Displaying publications 1 - 20 of 502 in total

  1. Ismail SN, Maulidiani M, Akhtar MT, Abas F, Ismail IS, Khatib A, et al.
    Molecules, 2017 Sep 25;22(10).
    PMID: 28946701 DOI: 10.3390/molecules22101612
    Gaharu (agarwood, Aquilaria malaccensis Lamk.) is a valuable tropical rainforest product traded internationally for its distinctive fragrance. It is not only popular as incense and in perfumery, but also favored in traditional medicine due to its sedative, carminative, cardioprotective and analgesic effects. The current study addresses the chemical differences and similarities between gaharu samples of different grades, obtained commercially, using ¹H-NMR-based metabolomics. Two classification models: partial least squares-discriminant analysis (PLS-DA) and Random Forests were developed to classify the gaharu samples on the basis of their chemical constituents. The gaharu samples could be reclassified into a 'high grade' group (samples A, B and D), characterized by high contents of kusunol, jinkohol, and 10-epi-γ-eudesmol; an 'intermediate grade' group (samples C, F and G), dominated by fatty acid and vanillic acid; and a 'low grade' group (sample E and H), which had higher contents of aquilarone derivatives and phenylethyl chromones. The results showed that ¹H- NMR-based metabolomics can be a potential method to grade the quality of gaharu samples on the basis of their chemical constituents.
    Matched MeSH terms: Magnetic Resonance Spectroscopy; Proton Magnetic Resonance Spectroscopy/methods*
  2. Darfizzi Derawi, Jumat Salimon
    Sains Malaysiana, 2013;42:1121-1129.
    Sebatian poliol minyak sawit olein (di-hidroksi-POo) (70% hasil) disintesis melalui pembukaan gelang oksirana minyak sawit olein terepoksida (EPOo) secara hidrolisis selanjar dan berkelompok. Hasil optimum pembukaan gelang oksirana (97.2%) bagi kedua-dua tindak balas selama 90 min (tindak balas selanjar) dan 75 min (tindak balas berkelompok) dengan menggunakan mangkin asid perklorik 3% v/wt. Spektrum transformasi Fourier inframerah (FTIR) di-hidroksi-POo menunjukkan kehadiran puncak lebar getaran regangan kumpulan hidroksil pada nombor gelombang 3429 cm-1, menunjukkan sebatian poliol telah berjaya dihasilkan. Spektrum resonan magnetik nukleus-karbon (13C-NMR) di-hidroksi-POo telah menunjukkan kehadiran puncak karbon yang terikat dengan kumpulan hidroksil (74.5 ppm). Spektrum resonan magnetik nukleus-proton (1H-NMR) di-hidroksi-POo telah menunjukkan kehadiran puncak proton yang terikat pada karbon poliol (3.4 ppm) dan proton pada kumpulan hidroksil (4.6 ppm). Kelikatan kinematik produk poliol (nilai hidroksil sebanyak 110.7 mgKOH/g minyak) adalah 1435.2 cSt (40oC) dan 55.2 cSt (100oC) dengan indeks kelikatan 78.
    Matched MeSH terms: Carbon-13 Magnetic Resonance Spectroscopy; Proton Magnetic Resonance Spectroscopy
  3. Ganesan K, Alias Y
    Int J Mol Sci, 2008 Jun;9(7):1207-13.
    PMID: 19325800 DOI: 10.3390/ijms9071207
    The (1)H-NMR shifts of the imidazolium protons of some novel dimeric ionic liquids were examined in various deuterated solvents. Interactions between the solvent and the imidazolium salt of butyl substituted ionic liquids were observed to give higher chemical shifts than methyl substitution.
    Matched MeSH terms: Magnetic Resonance Spectroscopy; Proton Magnetic Resonance Spectroscopy
  4. Goh TB, Mordi MN, Mas Haris MR, Mansor SM
    Magn Reson Chem, 2015 Oct;53(10):857-9.
    PMID: 26137893 DOI: 10.1002/mrc.4273
    Matched MeSH terms: Magnetic Resonance Spectroscopy*
  5. Elumalai K, Ali MA, Elumalai M, Eluri K, Srinivasan S
    PMID: 28626677 DOI: 10.1016/j.btre.2014.10.007
    A new series of some novel pyrazinamide condensed 1,2,3,4-tetrahydropyrimidines was prepared by reacting of N-(3-oxobutanoyl)pyrazine-2-carboxamide with urea/thiourea and appropriate aldehyde in the presence of catalytic amount of laboratory made p-toluenesulfonic acid as an efficient catalyst. Confirmation of the chemical structure of the synthesized compounds (4a-l) was substantiated by TLC, different spectral data IR, (1)H NMR, mass spectra and elemental analysis. The synthesized compounds were evaluated for acetyl and butyl cholinesterase (AChE and BuChE) inhibitor activity. The titled compounds exhibited weak, moderate or high AChE and BuChE inhibitor activity. Especially, compound (4l) showed the best AChE and BuChE inhibitory activity of all the 1,2,3,4-tetrahydropyrimidine derivatives, with an IC50 value of 0.11 μM and 3.4 μM.
    Matched MeSH terms: Magnetic Resonance Spectroscopy; Proton Magnetic Resonance Spectroscopy
  6. Athar Abbasi M, Raza H, Aziz-Ur-Rehman, Zahra Siddiqui S, Adnan Ali Shah S, Hassan M, et al.
    Bioorg Chem, 2019 03;83:63-75.
    PMID: 30342387 DOI: 10.1016/j.bioorg.2018.10.018
    Present work aimed to synthesize some unique bi-heterocyclic benzamides as lead compounds for the in vitro inhibition of urease enzyme, followed by in silico studies. These targeted benzamides were synthesized in good yields through a multi-step protocol and their structures were confirmed by IR, 1H NMR, 13C NMR, EI-MS and elemental analysis. The in vitro screening results showed that most of the ligands exhibited good inhibitory potentials against the urease. Chemo-informatics analysis envisaged that all these compounds obeyed the Lipinski's rule. Molecular docking results showed that 7h exhibited good binding energy value (-8.40 kcal/mol) and was bound within the active region of urease enzyme. From the present investigation, it was inferred that some of these potent urease inhibitors might serve as novel templates in drug designing.
    Matched MeSH terms: Carbon-13 Magnetic Resonance Spectroscopy; Proton Magnetic Resonance Spectroscopy
  7. Asniza M, Issam A, Abdul Khalil H
    Sains Malaysiana, 2011;40:1123-1127.
    A new heterocyclic coupling agent has been produced from the reaction of maleic anhydride and p-aminophenol, namely N-(4-hydroxylpheneyl)maleimide. The coupling agent underwent azo coupling reaction with aromatic amine, which is p-aminophenol to produce a new heterocyclic azo pigment. The pigment was then subjected to solubility, hiding power and light fastness test. Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet/Visible (UV/Vis) Spectroscopy, and Nuclear Magnetic Resonance Spectroscopy (1H-NMR, 13C-NMR) were used to obtain the characteristics and structural features of the pigment.
    Matched MeSH terms: Carbon-13 Magnetic Resonance Spectroscopy; Proton Magnetic Resonance Spectroscopy
  8. Chandradevan M, Simoh S, Mediani A, Ismail IS, Abas F
    Plant Foods Hum Nutr, 2020 Jun;75(2):243-251.
    PMID: 32152783 DOI: 10.1007/s11130-020-00805-3
    Gynura procumbens and Cleome gynandra are two herbs commonly used in Malaysia to treat various ailments and are also consumed as salads (ulam) and vegetables. The present study aims to evaluate the relationship between the chemical compositions of both herbs and their antioxidant and anti-inflammatory properties using nuclear magnetic resonance (NMR) metabolomics approach, which is being reported for the first time. Different ethanolic extracts of both herbs were tested for DPPH scavenging and inhibition of nitric oxide (NO) via RAW 264.7 macrophage cell induction. Principal component analysis (PCA) revealed a good separation between the extracts and the corresponding metabolites identified via 1H NMR spectroscopy. The 100% ethanolic extract from both herbs and 20% ethanolic extract of C. gynandra were found to have the best antioxidant and anti-inflammatory activities. Kaempferol, quercetin, caffeoylquinic, dicaffeoylquinic acids, gallic acid, mallic acid, citric acid, phenylalanine, and choline are among the metabolites that contributed to bioactivities. The partial least square (PLS) model for both herbs have an overall acceptable goodness of fit and predictive power, which further strengthens the validity of this study. The present study provides a preliminary reference for the selection of optimum extract and will shed some light on the potential use of G. procumbens and C. gynandra as a phytomedicinal preparation.
    Matched MeSH terms: Magnetic Resonance Spectroscopy; Proton Magnetic Resonance Spectroscopy
  9. Abdul-Hamid NA, Abas F, Maulidiani M, Ismail IS, Tham CL, Swarup S, et al.
    Anal Biochem, 2019 07 01;576:20-32.
    PMID: 30970239 DOI: 10.1016/j.ab.2019.04.001
    The variation in the extracellular metabolites of RAW 264.7 cells obtained from different passage numbers (passage 9, 12 and 14) was examined. The impact of different harvesting protocols (trypsinization and scraping) on recovery of intracellular metabolites was then assessed. The similarity and variation in the cell metabolome was investigated using 1H NMR metabolic profiling modeled using multivariate data analysis. The characterization and quantification of metabolites was performed to determine the passage-related and harvesting-dependent effects on impacted metabolic networks. The trypsinized RAW cells from lower passages gave higher intensities of most identified metabolites, including asparagine, serine and tryptophan. Principal component analysis revealed variation between cells from different passages and harvesting methods, as indicated by the formation of clusters in score plot. Analysis of S-plots revealed metabolites that acted as biomarkers in discriminating cells from different passages including acetate, serine, lactate and choline. Meanwhile lactate, glutamine and pyruvate served as biomarkers for differentiating trypsinized and scraped cells. In passage-dependent effects, glycolysis and TCA cycle were influential, whereas glycerophospholipid metabolism was affected by the harvesting method. Overall, it is proposed that typsinized RAW cells from lower passage numbers are more appropriate when conducting experiments related to NMR metabolomics.
    Matched MeSH terms: Magnetic Resonance Spectroscopy/methods*
  10. Ee, G.C.L., Jong, V.Y.M., Sukari, M.A., Lee, T.K., Tan, A.
    Our continuing interest in anthraquinones from the Guttiferae family has led us to look at the genus Cratoxylum. A detailed chemical study on Cratoxylum aborescens resulted in the isolation of three anthraquinones, namely 1,8-dihydroxy-3-methoxy-6-methylanthraquinone (1), vismiaquinone (2) and vismione (3). These compounds were identified using 1D and 2D NMR spectroscopy. This is the first report on the chemistry of Cratoxylum aborescens.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  11. Ee, G.C.L., Jong, V.Y.M., Sukari, M.A., Rahmani, M., Kua, A.S.M.
    The roots of Calophyllum inophyllum (Guttiferae), furnished six xanthones which are brasilixanthone (1), 1,3,5-trihydroxy-2- methoxy xanthone (2), caloxanthone A (3), pyranojacareubin (4), caloxanthone B (5) and tovopyrifolin (6), Structural elucidations of these compounds, were achieved through 1D and 2D NMR andMS techniques. In this paper, the isolation and structural elucidation data for these xanthones are reported.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  12. Syaidah Athirah Dzolin, Yusairie Mohd, Hadariah Bahron, Nurul Huda Abdul Halim
    The syntheses of salicylideneaniline (L1a) and 4-hydroxybenzalaniline (L1b) was carried out via condensation reaction giving yields of 80.74% and 81.65% respectively. The compounds were characterised by physical and spectroscopic techniques, namely melting point, micro elemental analysis (C, H and N), 1H Nuclear Magnetic Resonance (NMR) and Infrared (IR) spectroscopy. The characteristic n(C=N) peaks were observed at 1615 cm-1 and 1575 cm-1 respectively. Chronoamperometry (CA) was employed to electrodeposit both compounds on mild steel at 0.1 M inhibitor concentration in 0.3 M NaOH at three different potentials, +0.8 V, +1.05 V and +1.7 V. Formation of yellow imine films was observed on the mild steel. The corrosion behaviour of coated and uncoated mild steel was studied using Linear Polarization Resistance (LPR) in 0.5 M NaCl. Coated mild steel showed better corrosion resistance and with the highest inhibition efficiency of 90.34%, L1a provides a better protection against corrosion for mild steel than L1b.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  13. Nurwahidah, M., Wan, E.Z.W.A.R., Shaharuddin, C.S.
    This paper presents the application of active contours region-based method of image segmentation to Computed Tomography (CT) images. Previous researchers applied this region based method on Magnetic Resonance Image (MRI), in vivo images and synthetic images which contain intensity inhomogeneities. In this paper, a different modality known as Computed Tomography (CT) scan was applied. CT scan also produces images containing intensity inhomogeneity, and it is predicted that this method provide good segmentation results. The main objective of applying this method is to check its applicability on CT images. The segmentation process begins by finding the area of interest (black region). Results from this experiment are then used in estimating time of death. Experimental results show that this method has successfully segmented the black region when some parameters changed, provided that the regions are closed to each other. If the black regions are located far from each other, then this method will only segment certain areas.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  14. Darfizzi Derawi, Jumat Salimon
    Sains Malaysiana, 2016;45:817-823.
    Sebatian hidroksi-eter-POo
    (80% hasil) disintesis melalui pembukaan gelang oksirana minyak sawit olein terepoksida
    ) secara alkoholisis. Hasil optimum pembukaan gelang oksirana (99.2%) dicapai dengan menggunakan asid
    sulfurik 3% v/bt pada suhu tindak balas yang tinggi (80o
    C) selama 30 minit masa tindak balas. Spektrum resonan
    magnetik nukleus-proton (1
    H-NMR) hidroksi-eter-POo
    telah menunjukkan kehadiran puncak proton pada karbon eter
    (3.2, 3.5 ppm) dan proton pada kumpulan hidroksil (4.8 ppm). Spektrum resonan magnetik nukleus-karbon (13C-NMR)
    telah menunjukkan kehadiran puncak karbon yang terikat dengan kumpulan hidroksil (75 ppm) dan
    karbon pada karbonil kumpulan eter (72 ppm). Kelikatan kinematik hidroksi-eter-POo
    adalah 234.4 cSt (40o
    C) dan 28.1
    cSt (100o
    C) dengan indeks kelikatan 156.
    Matched MeSH terms: Carbon-13 Magnetic Resonance Spectroscopy
  15. Mazlan NW, Tate R, Yusoff YM, Clements C, Edrada-Ebel R
    Curr Med Chem, 2020;27(11):1815-1835.
    PMID: 31272343 DOI: 10.2174/0929867326666190704130105
    Endophytic fungi have been explored not just for their ecological functions but also for their secondary metabolites as a new source of these pharmacologically active natural products. Accordingly, many structurally unique and biologically active compounds have been obtained from the cultures of endophytic fungi. Fusarium sp. and Lasiodiplodia theobromae were isolated from the root and stem of the mangrove plant Avicennia lanata, respectively, collected from Terengganu, Malaysia. High-resolution mass spectrometry and NMR spectroscopy were used as metabolomics profiling tools to identify and optimize the production of bioactive secondary metabolites in both strains at different growth stages and culture media. The spectral data was processed by utilizing Mzmine 2, a quantitative expression analysis software and an in house MS-Excel macro coupled with the Dictionary of Natural Products databases for dereplication studies. The investigation for the potential bioactive metabolites from a 15-day rice culture of Fusarium sp. yielded four 1,4- naphthoquinone with naphthazarin structures (1-4). On the other hand, the endophytic fungus L. theobromae grown on the 15-day solid rice culture produced dihydroisocoumarins (5-8). All the isolated compounds (1-8) showed significant activity against Trypanosoma brucei brucei with MIC values of 0.32-12.5 µM. Preliminary cytotoxicity screening against normal prostate cells (PNT2A) was also performed. All compounds exhibited low cytotoxicity, with compounds 3 and 4 showing the lowest cytotoxicity of only 22.3% and 38.6% of the control values at 100 µg/mL, respectively. Structure elucidation of the isolated secondary metabolites was achieved using 2D-NMR and HRESI-MS as well as comparison with literature data.
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  16. Wun Fui Mark-Lee, Mohammad B. Kassim, Mohd Faizal Md Nasir
    Sains Malaysiana, 2018;47:741-747.
    A benzoylthiourea molecule namely 1,1-dibenzyl-3-(2-bromobenzoyl)thiourea (2BrBT) was synthesized and characterized
    by C, H, N and S elemental, mass spectrometry and spectroscopic analyses (infrared, ultraviolet-visible and nuclear
    magnetic resonance). The 2BrBT compound crystallized in a tetragonal system with the space group P43 and exhibits
    an acentric crystalline packing due to the presence of intermolecular H-bonding network that forms a self-assembly
    of 1D helical motif. The asymmetric delocalisation of electrons in the molecule retains its transparency throughout the
    visible and near-infrared region and hence, essentially propagates the macroscopic helical motif in the solid state. The
    highest-occupied and lowest-unoccupied molecular orbital (HOMO/LUMO) are mainly found on the thiourea moiety and
    the benzoylthiourea fragment, respectively and shows an optical bandgap of 3.50 eV. The influence of its geometrical
    characteristics to the optical properties of 2BrBT is established and discussed in view of nonlinear optical (NLO)
    Matched MeSH terms: Magnetic Resonance Spectroscopy
  17. Ali MS, AbuZaiter A, Schlosser C, Bycraft B, Takahata K
    Sensors (Basel), 2014 Jul 10;14(7):12399-409.
    PMID: 25014100 DOI: 10.3390/s140712399
    This paper reports a method that enables real-time displacement monitoring and control of micromachined resonant-type actuators using wireless radiofrequency (RF). The method is applied to an out-of-plane, spiral-coil microactuator based on shape-memory-alloy (SMA). The SMA spiral coil forms an inductor-capacitor resonant circuit that is excited using external RF magnetic fields to thermally actuate the coil. The actuation causes a shift in the circuit's resonance as the coil is displaced vertically, which is wirelessly monitored through an external antenna to track the displacements. Controlled actuation and displacement monitoring using the developed method is demonstrated with the microfabricated device. The device exhibits a frequency sensitivity to displacement of 10 kHz/µm or more for a full out-of-plane travel range of 466 µm and an average actuation velocity of up to 155 µm/s. The method described permits the actuator to have a self-sensing function that is passively operated, thereby eliminating the need for separate sensors and batteries on the device, thus realizing precise control while attaining a high level of miniaturization in the device.
    Matched MeSH terms: Magnetic Resonance Spectroscopy/instrumentation*
  18. Zainuddin N, Karpukhina N, Law RV, Hill RG
    Dent Mater, 2012 Oct;28(10):1051-8.
    PMID: 22841162 DOI: 10.1016/j.dental.2012.06.011
    The purpose of this study was to characterize commercial glass polyalkenoate cement (GPC) or glass ionomer cement (GIC), Glass Carbomer(®), which is designed to promote remineralization to fluorapatite (FAp) in the mouth. The setting reaction of the cement was followed using magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy.
    Matched MeSH terms: Magnetic Resonance Spectroscopy/methods*
  19. Sim YL, Ariffin A, Khan MN
    J. Org. Chem., 2008 May 16;73(10):3730-7.
    PMID: 18410141 DOI: 10.1021/jo702695k
    The apparent second-order rate constant (k OH) for hydroxide-ion-catalyzed conversion of 1 to N-(2'-methoxyphenyl)phthalamate (4) is approximately 10(3)-fold larger than k OH for alkaline hydrolysis of N-morpholinobenzamide (2). These results are explained in terms of the reaction scheme 1 --> k(1obs) 3 --> k(2obs) 4 where 3 represents N-(2'-methoxyphenyl)phthalimide and the values of k(2obs)/k(1obs) vary from 6.0 x 10(2) to 17 x 10(2) within [NaOH] range of 5.0 x 10(-3) to 2.0 M. Pseudo-first-order rate constants (k(obs)) for alkaline hydrolysis of 1 decrease from 21.7 x 10(-3) to 15.6 x 10(-3) s(-1) with an increase in ionic strength (by NaCl) from 0.5 to 2.5 M at 0.5 M NaOH and 35 degrees C. The values of k obs, obtained for alkaline hydrolysis of 2 within [NaOH] range 1.0 x 10(-2) to 2.0 M at 35 degrees C, follow the relationship k(obs) = kOH[HO(-)] + kOH'[HO (-)] (2) with least-squares calculated values of kOH and kOH' as (6.38 +/- 0.15) x 10(-5) and (4.59 +/- 0.09) x 10(-5) M (-2) s(-1), respectively. A few kinetic runs for aqueous cleavage of 1, N'-morpholino-N-(2'-methoxyphenyl)-5-nitrophthalamide (5) and N'-morpholino-N-(2'-methoxyphenyl)-4-nitrophthalamide (6) at 35 degrees C and 0.05 M NaOH as well as 0.05 M NaOD reveal the solvent deuterium kinetic isotope effect (= k(obs) (H 2) (O)/ k(obs) (D 2 ) (O)) as 1.6 for 1, 1.9 for 5, and 1.8 for 6. Product characterization study on the cleavage of 5, 6, and N-(2'-methoxyphenyl)-4-nitrophthalimide (7) at 0.5 M NaOD in D2O solvent shows the imide-intermediate mechanism as the exclusive mechanism.
    Matched MeSH terms: Magnetic Resonance Spectroscopy/methods
  20. Pariyani R, Ismail IS, Ahmad Azam A, Abas F, Shaari K
    J Sci Food Agric, 2017 Sep;97(12):4169-4179.
    PMID: 28233369 DOI: 10.1002/jsfa.8288
    BACKGROUND: Java tea is a well-known herbal infusion prepared from the leaves of Orthosiphon stamineus (OS). The biological properties of tea are in direct correlation with the primary and secondary metabolite composition, which in turn largely depends on the choice of drying method. Herein, the impact of three commonly used drying methods, i.e. shade, microwave and freeze drying, on the metabolite composition and antioxidant activity of OS leaves was investigated using proton nuclear magnetic resonance (1 H NMR) spectroscopy combined with multivariate classification and regression analysis tools.

    RESULTS: A total of 31 constituents comprising primary and secondary metabolites belonging to the chemical classes of fatty acids, amino acids, sugars, terpenoids and phenolic compounds were identified. Shade-dried leaves were identified to possess the highest concentrations of bioactive secondary metabolites such as chlorogenic acid, caffeic acid, luteolin, orthosiphol and apigenin, followed by microwave-dried samples. Freeze-dried leaves had higher concentrations of choline, amino acids leucine, alanine and glutamine and sugars such as fructose and α-glucose, but contained the lowest levels of secondary metabolites.

    CONCLUSION: Metabolite profiling coupled with multivariate analysis identified shade drying as the best method to prepare OS leaves as Java tea or to include in traditional medicine preparation. © 2017 Society of Chemical Industry.

    Matched MeSH terms: Magnetic Resonance Spectroscopy/methods*
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