Displaying publications 1 - 20 of 51 in total

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  1. Foodomics Reveals Anti-Obesity Properties of Cannabinoids from Hemp Oil
    Ding Z, Jiang F, Shi J, Wang Y, He M, Tan CP, et al.
    Mol Nutr Food Res, 2023 Jan;67(2):e2200508.
    PMID: 36382382 DOI: 10.1002/mnfr.202200508
    SCOPE: Molecular networking (MN) analysis intends to provide chemical insight of untargeted mass spectrometry (MS) data to the user's underlying biological questions. Foodomics is the study of chemical compounds in food using advanced omics methods. In this study, an MS-MN-based foodomics approach is developed to investigate the composition and anti-obesity activity of cannabinoids in hemp oil.

    METHODS AND RESULTS: A total of 16 cannabinoids are determined in optimized microwave pretreatment of hemp oil using the developed approach. Untargeted metabolomics analysis reveals that cannabinoid extract (CE) and its major constituent (cannabidiol, CBD), can alleviate high glucose-induced increases in lipids and carbohydrates, and decreases in amino acid and nucleic acid. Moreover, CE and CBD are also found to suppress the expression levels of mdt-15, sbp-1, fat-5, fat-6, fat-7, daf-2, and elevate the expression level of daf-1, daf-7, daf-16, sod-3, gst-4, lipl-4, resulting in the decrease of lipid synthesis and the enhance of kinetism. Canonical correspondence analysis (CCA) uncovers strong associations between specific metabolic alterations and gene expression levels.

    CONCLUSION: These findings from this exploratory study offer a new insight into the roles of cannabinoids in the treatment of obesity and related complications.

    Matched MeSH terms: Tandem Mass Spectrometry/methods
  2. Development of dispersive inclusion complex microextraction for the analysis of nitrosamines in medicinal products
    Tay KSJ, Breadmore MC, Soh ES, See HH
    J Chromatogr A, 2022 Dec 06;1685:463605.
    PMID: 36375217 DOI: 10.1016/j.chroma.2022.463605
    A new dispersive inclusion complex microextraction (DICM) approach coupled with ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) for the determination of n-nitrosamine impurities in different medicinal products is demonstrated for the first time. The proposed DICM procedures consist of a dispersive liquid phase microextraction steps employing cyclodextrin as an inclusion complex agent to extract n-nitrosamines namely N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosodiisopropylamine (NDIPA), N-ethyl-N-nitrosoisopropylamine (NEIPA) and N-nitroso-di-n-butylamine (NDBA) present in the medicinal products. The sample solutions were prepared by mixing 5% (m/v) NaCl solution with 1.5 mM β-cyclodextrin and 20 mM sodium dodecyl sulphate to form a stable inclusion complex and subsequently extracted into dichloromethane as an extraction solvent. The enriched solution was reconstituted into aqueous solution prior to UPLC-MS/MS analysis. The method showed good linearity in the range of 0.036-1 ng/mL with a correlation coefficient of at least 0.995, acceptable reproducibility (RSD 0.5-5.8%, n=5), low limits of detection (0.011-0.018 ng/mL), and satisfactory relative recoveries (96-105%). The results obtained were found to be at least 10-fold more sensitive comparable to those obtained using validated direct sample dissolutions coupled with UPLC-MS/MS approach.
    Matched MeSH terms: Tandem Mass Spectrometry/methods
  3. Assessment of 18 endocrine disrupting chemicals in tap water samples from Klang Valley, Malaysia
    Haron DEM, Yoneda M, Hod R, Ramli MR, Aziz MY
    Environ Sci Pollut Res Int, 2023 Nov;30(51):111062-111075.
    PMID: 37801249 DOI: 10.1007/s11356-023-30022-9
    Multiclass of endocrine disrupting chemicals (EDCs) such as nine perfluoroalkyl and polyfluoroalkyl substances (PFAS), five bisphenols, and four parabens were analysed in tap water samples from Malaysia's Klang Valley region. All samples were analysed using liquid chromatography mass tandem spectrometry (LC-MS/MS) with limit of quantitation (LOQ) ranged between 0.015 and 5 ng/mL. Fifteen of the 18 EDCs were tested positive in tap water samples, with total EDC concentrations ranging from 0.28 to 5516 ng/L for all 61 sampling point locations. In a specific area of the Klang Valley, the total concentration of EDCs was found to be highest in Hulu Langat, followed by Sepang, Putrajaya, Petaling, Kuala Lumpur, Seremban, and Gombak/Klang. PFAS and paraben were the most found EDCs in all tap water samples. Meanwhile, ethyl paraben (EtP) exhibited the highest detection rate, with 90.2% of all locations showing its presence. Over 60% of the regions showed the presence of perfluoro-n-butanoic acid (PFBA), perfluoro-n-hexanoic acid (PFHXA), perfluoro-n-octanoic acid (PFOA), perfluoro-n-nonanoic acid (PFNA), and perfluoro-1-octanesulfonate (PFOS), whereas the frequency of detection for other compounds was less than 40%. The spatial distribution and mean concentrations of EDCs in the Klang Valley regions revealed that Hulu Langat, Petaling Jaya, and Putrajaya exhibited higher levels of bisphenol A (BPA). On the other hand, Kuala Lumpur and Sepang displayed the highest mean concentrations of PFBA. In the worst scenario, the estimated daily intake (EDI) and risk quotient of some EDCs in this study exceeded the acceptable daily limits recommended by international standards, particularly for BPA, PFOA, PFOS, and PFNA, where the risk quotient (RQ) was found to be greater than 1, indicating a high risk to human health. The increasing presence of EDCs in tap water is undoubtedly a cause for concern as these substances can have adverse health consequences. This highlights the necessity for a standardised approach to evaluating EDC exposure and its direct impact on human populations' health.
    Matched MeSH terms: Tandem Mass Spectrometry/methods
  4. LC-PDA-MS/MS-Based Characterization of Key Phytochemicals in Eurycoma Longifolia Roots
    Chua LS, Segaran A, Wong HJ
    J Chromatogr Sci, 2021 Jun 21;59(7):659-669.
    PMID: 33876232 DOI: 10.1093/chromsci/bmab041
    The objective of the study was to fractionate the crude extract of Eurycoma longifolia (E. longifolia) roots and identify the intense peaks using HPLC-PDA-MS/MS, UPLC-MS/MS and H-NMR. Column chromatography was used to fractionate the crude extract into individual fractions using six solvent systems ranged from ethyl acetate, methanol and water in increasing polarity. Two fractions with nearly pure and intense peaks were selected for compound identification. Chromenone (coumarin) and chromone derivatives were putatively identified, besides several previously reported quassinoid glycosides (eurycomanone derived glycoside, 2,3-dehydro-4α-hydroxylongilactone glucoside, eurycomanol glycoside and eurycomanol trimer) in the fraction 11 of 100% methanol. A newly reported compound, namely hydroxyl glyyunanprosapogenin D (838 g/mol) was proposed to be the compound detected in the fraction 11 of 50% ethyl acetate and 50% methanol. This is also the first study to report the identification of chromenones and chromones in E. longifolia extract.
    Matched MeSH terms: Tandem Mass Spectrometry/methods*
  5. Poly-(MMA-IL) filter paper: A new class of paper-based analytical device for thin-film microextraction of multi-class antibiotics in environmental water samples using LC-MS/MS analysis
    Shahriman MS, Mohamad S, Mohamad Zain NN, Raoov M
    Talanta, 2023 Mar 01;254:124188.
    PMID: 36521327 DOI: 10.1016/j.talanta.2022.124188
    A paper-based polymeric ionic liquid (p-Poly-(MMA-IL)) was successfully developed by grafting the polymeric ionic liquid on the surface of commercial filter paper (FP) by using the dipping method, presenting a new cost-effective film. The newly developed p-Poly-(MMA-IL) FP was then applied as a paper-based thin-film microextraction (p-TFME) analytical device to extract 14 compounds as representative of five groups of antibiotic drugs, which were sulfonamides, tetracyclines, fluoroquinolones, penicillin and macrolides in environmental water samples. Besides, p-Poly-(MMA-IL) FP, p-Poly-(MMA) FP, and unmodified filter paper were successfully characterised by FTIR, NMR, FESEM, TGA, and XRD techniques. They underwent significant parameters optimisation, which affected the extraction efficiency. Under optimal conditions, the proposed (p-Poly-(MMA-IL) FP-TFME) device method was evaluated and applied to analyse multi-class antibiotic drugs in environmental water samples by using a liquid chromatography-mass spectrometry (LC-MS). The validation method showed that a good linearity (0.1 μg L-1 - 500 μg L-1) was noted (R2 > 0.993, n = 3). Detection and quantification limits were within 0.05 μg L-1 - 4.52 μg L-1 and 0.15 μg L-1 - 13.6 μg L-1, respectively. The relative standard deviation (RSD) values ranged at 1.4%-12.2% (intra-day, n = 15) and 4.4%-11.0% (inter-day, n = 10). The extraction recoveries of environmental water samples ranged from 79.1% to 126.8%, with an RSD of less than 15.4% (n = 3). The newly developed paper-based polymeric ionic liquid (p-Poly-(MMA-IL) FP) for analysis of multi-class antibiotic drugs under the p-TFME analytical device procedure was successfully achieved with limited sample volume and organic solvent, fast extraction, and feasible in daily analysis. The detection concentration and relative RSD of multi-class antibiotics determined in various environmental water samples by the proposed method (n = 5) were within 0.44 μg L-1 - 54.41 μg L-1 and 0.69%-15.56%, respectively. These results signified the potential of the p-Poly-(MMA-IL) FP-TFME device as an efficient, sensitive and environmentally friendly approach for analysing antibiotics.
    Matched MeSH terms: Tandem Mass Spectrometry/methods
  6. Fulltext Simultaneous determination of tramadol and paracetamol in human plasma using LC-MS/MS and application in bioequivalence study of -fixed-dose combination
    Loh GOK, Wong EYL, Goh CZ, Tan YTF, Lee YL, Pang LH, et al.
    Ann Med, 2023;55(2):2270502.
    PMID: 37857359 DOI: 10.1080/07853890.2023.2270502
    The study aimed to develop a sensitive and high-throughput liquid chromatography coupled with tandem mass spectrometry method to quantify concentrations of tramadol and paracetamol simultaneously in human plasma. Sample preparation involved single-step protein precipitation using methanol and two deuterated internal standards, tramadol D6 and paracetamol D4. Agilent Poroshell 120 EC-C18 (100 × 2.1 mm, 2.1 µm) analytical column was employed to achieve chromatographic separation. Detection was in positive ion multiple reaction monitoring mode. A tailing factor (Tf) of <1.2, separation factor (K prime) of >1.5 from the column dead time and signal-to-noise (S/N) ratio >10, were obtained for analytes and internal standards. The standard curve was linear over the concentration range of 2.5-500.00 ng/mL for tramadol and 0.025-20.00 μg/mL for paracetamol. A small injection volume of 1 µL, low flow rate of 440 µL/min and short analysis time of 3.5 min reduced the solvent consumption, analysis cost and system contamination. The results of method validation parameters fulfilled the acceptance criteria of bioanalytical guidelines. The method was successfully applied to a bioequivalence study of fixed-dose combination products of tramadol and paracetamol in Malaysian healthy subjects.
    Matched MeSH terms: Tandem Mass Spectrometry/methods
  7. Development and validation of a selective, sensitive and stability indicating UPLC-MS/MS method for rapid, simultaneous determination of six process related impurities in darunavir drug substance
    A VBR, Yusop Z, Jaafar J, Aris AB, Majid ZA, Umar K, et al.
    J Pharm Biomed Anal, 2016 Sep 05;128:141-148.
    PMID: 27262107 DOI: 10.1016/j.jpba.2016.05.026
    In this study a sensitive and selective gradient reverse phase UPLC-MS/MS method was developed for the simultaneous determination of six process related impurities viz., Imp-I, Imp-II, Imp-III, Imp-IV, Imp-V and Imp-VI in darunavir. The chromatographic separation was performed on Acquity UPLC BEH C18 (50 mm×2.1mm, 1.7μm) column using gradient elution of acetonitrile-methanol (80:20, v/v) and 5.0mM ammonium acetate containing 0.01% formic acid at a flow rate of 0.4mL/min. Both negative and positive electrospray ionization (ESI) modes were operated simultaneously using multiple reaction monitoring (MRM) for the quantification of all six impurities in darunavir. The developed method was fully validated following ICH guidelines with respect to specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision, robustness and sample solution stability. The method was able to quantitate Imp-I, Imp-IV, Imp-V at 0.3ppm and Imp-II, Imp-III, and Imp-VI at 0.2ppm with respect to 5.0mg/mL of darunavir. The calibration curves showed good linearity over the concentration range of LOQ to 250% for all six impurities. The correlation coefficient obtained was >0.9989 in all the cases. The accuracy of the method lies between 89.90% and 104.60% for all six impurities. Finally, the method has been successfully applied for three formulation batches of darunavir to determine the above mentioned impurities, however no impurity was found beyond the LOQ. This method is a good quality control tool for the trace level quantification of six process related impurities in darunavir during its synthesis.
    Matched MeSH terms: Tandem Mass Spectrometry/methods
  8. Fulltext Tandem mass spectrometry detection of quorum sensing activity in multidrug resistant clinical isolate Acinetobacter baumannii
    Chan KG, Cheng HJ, Chen JW, Yin WF, Ngeow YF
    ScientificWorldJournal, 2014;2014:891041.
    PMID: 25101326 DOI: 10.1155/2014/891041
    Many Proteobacteria communicate via production followed by response of quorum sensing molecules, namely, N-acyl homoserine lactones (AHLs). These molecules consist of a lactone moiety with N-acyl side chain with various chain lengths and degrees of saturation at C-3 position. AHL-dependent QS is often associated with regulation of diverse bacterial phenotypes including the expression of virulence factors. With the use of biosensor and high resolution liquid chromatography tandem mass spectrometry, the AHL production of clinical isolate A. baumannii 4KT was studied. Production of short chain AHL, namely, N-hexanoyl-homoserine lactone (C6-HSL) and N-octanoyl-homoserine lactone (C8-HSL), was detected.
    Matched MeSH terms: Tandem Mass Spectrometry/methods*
  9. Fulltext Detection of quorum sensing activity in the multidrug-resistant clinical isolate Pseudomonas aeruginosa strain GB11
    Cheng HJ, Ee R, Cheong YM, Tan WS, Yin WF, Chan KG
    Sensors (Basel), 2014;14(7):12511-22.
    PMID: 25019635 DOI: 10.3390/s140712511
    A multidrug-resistant clinical bacteria strain GB11 was isolated from a wound swab on the leg of a patient. Identity of stain GB11 as Pseudomonas aeruginosa was validated by using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Detection of the production of signaling molecules, N-acylhomoserine lactones (AHLs), was conducted using three different bacterial biosensors. A total of four different AHLs were found to be produced by strain GB11, namely N-butyryl homoserine lactone (C4-HSL), N-hexanoylhomoserine lactone (C6-HSL), N-octanoyl homoserine lactone (C8-HSL) and N-3-oxo-dodecanoylhomoserine lactone (3-oxo-C12-HSL) using high resolution liquid chromatography tandem mass spectrometry (LC-MS/MS). Of these detected AHLs, 3-oxo-C12-HSL was found to be the most abundant AHL produced by P. aeruginosa GB11.
    Matched MeSH terms: Tandem Mass Spectrometry/methods
  10. Micro-solid phase extraction with liquid chromatography-tandem mass spectrometry for the determination of aflatoxins in coffee and malt beverage
    Khayoon WS, Saad B, Salleh B, Manaf NH, Latiff AA
    Food Chem, 2014 Mar 15;147:287-94.
    PMID: 24206720 DOI: 10.1016/j.foodchem.2013.09.049
    A single step extraction-cleanup procedure using porous membrane-protected micro-solid phase extraction (μ-SPE) in conjunction with liquid chromatography-tandem mass spectrometry for the extraction and determination of aflatoxins (AFs) B1, B2, G1 and G2 from food was successfully developed. After the extraction, AFs were desorbed from the μ-SPE device by ultrasonication using acetonitrile. The optimum extraction conditions were: sorbent material, C8; sorbent mass, 20mg; extraction time, 90 min; stirring speed, 1,000 rpm; sample volume, 10 mL; desorption solvent, acetonitrile; solvent volume, 350 μL and ultrasonication period, 25 min without salt addition. Under the optimum conditions, enrichment factor of 11, 9, 9 and 10 for AFG2, AFG1, AFB2 and AFB1, respectively were achieved. Good linearity and correlation coefficient was obtained over the concentration range of 0.4-50 ng g(-1) (r(2) 0.9988-0.9999). Good recoveries for AFs ranging from 86.0-109% were obtained. The method was applied to 40 samples involving malt beverage (19) and canned coffee (21). No AFs were detected in the selected samples.
    Matched MeSH terms: Tandem Mass Spectrometry/methods*
  11. Development and validation of a rapid ultra high performance liquid chromatography with tandem mass spectrometry method for the simultaneous determination of darunavir, ritonavir, and tenofovir in human plasma: Application to human pharmacokinetics
    Reddy AV, Jaafar J, Aris AB, Majid ZA, Umar K, Talib J, et al.
    J Sep Sci, 2015 Aug;38(15):2580-7.
    PMID: 25989063 DOI: 10.1002/jssc.201500250
    A sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was developed for the simultaneous determination of darunavir, ritonavir and tenofovir in human plasma. Sample preparation involved a simple liquid-liquid extraction using 200 μL of human plasma extracted with methyl tert-butyl ether for three analytes and internal standard. The separation was accomplished on an Acquity UPLC BEH C18 (50 mm x 2.1 mm, 1.7 μm) analytical column using gradient elution of acetonitrile/methanol (80:20, v/v) and 5.0 mM ammonium acetate containing 0.01% formic acid at a flow rate of 0.4 mL/min. The linearity of the method ranged between 20.0 and 12 000 ng/mL for darunavir, 2.0 and 2280 ng/mL for ritonavir, and 14.0 and 1600 ng/mL for tenofovir using 200 μL of plasma. The method was completely validated for its selectivity, sensitivity, linearity, precision and accuracy, recovery, matrix effect, stability, and dilution integrity. The extraction recoveries were consistent and ranged between 79.91 and 90.04% for all three analytes and internal standard. The method exhibited good intra-day and inter-day precision between 1.78 and 6.27%. Finally the method was successfully applied for human pharmacokinetic study in eight healthy male volunteers after the oral administration of 600 mg darunavir along with 100 mg ritonavir and 100 mg tenofovir as boosters.
    Matched MeSH terms: Tandem Mass Spectrometry/methods*
  12. Application of a Mass Spectrometric Approach to Detect the Presence of Fatty Acid Biosynthetic Phosphopeptides
    Lau BY, Clerens S, Morton JD, Dyer JM, Deb-Choudhury S, Ramli US
    Protein J, 2016 Apr;35(2):163-70.
    PMID: 26993480 DOI: 10.1007/s10930-016-9655-0
    The details of plant lipid metabolism are relatively well known but the regulation of fatty acid production at the protein level is still not understood. Hence this study explores the importance of phosphorylation as a mechanism to control the activity of fatty acid biosynthetic enzymes using low and high oleic acid mesocarps of oil palm fruit (Elaeis guineensis variety of Tenera). Adaptation of neutral loss-triggered tandem mass spectrometry and selected reaction monitoring to detect the neutral loss of phosphoric acid successfully found several phosphoamino acid-containing peptides. These peptides corresponded to the peptides from acetyl-CoA carboxylase and 3-enoyl-acyl carrier protein reductase as identified by their precursor ion masses. These findings suggest that these enzymes were phosphorylated at 20th week after anthesis. Phosphorylation could have reduce their activities towards the end of fatty acid biosynthesis at ripening stage. Implication of phosphorylation in the regulation of fatty acid biosynthesis at protein level has never been reported.
    Matched MeSH terms: Tandem Mass Spectrometry/methods*
  13. Fulltext Simultaneous quantification of ten key Kratom alkaloids in Mitragyna speciosa leaf extracts and commercial products by ultra-performance liquid chromatography-tandem mass spectrometry
    Sharma A, Kamble SH, León F, Chear NJ, King TI, Berthold EC, et al.
    Drug Test Anal, 2019 Aug;11(8):1162-1171.
    PMID: 30997725 DOI: 10.1002/dta.2604
    Kratom (Mitragyna speciosa) is a psychoactive plant popular in the United States for the self-treatment of pain and opioid addiction. For standardization and quality control of raw and commercial kratom products, an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the quantification of ten key alkaloids, namely: corynantheidine, corynoxine, corynoxine B, 7-hydroxymitragynine, isocorynantheidine, mitragynine, mitraphylline, paynantheine, speciociliatine, and speciogynine. Chromatographic separation of diastereomers, or alkaloids sharing same ion transitions, was achieved on an Acquity BEH C18 column with a gradient elution using a mobile phase containing acetonitrile and aqueous ammonium acetate buffer (10mM, pH 3.5). The developed method was linear over a concentration range of 1-200 ng/mL for each alkaloid. The total analysis time per sample was 22.5 minutes. The analytical method was validated for accuracy, precision, robustness, and stability. After successful validation, the method was applied for the quantification of kratom alkaloids in alkaloid-rich fractions, ethanolic extracts, lyophilized teas, and commercial products. Mitragynine (0.7%-38.7% w/w), paynantheine (0.3%-12.8% w/w), speciociliatine (0.4%-12.3% w/w), and speciogynine (0.1%-5.3% w/w) were the major alkaloids in the analyzed kratom products/extracts. Minor kratom alkaloids (corynantheidine, corynoxine, corynoxine B, 7-hydroxymitragynine, isocorynantheidine) were also quantified (0.01%-2.8% w/w) in the analyzed products; however mitraphylline was below the lower limit of quantification in all analyses.
    Matched MeSH terms: Tandem Mass Spectrometry/methods
  14. Fulltext Prediction of Fluoroquinolone Susceptibility Directly from Whole-Genome Sequence Data by Using Liquid Chromatography-Tandem Mass Spectrometry To Identify Mutant Genotypes
    Wan Nur Ismah WAK, Takebayashi Y, Findlay J, Heesom KJ, Jiménez-Castellanos JC, Zhang J, et al.
    Antimicrob Agents Chemother, 2018 03;62(3).
    PMID: 29263066 DOI: 10.1128/AAC.01814-17
    Fluoroquinolone resistance in Gram-negative bacteria is multifactorial, involving target site mutations, reductions in fluoroquinolone entry due to reduced porin production, increased fluoroquinolone efflux, enzymes that modify fluoroquinolones, and Qnr, a DNA mimic that protects the drug target from fluoroquinolone binding. Here we report a comprehensive analysis, using transformation and in vitro mutant selection, of the relative importance of each of these mechanisms for fluoroquinolone nonsusceptibility using Klebsiella pneumoniae as a model system. Our improved biological understanding was then used to generate 47 rules that can predict fluoroquinolone susceptibility in K. pneumoniae clinical isolates. Key to the success of this predictive process was the use of liquid chromatography-tandem mass spectrometry to measure the abundance of proteins in extracts of cultured bacteria, identifying which sequence variants seen in the whole-genome sequence data were functionally important in the context of fluoroquinolone susceptibility.
    Matched MeSH terms: Tandem Mass Spectrometry/methods*
  15. QbD-Driven Development and Validation of Liquid Chromatography Tandem Mass Spectrometric Method for the Quantitation of Sildenafil in Human Plasma
    Hasnain MS, Ansari SA, Rao S, Tabish M, Singh M, Abdullah MS, et al.
    J Chromatogr Sci, 2017 Jul 01;55(6):587-594.
    PMID: 28335023 DOI: 10.1093/chromsci/bmx010
    The present work was employing the Quality by Design approach for the development and validation of a LC-MS-MS method to support the clinical advancement in determination of sildenafil in human plasma using lorazepam as an internal standard. Sample preparation involved solid phase extraction and calibration range observed between 3 and 1,700 ng/mL. The method was systematically optimized by employing Box-Behnken design and used mobile phase flow rate, pH and composition of mobile phase as the critical factors, and assessing the design for retention time and peak area as the responses. A substantial decrease in the variability associated with the method variables was shown in optimization studies and confirmed enhanced method robustness. The present studies revealed that developed method achieves all the regulatory requirements for linearity, accuracy, precision, selectivity, sensitivity and stability for the determination of sildenafil in human plasma. There was not any significant change in the stability of the drug shown by stability studies, performed in human plasma through freeze-thaw cycles, bench-top stability, short-term stability, long-term stability and auto sampler stability. In short, this method shows satisfactory results for the analysis of sildenafil in human plasma and possesses high degree of utility in pharmacokinetic and bioequivalence studies.
    Matched MeSH terms: Tandem Mass Spectrometry/methods*
  16. Risk assessment of pharmaceutically active compounds (PhACs) in the Klang River estuary, Malaysia
    Omar TFT, Aris AZ, Yusoff FM, Mustafa S
    Environ Geochem Health, 2019 Feb;41(1):211-223.
    PMID: 30051257 DOI: 10.1007/s10653-018-0157-1
    The concentration profile, distribution and risk assessment of pharmaceutically active compounds (PhACs) in the coastal surface water from the Klang River estuary were measured. Surface coastal water samples were extracted using offline solid phase, applying polymeric C18 cartridges as extraction sorbent and measuring with liquid chromatography mass spectrometry-mass spectrometry (LC MS-MS) technique. Extraction method was optimized for its recovery, sensitivity and linearity. Excellent recoveries were obtained from the optimized method with percentage of recoveries ranging from 73 to 126%. The optimized analytical method achieved good sensitivity with limit of detection ranging from 0.05 to 0.15 ng L-1, while linearity of targeted compounds in the LC MS-MS system was more than 0.990. The results showed that amoxicillin has the highest concentration (102.31 ng L-1) followed by diclofenac (10.80 ng L-1) and primidone (7.74 ng L-1). The percentage of contribution (% of total concentration) for the targeted PhACs is in the following order; amoxicillin (92.90%) > diclofenac (3.95%) > primidone (1.23%) > dexamethasone (0.75%) > testosterone (0.70%) > sulfamethoxazole (0.33%) > progesterone (0.14%). Environmental risk assessment calculated based on deterministic approach (the RQ method), showed no present risk from the presence of PhACs in the coastal water of Klang River estuary. Nonetheless, this baseline assessment can be used for better understanding on PhACs pollution profile and distribution in the tropical coastal and estuarine ecosystem as well as for future comparative studies.
    Matched MeSH terms: Tandem Mass Spectrometry/methods
  17. UHPLC-MS phytochemical profiling, biological propensities and in-silico studies of Alhagi maurorum roots: a medicinal herb with multifunctional properties
    Saleem H, Sarfraz M, Khan KM, Anwar MA, Zengin G, Ahmad I, et al.
    Drug Dev Ind Pharm, 2020 May;46(5):861-868.
    PMID: 32352878 DOI: 10.1080/03639045.2020.1762199
    The biological, chemical, and in silico properties of methanol and dichloromethane (DCM) extracts of Alhagi maurorum roots with respect to the antioxidant, enzyme inhibition, and phytochemical composition were evaluated. Total bioactive contents were determined spectrophotometrically, and the individual secondary metabolites composition was assessed via ultra-high-performance liquid chromatography mass spectrometry (UHPLC-MS) analysis. Antioxidant capacities were evaluated using a panoply of assays (2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging, ferric reducing antioxidant power (FRAP), cupric reducing antioxidant power (CUPRAC), phosphomolybdenum total antioxidant capacity (TAC), and metal chelating activity (MCA)). The enzyme inhibition potential was studied against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), α-amylase, α-glucosidase, tyrosinase, urease and lipoxygenase (LOX) enzymes. The methanol extract was found to contain higher total phenolic (105.91 mg GAE/g extract) and flavonoid (2.27 mg RE/g extract) contents which can be correlated to its more substantial antioxidant potential as well as AChE, BChE, tyrosinase and α-glucosidase inhibition. However, the DCM extract was the most effective against α-amylase (1.86 mmol ACAE/g extract) enzyme inhibition. The UHPLC-MS analysis of methanol extract identified the tentative presence of a total of 18 secondary metabolites, including flavonoids, saponins, phenolic and terpenoid derivatives. Three compounds named emmotin A, luteolin 5,3'-dimethyl ether, and preferrugone were further investigated for their in silico molecular docking studies against the tested enzymes. The selected compounds were found to have higher binding interaction with AChE followed by BChE, α-glucosidase, α-amylase, and tyrosinase. The results of the present study have demonstrated A. mauroram to be considered as a lead source of natural antioxidant and enzyme inhibitor compounds.
    Matched MeSH terms: Tandem Mass Spectrometry/methods
  18. Evaluation of extraction methods for the identification of proteins from date palm (Phoenix dactylifera L.) seed and flesh
    Lee HX, Ahmad F, Saad B, Ismail MN
    Prep Biochem Biotechnol, 2017 Nov 26;47(10):998-1007.
    PMID: 28857669 DOI: 10.1080/10826068.2017.1365250
    Date fruits are well known to be very nutritious. Nevertheless, the protein contents of the fruit, particularly the seed and flesh, are still understudied, largely due to their difficult physical characteristics. This study was conducted to compare three different protein extraction methods which were the trichloroacetic acid (TCA)-acetone (TCA-A), phenol (Phe), and TCA-acetone-phenol (TCA-A-Phe), and to perform proteomic analysis on date palm seed and flesh. Phe extraction method showed the highest protein yields for both seed (8.26 mg/g) and flesh (1.57 mg/g). Through sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Phe, and TCA-A-Phe extraction methods were shown to be efficient in removing interfering compounds and gave well-resolved bands over a wide range of molecular weights. Following liquid chromatography-tandem mass spectrometry analysis, about 50-64% of extracted proteins were identified with known functions including those involved in glycolysis, Krebs cycle, defense, and storage. Phe protein extraction method was proven to be the optimal method for date flesh and seed.
    Matched MeSH terms: Tandem Mass Spectrometry/methods
  19. A highly selective two-way purification method using liquid chromatography for isolating αS2-casein from goat milk of five different breeds
    Mohsin AZ, Sukor R, Selamat J, Meor Hussin AS, Ismail IH, Jambari NN, et al.
    J Chromatogr B Analyt Technol Biomed Life Sci, 2020 Dec 01;1160:122380.
    PMID: 32971369 DOI: 10.1016/j.jchromb.2020.122380
    The main challenges in the purification of αS2-casein are due to the low quantity in milk and high homology with other casein subunits, i.e., αS1-casein, β-casein, and κ-casein. To overcome these challenges, the aim of this study was to develop a two-step purification to isolate native αS2-casein in goat milk from five different breeds; British Alpine, Jamnapari, Saanen, Shami, and Toggenburg. The first step of the purification was executed by anion-exchange chromatography under optimal elution conditions followed by size exclusion chromatography. Tryptic peptides from in-gel digestion of purified αS2-casein were sequenced and analyzed by LC-ESI-MS/MS. From 1.05 g of whole casein, the highest yield of αS2-casein (6.7 mg/mL) was obtained from Jamnapari and the lowest yield (2.2 mg/mL) was from Saanen. A single band of pure αS2-casein was observed on SDS-PAGE for all breeds. The αS2-casein showed coverage percentage of amino acid sequence from 76.68 to 92.83%. The two-step purification process developed herein was successfully applied for isolating native αS2-casein from goat milk with high purity, which will allow for future in vitro studies to be conducted on this protein.
    Matched MeSH terms: Tandem Mass Spectrometry/methods
  20. LC-MS/MS quantitation of antimalarial drug piperaquine and metabolites in human plasma
    Aziz MY, Hoffmann KJ, Ashton M
    J Chromatogr B Analyt Technol Biomed Life Sci, 2017 Sep 15;1063:253-258.
    PMID: 28863865 DOI: 10.1016/j.jchromb.2017.06.035
    PURPOSE: This study aimed to develop a sensitive, quantitative assay for the antimalarial piperaquine (PQ) and its metabolites M1 and M2 in human plasma.

    RESULTS: Analytes were gradiently separated on a C18 column and detected with a Sciex API 4000 MS/MS with an ESI source operated in the positive ion mode with deuterated PQ as internal standard. The response was linear in the range 3.9-2508nM with a runtime of 7.0min per sample. The method was applied to clinical samples from healthy volunteers.

    CONCLUSION: This LC-MS/MS method for the simultaneous quantitation of PQ and two of its metabolites in plasma may prove helpful for assessment of metabolite safety issues in vivo.

    Matched MeSH terms: Tandem Mass Spectrometry/methods*
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