Displaying publications 381 - 400 of 529 in total

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  1. Fulltext Magnetically recoverable magnetite-reduced graphene oxide as a demulsifier for surfactant stabilized crude oil-in-water emulsion
    Yau XH, Khe CS, Mohamed Saheed MS, Lai CW, You KY, Tan WK
    PLoS One, 2020;15(4):e0232490.
    PMID: 32353051 DOI: 10.1371/journal.pone.0232490
    Oily wastewater, especially water-oil emulsion has become serious environmental issue and received global attention. Chemical demulsifiers are widely used to treat oil-water emulsion, but the toxicity, non-recyclable and non-environmental friendly characteristic of chemical demulsifiers had limited their practical application in oil-water separation. Therefore, it is imperative to develop an efficient, simple, eco-friendly and recyclable demulsifiers for breaking up the emulsions from the oily wastewater. In this study, a magnetic demulsifier, magnetite-reduced graphene oxide (M-rGO) nanocomposites were proposed as a recyclable demulsifier to break up the surfactant stabilized crude oil-in-water (O/W) emulsion. M-rGO nanocomposites were prepared via in situ chemical synthesis by using only one type Fe salt and GO solid as precursor at room temperature. The prepared composites were fully characterized by various techniques. The effect of demulsifier dosage and pH of emulsion on demulsification efficiency (ED) has been studied in detailed. The demulsification mechanism was also proposed in this study. Results showed that M-rGO nanocomposites were able to demulsify crude O/W emulsion. The ED reaches 99.48% when 0.050 wt.% of M-rGO nanocomposites were added to crude O/W emulsion (pH = 4). Besides, M-rGO nanocomposites can be recycled up to 7 cycles without showing a significant change in terms of ED. Thus, M-rGO nanocomposite is a promising demulsifier for surfactant stabilized crude O/W emulsion.
    Matched MeSH terms: Oxidation-Reduction
  2. Smart electrical bi-layers lipopeptides: Novel peptidic chains like zigzag map esterified with phospho-glyceride as mono-layer moieties capable in forming a meso-sphere- envelop with scaffold- ability to cellular impurities
    Saadi S, Saari N, Abdulkarim MS, Ghazali HM, Anwar F
    J Control Release, 2018 03 28;274:93-101.
    PMID: 29031897 DOI: 10.1016/j.jconrel.2017.10.011
    Cell impurities are an emerging nucleating molecular barriers having the capability in disordering the metabolic chain reactions of proteolysis, glycolysis and lipolysis. Their massive effects induced by copolymer crystal growth in compaction with metal and mineral transients are extended as well as in damaging DNA and mRNA structure motif and other molecular assembly e.g. histones structure unites. Their polycrystalline packing modes, polydispersity and their tendency to surface and interface adhesion prompted us in structuring scaffold biomaterials enriched with biopeptides, layered by phospho-glycerides ester-forms. The interface tension of the formed map is flexible and dependent to the surface exposure and its collapse modes to the surrounding molecular ligands. Thus, the attempts in increasing surface exposure e.g. the viscoelastic of structured lipopeptides and types of formed network structures interplays an extra- conjugating biomolecules having a least cytotoxicity effects to cells constituents. Disulfides molecules are selected to be the key regulatory element in rejoining both lipidic and proteic moieties by disordering atoms status via chemical ionization using organic catalyst. The insertion of methionine based peptidic chain at the lateral surfaces of scaffold biomaterials enhances the electron-meta-static motions by raising a molecular disordering status at distinct regions of the map e.g. epimerization into a nonpolar side that helps the chemical conjunction of disulfide groups with the esterified phosphoglycerides mono-layers. These effects in turn are accomplished by the formation of meso-sphere nonpolar- vesicles. The oxidation of disulfide group would alter the ordering of initial molecules by raising a newly molecular disorders to the map with high polarity to surface regions. In the same time indicates a continuation in the crystallization growth factor via a low chemical lesions between the impurities and a supersaturation in the intra-atomic distances with maximum cross linking to the deformed ligand with scaffold biomaterials.
    Matched MeSH terms: Oxidation-Reduction
  3. Surface modification of valve metals using plasma electrolytic oxidation for antibacterial applications: A review
    Rizwan M, Alias R, Zaidi UZ, Mahmoodian R, Hamdi M
    J Biomed Mater Res A, 2018 02;106(2):590-605.
    PMID: 28975693 DOI: 10.1002/jbm.a.36259
    Plasma electrolytic oxidation (PEO) is an advance technique to develop porous oxidation layer on light metals, primarily to enhance corrosion and wear resistance. The oxidation layer can also offer a wide variety of mechanical, biomedical, tribological, and antibacterial properties through the incorporation of several ions and particles. Due to the increasing need of antimicrobial surfaces for biomedical implants, antibacterial PEO coatings have been developed through the incorporation of antibacterial agents. Metallic nanoparticles that have been employed most widely as antibacterial agents are reported to demonstrate serious health and environmental threats. To overcome the current limitations of these coatings, there is a significant need to develop antibacterial surfaces that are not harmful for patient's health and environment. Attention of the readers has been directed to utilize bioactive glasses as antibacterial agents for PEO coatings. Bioactive glasses are well known for their excellent bioactivity, biocompatibility, and antibacterial character. PEO coatings incorporated with bioactive glasses can provide environment-friendly antimicrobial surfaces with exceptional bioactivity, biocompatibility, and osseointegration. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 590-605, 2018.
    Matched MeSH terms: Oxidation-Reduction
  4. Fulltext A response surface approach on hydrolysis condition of eel (Monopterus Sp.) protein hydrolysate with antioxidant activity
    Halim, N. R. A., Sarbon, N. M.
    International Food Research Journal, 2017;24(3):1081-1093.
    MyJurnal
    The study aims to determine the optimized condition of eel protein hydrolysate (EPH)
    produced using alcalase. The proximate compositions of eel flesh were determined as well.
    Enzymatic hydrolysis conditions were optimized using response surface methodology (RSM)
    by applying four factors, 3-levels Central Composite Design (CCD) with six centre points. The
    model equation was proposed with regards to the time (60min, 120min, 180min), temperature
    (40°C, 50°C, 60°C), pH (7, 8, 9) and enzyme concentration (1%, 2%, 3%). The optimum of
    hydrolysis condition that be suggested to obtain the optimum yield, degree of hydrolysis (DH)
    and antioxidant activity were 84.02 min, 50.18°C, pH 7.89 and 2.26% [enzyme]. The predicted
    response values using quadratic model were 10.03% for yield, 83.23% for DH and 89.24%
    for antioxidant activity. The chemical composition determination showed that the protein
    content increased by more than 5-fold (16.88% to 98.53%) while the fat content was decreased
    by 96.48% after hydrolysis. Hydrolysis process had significantly increased the amount of
    both hydrophilic (serine and threonine) and hydrophobic amino acids (valine, isoleucine,
    phenylalanine, methionine) which contributed to the antioxidant activity of hydrolyzed eel
    protein. The enzymatic hydrolysis of eel protein had improved the protein content of EPH with
    potential as new natural antioxidant.
    Matched MeSH terms: Oxidation-Reduction
  5. Fulltext In vitro and in silico Approaches to Study Cytochrome P450-Mediated Interactions
    Tan BH, Pan Y, Dong AN, Ong CE
    J Pharm Pharm Sci, 2017;20(1):319-328.
    PMID: 29145931 DOI: 10.18433/J3434R
    In vitro and in silico models of drug metabolism are utilized regularly in the drug research and development as tools for assessing pharmacokinetic variability and drug-drug interaction risk. The use of in vitro and in silico predictive approaches offers advantages including guiding rational design of clinical drug-drug interaction studies, minimization of human risk in the clinical trials, as well as cost and time savings due to lesser attrition during compound development process. This article gives a review of some of the current in vitro and in silico methods used to characterize cytochrome P450(CYP)-mediated drug metabolism for estimating pharmacokinetic variability and the magnitude of drug-drug interactions. Examples demonstrating the predictive applicability of specific in vitro and in silico approaches are described. Commonly encountered confounding factors and sources of bias and error in these approaches are presented. With the advent of technological advancement in high throughput screening and computer power, the in vitro and in silico methods are becoming more efficient and reliable and will continue to contribute to the process of drug discovery, development and ultimately safer and more effective pharmacotherapy. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.
    Matched MeSH terms: Oxidation-Reduction
  6. Revalorization of selected municipal solid wastes as new precursors of "green" nanocellulose via a novel one-pot isolation system: A source perspective
    Chen YW, Lee HV
    Int J Biol Macromol, 2018 Feb;107(Pt A):78-92.
    PMID: 28860064 DOI: 10.1016/j.ijbiomac.2017.08.143
    In the present work, four types of newly chosen municipal solid wastes (Panax ginseng, spent tea residue, waste cotton cloth, and old corrugated cardboard) were studied as the promising sources for nanocellulose, which has efficiently re-engineered the structure of waste products into highly valuable nanocellulose materials. The nanocellulose was produced directly via a facile one-pot oxidative hydrolysis process by using H2O2/Cr(NO3)3 solution as the bleaching agent and hydrolysis medium under acidic condition. The isolated nanocellulose products were well-characterized in terms of chemical composition, product yield, morphological structure and thermal properties. The study has found that the crystallinity index of the obtained nanocellulose products were significantly higher (62.2-83.6%) than that of its starting material due to the successive elimination of lignin, hemicellulose and amorphous regions of cellulose, which were in good agreement with the FTIR analysis. The evidence of the successful production of nanocellulose was given by TEM observation which has revealed the fibril widths were ranging from 15.6 to 46.2nm, with high cellulose content (>90%), depending on the cellulosic origin. The physicochemical properties of processed samples have confirmed that the isolation of high purity nanocellulose materials from different daily spent products is possible. The comparative study can help to provide a deep insight on the possibility of revalorizing the municipal solid wastes into nanocellulose via the simple and versatile one-pot isolation system, which has high potential to be used in commercial applications for sustainable development.
    Matched MeSH terms: Oxidation-Reduction
  7. Novel synergistic hydrous iron-nickel-manganese (HINM) trimetal oxide for hazardous arsenite removal
    Nasir AM, Goh PS, Ismail AF
    Chemosphere, 2018 Jun;200:504-512.
    PMID: 29501887 DOI: 10.1016/j.chemosphere.2018.02.126
    A novel hydrous iron-nickel-manganese (HINM) trimetal oxide was successfully fabricated using oxidation and coprecipitation method for metalloid arsenite removal. The atomic ratio of Fe:Ni:Mn for this adsorbent is 3:2:1. HINM adsorbent was identified as an amorphous nanosized adsorbent with particle size ranged from 30 nm to 60 nm meanwhile the total active surface area and pore diameter of HINM area of 195.78 m2/g and 2.43 nm, respectively. Experimental data of arsenite adsorption is best fitted into pseudo-second order and Freundlich isotherm model. The maximum adsorption capacity of arsenite onto HINM was 81.9 mg/g. Thermodynamic study showed that the adsorption of arsenite was a spontaneous and endothermic reaction with enthalpy change of 14.04 kJ/mol and Gibbs energy of -12 to -14 kJ/mol. Zeta potential, thermal gravimetric (TGA) and Fourier transform infrared (FTIR) analysis were applied to elucidate the mechanism of arsenite adsorption by HINM. Mechanism of arsenite adsorption by HINM involved both chemisorption and physisorption based on the electrostatic attraction between arsenite ions and surface charge of HINM. It also involved the hydroxyl substitution by arsenite ions through the formation of inner-sphere complex. Reusability of HINM trimetal oxide was up to 89% after three cycles of testing implied that HINM trimetal oxide is a promising and practical adsorbent for arsenite.
    Matched MeSH terms: Oxidation-Reduction
  8. Simultaneous determination of ascorbic acid, dopamine and uric acid by a novel electrochemical sensor based on N2/Ar RF plasma assisted graphene nanosheets/graphene nanoribbons
    Jothi L, Neogi S, Jaganathan SK, Nageswaran G
    Biosens Bioelectron, 2018 May 15;105:236-242.
    PMID: 29412948 DOI: 10.1016/j.bios.2018.01.040
    A novel nitrogen/argon (N2/Ar) radio frequency (RF) plasma functionalized graphene nanosheet/graphene nanoribbon (GS/GNR) hybrid material (N2/Ar/GS/GNR) was developed for simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). Various nitrogen mites introduced into GS/GNR hybrid structure was evidenced by a detailed microscopic, spectroscopic and surface area analysis. Owing to the unique structure and properties originating from the enhanced surface area, nitrogen functional groups and defects introduced on both the basal and edges, N2/Ar/GS/GNR/GCE showed high electrocatalytic activity for the electrochemical oxidations of AA, DA, and UA with the respective lowest detection limits of 5.3, 2.5 and 5.7 nM and peak-to-peak separation potential (ΔEP) (vs Ag/AgCl) in DPV of 220, 152 and 372 mV for AA/DA, DA/UA and AA/UA respectively. Moreover, the selectivity, stability, repeatability and excellent performance in real time application of the fabricated N2/Ar/GS/GNR/GCE electrode suggests that it can be considered as a potential electrode material for simultaneous detection of AA, DA, and UA.
    Matched MeSH terms: Oxidation-Reduction
  9. Post-treatment of palm oil mill effluent (POME) using combined persulphate with hydrogen peroxide (S2O8(2-)/H2O2) oxidation
    Lin CK, Bashir MJ, Abu Amr SS, Sim LC
    Water Sci Technol, 2016 Dec;74(11):2675-2682.
    PMID: 27973372
    The aim of the current study is to evaluate the effectiveness of combined persulphate with hydrogen peroxide (S2O8(2-)/H2O2) oxidation as a post-treatment of biologically treated palm oil mill effluent (POME) for the first time in the literature. The removal efficiencies of chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), and suspended solids (SS) were 36.8%, 47.6%, and 90.6%, respectively, by S2O8(2-) oxidation alone under certain operation conditions (i.e., S2O8(2-) = 0.82 g, pH 11, and contact time 20 min). Nevertheless, the combined process (S2O8(2-)/H2O2) achieved 75.8% and 87.1% removals of NH3-N and SS, respectively, under 2.45/1.63 g/g H2O2/S2O8(2-), pH 11, and 20 min oxidation. Moreover, 56.9% of COD was removed at pH 8.4.
    Matched MeSH terms: Oxidation-Reduction
  10. Acoustic cavitation induced generation of stabilizer-free, extremely stable reduced graphene oxide nanodispersion for efficient delivery of paclitaxel in cancer cells
    Geetha Bai R, Muthoosamy K, Shipton FN, Manickam S
    Ultrason Sonochem, 2017 May;36:129-138.
    PMID: 28069192 DOI: 10.1016/j.ultsonch.2016.11.021
    Graphene is one of the highly explored nanomaterials due to its unique and extraordinary properties. In this study, by utilizing a hydrothermal reduction method, graphene oxide (GO) was successfully converted to reduced graphene oxide (RGO) without using any toxic reducing agents. Following this, with the use of ultrasonic cavitation, profoundly stable few layer thick RGO nanodispersion was generated without employing any stabilizers or surfactants. During ultrasonication, shockwaves from the collapse of bubbles cause a higher dispersing energy to the graphene nanosheets which surpass the forces of Van der Waal's and π-π stacking and thus pave the way to form a stable aqueous nanodispersion of graphene. Ultrasonication systems with different power intensity have been employed to determine the optimum conditions for obtaining the most stable RGO dispersion. The optimised conditions of ultrasonic treatments led to the development of a very stable reduced graphene oxide (RGO) aqueous dispersion. The stability was observed for two years and was analyzed by using Zetasizer by measuring the particle size and zeta potential at regular intervals and found to have exceptional stability. The excellent stability at physiological pH promotes its utilization in nano drug delivery application as a carrier for Paclitaxel (Ptx), an anticancer drug. The in vitro cytotoxicity analysis of Ptx loaded RGO nanodispersion by MTT assay performed on the cell lines revealed the potential of the nanodispersion as a suitable drug carrier. Studies on normal lung cells, MRC-5 and nasopharyngeal cancer cells, HK-1 supported the biocompatibility of RGO-Ptx towards normal cell line. This investigation shows the potential of exceptionally stable RGO-Ptx nanodispersion in nano drug delivery applications.
    Matched MeSH terms: Oxidation-Reduction
  11. Sonophotocatalytic degradation of bisphenol A and its intermediates with graphitic carbon nitride
    Sunasee S, Leong KH, Wong KT, Lee G, Pichiah S, Nah I, et al.
    Environ Sci Pollut Res Int, 2019 Jan;26(2):1082-1093.
    PMID: 28290089 DOI: 10.1007/s11356-017-8729-7
    Since bisphenol A (BPA) exhibits endocrine disrupting action and high toxicity in aqueous system, there are high demands to remove it completely. In this study, the BPA removal by sonophotocatalysis coupled with nano-structured graphitic carbon nitride (g-C3N4, GCN) was conducted with various batch tests using energy-based advanced oxidation process (AOP) based on ultrasound (US) and visible light (Vis-L). Results of batch tests indicated that GCN-based sonophotocatalysis (Vis-L/US) had higher rate constants than other AOPs and especially two times higher degradation rate than TiO2-based Vis-L/US. This result infers that GCN is effective in the catalytic activity in Vis-L/US since its surface can be activated by Vis-L to transport electrons from valence band (VB) for utilizing holes (h+VB) in the removal of BPA. In addition, US irradiation exfoliated the GCN effectively. The formation of BPA intermediates was investigated in detail by using high-performance liquid chromatography-mass spectrometry (HPLC/MS). The possible degradation pathway of BPA was proposed.
    Matched MeSH terms: Oxidation-Reduction
  12. Mitigation of NOx emission using aromatic and phenolic antioxidant-treated biodiesel blends in a multi-cylinder diesel engine
    Adam IK, Heikal M, Aziz ARA, Yusup S
    Environ Sci Pollut Res Int, 2018 Oct;25(28):28500-28516.
    PMID: 30088249 DOI: 10.1007/s11356-018-2863-8
    The present work analyzes the effect of antioxidants on engine combustion performance of a multi-cylinder diesel engine fueled with PB30 and PB50 (30 and 50 vol.% palm biodiesel (PB)). Four antioxidants namely N,N'-diphenyl-1,4-phenylenediamine (DPPD), N-phenyl-1,4-phenylenediamine (NPPD), 2(3)-tert-Butyl-4-methoxyphenol (BHA), and 2-tert-butylbenzene-1,4-diol (TBHQ) were added at concentrations of 1000 and 2000 ppm to PB30 and PB50. TBHQ showed the highest activity in increasing oxidation stability in both PB30 and PB50 followed by BHA, DPPD, and NPPD respectively, without any negative effect on physical properties. Compared to diesel fuel, PB blends showed 4.61-6.45% lower brake power (BP), 5.90-8.69% higher brake specific fuel consumption (BSFC), 9.64-11.43% higher maximum in cylinder pressure, and 7.76-12.51% higher NO emissions. Carbon monoxide (CO), hydrocarbon (HC), and smoke opacity were reduced by 36.78-43.56%, 44.12-58.21%, and 42.59-63.94%, respectively, than diesel fuel. The start of combustion angles (SOC) of PB blends was - 13.2 to - 15.6 °CA BTDC, but the combustion delays were 5.4-7.8 °CA short compared to diesel fuel which were - 10 °CA BTDC and 11°CA respectively. Antioxidant fuels of PB showed higher BP (1.81-5.32%), CO (8.41-24.60%), and HC (13.51-37.35%) with lower BSFC (1.67-7.68%), NO (4.32-11.53%), maximum in cylinder pressure (2.33-4.91%) and peak heat release rates (HRR) (3.25-11.41%) than baseline fuel of PB. Similar SOC of - 13 to - 14 °CA BTDC was observed for PB blended fuels and antioxidants. It can be concluded that antioxidants' addition is effective in increasing the oxidation stability and in controlling the NOx emissions of palm biodiesel fuelled diesel engine.
    Matched MeSH terms: Oxidation-Reduction
  13. Enhancement of anaerobic digestibility of waste activated sludge using photo-Fenton pretreatment
    Heng GC, Isa MH, Lim JW, Ho YC, Zinatizadeh AAL
    Environ Sci Pollut Res Int, 2017 Dec;24(35):27113-27124.
    PMID: 28963706 DOI: 10.1007/s11356-017-0287-5
    Biological treatments, such as activated sludge process, are common methods to treat municipal and industrial wastewaters. However, they produce huge amounts of waste activated sludge (WAS). The excess sludge treatment and disposal are a challenge for wastewater treatment plants due to economic, environmental, and regulatory factors. In this study, photo-Fenton pretreatment (oxidation using hydrogen peroxide and iron catalyst aided with UV light) was optimized using response surface methodology (RSM) and central composite design (CCD) to determine the effects of three operating parameters (H2O2 dosage, H2O2/Fe2+ molar ratio, and irradiation time) on disintegration and dewaterability of WAS. MLVSS removal, capillary suction time (CST) reduction, sCOD, and EPS were obtained as 70%, 25%, 12,000 mg/L, and 500 mg/L, respectively, at the optimal conditions, i.e., 725 g H2O2/kg TS, H2O2/Fe2+ molar ratio 80, and irradiation time 40 min. Two batch-fed completely mixed mesophilic anaerobic digesters were then operated at 15-day solid retention time (SRT) and 37 ± 0.5 °C to compare the digestibility of untreated and photo-Fenton pretreated sludge in terms of volatile solids (VS) reduction, COD removal, and biogas production at steady-state operations. Photo-Fenton pretreatment followed by anaerobic digestion of WAS was very effective and yielded 75.7% total VS reduction, 81.5% COD removal, and 0.29-0.31 m3/kg VSfed·d biogas production rate, compared to 40.7% total VS solid reduction, 54.7% COD removal, and 0.12-0.17 m3/kg VSfed·d biogas production rate for control. Thus, photo-Fenton can be a useful pretreatment step in sludge management.
    Matched MeSH terms: Oxidation-Reduction
  14. Ozonation of metoprolol in aqueous solution: ozonation by-products and mechanisms of degradation
    Tay KS, Rahman NA, Abas MR
    Environ Sci Pollut Res Int, 2013 May;20(5):3115-21.
    PMID: 23054788 DOI: 10.1007/s11356-012-1223-3
    This study investigated the degradation pathway of metoprolol, a widely used β-blocker, in the ozonation via the identification of generated ozonation by-products (OPs). Structure elucidation of OPs was performed using HPLC coupled with quadrupole time-of-flight high-resolution mass spectrometry. Seven OPs were identified, and four of these have not been reported elsewhere. Identified OPs of metoprolol included aromatic ring breakdown by-products; aliphatic chain degraded by-products and aromatic ring mono-, di-, and tetrahydroxylated derivatives. Based on the detected OPs, metoprolol could be degraded through aromatic ring opening reaction via reaction with ozone (O3) and degradation of aliphatic chain and aromatic ring via reaction with hydroxyl radical (•OH).
    Matched MeSH terms: Oxidation-Reduction
  15. Methylene blue dye removal on silver nanoparticles reduced by Kyllinga brevifolia
    Isa N, Lockman Z
    Environ Sci Pollut Res Int, 2019 Apr;26(11):11482-11495.
    PMID: 30806934 DOI: 10.1007/s11356-019-04583-7
    Silver nanoparticles (AgNPs) were prepared by reacting Kyllinga brevifolia extract (KBE) with AgNO3 aqueous solution at room temperature (22 ± 3 °C). The phytochemical constituents in KBE responsible for the reduction process were identified as carbohydrate, protein, and plant sterols (stigmasterol and campesterol). KBE was also found to function as a capping agent for stabilization of AgNPs. The AgNPs were stable at room temperature and had a quasi-spherical shape with an average particle size 22.3 nm. The use of KBE offers not only eco-friendly and non-pathogenic path for AgNPs formation, it also induced rapid formation of the AgNPs. Methylene blue (MB) removal was then done on the AgNPs in the presence of either KBE or NaBH4. Ninety-three percent removal of MB was achieved with a rate of reaction 0.2663 min-1 in the solution with KBE+AgNPs (pH 2). However, in NaBH4+AgNPs system, 100% MB removal was achieved at pH 8-10. The reaction rate was 2.5715 min-1 indicating a fast removal rate of MB dye. The process of reduction occurs via electron relay effect whereas in KBE+AgNPs system, sedimentation occurred along with the reduction process. Nevertheless, the use of KBE+AgNPs system is preferred as the reducing agent is more benign to the environment.
    Matched MeSH terms: Oxidation-Reduction
  16. Fulltext Phenolic content, antioxidant effect and cytotoxic activity of Leea indica leaves
    Reddy NS, Navanesan S, Sinniah SK, Wahab NA, Sim KS
    BMC Complement Altern Med, 2012 Aug 17;12:128.
    PMID: 22898370 DOI: 10.1186/1472-6882-12-128
    BACKGROUND: The leaves of Leea indica (Vitaceae), commonly known as 'Huo Tong Shu' in Malaysia, have been traditionally used as natural remedy in folk medicine by the locals. The current study reports the outcome of antioxidant and cytotoxic investigation of L. indica leaves. To the best of our knowledge, this is the first report of L. indica leaf crude ethanol and its fractionated extracts (hexane, ethyl acetate and water) for evaluation of total phenolic content, antioxidant effect and cytotoxic activity against colon cancer cell lines.

    METHODS: In the present study, L. indica leaf crude ethanol and its fractionated extracts (hexane, ethyl acetate and water) were firstly prepared prior to phenolic content, antioxidant effect and cytotoxic activity assessment. Folin-Ciocalteau's method was used for the measurement of total phenolic content of the extracts. The antioxidant activity was measured by employing three different established testing systems, such as scavenging activity on DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals, reducing power assay and SOD (superoxide dismutase) activity assay. The cytotoxic activity of the extracts were evaluated against three colon cancer cell lines with varying molecular characteristics (HT-29, HCT-15 and HCT-116) by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay.

    RESULTS: The total phenolic content and antioxidant capabilities differed significantly among the L. indica leaf extracts. A strong correlation between total phenolic content and antioxidant properties was found, indicating that phenolic compounds are the major contributor to the antioxidant properties of these extracts. Among the crude ethanol and its fractionated extracts, fractionated water extract showed significantly the highest total phenolic content and strongest antioxidant effect in all the antioxidant testing systems employed in this study. All the four extracts exert no damage to the selected colon cancer cells.

    CONCLUSIONS: The data obtained in these testing systems clearly establish the antioxidant potency of the fractionated water extract of L. indica leaves. Additional studies should be carried out to isolate and identify the bioactive compounds in the fractionated water extract, in order to provide more convincing evidence.

    Matched MeSH terms: Oxidation-Reduction
  17. Fulltext Genome sequence of Citrobacter sp. strain A1, a dye-degrading bacterium
    Chan GF, Gan HM, Rashid NA
    J Bacteriol, 2012 Oct;194(19):5485-6.
    PMID: 22965102 DOI: 10.1128/JB.01285-12
    Citrobacter sp. strain A1, isolated from a sewage oxidation pond, is a facultative aerobe and mesophilic dye-degrading bacterium. This organism degrades azo dyes efficiently via azo reduction and desulfonation, followed by the successive biotransformation of dye intermediates under an aerobic environment. Here we report the draft genome sequence of Citrobacter sp. A1.
    Matched MeSH terms: Oxidation-Reduction
  18. Fulltext Fish oil supplements, oxidative status, and compliance behaviour: Regulatory challenges and opportunities
    Jairoun AA, Shahwan M, Zyoud SH
    PLoS One, 2020;15(12):e0244688.
    PMID: 33382790 DOI: 10.1371/journal.pone.0244688
    BACKGROUND: Fish oil supplements that are rich in omega-3 long-chain polyunsaturated fatty acids (n-3 PUFAs). PUFAs are among the most widely-used dietary supplements globally, and millions of people consume them regularly. There have always been public concerns that these products should be guaranteed to be safe and of good quality, especially as these types of fish oil supplements are extremely susceptible to oxidative degradation.

    OBJECTIVES: The aim of the current study is to investigate and examine the oxidation status of dietary supplements containing fish oils and to identify important factors related to the oxidation status of such supplements available in the United Arab Emirates (UAE).

    METHODS: A total of 44 fish oil supplements were analysed in this study. For each product, the oxidative parameters peroxide value (PV), anisidine value (AV), and total oxidation (TOTOX) were calculated, and comparisons were made with the guidelines supplied by the Global Organization for EPA and DHA Omega-3s (GOED). Median values for each of the above oxidative parameters were tested using the Kruskal-Wallis and Mann-Whitney U tests. P values < 0.05 were chosen as the statistically significant boundary.

    RESULTS: The estimate for the average PV value was 6.4 with a 95% confidence interval (CI) [4.2-8.7] compared to the maximum allowable limit of 5 meq/kg. The estimate for the average P-AV was 11 with a 95% CI [7.8-14.2] compared to the maximum allowable limit of 20. The estimate for the average TOTOX value was 23.8 meq/kg with a 95% CI [17.4-30.3] compared to the maximum allowable limit of 26 according to the GOED standards.

    CONCLUSION: This research shows that most, although not all, of the fish oil supplements tested are compliant with the GOED oxidative quality standards. Nevertheless, it is clear that there should be a high level of inspection and control regarding authenticity, purity, quality, and safety in the processes of production and supply of dietary supplements containing fish oils.

    Matched MeSH terms: Oxidation-Reduction
  19. Fulltext Highly exposed {001} facets of titanium dioxide modified with reduced graphene oxide for dopamine sensing
    How GT, Pandikumar A, Ming HN, Ngee LH
    Sci Rep, 2014;4:5044.
    PMID: 24853929 DOI: 10.1038/srep05044
    Titanium dioxide (TiO2) with highly exposed {001} facets was synthesized through a facile solvo-thermal method and its surface was decorated by using reduced graphene oxide (rGO) sheets. The morphology and chemical composition of the prepared rGO/TiO2 {001} nanocomposite were examined by using suitable characterization techniques. The rGO/TiO2 {001} nanocomposite was used to modify glassy carbon electrode (GCE), which showed higher electrocatalytic activity towards the oxidation of dopamine (DA) and ascorbic acid (AA), when compared to unmodified GCE. The differential pulse voltammetric studies revealed good sensitivity and selectivity nature of the rGO/TiO2 {001} nanocomposite modified GCE for the detection of DA in the presence of AA. The modified GCE exhibited a low electrochemical detection limit of 6 μM over the linear range of 2-60 μM. Overall, this work provides a simple platform for the development of GCE modified with rGO/TiO2 {001} nanocomposite with highly exposed {001} facets for potential electrochemical sensing applications.
    Matched MeSH terms: Oxidation-Reduction
  20. Fulltext Antioxidant and cytotoxic activities of three species of tropical seaweeds
    Chia YY, Kanthimathi MS, Khoo KS, Rajarajeswaran J, Cheng HM, Yap WS
    BMC Complement Altern Med, 2015;15:339.
    PMID: 26415532 DOI: 10.1186/s12906-015-0867-1
    Three species of seaweeds (Padina tetrastromatica, Caulerpa racemosa and Turbinaria ornata) are widely consumed by Asians as nutraceutical food due to their antioxidant properties. Studies have shown that these seaweeds exhibit bioactivities which include antimicrobial, antiviral, anti-hypertensive and anticoagulant activities. However, investigations into the mechanisms of action pertaining to the cytotoxic activity of the seaweeds are limited. The aim of this study was to determine the antioxidant and cytotoxic activities of whole extracts of P. tetrastromatica, C. racemosa and T. ornata, including the cellular events leading to the apoptotic cell death of the extract treated-MCF-7 cells. Bioassay guided fractionation was carried out and the compounds identified.
    Matched MeSH terms: Oxidation-Reduction
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