Oxidative Fragmentation Research Articles

The effects of zinc nanooxide on cellular stress responses of the freshwater mussels Unio tumidus are modulated by elevated temperature and organic pollutants

Nanoparticle toxicity is a growing concern in freshwater habitats. However, understanding of the nanoparticle effects on aquatic organisms is impeded by the lack of the studies of the nanoparticles effects in the environmentally relevant context of multiple stress exposures. Zinc oxide nanoparticles (n-ZnO) are widely used metal-based nanoparticles in electronics and personal care products that accumulate in aquatic environments from multiple non-point sources. In this study, we evaluated the effects of n-ZnO in a model organism, a mussel Unio tumidus, and the potential modulation of these effects by common co-occurring environmental stressors. Male U. tumidus were exposed for 14 days to n-ZnO (3.1μM), Zn2+ (3.1μM), Ca-channel blocker nifedipine (Nfd 10μM), combinations of n-ZnO and Nfd or n-ZnO and thiocarbamate fungicide Tattoo (Ta, 91μgL−1) at 18°C, and n-ZnO at 25°C (n-ZnO+t°). Total and metallothionein-bound Zn levels as well as levels of metallothioneins (MT), cellular stress responses and cytotoxicity biomarkers were assessed in the mussels. The key biomarkers that showed differential responses to different single and combined stressors in this study were activities of caspase-3 and lysosomal cathepsin D, as well as protein carbonyl content. At 18°C, exposures to n-ZnO, organic pollutants and their combinations led to a prominent up-regulation of MT levels (by ∼30%) and oxidative stress response including up-regulation of superoxide dismutase activity, an increase in oxyradical production, and a 2–3-fold decrease in the levels of protein carbonyls in all exposures except nZnO+Ta. Expos ure to n-ZnO in the absence of other stressors also led to a strong (∼7-fold) elevation of cathepsin D activity. Cellular responses to Zn2+ and n-ZnO were different indicating that n-ZnO was not due exclusively to Zn release. Ca-channel blocker Nfd affected intracellular Zn distribution (reflected in the prominent elevation of Zn-MT levels) and caused reductive stress indicated by elevated levels of reduced glutathione levels and an increase in lactate/pyruvate ratio (reflecting higher NADH/NAD ratio). Elevated temperature (25°C) abolished most of the typical responses to n-ZnO and induced oxidative injury, DNA fragmentation and caspase-3 mediated apoptosis in n-ZnO-exposed mussels. DNA fragmentation was also induced by exposure to organic toxins (alone and in combination with n-ZnO) but not by n-ZnO alone. These data indicate that n-ZnO toxicity to freshwater organisms is modulated by organic pollutants and enhanced by elevated temperatures.

Nerve growth factor in human semen: Effect of nerve growth factor on the normozoospermic men during cryopreservation process.

Although routinely applied in assisted reproductive technology, human sperm cryopreservation is not a completely successful procedure. Adverse effects of cryopreservation on the fertilization capacity, motility, morphology, and viability of spermatozoa have been proven; cryopreservation has also shown a role in sperm DNA fragmentation and infertility. The post-thaw survival of spermatozoa improved after addition of supplementation of antioxidant molecules to freezing media. Nerve growth factor (NGF) as one of the prosurvival substances has gained great attention in recent years. The aim of this study was the usage of NGF as prosurvival factor after cryopreservation process of human semen samples to assess the motility and viability of sperm, nitric oxide (NO) concentration, and DNA fragmentation in normozoospermic men. Semen samples were collected from 25 normozoospermic men and were divided into fresh semen samples as control group, frozen-thawed semen samples without addition of exogenous NGF, and three groups of semen samples cryopreserved with addition of exogenous NGF (0.5, 1, and 5 ng/ml) in freezing medium. Viability was assessed by eosin-negrosin staining technique. Motility was evaluated with inverted microscope. NO concentration and apoptosis content were measured with flow cytometry. Results showed that exogenous NGF at 0.5 ng/ml could significantly (P-value <0.05) influence viability, motility, nitric oxide, and DNA fragmentation content. Exogenous NGF as cryoprotectant improved sperm viability and motility, increased intracellular NO concentration, and decreased apoptosis content in normal human spermatozoa.

Mitochondrial permeability transition increases reactive oxygen species production and induces DNA fragmentation in human spermatozoa.

Does mitochondrial permeability transition (MPT) induced by calcium overload cause reactive oxygen species (ROS) production and DNA fragmentation in human spermatozoa? Studies conducted in vitro suggest that in human spermatozoa, MPT occurs in response to intracellular calcium increase and is associated with mitochondrial membrane potential (ΔΨm) dissipation, increased ROS production and DNA fragmentation. Oxidative stress is a major cause of defective sperm function in male infertility. By opening calcium-dependent pores in the inner mitochondrial membrane (IMM), MPT causes, among other things, increased ROS production and ΔΨm dissipation in somatic cells. MPT as a mechanism for generating oxidative stress and DNA fragmentation in human spermatozoa has not been studied. Human sperm were exposed to ionomycin for 1.5 h (n = 8) followed by analysis of sperm IMM permeability, ΔΨm, ROS production and DNA fragmentation. To evaluate the MPT in sperm cells, the calcein-AM and cobalt chloride method was used. The ΔΨm was evaluated by JC-1 staining, intracellular ROS production was evaluated with dihydroethidium and DNA fragmentation was evaluated by a modified TUNEL assay. Measurements were performed by fluorescence microscopy, confocal laser microscopy and flow cytometry. Decreased calcein fluorescence after treatment with ionomycin (P < 0.05) suggests the opening of pores in the sperm IMM and this was accompanied by ΔΨm dissipation, increased ROS production and DNA fragmentation. ROS production occurred prior to the decrease in ΔΨm. The study was carried out in vitro using motile sperm from healthy donors; tests on sperm from infertile patients were not carried out. We propose that the MPT, due to pores opening in sperm IMM, is an important mechanism of increased ROS and DNA fragmentation. Therefore, agents that modulate the opening of these pores might contribute to the prevention of damage by oxidative stress in human spermatozoa. This study was funded by grant DI12-0102 from the Universidad de La Frontera (J.V.V.) and a doctoral scholarship from CONICYT Chile (F.T.). The authors disclose no potential conflicts of interest.

Standardized extract of Vitex doniana Sweet stalls protein oxidation, lipid peroxidation and DNA fragmention in acetaminophen-induced hepatotoxicity

Ethnopharmacological relevanceVitex doniana fruits are locally used in Nigeria as a remedy in the treatment of jaundice and liver related disease. The effect of methanolic extract of Vitex doniana fruits on acetaminophen induced protein oxidation, lipid peroxidation and DNA fragmentation was investigated in mice. Materials and methodsAntioxidant activity of the extract (0.2–1.0mg/mL) was investigated in vitro using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, superoxide ion, hydrogen peroxide, hydroxyl radical and ferric ion reducing system. Vitex doniana extract at 1.0mg/mL scavenged DPPH, superoxide ion, hydrogen peroxide, and hydroxyl radical by 86%, 78%, 80% and 72% respectively, it also reduced ferric ion significantly. Hepatoprotective effect of Vitex doniana fruits was monitored in acetaminophen-induced hepatotoxicity in mice. ResultsAcetaminophen-mediated alterations in serum alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, albumin and total bilirubin levels in mice were significantly (P<0.05) attenuated by the extract. Similarly, acetaminophen-mediated decrease in activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glucose 6-phosphate dehydrogenase was significantly (P<0.05) attenuated in the liver of mice. Increased levels of conjugated dienes, lipid hydroperoxides, malondialdehyde, protein carbonyl and fragmented DNA were significantly (P<0.05) lowered by methanolic extract of Vitex doniana fruits. ConclusionsOverall, the results of this study show that Vitex doniana fruits possess antioxidant properties and halted acetaminophen-mediated oxidative rout on cellular proteins, lipids and DNA, made possible by β-sitosterol, platycodin D, apigenin, saikosaponin, chrysin and ellagitanin in the extract.

High-performance Ge quantum dot decorated graphene/zinc-oxide heterostructure infrared photodetector.

A novel size-controllable germanium quantum dot (Ge QD) is synthesized and decorated onto reduced graphene oxide (RGO) fragments to overcome the low infrared (IR) photoresponses (∼0.1 A/W)13,14 of pristine graphene. With the integration of flexible substrate, monolayer graphene (MLG) electrode and n-type zinc oxide (ZnO), a high-performance QD-decorated-RGO/ZnO heterostructure infrared photodetector is reported in this study. The Ge QD-decorated-RGO hybrid photosensitive composite improves the responsivity (∼9.7 A/W, 1400 nm) in IR waveband without sacrificing the response speed (∼40 μs rise time and 90 μs recovery time). In addition, the effective barrier formed between graphene and ZnO interface restricts the dark current (∼1.4 nA, -3 V) to guarantee the relatively excellent rectifying behavior and high on/off ratio (∼10(3)) for this IR photodetector. With these superior inherent properties and micron-sized sensing active area, this photodetector manifests great potential in the future application of graphene-based IR photodetector.

The Effects of Melatonin on Oxidative Stress Parameters and DNA Fragmentation in Testicular Tissue of Rats Exposed to Microwave Radiation.

Microwaves from mobile phones are one of the environmental toxicants that are capable of compromising male fertility by inducing oxidative stress and apoptosis in the testes. Melatonin is a lipophilic tryptophan indole amine and a potent antioxidant. The aim of the study was to evaluate the effect of melatonin treatment on oxidative stress parameters and DNA fragmentation in the testicular tissue of rats exposed to microwave radiation (4 h/day). Adult Wistar rats were divided in 4 groups: I--treated with saline; II--treated with melatonin; III--exposed to microwaves; IV--exposed to microwaves and treated with melatonin. The melatonin (2 mg/kg ip) was administered daily. The animals were sacrificed after 20, 40 and 60 days. Melatonin treatment prevented previously registered increases in malondialdehyde after only 20 days. Furthermore, it reversed the effects of microwave exposure on xanthine oxidase (after 40 days) and acid-DNase activity (after 20 days). However, neither protein carbonyl content nor catalase and alkaline Dnase activity were changed due to melatonin treatment. Melatonin exerts potent antioxidant effects in the testes of rats exposed to microwaves by decreasing the intensity of oxidative stress; it also reduces DNA fragmentation.

Antiproliferative activity and nitric oxide production of a methanolic extract of Fraxinus micrantha on Michigan Cancer Foundation-7 mammalian breast carcinoma cell line.

Aim:Methanolic extract of a Fraxinus micrantha (MeFM) was evaluated for antiproliferative activity in vitro using Michigan Cancer Foundation-7 (MCF-7) breast carcinoma cell line. This plant was selected and studied for naturally available bioactive compound as different synthetic drugs available for cancer treatment has certain limitations and side effects.Materials and Methods:The anti-proliferative activity of a methanolic extract from the aerial parts of F. micrantha was assessed on MCF-7 breast cancer cell line using 3(4,5-dimethylthiazol-2-yl)2,5-diphenyl-tetrazolium bromide assay. Furthermore, to understand the mechanism of anti-proliferation, production of nitric oxide (NO) and DNA fragmentation was also determined on MCF-7 cells. Different phytoconstituents of the extract were determined qualitatively based on various biochemical assays.Results:The results demonstrated anti-proliferative activity of an MeFM in a concentration and time-dependent manner. The percentage viability determined was 31.24% at 125 µg/ml as compared to 80.46% in negative control group. An MeFM has also shown NO production in a concentration (0.2-125 µg/ml) and time-dependent manner (24-48 h). DNA fragmentation studies showed that a methanolic extract was causing DNA fragmentation thus inducing apoptosis in MCF-7 breast carcinoma cells. Biochemical analysis result showed the presence of flavonoids, polyphenols, and sterols in an MeFM.Conclusion:In conclusion, F. micrantha possesses potent anti-proliferative activity on the malignant MCF-7 cell line which is correlated with the production of NO and DNA fragmentation. Further studies are required to identify, isolate, and characterize the phytochemicals present in the methanolic extract that might have antiproliferative potential in the treatment of different cancer conditions.

Chitosan nanoparticles and quercetin modulate gene expression and prevent the genotoxicity of aflatoxin B1 in rat liver

The aims of the current study were to prepare chitosan nanoparticles (CNPs) and to evaluate its protective role alone or in combination with quercetin (Q) against AFB1-induce cytotoxicity in rats. Male Sprague-Dawley rats were divided into 12 groups and treated orally for 4 weeks as follow: the control group, the group treated with AFB1 (80μg/kgb.w.) in corn oil, the groups treated with low (140mg/kgb.w.) or high (280mg/kgb.w.) dose of CNPs, the group treated with Q (50mg/kgb.w.), the groups treated with Q plus the low or the high dose of CNPs and the groups treated with AFB1 plus Q and/or CNPs at the two tested doses. The results also revealed that administration of AFB1 resulted in a significant increase in serum cytokines, Procollagen III, Nitric Oxide, lipid peroxidation and DNA fragmentation accompanied with a significant decrease in GPx I and Cu–Zn SOD-mRNA gene expression. Q and/or CNPs at the two tested doses overcome these effects especially in the group treated with the high dose of CNPs plus Q. It could be concluded that CNPs is a promise candidate as drug delivery enhances the protective effect of Q against the cytogenetic effects of AFB1 in high endemic areas.

Multistages Preparation for Microfibrillated Celluloses Based on Arenga Pinnata “ijuk” fiber

Microfibrillated celluloses (MFC) extraction from “ijuk” fibers with chemically multistages method has been investigated. The fibers were prepared by alkalinization with 10% sodium hydroxide (NaOH), oxidation with 3-6% sodium hypochlorite (NaClO) and hydrolysis with 20% sulphuric acid (H2SO4), respectively. The alkalinization removes the fiber surface components such as lignin and wax so the pore on the surface clearly appeared. Addition of NaClO leads an oxidative fragmentation from remaining lignin and then the lignin dissolve out from the fiber. Furthermore, hydrolysis fibrilates fiber into MFC and annihillates the amorphous parts in MFC by keeping the crystalline parts. Fourier Transform Infrared (FT-IR) confirmed the removal of some cellulosic components such as lignin, wax and hemicelluloses, X-Ray Diffraction (XRD) reveals an increasing of crystalline parts in the fiber. The micrograph by Field Emission Scanning Electron Microscopy (FESEM) displayed dimension and surface morphology of MFC. The experimental indicated that multistages preparation with 6% NaClO resulted better fibrillation and crystallinity than 3% NaClO. The microfibrillated celluloses resulted from this multistages preparation, has some potential applications, such as filler and nucleating agent in polymer, which are studied in the next study.

Vitamin E attenuates neurotoxicity induced by deltamethrin in rats.

BackgroundThe safety of Deltamethrin (DM) has been raised as a point of concern. The current investigation was envisaged to explore the responsiveness of oxidative stress parameters, DNA fragmentation and expression levels of TP53, cycloxygenase 2 (COX2) and cytochrome p4502E1 (CYP2E1) as toxicological endpoint in rats treated with DM. as well as attention was provided to the neuroprotective effect of vitamin E (VE).MethodsFour different groups of rats were used in this study, group I served as control, group II received DM (0.6 mg/kg BW), group III received both DM plus VE and finally group IV received VE only (200 mg/kg BW). The treatment regimen was extending for one month for all groups and the brain tissues were collected for further analysis.ResultsThe obtained results showed a highly statistically significant increase in lipid peroxidation (LPO) content, nitric oxide concentration, and DNA fragmentation percentage and expression level of CYP2E1, TP53 and COX2 genes, in addition statistical significant reduction in total antioxidant capacity in DM treated group as compared to control were detected. Oral administration of VE attenuated the neurotoxic effects of DM through improvement of oxidative status, DNA fragmentation percentage and suppressing the expression level of CYP2E1, TP53 and COX2 genes.ConclusionFrom this study we concluded that VE supplementation has beneficial impacts on DM neurotoxicity in rats through its antioxidant and antiapoptotic properties.

Azoxystrobin causes oxidative stress and DNA damage in the aquatic macrophyte Myriophyllum quitense.

Among the search for new types of pesticides, the fungicide azoxystrobin (AZX) was the first patent of the strobilurin compounds, entering in the market in 1996. Its use worldwide is growing, mainly linked to soybean production, although its effects in non-target organisms are almost unknown. The goal of the present work was to evaluate effects of short-term AZX exposure to the aquatic macrophyte Myriophyllum quitense, focusing on oxidative stress parameters and DNA fragmentation. Significant inhibition of the antioxidant enzyme systems were observed at 50μg/L AZX for catalase and peroxidase (p<0.05). Lipid and DNA damage were significant at 50 and 100μg/L AZX. These biomarkers were sensitive to AZX and can be used in a battery to evaluate the occurrence of AZX in freshwater ecosystems.

Oxygen Enhances Polyoxometalate-based Catalytic Dissolution and Delignification of Woody Biomass in Ionic Liquids

Complete dissolution and over 90% delignification of Southern yellow pine (<0.125 mm) can be achieved in the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) at 110 °C for 6 h by the catalytic action of polyoxometalate in the presence of an appropriate O2 feed. Cellulose-rich materials (CRMs), or pulps, and hemicellulose with a limited lignin content and free lignin were subsequently recovered by adding antisolvents to the IL solution, followed by filtration. Comparison of wood processing in [C2mim][OAc]/POM with or without O2 revealed that the presence of oxygen can greatly facilitate the dissolution, delignification, separation of hemicellulose, and oxidation of lignin. The main products from lignin oxidation were extracted from the IL using benzene and then tetrahydrofuran, and were shown by gas chromatography−mass spectrometry (GC–MS) to be methyl vanillate, acetovanillone, vanillic acid, methyl 3-(3-methoxy-4-hydroxyphenyl) propionate, and methyl 4-hydroxybenzoate. This study suggests that treating wood with a [C2mim][OAc]/POM/O2 system could be a viable strategy to separate wood components with high efficiency and obtain cellulose with high purity for materials or biorefinery applications, particularly those that desire smaller lignin oxidation fragments for further processing.

Phenolic extract of Parkia biglobosa fruit pulp stalls aflatoxin B1 – mediated oxidative rout in the liver of male rats

The effect of phenolic extract of Parkia biglobosa (Jacq.) R. Br. ex G. Don, Fabaceae, pulp on aflatoxin B1 induced oxidative imbalance in rat liver was evaluated. Thirty-five male rats were randomized into seven groups of five animals each. Rats in group A served as control and received vehicle for drug administration (0.5% DMSO) once daily at 24h intervals for six weeks. Rats in groups B, D, E, F and G, received aflatoxin B1 (167μg/kg body weight) in 0.5% DMSO for three weeks, starting from the third week of the experimental period. Rats in Group C received 400mg/kg bodyweight of the extract for six weeks, while groups D, E and F rats were treated with 100, 200 and 400mg/kg bodyweight of the extract for six weeks respectively. Group G rats received 100mg/kg body weight of vitamin C. Aflatoxin B1-mediated decrease in the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glucose-6-phosphate dehydrogenase were significantly attenuated. Aflatoxin B1 mediated the elevation in malondialdehyde, conjugated dienes, lipid hydroperoxides, protein carbonyl, and significantly lowered DNA fragmentation percentage. Overall, the phenolic extract of P. biglobosa pulp stalls aflatoxin B1-mediated oxidative rout by enhancing antioxidant enzyme activities leading to decreased lipid peroxidation, protein oxidation and DNA fragmentation.

X-Ray-Induced Nanoparticle-Based Photodynamic Therapy of Cancer

In this study, Ce(3+)-doped lanthanum(III) fluoride (LaF3:Ce(3+)) nanoparticles were synthesized by a wet-chemistry method in dimethyl sulfoxide (DMSO) and their application as an intracellular light source for photodynamic activation was demonstrated. The LaF3:Ce(3+)/DMSO nanoparticles have a strong green emission with a peak at approximately 520 nm, which is effectively overlapped with the absorption of protoporphyrin IX (PPIX). The nanoparticles were encapsulated into poly(D,L-lactide-co-glycolide (PLGA) microspheres along with PPIX. Upon irradiation with x-rays (90 kV), energy transfer from the LaF3:Ce(3+)/DMSO nanoparticles to PPIX occurs and singlet oxygen is generated for cancer cell damage. The LaF3:Ce(3+)/DMSO/PLGA or LaF3:Ce(3+)/DMSO/PPIX/PLGA microspheres alone caused only sublethal cytotoxicity to the cancer cells. Upon x-ray irradiation, the LaF3:Ce(3+)/DMSO/PPIX/PLGA microspheres induced oxidative stress, mitochondrial damage and DNA fragmentation on prostate cancer cells (PC3). The results indicate that x-rays can activate LaF3:Ce(3+) and PPIX nanocomposites, which can be a novel method for cancer destruction.

Metabolomics analysis and modeling suggest a lysophosphocholines-PAF receptor interaction in fibromyalgia.

Fibromyalgia Syndrome (FMS) is a chronic disease characterized by widespread pain, and difficult to diagnose and treat. We analyzed the plasma metabolic profile of patients with FMS by using a metabolomics approach combining Liquid Chromatography-Quadrupole-Time Of Flight/Mass Spectrometry (LC-Q-TOF/MS) with multivariate statistical analysis, aiming to discriminate patients and controls. LC-Q-TOF/MS analysis of plasma (FMS patients: n = 22 and controls: n = 21) identified many lipid compounds, mainly lysophosphocholines (lysoPCs), phosphocholines and ceramides. Multivariate statistical analysis was performed to identify the discriminating metabolites. A protein docking and molecular dynamic (MD) study was then performed, using the most discriminating lysoPCs, to validate the binding to Platelet Activating Factor (1-alkyl-2-acetyl-sn-glycero-3-phosphocholine, PAF) Receptor (PAFr). Discriminating metabolites between FMS patients and controls were identified as 1-tetradecanoyl-sn-glycero-3-phosphocholine [PC(14∶0/0∶0)] and 1-hexadecanoyl-sn-glycero-3-phosphocholine [PC(16∶0/0∶0)]. MD and docking indicate that the ligands investigated have similar potentialities to activate the PAFr receptor. The application of a metabolomic approach discriminated FMS patients from controls, with an over-representation of PC(14∶0/0∶0) and PC(16∶0/0∶0) compounds in the metabolic profiles. These results and the modeling of metabolite-PAFr interaction, allowed us to hypothesize that lipids oxidative fragmentation might generate lysoPCs in abundance, that in turn will act as PAF-like bioactivators. Overall results suggest disease biomarkers and potential therapeutical targets for FMS.

ChemInform Abstract: Silicon‐Directed Rhenium‐Catalyzed Allylic Carbaminations and Oxidative Fragmentations of γ‐Silyl Allylic Alcohols.

ChemInformVolume 45, Issue 39 Preparative Organic Chemistry ChemInform Abstract: Silicon-Directed Rhenium-Catalyzed Allylic Carbaminations and Oxidative Fragmentations of γ-Silyl Allylic Alcohols. Sanjay W. Chavhan, Sanjay W. Chavhan Sch. Chem. Chem. Eng., Queen′s Univ., Belfast BT9 5AG, UKSearch for more papers by this authorMatthew J. Cook, Matthew J. Cook Sch. Chem. Chem. Eng., Queen′s Univ., Belfast BT9 5AG, UKSearch for more papers by this author Sanjay W. Chavhan, Sanjay W. Chavhan Sch. Chem. Chem. Eng., Queen′s Univ., Belfast BT9 5AG, UKSearch for more papers by this authorMatthew J. Cook, Matthew J. Cook Sch. Chem. Chem. Eng., Queen′s Univ., Belfast BT9 5AG, UKSearch for more papers by this author First published: 11 September 2014 https://doi.org/10.1002/chin.201439054Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume45, Issue39September 23, 2014 RelatedInformation

ChemInform Abstract: A Highly Stereoselective Route to Medium‐Ring‐Sized trans‐Alkenolides (II) via Oxidative Fragmentation of Bicyclic Oxycyclopropane Precursors (I): Application to the Synthesis of (+)‐Recifeiolide (III).

ChemInform Abstract: A Highly Stereoselective Route to Medium‐Ring‐Sized trans‐Alkenolides (II) via Oxidative Fragmentation of Bicyclic Oxycyclopropane Precursors (I): Application to the Synthesis of (+)‐Recifeiolide (III).

Trichosanthes CucumerinaFruit Extenuates Dyslipidemia, Protein Oxidation, Lipid Peroxidation and DNA Fragmentation in the liver of high-fat diet-fed rats

The effect of Trichosanthes cucumerina fruit pulp extract on dyslipidemia, protein oxidation, lipid peroxidation and DNA fragmentation in the liver of high-fat diet-fed rats was investigated. High-fat diet-mediated alterations in liver and serum total cholesterol, triacylglycerol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, very-low-density lipoprotein cholesterol, alkaline phosphatase, and alanine and aspartate aminotransferase were significantly (P < 0.05) reversed by the T. cucumerina pulp extract. The extract increased the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glucose 6-phosphate dehydrogenase in the mitochondria and post-mitochondria fractions of rat liver. The increase significantly (P < 0.05) attenuated high-fat diet-mediated reductions in antioxidant enzyme activities. High-fat diet-mediated elevation in the levels of conjugated dienes, lipid hydroperoxides, malondialdehyde, protein carbonyl and DNA fragmentation in rat liver was dose-dependently lowered by the extract. The data obtained from this study showed that the T. cucumerina fruit pulp extract palliated high-fat diet-mediated dyslipidemia, protein oxidation, lipid peroxidation and DNA fragmentation in rats. Practical Applications Trichosanthes cucumerina fruit pulp can be developed into a nutraceutical product to treat liver disorders. It can also be consumed at home and as substitute to Lycopersicon esculentum (L.) Mill. The fruit pulp of T. cucumerina is sweet tasting, aromatic, deep red in color and does not go sour as quickly as paste of L. esculentum.

Minimally oxidized LDL inhibits macrophage selective cholesteryl ester uptake and native LDL-induced foam cell formation

Scavenger receptor-mediated uptake of oxidized LDL (oxLDL) is thought to be the major mechanism of foam cell generation in atherosclerotic lesions. Recent data has indicated that native LDL is also capable of contributing to foam cell formation via low-affinity receptor-independent LDL particle pinocytosis and selective cholesteryl ester (CE) uptake. In the current investigation, Cu(2+)-induced LDL oxidation was found to inhibit macrophage selective CE uptake. Impairment of selective CE uptake was significant with LDL oxidized for as little as 30 min and correlated with oxidative fragmentation of apoB. In contrast, LDL aggregation, LDL CE oxidation, and the enhancement of scavenger receptor-mediated LDL particle uptake required at least 3 h of oxidation. Selective CE uptake did not require expression of the LDL receptor (LDL-R) and was inhibited similarly by LDL oxidation in LDL-R(-/-) versus WT macrophages. Inhibition of selective uptake was also observed when cells were pretreated or cotreated with minimally oxidized LDL, indicating a direct inhibitory effect of this oxLDL on macrophages. Consistent with the effect on LDL CE uptake, minimal LDL oxidation almost completely prevented LDL-induced foam cell formation. These data demonstrate a novel inhibitory effect of mildly oxidized LDL that may reduce foam cell formation in atherosclerosis.

Quantification of mass-specific laser energy input converted into particle properties during picosecond pulsed laser fragmentation of zinc oxide and boron carbide in liquids

Pulsed laser fragmentation in liquids is an effective method to fabricate organic, metal or semiconductor nanoparticles by ablation of suspended particles. However, modelling and up-scaling of this process lacks quantification of the laser energy required for a specific product property like particle diameter of the colloid or bandgap energy of the fabricated nanoparticles. A novel set-up for defined laser energy dose in a free liquid jet enables mass-specific energy balancing and exact threshold determination for pulsed laser fragmentation. By this technique laser energy and material responses can be precisely correlated. Linear decrease of the particle diameter and linear increase of the bandgap energy with mass-specific laser energy input has been observed for the examples of ZnO and B4C particles. Trends are analysed by density gradient centrifugation, electron microscopy, UV–vis and X-ray diffraction analysis of the crystal structure. The study contributes to quantitative model parameters for up-scaling and provides insight into the mechanisms occurring when suspended particles are irradiated with pulsed laser sources.