Displaying publications 161 - 180 of 326 in total

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  1. Simple and fast LC-MS/MS method for quantification of terazosin in human plasma and application to bioequivalence study
    Loh GOK, Wong EYL, Tan YTF, Ong LM, Ng RS, Wee HC, et al.
    J Chromatogr B Analyt Technol Biomed Life Sci, 2021 Jan 15;1163:122517.
    PMID: 33429127 DOI: 10.1016/j.jchromb.2020.122517
    A simple, fast and sensitive LC-MS/MS method was developed to quantify terazosin in human plasma. The mobile phase consisted of acetonitrile-0.1% (v/v) formic acid (70:30, v/v). Prazosin was used as internal standard (IS). As deproteinization agent, acetonitrile produced a clean sample. A higher response intensity with more symmetrical peak was obtained using Agilent Poroshell 120 EC-C18 - Fast LC column (100 × 2.1mmID, 2.7 μm) compared with Kinetex XB-C18 (100 × 2.1 mm, 2.6 µm) column. The response of terazosin and IS were approximately two times in citrate phosphate dextrose (CPD) plasma compared with dipotassium ethylenediaminetetraacetic acid (K2EDTA) plasma. Plasma calibration curve was linear from 1.0 to 100.0 ng/mL, with coefficient of determination r2 ≥ 0.99. The within-run and between-run precision values (CV, %) were <5.2% and <7.8%, while accuracy values were 102.8-112.7% and 103.4-112.2%. The extended run accuracy was 98.6-102.8% and precision (CV, %) 4.3-10.4%. The recovery of analyte was >98% and IS >94%. Terazosin in plasma kept at benchtop was stable for 24 h, in autosampler tray for 48 h, in instrumentation room for 48 h, for 7 freeze-thaw cycles and in freezer for 140 days. Terazosin and IS stock standard solutions were stable for 140 days at room temperature and in the chiller. The high throughput method was successfully utilized to measure 935 samples in a bioequivalence study of terazosin.
    Matched MeSH terms: Tandem Mass Spectrometry/methods*
  2. LC-MS/MS-based metabolites of Eurycoma longifolia (Tongkat Ali) in Malaysia (Perak and Pahang)
    Chua LS, Amin NA, Neo JC, Lee TH, Lee CT, Sarmidi MR, et al.
    J Chromatogr B Analyt Technol Biomed Life Sci, 2011 Dec 15;879(32):3909-19.
    PMID: 22119436 DOI: 10.1016/j.jchromb.2011.11.002
    A number of three LC-MS/MS hybrid systems (QTof, TripleTof and QTrap) has been used to profile small metabolites (m/z 100-1000) and to detect the targeted metabolites such as quassinoids, alkaloids, triterpene and biphenylneolignans from the aqueous extracts of Eurycoma longifolia. The metabolite profiles of small molecules showed four significant clusters in the principle component analysis for the aqueous extracts of E. longifolia, which had been collected from different geographical terrains (Perak and Pahang) and processed at different extraction temperatures (35°C and 100°C). A small peptide of leucine (m/z 679) and a new hydroxyl methyl β-carboline propionic acid have been identified to differentiate E. longifolia extracts that prepared at 35°C and 100°C, respectively. From the targeted metabolites identification, it was found that 3,4ɛ-dihydroeurycomanone (quassinoids) and eurylene (squalene-type triterpene) could only be detected in the Pahang extract, whereas canthin-6-one-3N-oxide could only be detected in the Perak extract. Overall, quassinoids were present in the highest concentration, particularly eurycomanone and its derivatives compared to the other groups of metabolites. However, the concentration of canthin-6-one and β-carboline alkaloids was significantly increased when the roots of the plant samples were extracted at 100°C.
    Matched MeSH terms: Tandem Mass Spectrometry/methods*
  3. UHPLC-MS/MS standardized extract of Vernonia amygdalina leaf inhibits CYP2C9 and CYP3A4 activities in hepatic cells of control and streptozotocin-induced diabetic rats
    Sabbagh BA, Palanirajan VK, Chew YL, Chin JH, Ahmad M, Akowuah GA
    Drug Metab Pers Ther, 2024 Dec 01;39(4):231-241.
    PMID: 39658558 DOI: 10.1515/dmpt-2024-0005
    OBJECTIVES: Vernonia amygdalina Del. is a perennial tropical shrub from Asteraceae. The fresh leaf of V. amygdalina is consumed as a vegetable due to its medicinal and nutritional properties. The present study focused on the quantification of bioactive compounds, luteolin-7-O-glucoside, luteolin-7-O-glucuronide, and 1,5-O-dicaffeoylquinic acid from aqueous leaf extract of V. amygdalina. The study also aims to investigate the effects of the aqueous leaf extract of V. amygdalina on cytochrome P450 2C9 (CYP2C9), and cytochrome P450 3A4 (CYP3A4) in hepatic cells of control and diabetic rats.

    METHODS: The quantification of the bioactive compounds was conducted using ultra-high-performance liquid chromatography multiple reactions monitoring tandem mass spectrometry (UHPLC-MS/MS-MRM) technique. The effect of the extract on CYP2C9 and CYP3A4 activities was determined using a fluorometric screening kit according to the manufacturer's instructions.

    RESULTS: The three bioactive compounds were detected and quantified in the aqueous leaf extract. Results showed that the content of luteolin-7-O-glucuronide (47 μg/mg) was the highest followed by luteolin-7-O-glucoside (3.5 μg/mg) and 1,5-O-dicaffeoylquinic acid (1.07 μg/mg). The extract showed an inhibitory effect on CYP3A4 and CYP2C9 enzyme activities in control and diabetic rats.

    CONCLUSIONS: The UHPLC-MS/MS-MRM method is sensitive and reliable for the quality control of V. amygdalina leaf extract. The inhibitory effect of the extract suggests that concomitant use of V. amygdalina leaf preparations with conventional drugs metabolized and eliminated from the body by CYP3A4 and CYP2C9 enzymes may lead to possible interaction.

    Matched MeSH terms: Tandem Mass Spectrometry*
  4. Apixaban Pharmacokinetics and Bioequivalence of Two Tablet Formulations: A Randomized, Open-Label, Crossover Study, Fasting Condition in Healthy Indonesian Volunteers
    Leong CW, Yee KM, Liew I, Khaleb NA, Ahmad S, Rani TA, et al.
    Clin Pharmacol Drug Dev, 2024 Aug;13(8):890-896.
    PMID: 38685874 DOI: 10.1002/cpdd.1409
    The present study aimed to assess the bioequivalence of a new apixaban generic with reference formulation. Twenty-six healthy volunteers were recruited for an open-label, balanced, randomized, 2-treatment, 2-sequence, 2-period, single oral dose study. Following overnight fasting, each volunteer received 5 mg of apixaban test and reference formulations as single doses, separated by a 1-week washout period. Twenty blood samples were collected at predose and multiple time points between 0.5 and 72 hours after dosing. A validated ultra-performance liquid chromatography-tandem mass spectrometry detection method following a protein precipitation step was implemented to determine apixaban concentrations. Noncompartmental analysis was used to derive the pharmacokinetic parameters, which were then compared between the test and reference products using a multivariate analysis of variance. The pharmacokinetic parameters of the test product were not statistically different from the reference product, and the 90% confidence intervals of apixaban natural log-transformed area under the concentration-time curve from time 0 to infinity, area under the concentration-time curve from time 0 to the last measurable concentration, and maximum concentration were within 80%-125% based on the bioequivalence acceptance range criteria. The test and reference formulations of apixaban are bioequivalent in healthy subjects under fasting conditions.
    Matched MeSH terms: Tandem Mass Spectrometry/methods
  5. Development, validation and determination of multiclass pesticide residues in cocoa beans using gas chromatography and liquid chromatography tandem mass spectrometry
    Zainudin BH, Salleh S, Mohamed R, Yap KC, Muhamad H
    Food Chem, 2015 Apr 1;172:585-95.
    PMID: 25442595 DOI: 10.1016/j.foodchem.2014.09.123
    An efficient and rapid method for the analysis of pesticide residues in cocoa beans using gas and liquid chromatography-tandem mass spectrometry was developed, validated and applied to imported and domestic cocoa beans samples collected over 2 years from smallholders and Malaysian ports. The method was based on solvent extraction method and covers 26 pesticides (insecticides, fungicides, and herbicides) of different chemical classes. The recoveries for all pesticides at 10 and 50 μg/kg were in the range of 70-120% with relative standard deviations of less than 20%. Good selectivity and sensitivity were obtained with method limit of quantification of 10 μg/kg. The expanded uncertainty measurements were in the range of 4-25%. Finally, the proposed method was successfully applied for the routine analysis of pesticide residues in cocoa beans via a monitoring study where 10% of them was found positive for chlorpyrifos, ametryn and metalaxyl.
    Matched MeSH terms: Tandem Mass Spectrometry*
  6. Pharmacokinetic-pharmacodynamic study of subcutaneous injection of depot nandrolone decanoate using dried blood spots sampling coupled with ultrapressure liquid chromatography tandem mass spectrometry assays
    Singh GK, Turner L, Desai R, Jimenez M, Handelsman DJ
    J Clin Endocrinol Metab, 2014 Jul;99(7):2592-8.
    PMID: 24684468 DOI: 10.1210/jc.2014-1243
    Testosterone (T) and nandrolone (N) esters require deep im injections by medical personnel but these often deposit injectate into sc fat so that more convenient sc self-administration may be feasible.
    Matched MeSH terms: Tandem Mass Spectrometry/methods*
  7. Application MALDI TOF on protein identification of vitellogenin in giant grouper (Epinephelus lanceolatus)
    Om AD, Jasmani S, Ismail N, Yeong SY, Abol-Munafi AB
    Fish Physiol Biochem, 2013 Oct;39(5):1277-86.
    PMID: 23494207 DOI: 10.1007/s10695-013-9782-x
    A new proteomics technology has been implemented to study the protein repertoires of developing oocytes of giant grouper (Epinephelus lanceolatus). Knowledge of the chemical composition and physiochemical properties of vitellogenin (Vtg) is necessary to interpret the functional and biological properties attributed during ovulation. Vtg, as a biomarker indicator in sex determination, has been analyzed to determine the sex and maturational status of fish in the absence of the gonad tissue. A male giant grouper was induced by 2 mg/kg of 17ß-estradiol (E2), and blood was sampled at days 0, 1, 3, 5, and 10. SDS-PAGE 1D electrophoresis was used to analyze Vtg protein, and Vtg identification was done with 4800 Plus MALDI TOF/TOF™ mass spectrophotometer (Applied Biosystems/MDS SCIEX, USA). Meanwhile, MS/MS de novo sequencing identified the proteins by matching sequences of tryptic peptides to the known sequences of other species. Vtg was confirmed by MASCOT at 95% significant level, and molecular mass was 187 kDa. Protein resolved on SDS-PAGE as a double band of approximately the same mass as determined with MALDI-TOF. The N-terminal sequences and identification of Vtg were also determined. The potential of using MS methods to understand the structure and function of Vtg is discussed.
    Matched MeSH terms: Tandem Mass Spectrometry/veterinary
  8. 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: Tandem Mass Spectrometry/methods
  9. Liquid chromatography-tandem mass spectroscopic method for the determination of zerumbone in human plasma and its application to pharmacokinetics
    Eid EE, Abdul AB, Rasedee A, Suliman FE, Sukari MA, Fatah SA
    J Mass Spectrom, 2011 Aug;46(8):772-81.
    PMID: 21834015 DOI: 10.1002/jms.1942
    A rapid, sensitive, specific and selective LC-MS/MS method for the determination of zerumbone (ZER) in human plasma using 2,4-diamino-6-(4-methoxyphenyl)-1,3,5-triazine (DMTZ) as an internal standard (IS) has been developed and validated. ZER was chromatographed on C8 column using a mobile phase of acetonitrile/water (80:20, v/v) at a flow rate of 0.25 ml min(-1) . Quantitation was achieved using ESI+ interface, employing multiple reaction monitoring (MRM) mode at m/z 219 > 81 and 218 > 134 for ZER and IS, respectively. The calibration standards were linear over a range of 5-3000 ng ml(-1) (r(2)=0.9994) with an LLOQ of 5 ng ml(-1) (RSD %; 11.4% and bias%; 9.5%). Intra- and inter-day precision of ZER assay ranged from 0.18 to 3.56% with accuracy (bias) that varied between -5.09 and 4.3%, demonstrating good precision and accuracy. Recoveries of ZER and the IS from human plasma were above 85%. The developed method was validated for the determination of ZER in rat plasma. Linearity, stability of ZER and the ME on rat plasma were discussed. The applicability of the developed method was demonstrated by measuring ZER in rat plasma samples following intravenous and intraperitoneal administration of ZER prepared in hydroxypropyl-β-cyclodextrin (HPβCD) and sodium carboxymethyl cellulose (CMC), respectively, in 20 mg kg(-1) and this study indicated a clear significant difference (p<0.05) in pharmacokinetic parameters of ZER in ZER/HPβCD complex compared with ZER in CMC preparation.
    Matched MeSH terms: Tandem Mass Spectrometry/methods*
  10. Multi-residue analytical method for human pharmaceuticals and synthetic hormones in river water and sewage effluents by solid-phase extraction and liquid chromatography-tandem mass spectrometry
    Al-Odaini NA, Zakaria MP, Yaziz MI, Surif S
    J Chromatogr A, 2010 Oct 29;1217(44):6791-806.
    PMID: 20851398 DOI: 10.1016/j.chroma.2010.08.033
    Pollutants such as human pharmaceuticals and synthetic hormones that are not covered by environmental legislation have increasingly become important emerging aquatic contaminants. This paper reports the development of a sensitive and selective multi-residue method for simultaneous determination and quantification of 23 pharmaceuticals and synthetic hormones from different therapeutic classes in water samples. Target pharmaceuticals include anti-diabetic, antihypertensive, hypolipidemic agents, β2-adrenergic receptor agonist, antihistamine, analgesic and sex hormones. The developed method is based on solid phase extraction (SPE) followed by instrumental analysis using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) with 30 min total run time. River water samples (150 mL) and (sewage treatment plant) STP effluents (100 mL) adjusted to pH 2, were loaded into MCX (3 cm(3), 60 mg) cartridge and eluted with four different reagents for maximum recovery. Quantification was achieved by using eight isotopically labeled internal standards (I.S.) that effectively correct for losses during sample preparation and matrix effects during LC-ESI-MS/MS analysis. Good recoveries higher than 70% were obtained for most of target analytes in all matrices. Method detection limit (MDL) ranged from 0.2 to 281 ng/L. The developed method was applied to determine the levels of target analytes in various samples, including river water and STP effluents. Among the tested emerging pollutants, chlorothiazide was found at the highest level, with concentrations reaching up to 865 ng/L in STP effluent, and 182 ng/L in river water.
    Matched MeSH terms: Tandem Mass Spectrometry/methods*
  11. Solid-liquid extraction of bioactive compounds with antioxidant potential from Alternanthera sesillis (red) and identification of the polyphenols using UHPLC-QqQ-MS/MS
    Mohd Hazli UHA, Abdul-Aziz A, Mat-Junit S, Chee CF, Kong KW
    Food Res Int, 2019 01;115:241-250.
    PMID: 30599938 DOI: 10.1016/j.foodres.2018.08.094
    Alternanthera sessilis (red) (ASR) is an edible herbal plant with many beneficial health effects. This study aimed to investigate the antioxidant components and antioxidant activities of the edible leaves and stems of ASR extracted using solvent of varying polarities namely water, ethanol, ethyl acetate and hexane. ASR leaf extracts showed higher in both antioxidant components and activities than the stem extracts. Among the antioxidant components, the ethanol leaf extract showed higher phenolic (77.29 ± 1.02 mg GAE/g extract) content while the ethyl acetate leaf extract was rich in flavonoids (157.44 ± 10.19 mg RE/g extract), carotenoids (782.97 ± 10.78 mg BE/g extract) and betalains (betanin: 67.08 ± 0.49 mg/g extract; amaranthin: 93.94 ± 0.68 mg/g extract and betaxanthin: 53.92 ± 0.88 mg/g extract). Nevertheless, the ethanol leaf extract showed the highest DPPH radical scavenging activity and ABTS radical cation scavenging activity. It also exhibited highest ferric reducing activity among all the extracts. Four polyphenolic compounds from ASR leaf, namely ferulic acid, rutin, quercetin and apigenin, were identified and quantified using ultra high performance liquid chromatography. The existence of these compounds was further verified using tandem mass spectrometry. These current results indicate that ASR leaf particularly the ethanol extract has the potential to be exploited as a source of natural antioxidants.
    Matched MeSH terms: Tandem Mass Spectrometry/methods*
  12. Annexin A2 and alpha actinin 4 expression correlates with metastatic potential of primary endometrial cancer
    Mittal P, Klingler-Hoffmann M, Arentz G, Winderbaum L, Kaur G, Anderson L, et al.
    Biochim Biophys Acta Proteins Proteom, 2017 Jul;1865(7):846-857.
    PMID: 27784647 DOI: 10.1016/j.bbapap.2016.10.010
    The prediction of lymph node metastasis using clinic-pathological data and molecular information from endometrial cancers lacks accuracy and is therefore currently not routinely used in patient management. Consequently, although only a small percentage of patients with endometrial cancers suffer from metastasis, the majority undergo radical surgery including removal of pelvic lymph nodes. Upon analysis of publically available data and published research, we compiled a list of 60 proteins having the potential to display differential abundance between primary endometrial cancers with versus those without lymph node metastasis. Using data dependent acquisition LC-ESI-MS/MS we were able to detect 23 of these proteins in endometrial cancers, and using data independent LC-ESI-MS/MS the differential abundance of five of those proteins was observed. The localization of the differentially expressed proteins, was visualized using peptide MALDI MSI in whole tissue sections as well as tissue microarrays of 43 patients. The proteins identified were further validated by immunohistochemistry. Our data indicate that annexin A2 protein level is upregulated, whereas annexin A1 and α actinin 4 expression are downregulated in tumours with lymph node metastasis compared to those without lymphatic spread. Moreover, our analysis confirmed the potential of these markers, to be included in a statistical model for prediction of lymph node metastasis. The predictive model using highly ranked m/z values identified by MALDI MSI showed significantly higher predictive accuracy than the model using immunohistochemistry data. In summary, using publicly available data and complementary proteomics approaches, we were able to improve the prediction model for lymph node metastasis in EC.
    Matched MeSH terms: Tandem Mass Spectrometry/methods
  13. Antithrombocytopenic activity of carpaine and alkaloidal extract of Carica papaya Linn. leaves in busulfan induced thrombocytopenic Wistar rats
    Zunjar V, Dash RP, Jivrajani M, Trivedi B, Nivsarkar M
    J Ethnopharmacol, 2016 Apr 02;181:20-5.
    PMID: 26812680 DOI: 10.1016/j.jep.2016.01.035
    ETHNOPHARMACOLOGICAL RELAVANCE: The decoction of Carica papaya Linn. leaves is used in folklore medicine in certain parts of Malaysia and Indonesia for the treatment of different types of thrombocytopenia associated with diseases and drugs. There are several scientific studies carried out on humans and animal models to confirm the efficacy of decoction of papaya leave for the treatment of disease induced and drug induced thrombocytopenia, however very little is known about the bio-active compounds responsible for the observed activity. The aim of present study was to identify the active phytochemical component of Carica papaya Linn. leaves decoction responsible for anti-thrombocytopenic activity in busulfan-induced thrombocytopenic rats.

    MATERIALS AND METHODS: Antithrombocytopenic activity was assessed on busulfan induced thrombocytopenic Wistar rats. The antithrombocytopenic activity of different bio-guided fractions was evaluated by monitoring blood platelet count. Bioactive compound carpaine was isolated and purified by chromatographic methods and confirmed by spectroscopic methods (LC-MS and 1D/2D-1H/13C NMR) and the structure was confirmed by single crystal X-ray diffraction. Quantification of carpaine was carried out by LC-MS/MS equipped with XTerra(®) MS C18 column and ESI-MS detector using 90:10 CH3CN:CH3COONH4 (6mM) under isocratic conditions and detected with multiple reaction monitoring (MRM) in positive ion mode.

    RESULTS: Two different phytochemical groups were isolated from decoction of Carica papaya leaves: phenolics, and alkaloids. Out of these, only alkaloid fraction showed good biological activity. Carpaine was isolated from the alkaloid fraction and exhibited potent activity in sustaining platelet counts upto 555.50±85.17×10(9)/L with no acute toxicity.

    CONCLUSIONS: This study scientifically validates the popular usage of decoction of Carica papaya leaves and it also proves that alkaloids particularly carpaine present in the leaves to be responsible for the antithrombocytopenic activity.

    Matched MeSH terms: Tandem Mass Spectrometry/methods
  14. Pharmacokinetics and Bioequivalence of Fixed-Dose Combination of Simvastatin and Ezetimibe Tablets: A Randomized, Crossover, Open-Label Study in Healthy Volunteers
    Leong CW, Yee KM, Rani TA, Lau KJ, Ahmad S, Amran A, et al.
    Clin Pharmacol Drug Dev, 2024 Aug;13(8):938-946.
    PMID: 38745538 DOI: 10.1002/cpdd.1411
    The current study aimed to evaluate the bioequivalence of a new generic combination of simvastatin and ezetimibe with the reference formulation. An open-label, randomized, 3-period, 3-sequence, crossover study, including 60 healthy volunteers, was implemented. Participants received the test and reference formulation, each containing 20 mg of simvastatin and 10 mg of ezetimibe as a single-dose tablet, separated by a minimum of 2-week washout periods. Blood samples were collected for 20 time points from predose to 72 hours after the dose. The total ezetimibe assay was carried out using a validated liquid chromatography-tandem mass spectrometry, while unconjugated ezetimibe, simvastatin, and simvastatin β-hydroxy acid determination was done via a validated ultra-performance liquid chromatography-tandem mass spectrometry. Each assay was preceded by a liquid-liquid extraction step. The pharmacokinetic parameters were derived using noncompartmental analysis and then compared between the reference and test formulations via a multivariate analysis of variance. No statistical difference was found in under the concentration-time curve from time 0 to the last quantifiable concentration and maximum concentration of unconjugated ezetimibe, total ezetimibe, and simvastatin between the reference and test formulations. The 90% confidence intervals of unconjugated ezetimibe, total ezetimibe, and simvastatin natural log-transformed under the concentration-time curve from time 0 to the last quantifiable concentration, and maximum concentration were in the range of 80%-125% as per the bioequivalence acceptance criteria. Therefore, the test formulation was bioequivalent to the reference formulation.
    Matched MeSH terms: Tandem Mass Spectrometry/methods
  15. Fulltext Urinary Sex Steroids and Anthropometric Markers of Puberty - A Novel Approach to Characterising Within-Person Changes of Puberty Hormones
    Singh GK, Balzer BW, Kelly PJ, Paxton K, Hawke CI, Handelsman DJ, et al.
    PLoS One, 2015;10(11):e0143555.
    PMID: 26599397 DOI: 10.1371/journal.pone.0143555
    The longitudinal relationships of within-individual hormone and anthropometric changes during puberty have not ever been fully described. The objectives of this study were to demonstrate that 3 monthly urine collection was feasible in young adolescents and to utilise liquid chromatography-tandem mass spectrometry assay methods for serum and urine testosterone (T), estradiol (E2) and luteinizing hormone (LH) in adolescents by relating temporal changes in urine and serum hormones over 12 months to standard measures of pubertal development.
    Matched MeSH terms: Tandem Mass Spectrometry
  16. Novel angiotensin I-converting enzyme inhibitory peptides derived from edible mushroom Agaricus bisporus (J.E. Lange) Imbach identified by LC-MS/MS
    Lau CC, Abdullah N, Shuib AS, Aminudin N
    Food Chem, 2014 Apr 1;148:396-401.
    PMID: 24262574 DOI: 10.1016/j.foodchem.2013.10.053
    Angiotensin I-converting enzyme (ACE) inhibitors derived from foods are valuable auxiliaries to agents such as captopril. Eight highly functional ACE inhibitory peptides from the mushroom, Agaricus bisporus, were identified by LC-MS/MS. Among these peptides, the most potent ACE inhibitory activity was exhibited by AHEPVK, RIGLF and PSSNK with IC₅₀ values of 63, 116 and 129 μM, respectively. These peptides exhibited high ACE inhibitory activity after gastrointestinal digestion. Lineweaver-Burk plots suggested that AHEPVK and RIGLF act as competitive inhibitors against ACE, whereas PSSNK acts as a non-competitive inhibitor. Mushrooms can be a good component of dietary supplement due to their readily available source and, in addition, they rarely cause food allergy. Compared to ACE inhibitory peptides isolated from other edible mushrooms, AHEPVK, RIGLF and PSSNK have lower IC₅₀ values. Therefore, these peptides may serve as an ideal ingredient in the production of antihypertensive supplements.
    Matched MeSH terms: Tandem Mass Spectrometry
  17. Analysis of differentially expressed proteins in late-stationary growth phase of Mycobacterium tuberculosis H37Rv
    Ang KC, Ibrahim P, Gam LH
    Biotechnol Appl Biochem, 2014 Mar-Apr;61(2):153-64.
    PMID: 23826872 DOI: 10.1002/bab.1137
    Mycobacterium tuberculosis is a causative agent of tuberculosis (TB). The ability of M. tuberculosis to be quiescent in the cell has caused the emergence of latent infection. A comprehensive proteomic analysis of M. tuberculosis H37Rv over three growth phases, namely mid-log (14-day culture), early stationary (28-day culture), and late stationary (50-day culture), was performed in order to study the change in proteome from the mid-log phase to late-stationary phase. Combination methods of two-dimensional electrophoresis (2-DE) and tandem mass spectrometry were used to generate proteome maps of M. tuberculosis at different growth phases. Ten proteins were detected differentially expressed in the late-stationary phase compared with the other two phases. These proteins were SucD, TrpD, and Rv2161c, which belong to metabolic pathway proteins; FadE5, AccD5, DesA1, and Rv1139c are proteins involved in cell wall or lipid biosynthesis, whereas TB21.7 and Rv3224 are conserved hypothetical proteins with unknown function. A surface antigen protein, DesA1, was not detectable in the late-stationary phase, although present in both log and early-stationary phases. The changes in the expression levels of these proteins were in line with the growth environment changes of the bacteria from mid-log phase to late-stationary phase. The information gathered may be valuable in the intervention against latent TB infection.
    Matched MeSH terms: Tandem Mass Spectrometry
  18. In vitro approaches to investigate cytochrome P450 activities: update on current status and their applicability
    Ong CE, Pan Y, Mak JW, Ismail R
    Expert Opin Drug Metab Toxicol, 2013 Sep;9(9):1097-113.
    PMID: 23682848 DOI: 10.1517/17425255.2013.800482
    Cytochromes P450 (CYPs) play a central role in the Phase I metabolism of drugs and other xenobiotics. It is estimated that CYPs can metabolize up to two-thirds of drugs present in humans. Over the past two decades, there have been numerous advances in in vitro methodologies to characterize drug metabolism and interaction involving CYPs.
    Matched MeSH terms: Tandem Mass Spectrometry
  19. Fulltext Isolation and identification of myo-inositol crystals from dragon fruit (Hylocereus polyrhizus)
    Rebecca OP, Boyce AN, Somasundram C
    Molecules, 2012 Apr 17;17(4):4583-94.
    PMID: 22510607 DOI: 10.3390/molecules17044583
    Crystals isolated from Hylocereus polyrhizus were analyzed using four different approaches--X-ray Crystallography, High Performance Liquid Chromatography (HPLC), Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) and Nuclear Magnetic Resonance (NMR) and identified as myo-inositol. The X-ray crystallography analysis showed that the unit-cell parameters were: a = 6.6226 (3) Å, b = 12.0462 (5) Å, c = 18.8942 (8) Å, α = 90.00, β = 93.98, δ = 90.00. The purity of the crystals were checked using HPLC, whereupon a clean single peak was obtained at 4.8 min with a peak area of 41232 μV*s. The LC-MS/MS technique, which is highly sensitive and selective, was used to provide a comparison of the isolated crystals with a myo-inositol standard where the results gave an identical match for both precursor and product ions. NMR was employed to confirm the molecular structure and conformation of the crystals, and the results were in agreement with the earlier results in this study. The discovery of myo-inositol crystals in substantial amount in H. polyrhizus has thus far not been reported and this is an important finding which will increase the marketability and importance of H. polyrhizus as a crop with a wide array of health properties.
    Matched MeSH terms: Tandem Mass Spectrometry
  20. Fulltext Proteomic analysis of saliva identifies potential biomarkers for orthodontic tooth movement
    Ellias MF, Zainal Ariffin SH, Karsani SA, Abdul Rahman M, Senafi S, Megat Abdul Wahab R
    ScientificWorldJournal, 2012;2012:647240.
    PMID: 22919344 DOI: 10.1100/2012/647240
    Orthodontic treatment has been shown to induce inflammation, followed by bone remodelling in the periodontium. These processes trigger the secretion of various proteins and enzymes into the saliva. This study aims to identify salivary proteins that change in expression during orthodontic tooth movement. These differentially expressed proteins can potentially serve as protein biomarkers for the monitoring of orthodontic treatment and tooth movement. Whole saliva from three healthy female subjects were collected before force application using fixed appliance and at 14 days after 0.014'' Niti wire was applied. Salivary proteins were resolved using two-dimensional gel electrophoresis (2DE) over a pH range of 3-10, and the resulting proteome profiles were compared. Differentially expressed protein spots were then identified by MALDI-TOF/TOF tandem mass spectrometry. Nine proteins were found to be differentially expressed; however, only eight were identified by MALDI-TOF/TOF. Four of these proteins-Protein S100-A9, immunoglobulin J chain, Ig alpha-1 chain C region, and CRISP-3-have known roles in inflammation and bone resorption.
    Matched MeSH terms: Tandem Mass Spectrometry
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