149 research outputs found

    Quantitative analysis of malondialdehyde-guanine adducts in genomic DNA samples by liquid chromatography tandem mass spectrometry.

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    RATIONALE: The lipid peroxidation product malondialdehyde forms M1 dG adducts with guanine bases in genomic DNA. The analysis of these adducts is important as a biomarker of lipid peroxidation, oxidative stress and inflammation which may be linked to disease risk or exposure to a range of chemicals. METHODS: Genomic DNA samples were subjected to acid hydrolysis to release the adducts in the base form (M1 G) alongside the other purines. A liquid chromatography-mass spectrometry method was optimised for the quantitation of the M1 G adducts in genomic DNA samples using product ion and multiple reaction mode scans. RESULTS: Product ion scans revealed four product ions from the precursor ion; m/z 188 → 160, 133, 106 and 79. The two smallest ions have not been observed previously and optimisation of the method revealed that these gave better sensitivity (LOQ m/z 79: 162 adducts per 10(7) nucleotides; m/z 106: 147 adducts per 10(7) nucleotides) than the other two ions. An MRM method gave similar sensitivity but the two smallest product ions gave better accuracy (94-95%). Genomic DNA treated with malondialdehyde showed a linear dose-response relationship. CONCLUSION: A fast reliable sample preparation method was used to release adducts in the base form rather than the nucleoside. The methods were optimised to selectively analyse the adducts in the presence of other DNA bases without the need for further sample clean-up. Analysis of genomic DNA gave results consistent with previous work and was applied to new samples. Thus, the method is suitable for the analysis of M1 (d)G adducts in biological samples

    Lyophilised Biopolymer-Clay Hydrogels for Drug Delivery

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    Clays have previously demonstrated potential as drug delivery carriers for the extended release of a variety of drugs. The objective of this study was to develop and characterise drug-containing clays in combination with natural hydrogels for the preparation of lyophilised xerogels. Sulfathiazole (STH) (a hydrophobic model drug) was intercalated within the interlayer spaces of LaponiteÂź RDS (LAP RDS) or refined montmorillonite (MMT) and then mixed with either carageenen 812 (CAR 812) or hydrohydroxy ethyl cellulose (HEC) hydrogels prior to lyophilisation. The resulting xerogels were characterised visually, using differential scanning calorimetry (DSC) and with scanning electron microscopy (SEM). Optimal geo-polymeric wafers contained 1.5% W/W CAR 812 with 2% LAP RDSand 1% W/W intercalated STH. DSC and SEM results indicated the amorphous form of STH was intercalated inLAP RDS within theleafy structure of CAR 812. This xerogel hydrated up to1700% within 40 minutes and released the STH by Higuchikinetic model. Keywords: Polymer; Clay, Intercalation, Xerogel, Wound delivery, Amorphous, Physicochemical characterisation, Polymers, hydrogel, drug delivery, lyophilised wafer

    Analytical investigation of hydration mechanism of a non-Portland binder with waste paper sludge ash

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    The development and production of new materials requires advanced analytical characterisation to explain the relation between the physico-chemical structure of the material and its properties. Highly integrated microelectronic structure analysis of surfaces with laser beams and X-ray fluorescence aided devices are found to be helpful for providing important information, including the interrelationships between physical, chemical, mechanical and durability characteristics of the new developed products. In most instances no single technique provides all the needed information and hence simultaneous application of several techniques becomes necessary. This study was aimed for hydration analysis, characterization and evaluation of a new novel non-Portland binder (NPB) with waste paper sludge ash (PSA) using FTIR and TG/DTA. The progressive formation of hydration products within the non-Portland binder was identified and their microstructural characteristics were analysed. The stable and non-expansive nature of secondary ettringite formation was also identified after a period of 365 days curing

    Justicialosides A and B, two new flavone glycosides from the leaves of Ruspolia hypocrateriformis (Vahl) Milne-Redh. (Acanthaceae)

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    Two new flavone glycosides, luteolin 7-O-α-L-rhamnopyranosyl-(1→2)-ÎČ-D-xylopyranoside (1) and chrysoeriol 7-O-α-L-rhamnopyranosyl-(1→2)-ÎČ-D-xylopyranoside (2), along with five known compounds, luteolin 7-O-ÎČ-D-apiofuranosyl-(1→2)-ÎČ-D-xylopyranoside (3), grandulosides A and B (4 and 5), luteolin 7-O-[ÎČ-D-glucopyranosyl-(1→2)-α-L-rhamnosyl-(1→6)]-ÎČ-D-glucopyranoside (6) and 10H-quindoline (7) were isolated from the leaves of Ruspolia hypocrateriformis (Acanthaceae). Their structures were elucidated by spectroscopic means, including 1D and 2D NMR, HRESIMS and by comparison with published data

    Analytical characterization of bioactive N-benzyl-substituted phenethylamines and 5-methoxytryptamines

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    RationaleSubstances based on the N-(2-methoxybenzyl)phenethylamine template ('NBOMe' derivatives) play an important role in medicinal research but some of these derivatives have also appeared as 'research chemicals' for recreational use which has attracted attention worldwide. A major challenge associated with newly emerging substances includes the lack of analytical data and the ability to correctly identify positional isomers.Methods Six N-benzylphenethylamines based on the 2,5-dimethoxy-4-iodophenethylamine structure ('25I') and twelve substituted N-benzyl-5-methoxytryptamines ('5MT') have been prepared and extensively characterized. Techniques used for characterization were gas chromatography/ion trap mass spectrometry in electron and chemical ionization mode, liquid chromatography/diode array detection (DAD), infrared spectroscopy, electrospray high mass accuracy quadrupole time-of-flight tandem mass spectrometry, and triple quadrupole tandem mass spectrometry.ResultsThe characterization of 18 'NBOMe' compounds provided a comprehensive collection of chromatographic and spectral data. Four groups of three positional isomers, i.e. 25I-NB2OMe, 25I-NB3OMe, 25I-NB4OMe, 25I-NB2B, 25I-NB3B, 25I-NB4B and their 5-methoxytryptamine counterparts, were included and assessed for ability to obtain differentiation. Six meta-substituted N-benzyl derivatives of 5-methoxytryptamine (CF3, F, CH3, Cl, I, SCH3) were also studied.Conclusions The implementation of mass spectral techniques was helpful for the differentiation between isomers, for example, when considering the difference in a number of ion ratios. This was considered beneficial in cases where chromatographic separation was only partially achieved under liquid chromatography (LC) conditions. The use of LC/DAD analysis was also found to be valuable for this particular purpose, which confirmed the integrative value of complementary techniques used in areas related to forensic toxicology

    Four new neo-clerodane diterpenes from the stem bark of Croton oligandrus.

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    Four new neo-clerodanes, crotonolins C-F (3-6), were isolated from the stem bark of Croton oligandrus together with the known clerodane crotonzambefuran A, the abietanes 7-ÎČ-hydroxydehydroabietic acid and 7-oxodehydroabietic acid, and ferulic acid. Their structures were elucidated by spectroscopic analyses including 1D and 2D NMR and HRESIMS and by comparison with previously reported data. The cytotoxicity of the isolated compounds against A549, MCF7, PC3 and PNT2 cells was evaluated using the MTT assay. Only 7-ÎČ-hydroxydehydroabietic acid showed a moderate level of activity against PC3 cells with an IC50 value of 68.9 ± 6.6 ÎŒM

    Growth inhibitory activity of biflavonoids and diterpenoids from the leaves of the Libyan Juniperus phoenicea against human cancer cells

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    Three biflavonoids [cupressuflavone (1), amentoflavone (2)and sumaflavone (3)], four diterpenoids [13-epi-cupressic acid (4), imbricatholic acid (5), 3-hydroxy-sandaracopimaric acid (6)and dehydroabietic acid (7)]and onelignan [ÎČ-peltatin methyl ether (8)],were isolated from the cytotoxicfractions of the extracts of the leaves of the Libyan Juniperus phoeniceaL. The structures of these compounds were elucidated by spectroscopic means.Cytotoxicity of the compounds 1-6were assessedagainst the human lung cancer cell lineA549 using the MTT assay. Compounds 1and 3showed cytotoxicityagainst the A549cells(IC50= 65 ”Mand 77 ”M, respectively), whereas, compound 2did not show any activity. Diterpenes4-6exhibited weak cytotoxicity against the A549 cells with the IC50values of 159 ”M, 263 ”Mand 223 ”M, respectively. The cytotoxicity of each compound was compared with the anticancer drug,etoposide (IC50=61 ”M).Cupressuflavone (1)wasevaluatedalso for cytotoxicity against both the human PC3 cancer cell lineand the normal prostatecell line (PNT2), and this compoundrevealed a high degreeof cytotoxic selectivity towards the prostate cancer cells (PC3), with IC50value of 19.9 ”M, without any evidence of cytotoxicity towards the normal prostatecell line(PNT2)

    Development of High-Throughput Glass Inkjet Devices for Pharmaceutical Applications

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    The application of the inkjet method to pharmaceutical products is promising. To make this realistic, not only does the throughput of this method need to be increased, but also the components should be inert to pharmaceutical preparations. We present designs of glass‐based inkjet devices that are capable of producing droplets at high rates. To achieve this, inkjet devices from glass capillary tubes were manufactured with orifice diameters of 5, 10 and 20 ÎŒm and were actuated with diaphragm piezoelectric disks. Also, a pressure capsule was formed by creating a manifold at a distance from the orifice tip. Placing the piezoelectric disk at 0.5 mm distance from the tip allowed the formation of a jet at 3.2 MHz in certain designs, but for a short period of time because of overheating. The length of the pressure capsule, its inlet diameter, and the nozzle tip geometry were crucial to lower the required power. Actuating an inkjet device with 10 ÎŒm orifice diameter comfortably at 900 kHz and drying the droplets from 1% salbutamol sulphate solution allowed the formation of particles with diameters of 1.76 ± 0.15 ÎŒm and the geometric standard deviation of 1.08. In conclusion, optimising internal design of glass inkjet devices allowed the production of high‐throughput droplet ejectors. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:3733–3742, 201

    One-pot synthesis and negative ion mass spectrometric investigation of a densely functionalized cinnoline, 3-amino-5,7,8-trichloro-6-hydroxycinnoline-4-carbonitrile

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    Known densely substituted 3-amino-5,7,8-trichloro-6-hydroxycinnoline-4-carbonitrile was synthesized using a new synthetic protocol involving chloranil and malonitrile via quinone methide formation. This one-pot synthesis occurs under base mediated conditions in a polar medium. The method involves condensation of excess malononitrile with chloranil in ethanol at reflux to 2-(2,4,5-trichloro-3-hydroxy-6-oxocyclohexa-2,4-dien-1-ylidene) malononitrile. This is an atom efficient, simple and effective procedure for the preparation of a highly substituted cinnoline that can serve as a relay to antimalarial prototypes

    Liquid chromatography mass spectrometry analysis and cytotoxicity of Asparagus adscendens roots against human cancer cell lines

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    Background: Asparagus adscendens Roxb. (Asparagaceae), is native to the Himalayas. This plant has been used in the prevention and effective treatment of various forms of cancers. Objective: This paper reports, for the first time, on the cytotoxicity of the methanol (MeOH) extract of the roots of A. adscendens and its solid‑phase extraction (SPE) fractions against four human carcinoma cell lines and LC‑ESI‑QTOF‑MS analysis of the SPE fractions. Materials and Methods: Finely powdered roots of A. adscendens were macerated in methanol and extracted through SPE using gradient solvent system (water: methanol) proceeded for analysis on LC‑ESI‑QTOF‑MS and cytotoxicity against four human carcinoma cell lines: breast (MCF7), liver (HEPG2), lung (A549), and urinary bladder (EJ138), using the 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazoliumbromide assay. Results: The MeOH extract and four SPE fractions exhibited cytotoxicity against all cell lines with the IC50 values ranging from 6 to 79 ÎŒg/mL. As observedin other Asparagus species, the presence of saponins and sapogenins in the SPE fractions was evident in the liquid chromatography‑mass spectrometry data. Conclusion: It is reasonable to assume that the cytotoxicity of the MeOH extract of the roots of A. adscendens and its SPE fractions, at least partly, due to the presence of saponins and their aglycones. This suggests that A. adscendens could be exploited as a potential source of cytotoxic compounds with putative anticancer potential
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