Displaying publications 41 - 56 of 56 in total

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  1. Fulltext Preliminary Large Scale Mitigation of 3-Monochloropropane-1, 2-diol (3-MCPD) Esters and Glycidyl Esters in Palm Oil
    Ramli MR, Tarmizi AHA, Hammid ANA, Razak RAA, Kuntom A, Lin SW, et al.
    J Oleo Sci, 2020 Aug 06;69(8):815-824.
    PMID: 32641608 DOI: 10.5650/jos.ess20021
    Approximately 900 tonne of crude palm oil (CPO) underwent washing using 5 to 10% hot water (90 to 95°C) at a palm oil mill. The aim of the CPO washing was to eliminate and/or reduce total chlorine content present in the conventional CPO, as it is known as the main precursor for the formation of 3-monochloropropane-1, 2-diol esters (3-MCPDE). By a simple hot water washing, more than 85% of the total chlorine was removed. However, washing did not have significant (p > 0.05) effect on other oil quality parameters such as the deterioration of bleachability index (DOBI), free fatty acid (FFA) content and diacylglycerol (DAG) content of the oil. The latter has been established as the main precursor for glycidyl esters (GE) formation. The treated CPO was then transported using tankers and further refined at a commercial refinery. Refining of washed CPO resulted in significantly (p < 0.05) lower formation of 3-MCPDE, but GE content remained slightly high. Post-treatment of refined oil significantly reduced the GE content (p < 0.05) to an acceptable level whilst almost maintaining the low 3-MCPDE level. The study has proven that water washing of CPO prior to refining and subsequent post-refining is so far the most effective way to produce good quality refined oil with considerably low 3-MCPDE and GE contents. Dry fractionation of refined palm oil showed these contaminants partitioned more into the liquid olein fraction compared to the stearin fraction.
    Matched MeSH terms: Chemical Fractionation/methods*
  2. Combination of Cyclodextrin and Ionic Liquid in Analytical Chemistry: Current and Future Perspectives
    Hui BY, Raoov M, Zain NNM, Mohamad S, Osman H
    Crit Rev Anal Chem, 2017 Sep 03;47(5):454-467.
    PMID: 28453309 DOI: 10.1080/10408347.2017.1320936
    The growth in driving force and popularity of cyclodextrin (CDs) and ionic liquids (ILs) as promising materials in the field of analytical chemistry has resulted in an exponentially increase of their exploitation and production in analytical chemistry field. CDs belong to the family of cyclic oligosaccharides composing of α-(1,4) linked glucopyranose subunits and possess a cage-like supramolecular structure. This structure enables chemical reactions to proceed between interacting ions, radical or molecules in the absence of covalent bonds. Conversely, ILs are an ionic fluids comprising of only cation and anion often with immeasurable vapor pressure making them as green or designer solvent. The cooperative effect between CD and IL due to their fascinating properties, have nowadays contributed their footprints for a better development in analytical chemistry nowadays. This comprehensive review serves to give an overview on some of the recent studies and provides an analytical trend for the application of CDs with the combination of ILs that possess beneficial and remarkable effects in analytical chemistry including their use in various sample preparation techniques such as solid phase extraction, magnetic solid phase extraction, cloud point extraction, microextraction, and separation techniques which includes gas chromatography, high-performance liquid chromatography, capillary electrophoresis as well as applications of electrochemical sensors as electrode modifiers with references to recent applications. This review will highlight the nature of interactions and synergic effects between CDs, ILs, and analytes. It is hoped that this review will stimulate further research in analytical chemistry.
    Matched MeSH terms: Chemical Fractionation/methods
  3. Monitoring of tobramycin in human plasma via mixed matrix membrane extraction prior to capillary electrophoresis with contactless conductivity detection
    Mukhtar NH, Mamat NA, See HH
    J Pharm Biomed Anal, 2018 Sep 05;158:184-188.
    PMID: 29883881 DOI: 10.1016/j.jpba.2018.05.044
    A sample pre-treatment method based on a dynamic mixed matrix membrane tip extraction followed by capillary electrophoresis with contactless conductivity detection (CE-C4D) was evaluated for the determination of tobramycin in human plasma. The extraction tip device consisted of a cellulose triacetate membrane tip wall immobilised with 15% (w/w) of hydrophilic lipophilic balance (HLB) nanoparticles as adsorbent. The extraction was performed dynamically by withdrawing/dispensing the plasma sample through the tip device followed by desorption into 20 μL of acidified aqueous solution at pH 3 prior to the CE-C4D analysis. Under the optimum conditions, the detection limit of the method for tobramycin was 10 ng/mL, with intraday and interday repeatability RSDs of 3.5% and 4.5%, respectively. Relative recoveries in spiked human plasma were 99.6%-99.9%. The developed approach was successfully demonstrated for the quantification of tobramycin in human plasma samples.
    Matched MeSH terms: Chemical Fractionation/methods*
  4. Application of Box-Behnken design for ultrasound-assisted extraction and recycling preparative HPLC for isolation of anthraquinones from Cassia singueana
    Jibril S, Basar N, Sirat HM, Wahab RA, Mahat NA, Nahar L, et al.
    Phytochem Anal, 2019 Jan;30(1):101-109.
    PMID: 30288828 DOI: 10.1002/pca.2795
    INTRODUCTION: Cassia singueana Del. (Fabaceae) is a rare medicinal plant used in the traditional medicine preparations to treat various ailments. The root of C. singueana is a rich source of anthraquinones that possess anticancer, antibacterial and antifungal properties.

    OBJECTIVE: The objective of this study was to develop an ultrasound-assisted extraction (UAE) method for achieving a high extraction yield of anthraquinones using the response surface methodology (RSM), Box-Behnken design (BBD), and a recycling preparative high-performance liquid chromatography (HPLC) protocol for isolation of anthraquinones from C. singueana.

    METHODOLOGY: Optimisation of UAE was performed using the Box-Behnken experimental design. Recycling preparative HPLC was employed to isolate anthraquinones from the root extract of C. singueana.

    RESULTS: The BBD was well-described by a quadratic polynomial model (R2  = 0.9751). The predicted optimal UAE conditions for a high extraction yield were obtained at: extraction time 25.00 min, temperature 50°C and solvent-sample ratio of 10 mL/g. Under the predicted conditions, the experimental value (1.65 ± 0.07%) closely agreed to the predicted yield (1.64%). The obtained crude extract of C. singueana root was subsequently purified to afford eight anthraquinones.

    CONCLUSION: The extraction protocol described here is suitable for large-scale extraction of anthraquinones from plant extracts.

    Matched MeSH terms: Chemical Fractionation/methods
  5. Isolation of Wheat Genomic DNA for Gene Mapping and Cloning
    Yu G, Hatta A, Periyannan S, Lagudah E, Wulff BBH
    Methods Mol Biol, 2017;1659:207-213.
    PMID: 28856653 DOI: 10.1007/978-1-4939-7249-4_18
    DNA is widely used in plant genetic and molecular biology studies. In this chapter, we describe how to extract DNA from wheat tissues. The tissue samples are ground to disrupt the cell wall. Then cetyltrimethylammonium bromide (CTAB) or sodium dodecyl sulfate (SDS) is used to disrupt the cell and nuclear membranes to release the DNA into solution. A reducing agent, β-mercaptoethanol, is added to break the disulfide bonds between the cysteine residues and to help remove the tanins and polyphenols. A high concentration of salt is employed to remove polysaccharides. Ethylenediaminetetraacetic acid (EDTA) stops DNase activity by chelating the magnesium ions. The nucleic acid solution is extracted with chloroform-isoamyl alcohol (24:1) or 6 M ammonium acetate. The DNA in aqueous phase is precipated with ethanol or isopropanol, which makes DNA less hydrophilic in the presence of sodium ions (Na+).
    Matched MeSH terms: Chemical Fractionation/methods*
  6. Novel IEF Peptide Fractionation Method Reveals a Detailed Profile of N-Terminal Acetylation in Chemotherapy-Responsive and -Resistant Ovarian Cancer Cells
    Weiland F, Arentz G, Klingler-Hoffmann M, McCarthy P, Lokman NA, Kaur G, et al.
    J Proteome Res, 2016 11 04;15(11):4073-4081.
    PMID: 27569743
    Although acetylation is regarded as a common protein modification, a detailed proteome-wide profile of this post-translational modification may reveal important biological insight regarding differential acetylation of individual proteins. Here we optimized a novel peptide IEF fractionation method for use prior to LC-MS/MS analysis to obtain a more in depth coverage of N-terminally acetylated proteins from complex samples. Application of the method to the analysis of the serous ovarian cancer cell line OVCAR-5 identified 344 N-terminally acetylated proteins, 12 of which are previously unreported. The protein peptidyl-prolyl cis-trans isomerase A (PPIA) was detected in both the N-terminally acetylated and unmodified forms and was further analyzed by data-independent acquisition in carboplatin-responsive parental OVCAR-5 cells and carboplatin-resistant OVCAR-5 cells. This revealed a higher ratio of unacetylated to acetylated N-terminal PPIA in the parental compared with the carboplatin-resistant OVCAR-5 cells and a 4.1-fold increase in PPIA abundance overall in the parental cells relative to carboplatin-resistant OVCAR-5 cells (P = 0.015). In summary, the novel IEF peptide fractionation method presented here is robust, reproducible, and can be applied to the profiling of N-terminally acetylated proteins. All mass spectrometry data is available as a ProteomeXchange repository (PXD003547).
    Matched MeSH terms: Chemical Fractionation/methods
  7. Stereoselective method development and validation for determination of concentrations of amphetamine-type stimulants and metabolites in human urine using a simultaneous extraction-chiral derivatization approach
    Wan Raihana WA, Gan SH, Tan SC
    J Chromatogr B Analyt Technol Biomed Life Sci, 2011 Jan 1;879(1):8-16.
    PMID: 21147046 DOI: 10.1016/j.jchromb.2010.10.037
    Amphetamine-type stimulants (ATS) are a group of chiral amine drugs which are commonly abused for their sympathomimetic and stimulant properties. ATS are extensively metabolised by hepatic cytochrome P450 enzymes. As metabolism of ATS has been shown to be highly stereospecific, stereoselective analytical methods are essential for the quantitative determination of ATS concentrations for both in vivo and in vitro studies of ATS metabolism. This paper describes a new stereoselective method for the simultaneous determination of amphetamine (AM), methamphetamine (MA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), 4-hydroxy-3-methoxymethamphetamine (HMMA), 4-hydroxy-3-methoxyamphetamine (HMA), 3,4-hydroxymethamphetamine (HHMA) and 3,4-hydroxyamphetamine (HHA) in human urine samples validated according to the United States Food and Drug Administration guidelines. In this method, analytes are simultaneously extracted and derivatized with R-(-)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride (R-MTPCl) as the chiral derivatization reagent. Following this, the analytes were subjected to a second derivatization with N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA) which targets the hydroxyl groups present in HMMA, HMA, HHMA and HHA. The derivatized analytes were separated and quantified using gas chromatography-mass spectrometry (GC-MS). The method was evaluated according to the established guidelines for specificity, linearity, precision, accuracy, recovery and stability using a five-day protocol. Intra-day precision ranged from 0.89 to 11.23% RSD whereas inter-day precision was between 1.03 and 12.95% RSD. Accuracy values for the analytes ranged from -5.29% to 13.75%. Limits of quantitation were 10 μg/L for AM, MA, MDMA, HMA and HMMA and 2μg/L for MDA, HMA and HHA. Recoveries and stability values were also within accepted values. The method was applied to authentic ATS-positive samples.
    Matched MeSH terms: Chemical Fractionation/methods*
  8. Fulltext Effect of supercritical fluid extraction on the reduction of toxic elements in fish oil compared with other extraction methods
    Hajeb P, Selamat J, Afsah-Hejri L, Mahyudin NA, Shakibazadeh S, Sarker MZ
    J Food Prot, 2015 Jan;78(1):172-9.
    PMID: 25581193 DOI: 10.4315/0362-028X.JFP-14-248
    High-quality fish oil for human consumption requires low levels of toxic elements. The aim of this study was to compare different oil extraction methods to identify the most efficient method for extracting fish oil of high quality with the least contamination. The methods used in this study were Soxhlet extraction, enzymatic extraction, wet reduction, and supercritical fluid extraction. The results showed that toxic elements in fish oil could be reduced using supercritical CO2 at a modest temperature (60°C) and pressure (35 MPa) with little reduction in the oil yield. There were significant reductions in mercury (85 to 100%), cadmium (97 to 100%), and lead (100%) content of the fish oil extracted using the supercritical fluid extraction method. The fish oil extracted using conventional methods contained toxic elements at levels much higher than the accepted limits of 0.1 μg/g.
    Matched MeSH terms: Chemical Fractionation/methods
  9. Enhanced recovery and purification of P(3HB-co-3HHx) from recombinant Cupriavidus necator using alkaline digestion method
    Anis SN, Nurhezreen MI, Sudesh K, Amirul AA
    Appl Biochem Biotechnol, 2012 Jun;167(3):524-35.
    PMID: 22569781 DOI: 10.1007/s12010-012-9677-9
    A simple, efficient and economical method for the recovery of P(3HB-co-3HHx) was developed using various chemicals and parameters. The initial content of P(3HB-co-3HHx) in bacterial cells was 50-60 wt%, whereas the monomer composition of 3HHx used in this experiments was 3-5 mol%. It was found that sodium hydroxide (NaOH) was the most effective chemical for the recovery of biodegradable polymer. High polyhydroxyalkanoate purity and recovery yield both in the range of 80-90 wt% were obtained when 10-30 mg/ml of cells were incubated in NaOH at the concentration of 0.1 M for 60-180 min at 30 °C and polished using 20 % (v/v) of ethanol.
    Matched MeSH terms: Chemical Fractionation/methods*
  10. Characterisation of galloylated cyanogenic glucosides and hydrolysable tannins from leaves of Phyllagathis rotundifolia by LC-ESI-MS/MS
    Hooi Poay T, Sui Kiong L, Cheng Hock C
    Phytochem Anal, 2011 Nov-Dec;22(6):516-25.
    PMID: 21495106 DOI: 10.1002/pca.1312
    Phyllagathis rotundifolia (Jack) Bl. (Melastomataceae) is a creeping herb found in Peninsular Malaysia and Sumatra. Traditionally, a decoction of the leaves is used in the treatment of malaria, fever and stomach ache.
    Matched MeSH terms: Chemical Fractionation/methods
  11. Comparison of unmodified and modified BCR sequential extraction schemes for the fractionation of heavy metals in shrimp aquaculture sludge from Selangor, Malaysia
    Nemati K, Abu Bakar NK, Abas MR, Sobhanzadeh E, Low KH
    Environ Monit Assess, 2011 May;176(1-4):313-20.
    PMID: 20632089 DOI: 10.1007/s10661-010-1584-3
    A study was carried out to investigate the fractionation of Cd, Cr, Cu, Fe, Mn, Pb, and Zn in shrimp aquaculture sludge from Selangor, Malaysia, using original (unmodified) and modified four-steps BCR (European Community Bureau of Reference, now known as the Standards Measurements and Testing Program) sequential extraction scheme. Step 2 of the unmodified BCR procedure (subsequently called Method A) involves treatment with 0.1 M hydroxylammonium chloride at pH 2, whereas 0.5 M hydroxylammonium chloride at pH 1.5 was used in the modified BCR procedure (subsequently called Method B). Metal analyses were carried out by flame atomic absorption spectrometry. A pseudo-total aqua-regia digest of BCR CRM 701 has also been undertaken for quality assurance purposes. The recovery of Method A for all metals studied ranges from 96.14% to 105.26%, while the recovery for Method B ranges from 95.94% to 122.40%. Our results reveal that Method A underestimated the proportion of metals bound to the easily reducible fraction except for copper. Therefore, the potential mobility of these elements is higher than others. Thus, to use this sludge as a fertilizer we have to first find a remediation for reduction of heavy metal contamination.
    Matched MeSH terms: Chemical Fractionation/methods*
  12. Optimization of protein extraction for proteomic analyses of fresh and frozen "Musang King" durian pulps
    Tan XY, Misran A, Daim LDJ, Lau BYC
    Food Chem, 2021 May 01;343:128471.
    PMID: 33143964 DOI: 10.1016/j.foodchem.2020.128471
    Four different methods were evaluated to extract proteins from "Musang King" durian pulps and subsequently proteins with different abundance between fresh and long term frozen storage were identified using two-dimensional polyacrylamide gel electrophoresis coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometer analyses. The acetone-phenol method was found to produce good protein yields and gave the highest gel resolution and reproducibility. Differential protein analyses of the durian pulp revealed that 15 proteins were down-regulated and three other proteins were up-regulated after a year of frozen storage. Isoflavone reductase-like protein, S-adenosyl methionine synthase, and cysteine synthase isoform were up-regulated during frozen storage. The down-regulation of proteins in frozen durian pulps indicated that frozen storage has affected proteins in many ways, especially in their functions related to carbohydrate and energy metabolisms, cellular components, and transport processes. This study will enable future detailed investigations of proteins associated with quality attributes of durians to be studied.
    Matched MeSH terms: Chemical Fractionation/methods*
  13. Fulltext Functional expression of a novel α-amylase from Antarctic psychrotolerant fungus for baking industry and its magnetic immobilization
    He L, Mao Y, Zhang L, Wang H, Alias SA, Gao B, et al.
    BMC Biotechnol, 2017 02 28;17(1):22.
    PMID: 28245836 DOI: 10.1186/s12896-017-0343-8
    BACKGROUND: α-Amylase plays a pivotal role in a broad range of industrial processes. To meet increasing demands of biocatalytic tasks, considerable efforts have been made to isolate enzymes produced by extremophiles. However, the relevant data of α-amylases from cold-adapted fungi are still insufficient. In addition, bread quality presents a particular interest due to its high consummation. Thus developing amylases to improve textural properties could combine health benefits with good sensory properties. Furthermore, iron oxide nanoparticles provide an economical and convenient method for separation of biomacromolecules. In order to maximize the catalytic efficiency of α-amylase and support further applications, a comprehensive characterization of magnetic immobilization of α-amylase is crucial and needed.

    RESULTS: A novel α-amylase (AmyA1) containing an open reading frame of 1482 bp was cloned from Antarctic psychrotolerant fungus G. pannorum and then expressed in the newly constructed Aspergillus oryzae system. The purified recombinant AmyA1 was approximate 52 kDa. AmyA1 was optimally active at pH 5.0 and 40 °C, and retained over 20% of maximal activity at 0-20 °C. The K m and V max values toward soluble starch were 2.51 mg/mL and 8.24 × 10-2 mg/(mL min) respectively, with specific activity of 12.8 × 103 U/mg. AmyA1 presented broad substrate specificity, and the main hydrolysis products were glucose, maltose, and maltotetraose. The influence of AmyA1 on the quality of bread was further investigated. The application study shows a 26% increase in specific volume, 14.5% increase in cohesiveness and 14.1% decrease in gumminess in comparison with the control. AmyA1 was immobilized on magnetic nanoparticles and characterized. The immobilized enzyme showed improved thermostability and enhanced pH tolerance under neutral conditions. Also, magnetically immobilized AmyA1 can be easily recovered and reused for maximum utilization.

    CONCLUSIONS: A novel α-amylase (AmyA1) from Antarctic psychrotolerant fungus was cloned, heterologous expression in Aspergillus oryzae, and characterized. The detailed report of the enzymatic properties of AmyA1 gives new insights into fungal cold-adapted amylase. Application study showed potential value of AmyA1 in the food and starch fields. In addition, AmyA1 was immobilized on magnetic nanoparticles and characterized. The improved stability and longer service life of AmyA1 could potentially benefit industrial applications.

    Matched MeSH terms: Chemical Fractionation/methods
  14. Dichloromethane fraction of Moringa oleifera leaf methanolic extract selectively inhibits breast cancer cells (MCF7) by induction of apoptosis via upregulation of Bax, p53 and caspase 8 expressions
    Mohd Fisall UF, Ismail NZ, Adebayo IA, Arsad H
    Mol Biol Rep, 2021 May;48(5):4465-4475.
    PMID: 34086162 DOI: 10.1007/s11033-021-06466-y
    Moringa oleifera is a well-known medicinal plant which has anti-cancer and other biological activities. This research aims to determine the cytotoxic and apoptotic effect of M. oleifera leave extract on the breast cancer (MCF7) cells. The extracts were prepared using hexane, dichloromethane, chloroform and n-butanol by fractionating the crude 80% methanol extract of the plant leaves. The cytotoxic effect of the extracts on MCF7 cells were determined using CellTiter 96® AQueous One Solution Cell Proliferation (MTS) assay. The apoptosis study was conducted using Annexin V-FITC analysis and confirmed by Western blotting using selected proteins, which are p53, Bax, cytochrome c and caspase 8. Our results showed that the dichloromethane (DF-CME-MOL) extract was selectively cytotoxic to MCF7 cells (5 μg/mL) without significantly inhibiting the non-cancerous breast (MCF 10A) cells. It had the highest selectivity index (SI) value of 9.5 among the tested extracts. It also induced early apoptosis and increased the expressions of pro-apoptotic proteins Bax, caspase 8 and p53 in MCF7 cells. Gas chromatography-mass spectrometry analysis (GC-MS) analysis showed that the major compounds found in DF-CME-MOL were benzeneacetonitrile, 4-hydroxy- and benzeneacetic acid, 4-hydroxy-, methyl ester among others that were detected. Thus, DF-CME-MOL extract was found to inhibit the proliferation of MCF7 cells by apoptosis induction, which is likely due to the activities of the detected phytochemical compounds of the extract.
    Matched MeSH terms: Chemical Fractionation/methods*
  15. Benchtop Isolation and Characterisation of Small Extracellular Vesicles from Human Mesenchymal Stem Cells
    Tan KL, Chia WC, How CW, Tor YS, Show PL, Looi QHD, et al.
    Mol Biotechnol, 2021 Sep;63(9):780-791.
    PMID: 34061307 DOI: 10.1007/s12033-021-00339-2
    The objective of this study is to develop a simple protocol to isolate and characterise small extracellular vesicles (sEVs) from human umbilical cord-derived MSCs (hUC-MSCs). hUC-MSCs were characterised through analysis of morphology, immunophenotyping and multidifferentiation ability. SEVs were successfully isolated by ultrafiltration from the conditioned medium of hUC-MSCs. The sEVs' size distribution, intensity within a specific surface marker population were measured with zetasizer or nanoparticle tracking analysis. The expression of surface and internal markers of sEVs was also assessed by western blotting. Morphology of hUC-MSCs displayed as spindle-shaped, fibroblast-like adherent cells. Phenotypic analysis by flow cytometry revealed that hUC-MSCs expressed MSC surface marker, including CD90, CD73, CD105, CD44 and exhibited the capacity for osteogenic, adipogenic and chondrogenic differentiation. Populations of sEVs with CD9, CD63 and CD81 positive were detected with size distribution in the diameter of 63.2 to 162.5 nm. Typical sEVs biomarkers such as CD9, CD63, CD81, HSP70 and TSG101 were also detected with western blotting. Our study showed that sEVs from hUC-MSCs conditioned medium were successfully isolated and characterised. Downstream application of hUC-MSCs-sEVs will be further explored.
    Matched MeSH terms: Chemical Fractionation/methods*
  16. Fulltext Optimization protocol for the extraction of 6-gingerol and 6-shogaol from Zingiber officinale var. rubrum Theilade and improving antioxidant and anticancer activity using response surface methodology
    Ghasemzadeh A, Jaafar HZ, Rahmat A
    BMC Complement Altern Med, 2015;15:258.
    PMID: 26223685 DOI: 10.1186/s12906-015-0718-0
    Analysis and extraction of plant matrices are important processes for the development, modernization, and quality control of herbal formulations. Response surface methodology is a collection of statistical and mathematical techniques that are used to optimize the range of variables in various experimental processes to reduce the number of experimental runs, cost , and time, compared to other methods.
    Matched MeSH terms: Chemical Fractionation/methods*
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