using suitable eukaryotic a model organism.

Hepatotoxicity in rats induced by the poisonous dreamfish (Sarpa salpa)

AIMS

The present study was aimed to assess the cytotoxic effects of not-yet identified compounds present in organ extracts of Sarpa salpa, collected in autumn, the period with a peak in health problems.

METHODS

The toxicity was assessed by mouse bioassay of extract of the fish's organs. Wistar rats received daily extracts of different organs of S. salpa by gastric gavage for 7 d (0.3 ml of extract/100 g body weight, BW). The dose of tissue extracts of viscera, liver, brain and flesh of S. salpa administered to rats were as follows: 17.2, 31.3, 205, 266 mg/100g BW, respectively. No deaths occurred during the period of treatment.

RESULTS

The lethal dose (LD50%) determined for the crude ciguatoxin (neurotoxins) extracts of viscera, liver, brain and flesh of S. salpa were as follows: 1.2, 2.2, 14.4, 18.6 g/kg mouse, respectively. Changes in locomotor activity during the first 2 h and failure breathing and no evident signs of gastrointestinal problems were recorded. We observed: (1) Induction of oxidative stress, indicated by an increase in lipid peroxidation (TBARS) in groups that received extracts of liver (+490%) or viscera (+592%). Accompanied by a significant decrease in antioxidant enzyme activities (SOD, CAT, GPx) in liver tissue by 15%, 17%, 18% (LT: animals receiving liver extracts) and by 19%, 22%, 22% (VT: animals receiving viscera extracts), respectively. In contrast the administration of extracts of flesh and brain induced an increase in antioxidant enzyme activities (SOD, CAT, GPx) in liver tissue by 15%, 19%, 15% (FT: flesh extract) and 18%, 55%, 55% (BT: brain extract), respectively; (2) A significant increase in total metallothionein levels in liver tissue was recorded in (FT), (BT), (LT) and (VT) by 55%, 88%, 255% and 277%, respectively, (3) The histological findings confirmed the biochemical results.

CONCLUSIONS

Liver and especially visceral part of S. salpa presented toxicity, which clearly indicates the danger of using this fish as food.

NAD⁺-carrying mesoporous silica nanoparticles can prevent oxidative stress-induced energy failures of both rodent astrocytes and PC12 cells

Aim

To test the hypothesis that NAD⁺-carrying mesoporous silica nanoparticles (M-MSNs@NAD+) can effectively deliver NAD⁺ into cells to produce cytoprotective effects.

Methods & Materials

NAD⁺ was incorporated into M-MSNs. Primary rat astrocyte cultures and PC12 cells were treated with H₂O₂, followed by post-treatment with M-MSNs@NAD+. After various durations of the post-treatment, intracellular NAD⁺ levels, intracellular ATP levels and lactate dehydrogenase (LDH) release were determined.

Results & Discussion

M-MSNs can be effectively loaded with NAD⁺. The M-MSNs@NAD+ can significantly attenuate H₂O₂-induced NAD⁺ and ATP decreases in both astrocyte cultures and PC12 cells. M-MSNs@NAD+ can also partially prevent the H₂O₂-induced LDH release from both astrocyte cultures and PC12 cells. In contrast, the NAD⁺ that is spontaneously released from the M-MSNs@NAD+ is insufficient to prevent the H₂O₂-induced damage.

Conclusions

Our study has suggested the first approach that can effectively deliver NAD⁺ into cells, which provides an important basis both for elucidating the roles of intracellular NAD⁺ in biological functions and for therapeutic applications of NAD⁺. Our study has also provided the first direct evidence demonstrating a key role of NAD⁺ depletion in oxidative stress-induced ATP decreases.

Curcumin and its carbocyclic analogs: structure-activity in relation to antioxidant and selected biological properties

Curcumin is the major phenolic compound present in turmeric (Curcuma longa L.). Curcumin and 15 novel analogs were investigated for their antioxidant and selected biological activities. Strong relationships between the structure and evaluated activity revealed that the compounds with specific functional groups and carbon skeleton had specific biological profiles. Among the compounds tested, the derivatives (E)-2-(3,4-dimethoxybenzylidene)-5-((E)-3-(3,4-dimethoxyphenyl)acryloyl)cyclopentanone (3e), and (E)-2-(4-hydroxy-3-methoxybenzylidene)-5-((E)-3-(4-hydroxy-3-methoxyphenyl)acryloyl)-cyclopentanone (3d) and the parent compound curcumin exhibited the strongest free radical scavenging and antioxidant capacity. Concerning the other biological activities studied the compound (E)-2-(4-hydroxy-3-methoxybenzylidene)-5-((E)-3-(4-hydroxy-3-methoxy-phenyl)-acryloyl)cyclopentanone (3d) was the most potent angiotensin converting enzyme (ACE) inhibitor, while the derivatives (E)-2-(4-hydroxybenzylidene)-6-((E)-3-(4-hydroxyphenyl)acryloyl)cyclohexanone (2b), (E)-2-(3,4-dimethoxybenzylidene)-6-((E)-3-(3,4-dimethoxyphenyl)acryloyl)cyclohexanone (2e) and (E)-2-(3,4-dimethoxybenzylidene)-5-((E)-3-(3,4-dimethoxyphenyl)acryloyl)cyclopentanone (3e) exhibited strong tyrosinase inhibition. Moreover, (E)-2-(3,4-dimethoxybenzylidene)-6-((E)-3-(3,4-dimethoxyphenyl)-acryloyl)cyclohexanone (2e) was also found to be the strongest human HIV-1 protease inhibitor in vitro among the tested compounds. Cytotoxicity studies using normal human lung cells revealed that the novel curcumin as well as its carbocyclic analogs are not toxic.

Hepatoprotection by chemical constituents of the marine brown alga Spatoglossum variabile: a relation to free radical scavenging potential

CONTEXT

In the course of searching hepatoprotective agents from natural sources, the protective effect of chemical constituents of the marine brown alga Spatoglossum variabile Figaro et DE Notar (Dictyoaceae) against CCl₄-induced liver damage in Wistar rats was investigated. The compounds were first investigated for in vitro radical scavenging potential and were also tested for β-glucuronidase inhibition to further explore the relationship between hepatoprotection and antiradical potential.

METHODS

The compounds cinnamic acid esters 1 and 2 and aurone derivatives 3 and 4 were first investigated for in vitro radical scavenging potential against 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), and superoxide anion radicals. In vivo hepatoprotective studies were performed in seven groups (n = 6) of Wistar rats. The test groups were pretreated with compounds (10 mg/kg body weight, po) orally for 30 min before the intraperitoneal administration of a dose of 20% CCl₄ diluted with dietary cooking oil. Moreover, compounds were also tested for β-glucuronidase inhibition to explore the relationship between hepatoprotection and radical scavenging potential.

RESULTS

The test compounds 1-4 were found to exhibit antiradical activity against 1,1-diphenyl-2-picrylhydrazyl radicals with IC₅₀ values ranging between 54 and 138 µM, whereas aurone derivatives 3 and 4 additionally exhibited superoxide anion scavenging effects with IC₅₀ values of 95 and 87 µM, respectively. In addition, these compounds were found to be weak inhibitors of xanthine oxidase (IC₅₀ ≥1000 µM). In animal model, pretreatment with compounds 2-4 significantly blocked the CCl₄-induced increase in the levels of the serum biochemical markers.

CONCLUSION

It appears that the hepatoprotection afforded by these compounds was mainly due to their radical scavenging activity that protected the cells from the free radicals generated by CCl₄-induced hepatotoxicity.