ORCID Profile
0000-0003-0129-3178
Current Organisation
Deakin University
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Analytical spectrometry | Analytical chemistry | Instrumental methods (excl. immunological and bioassay methods) | Separation science |
Publisher: MDPI AG
Date: 24-09-2012
DOI: 10.3390/MD10092089
Publisher: Elsevier BV
Date: 09-2015
DOI: 10.1016/J.JCHROMB.2015.07.002
Abstract: This study reports a GC-QqQ-MS method for the quantification of forty-eight primary metabolites from four major classes (sugars, sugar acids, sugar phosphates, and organic acids) which can be applied to a number of biological systems. The method was validated in terms of linearity, reproducibility and recovery, using both calibration standards and real s les. Additionally, twenty-eight biogenic amines and amino acids were quantified using an established LC-QqQ-MS method. Both GC-QqQ-MS and LC-QqQ-MS quantitative methods were applied to plant extracts from flower and pod tissue of two chickpea (Cicer arietinum L.) cultivars differing in their ability to tolerate salinity, which were grown under control and salt-treated conditions. Statistical analysis was applied to the data sets using the absolute concentrations of metabolites to investigate the differences in metabolite profiles between the different cultivars, plant tissues, and treatments. The method is a significant improvement of present methodology for quantitative GC-MS metabolite profiling of organic acids and sugars, and provides new insights of chickpea metabolic responses to salinity stress. It is applicable to the analysis of dynamic changes in endogenous concentrations of polar primary metabolites to study metabolic responses to environmental stresses in complex biological tissues.
Publisher: Wiley
Date: 02-2009
Abstract: Rapid chemical profiling of the antitumour active crude dichloromethane extract of the marine sponge, Dactylospongia sp. was undertaken. A combination of both offline (HPLC followed by NMR and MS) and on-line (on-flow and stop-flow HPLC-NMR) chemical profiling approaches was adopted to establish the exact nature of the major constituents present in the dichloromethane extract of this sponge. On-flow HPLC-NMR analysis was employed to initially identify components present in the dichloromethane extract, while stop-flow HPLC-NMR experiments were then conducted on the major component present, resulting in the partial identification of pentaprenylated p-quinol (5). Subsequent off-line RP semi-preparative HPLC isolation of 5 followed by detailed spectroscopic analysis using NMR and MS permitted the complete structure to be established. This included the first complete carbon NMR chemical shift assignment of 5 based on the heteronuclear 2-D NMR experiments, together with the first report of its antitumour activity. This study represents one of the few reports describing the application of HPLC-NMR to chemically profile secondary metabolites from a marine organism.
Publisher: Elsevier BV
Date: 11-2011
DOI: 10.1016/J.PHYTOCHEM.2011.06.012
Abstract: Chemical profiling of the southern Australian marine alga Laurencia elata (Rhodomelaceae) employing on-flow and stop-flow HPLC-NMR methodology followed by off-line chemical investigations resulted in the isolation of two C16 chamigrenes, cycloelatanene A and B together with three previously reported sesquiterpenes, (3Z)-chlorofucin, pacifenol and elatenyne. The chemical structures were elucidated via detailed spectroscopic analyses.
Publisher: Elsevier BV
Date: 10-2015
Publisher: Oxford University Press (OUP)
Date: 05-03-2016
DOI: 10.1093/JXB/ERW059
Publisher: Wiley
Date: 14-01-2013
DOI: 10.1111/AEC.12019
Publisher: Public Library of Science (PLoS)
Date: 29-08-2014
Publisher: Wiley
Date: 09-2008
DOI: 10.1002/PCA.1075
Abstract: Over the last decade HPLC-NMR has become a robust analytical technique that has been applied to a wide range of studies, particularly plant extracts. There have been only a few applications of the use of HPLC-NMR to profile marine natural product extracts and no studies involving marine algae. The marine alga selected for this study belongs to the genus Plocamium, which is a well known source of polyhalogenated monoterpenes. To chemically profile the marine alga P. mertensii, using a combination of on-line (HPLC-NMR) and off-line approaches. P. mertensii was extracted with 3:1 methanol-dichloromethane and subsequently partitioned into dichloromethane and methanol-soluble fractions. The methanol partition was exclusively profiled by HPLC-NMR (on-flow, stop-flow and time-slice experiments) whilst the dichloromethane partition was investigated by conventional isolation and purification procedures. HPLC-NMR analysis of the methanol partition partially identified the presence of the major compounds 7, 13, 27 and 37, the structures of which were unequivocally elucidated by off-line characterisation of the dichloromethane partition. Two additional minor metabolites (3 and 8) present in the dichloromethane partition were only tentatively identified as these co-occurred in a mixture with compounds 7 and 13. As a result of this study a number of chemical shift reassignments were made for compound 37. This is one of the few reports describing the application of HPLC-NMR to rapidly profile or dereplicate a marine organism and the first application of HPLC-NMR to successfully profile the chemistry of a marine alga.
Publisher: Elsevier BV
Date: 04-2016
DOI: 10.1016/J.FOODCHEM.2015.11.015
Abstract: Regulation of the human immune system requires controlled pro- and anti-inflammatory responses for host defence against infection and disease states. Yeasts (Saccharomyces cerevisiae), as used in brewing and baking, are mostly known for ability to stimulate the human immune-system predominantly reflecting the pro-inflammatory cell wall β-glucans. However, in this study, using food-compatible processing methods, glycopeptide-enriched and β-glucan-depleted products were each prepared from Brewer's and Baker's yeasts, which suppressed production of interferon-γ (IFN-γ) in human whole blood cell assay, signifying that anti-inflammatory factors are also present in yeast. Anti-inflammatory bioactivities of products prepared from Brewer's and Baker's yeast were compared with the commercial yeast product, Epicor®. While unfractionated Epicor was inactive, the C18 resin-binding fractions of Brewer's and Baker's yeast products and Epicor dose-dependently lowered IFN-γ, demonstrating that Epicor also contained both pro-inflammatory (β-glucans) and anti-inflammatory components. Anti-inflammatory activity was attributed to C18 resin-binding species glyco-peptides in Epicor and experimental yeast products. This study demonstrated that pro- and anti-inflammatory factors could be resolved and enriched in yeasts by suitable processing, with potential to improve specific activities.
Publisher: Springer Science and Business Media LLC
Date: 20-02-2021
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 08-10-2014
Abstract: To investigate the role of epoxyeicosatrienoic acids (EETs) and prostaglandins (PGs) in retinal blood vessel calibers and vasodilation during flicker light stimulation in humans. Twelve healthy nonsmokers participated in a balanced crossover study. Oral fluconazole 400 mg and dispersible aspirin 600 mg were used to inhibit production of EETs and PGs, respectively. Retinal imaging was performed 1 hour after drug ingestion with the Dynamic Vessel Analyzer. Resting calibers of selected vessel segments were recorded in measurement units (MU). Maximum percentage dilations during flicker stimulation were calculated from baseline calibers. We then studied six participants each after fluconazole and aspirin ingestions at 30-minute intervals for 2 hours. Within-subject differences were assessed by ANOVA and Dunnett-adjusted pairwise comparisons with significance taken at P < 0.05. In crossover study participants, mean (SD) arteriole and venule dilations without drug administration were 4.4% (2.0%) and 4.6% (1.7%), respectively. Neither drug affected vasodilation during flicker stimulation. Mean (SD) resting arteriole and venule calibers on no-drug visits were 119.6 (10.6) MU and 145.7 (17.0) MU, respectively. Fluconazole reduced mean (±95% CI) resting venule calibers by 5.1 (4.3) MU. In repeated measures participants, neither drug affected vasodilations, but fluconazole reduced resting venule calibers over 2 hours (P < 0.001). Epoxyeicosatrienoic acids and prostaglandins are unlikely to be primary mediators of flicker light-induced retinal vasodilation in humans. However, EETs may play a role in the regulation of retinal vascular tone and blood flow under resting physiological conditions.
Publisher: MDPI AG
Date: 14-11-2019
DOI: 10.3390/BIOM9110738
Abstract: α- and β-pinene are well-known representatives of the monoterpenes group, and are found in many plants’ essential oils. A wide range of pharmacological activities have been reported, including antibiotic resistance modulation, anticoagulant, antitumor, antimicrobial, antimalarial, antioxidant, anti-inflammatory, anti-Leishmania, and analgesic effects. This article aims to summarize the most prominent effects of α- and β-pinene, namely their cytogenetic, gastroprotective, anxiolytic, cytoprotective, anticonvulsant, and neuroprotective effects, as well as their effects against H2O2-stimulated oxidative stress, pancreatitis, stress-stimulated hyperthermia, and pulpal pain. Finally, we will also discuss the bioavailability, administration, as well as their biological activity and clinical applications.
Publisher: Springer Science and Business Media LLC
Date: 12-12-2018
DOI: 10.1007/S11306-017-1306-8
Abstract: Rising seawater temperatures are threatening the persistence of coral reefs where above critical thresholds, thermal stress results in a breakdown of the coral-dinoflagellate symbiosis and the loss of algal symbionts (coral bleaching). As symbiont-derived organic products typically form a major portion of host energy budgets, this has major implications for the fitness and persistence of symbiotic corals. We aimed to determine change in autotrophic carbon fate within in idual compounds and downstream metabolic pathways in a coral symbiosis exposed to varying degrees of thermal stress and bleaching. We applied gas chromatography-mass spectrometry coupled to a stable isotope tracer ( Thermal stress resulted in partner-specific changes in carbon fate, which progressed with heat stress duration. We detected modifications to carbohydrate and fatty acid metabolism, lipogenesis, and homeostatic responses to thermal, oxidative and osmotic stress. Despite pronounced photodamage, remaining in hospite symbionts continued to produce organic products de novo and translocate to the coral host. However as bleaching progressed, we observed minimal These data have major implications for our understanding of coral symbiosis function during bleaching. Our findings suggest that during early stage bleaching, remaining symbionts continue to effectively translocate a variety of organic products to the host, however under prolonged thermal stress there is likely a reduction in the quality of these products.
Publisher: John Wiley & Sons, Ltd
Date: 06-03-2014
Publisher: Elsevier BV
Date: 03-2014
Publisher: Springer Science and Business Media LLC
Date: 2014
Publisher: Elsevier BV
Date: 08-2018
DOI: 10.1016/J.PLAPHY.2018.05.001
Abstract: This study provides a comprehensive investigation on the impact of increasing NaCl concentrations on hydroponically grown Stevia rebaudiana cultivars (Shoutian-2 and Fengtian). Growth parameters including plant height, biomass and physiological responses including osmotic potential were measured. In addition, the levels of steviol glycosides, elements and primary metabolites were measured and statistically evaluated. The cultivar Fengtian grew faster, accumulated less Na
Publisher: MDPI AG
Date: 26-12-2022
DOI: 10.3390/AGRICULTURE13010073
Abstract: Biofuel generation from algae can be increased by using nanotechnology. The present study emphasizes the use of silver nanoparticles on algae for algal fuel generation along with the impact of nanoparticles on biomass, metabolites and lipid profile. Silver ion amassing was enhanced in each algal species, but maximum phytoremediation was found in Ulothrix sp. Carbohydrates increased 3.2 times in Oedogonium sp., 3.3 times in Ulothrix sp., 3 times in Cladophora sp. and 2.7 times in Spirogyra sp. Additionally, the application of nanoparticles enhanced by 2 times the production of proteins in Oedogonium sp., 1.9 times in Ulothrix sp., 1.9 times in Cladophora sp. and 2.1 times in Spirogyra sp. Finally, the total lipid yield increased 60% DCW in Oedogonium sp., 56% DCW in Ulothrix sp., 58% DCW in Cladophora sp. and 63% DCW in Spirogyra sp. using 0.08 mg/L silver nanoparticle application. The lipids and fatty acid fractions from algae containing high concentrations of C16:0, C18:0 and C18:1 enhanced with silver nanoparticle addition were comparable with EN 14214 and ASTM 6751 biodiesel standards. This study indicates that the uptake of AgNPs can enhance the production of fatty acids and be commercialized as sustainable biodiesel. The algae Ulothrix sp. is evidenced as the best competent feedstock for biofuel production.
Publisher: Informa UK Limited
Date: 10-07-2009
DOI: 10.1080/14786410802682536
Abstract: A detailed chemical and spectroscopic investigation of the terrestrial lichen Candelaria concolor has yielded several lichenic metabolites belonging to the pulvinic acid series, as well as several depside derivatives including pulvinic dilactone (1), vulpinic acid (4) and calycin (5). The chemical transformation of 1 to pulvinic acid (3) is reported for the first time, as is the conversion of atranorin (6) to 5-chloroatranorin (7) and then finally to 5,5'-dichloroatranorin (8) under very mild conditions. Also presented is the complete 1D and 2D NMR assignment for compounds 1, 3, 4, 5 and 8, including partial NMR chemical shift assignments for the unstable depside (7). Previously, these metabolites had only been partially assigned by NMR spectroscopy.
Publisher: Humana Press
Date: 2013
DOI: 10.1007/978-1-62703-577-4_2
Abstract: Plants are not only important producers of foods and energy storages (e.g., sugars, carbohydrates, proteins, and fats) in the form of grains, fruits, and vegetables, they also provide many valuable products to human existence including wood, fibers, oils, resins, pigments, antioxidants, and sources of medicine. Most importantly in light of this book, plants have been a source of therapeutic and health promoting compounds throughout history. This chapter describes several essential considerations for the extraction process when aiming to study plant metabolism or to characterize the chemical composition of plant originated s les using metabolomics technologies.
Publisher: Wiley
Date: 06-02-2015
Publisher: American Chemical Society (ACS)
Date: 29-11-2012
DOI: 10.1021/JF3034072
Abstract: This study characterizes a novel glutathione-substituted dihydroxyphenyl compound formed during the oxidation of white wine and model wine solutions, which may contribute to the synergistic role of glutathione and hydroxycinnamic acids in delaying oxidative coloration. The critical components for the formation of the compound were found to be hydroxycinnamic acids and glutathione, while ascorbic acid enabled the product to accumulate to higher concentrations. The presence of the wine components important in other wine oxidation mechanisms, (+)-catechin, ethanol and/or tartaric acid, was not essential for the formation of this new compound. Via LC-MS/MS, HR-MS and (1)H NMR (1D and 2D NMR) analyses, the major isomer of the compound formed from glutathione and caffeic acid was found to be 4-[(E)-2'-(S)-glutathionyl ethenyl]-catechol (GEC). Equivalent products were also confirmed via LC-MS/MS for other hydroxycinnamic acids (i.e., ferulic and coumaric acids). Only trace amounts of GEC were formed with the quinic ester of caffeic acid (i.e., chlorogenic acid), and no equivalent product was found for cinnamic acid. GEC was detected in a variety of white wines supplemented with glutathione and caffeic acid. A radical mechanism for the formation of the styrene-glutathione derivatives is proposed.
Publisher: Humana Press
Date: 2013
DOI: 10.1007/978-1-62703-577-4_8
Abstract: The structure elucidation of new secondary metabolites derived from marine and terrestrial sources is frequently a challenging task. The hurdles include the ability to isolate stable secondary metabolites of sufficient purity that are often present in <0.5 % of the dry weight of the s le. This usually involves a minimum of several chromatographic purification steps. The second issue is the stability of the compound isolated. It must always be assumed when dealing with the isolation of natural products that the compound may rapidly degrade during and/or after the isolation, due to sensitivity to light, air oxidation, and/or temperature. In this way, precautions need to be taken, as much as possible to avoid any such chemical inter-conversions and/or degradations. Immediately after purification, the next step is to rapidly acquire all analytical spectroscopic data in order to complete the characterization of the isolated secondary metabolite(s), prior to any possible decomposition. The final hurdle in this multiple step process, especially in the acquisition of the NMR spectroscopic and other analytical data (mass spectra, infrared and ultra-violet spectra, optical rotation, etc.), is to assemble the structural moieties/units in an effort to complete the structure elucidation. Often ambiguity with the elucidation of the final structure remains when structural fragments identified are difficult to piece together on the basis of the HMBC NMR correlations or when the relative configuration cannot be unequivocally identified on the basis of NOE NMR enhancements observed. Herein, we describe the methodology used to carry out the structure elucidation of a new C16 chamigrene, cycloelatanene A (5) which was isolated from the southern Australian marine alga Laurencia elata (Rhodomelaceae). The general approach and principles used in the structure determination of this compound can be applied to the structure elucidation of other small molecular weight compounds derived from either natural or synthetic sources.
Publisher: Springer Science and Business Media LLC
Date: 07-09-2019
Publisher: Springer Science and Business Media LLC
Date: 18-10-2017
Publisher: Springer Science and Business Media LLC
Date: 15-03-2019
DOI: 10.1007/S11306-019-1507-4
Abstract: Transgenic herbicide-resistant (HR) turfgrass together with its associated, broad spectrum herbicides promise cheap, selective and efficient weed control by excluding infested weeds resulting in turf lawn with high uniformity and aesthetic value. The concept of this "weeding program" initiated from modern biotechnology has been widely implemented in several principal crops including maize, soybean, canola and cotton as early as the 1990s. Transgenic HR turfgrass classified as a genetically modified organism (GMO) has undoubtedly caused public concern with respect to its biosafety and legalities similar to well-established HR crops. Nevertheless, applying metabolomics-based approaches which focuses on the identification of the global metabolic state of a biological system in response to either internal or external stimuli can also provide a comprehensive characterization of transgenic grass metabolism and its involvement in biosecurity and public perception. This review summaries the recent applications of metabolomics applied to HR crops to predict the molecular and physiological phenotypes of HR turfgrass species, glyphosate-resistant Kentucky bluegrass (Poa pratensis L.) and glufosinate-resistant creeping bentgrass (Agrotis stonifera L.). Additionally, this review also presents background knowledge with respect to the application of metabolomics, transformation of HR crops and its biosafety concerns, turfgrass botanical knowledge and its economic and aesthetic value. The purpose of this review is to demonstrate the molecular and physiological phenotypes of HR turfgrass based on several lines of evidence primarily derived from metabolomics data applied to HR crops to identify alterations on HR turfgrass metabolism as a result of genetic modification that confers resistant traits.
Publisher: Humana Press
Date: 2013
DOI: 10.1007/978-1-62703-577-4_4
Abstract: Fatty acids (FAs) are involved in a wide range of functions in biological systems. It is important to measure the exact amount of fatty acids in biological matrices in order to determine the level of fatty acids and understand the role they play. The ability to quantify fatty acids in various systems, especially plant species and microbes has recently paved the way to the mass production of pharmaceuticals and energy substitutes including biodiesel. This chapter describes an efficient method to quantify the total fatty acids (TFAs) in biological systems using gas chromatography-mass spectrometry (GC-MS) and a commercially available standard mix of fatty acid methyl esters (FAMEs) using a step-by-step methodology to setup a quantitation method using the Agilent Chemstation software.
Publisher: Bentham Science Publishers Ltd.
Date: 02-07-2018
DOI: 10.2174/1874467211666180125163009
Abstract: In age-related macular degeneration, oxidative damage and abnormal neovascularization in the retina are caused by the upregulation of vascular endothelium growth factor and reduced expression of Glutathione-S-transferase genes. Current treatments are only palliative. Compounds from cruciferous vegetables (e.g. L-Sulforaphane) have been found to restore normal gene expression levels in diseases including cancer via the activity of histone deacetylases and DNA methyltransferases, thus retarding disease progression. To examine L-Sulforaphane as a potential treatment to ameliorate aberrant levels of gene expression and metabolites observed in age-related macular degeneration. The in vitro oxidative stress model of AMD was based on the exposure of Adult Retinal Pigment Epithelium-19 cell line to 200μM hydrogen peroxide. The effects of L-Sulforaphane on cell proliferation were determined by MTS assay. The role of GSTM1, VEGFA, DNMT1 and HDAC6 genes in modulating these effects was investigated using quantitative real-time polymerase chain reaction. The metabolic profiling of L-Sulforaphane-treated cells via gas-chromatography massspectrometry was established. Significant differences between control and treatment groups were validated using one-way ANOVA, student t-test and post-hoc Bonferroni statistical tests (p<0.05). L-Sulforaphane induced a dose-dependent increase in cell proliferation in the presence of hydrogen peroxide by upregulating Glutathione-S-Transferase μ1 gene expression. Metabolic profiling revealed that L-Sulforaphane increased levels of 2-monopalmitoglycerol, 9, 12, 15,-(Z-Z-Z)- Octadecatrienoic acid, 2-[Bis(trimethylsilyl)amino]ethyl bis(trimethylsilyl)-phosphate and nonanoic acid but decreased β-alanine levels in the absence or presence of hydrogen peroxide, respectively. This study supports the use of L-Sulforaphane to promote regeneration of retinal cells under oxidative stress conditions.
Publisher: Informa UK Limited
Date: 04-2007
DOI: 10.1080/14786410701194484
Abstract: Chemical investigation of a terrestrial lichen has yielded the pulvinic acid derivative pinastric acid (4). The structure of 4 was secured by detailed spectroscopic analysis as well as via a single X-ray diffraction study. This is the first report of the X-ray structure and 2D NMR assignment of pinastric acid (4). Pinastric acid (4) displayed antitumour, antiviral and antimicrobial (both antibacterial and antifungal) activities. Whilst the antiviral and antimicrobial activities are consistent with previous findings of 4 this is the first report of the antitumour properties for the compound.
Publisher: Georg Thieme Verlag KG
Date: 25-05-2009
Abstract: The crude extract of the roots from the Australian medicinal plant Dianella callicarpa (Liliaceae) displayed significant antimicrobial and antiviral activities. This prompted a chemical investigation, resulting in the isolation of the new naphthalene glycoside, dianellose (10), together with dianellin (1), dianellidin (2), dianellinone (3), stellalderol (9) and 5-hydroxydianellin (11). The structures for compounds 1, 9 and 10 were secured by detailed spectroscopic analyses, while compounds 2, 3 and 11 were identified on the basis of comparisons to literature data. Whilst the chemistry of the genus Dianella has previously been investigated, we report the first isolation of stellalderol (9) from this genus, together with the chemical and biological evaluation of the callicarpa species. Biological evaluation of the isolated compounds established that 2 showed antiviral and mild antimicrobial properties and that compounds 1, 9 and 10 displayed moderate antitumour activities.
Publisher: Springer New York
Date: 2018
DOI: 10.1007/978-1-4939-7819-9_15
Abstract: Gas chromatography coupled with triple quadrupole mass spectrometry (GC-QqQ-MS) can be used to accurately quantify endogenous small molecules extracted from biological s les such as plants and human fluids including sera and urine. In order to quantify primary metabolites typically from central carbon metabolism such as sugars from glycolysis and the pentose phosphate pathway and organic acids involved in the tricarboxylic acid (TCA) cycle polar endogenous metabolites must be extracted from the s les of interest, chemically derivatized and quantified against a linear calibration curve to a corresponding authentic standard. This chapter describes how to quantify a combination of 48 primary metabolites belonging to classes of sugars, sugar alcohols, sugar acids, sugar phosphates, and organic acids using a robust, optimized, multiple reaction monitoring (MRM)-based GC-QqQ-MS method.
Publisher: Wiley
Date: 08-03-2017
DOI: 10.1111/NPH.14515
Abstract: Coral bleaching is a major threat to the persistence of coral reefs. Yet we lack detailed knowledge of the metabolic interactions that determine symbiosis function and bleaching‐induced change. We mapped autotrophic carbon fate within the free metabolite pools of both partners of a model cnidarian–dinoflagellate symbiosis ( Aiptasia–Symbiodinium ) during exposure to thermal stress via the stable isotope tracer ( 13 C bicarbonate), coupled to GC‐MS. Symbiont photodamage and pronounced bleaching coincided with substantial increases in the turnover of non 13 C‐labelled pools in the dinoflagellate (lipid and starch store catabolism). However, 13 C enrichment of multiple compounds associated with ongoing carbon fixation and de novo biosynthesis pathways was maintained (glucose, fatty acid and lipogenesis intermediates). Minimal change was also observed in host pools of 13 C‐enriched glucose (a major symbiont‐derived mobile product). However, host pathways downstream showed altered carbon fate and/or pool composition, with accumulation of compatible solutes and nonenzymic antioxidant precursors. In hospite symbionts continue to provide mobile products to the host, but at a significant cost to themselves, necessitating the mobilization of energy stores. These data highlight the need to further elucidate the role of metabolic interactions between symbiotic partners, during the process of thermal acclimation and coral bleaching.
Publisher: Springer Science and Business Media LLC
Date: 11-2018
DOI: 10.1007/S11306-018-1449-2
Abstract: Metabolomics aims to identify the changes in endogenous metabolites of biological systems in response to intrinsic and extrinsic factors. This is accomplished through untargeted, semi-targeted and targeted based approaches. Untargeted and semi-targeted methods are typically applied in hypothesis-generating investigations (aimed at measuring as many metabolites as possible), while targeted approaches analyze a relatively smaller subset of biochemically important and relevant metabolites. Regardless of approach, it is well recognized amongst the metabolomics community that gas chromatography-mass spectrometry (GC-MS) is one of the most efficient, reproducible and well used analytical platforms for metabolomics research. This is due to the robust, reproducible and selective nature of the technique, as well as the large number of well-established libraries of both commercial and 'in house' metabolite databases available. This review provides an overview of developments in GC-MS based metabolomics applications, with a focus on s le preparation and preservation techniques. A number of chemical derivatization (in-time, in-liner, offline and microwave assisted) techniques are also discussed. Electron impact ionization and a summary of alternate mass analyzers are highlighted, along with a number of recently reported new GC columns suited for metabolomics. Lastly, multidimensional GC-MS and its application in environmental and biomedical research is presented, along with the importance of bioinformatics. The purpose of this review is to both highlight and provide an update on GC-MS analytical techniques that are common in metabolomics studies. Specific emphasis is given to the key steps within the GC-MS workflow that those new to this field need to be aware of and the common pitfalls that should be looked out for when starting in this area.
Publisher: Springer Science and Business Media LLC
Date: 08-2015
DOI: 10.1007/S10886-015-0604-8
Abstract: Numerous tree species' seeds contain an 'elaiosome' that acts as a food reward for ants and thus induces dispersal of the seeds. Many stick and leaf insect species appear to have evolved a convergent adaptation for dispersal whereby the egg 'capitulum' serves to induce ants to pick up and carry their eggs. Here, we investigated whether the capitulum facilitates egg dispersal by ants in the Australian stick insect Eurycnema goliath. The total fatty acid composition of E. goliath egg capsules and egg capitula were characterized to identify potential signaling compounds. Removing capitula from E. goliath eggs significantly reduced the likelihood of eggs being carried into the nests of Rhytidoponera metallica ants. Furthermore, attaching capitula to inert objects (polystyrene balls) resulted in these objects being carried into nests by R. metallica. Several fatty acids were present on the egg capsule surface in only trace amounts, whereas they made up over 10% of the dry weight of egg capitula. The fatty acid composition of egg capitula consisted mostly of palmitic acid (C16:0), linoleic acid (C18: 2n6c), oleic acid (C18:1n9c), linolenic acid (C18:3n3), and stearic acid (C18:0). Previously reported research has found that a diglyceride lipid species of oleic acid induces carrying behavior in R. metallica when added to inert artificial stimuli. Therefore, we propose that the dispersal mechanism of E. goliath eggs has converged upon the same chemical signaling pathway used by plants to exploit ant behavior.
Publisher: American Chemical Society (ACS)
Date: 06-05-2009
DOI: 10.1021/NP900016H
Abstract: Chemical investigation of the Australian plant Haemodorum simplex resulted in the isolation of three new phenylphenalenones, haemodorone (10), haemodorol (11), and haemodorose (12), together with the previously reported compounds 5, dilatrin (6), and xiphidone (8). The first complete 2D NMR characterization for all of the compounds isolated, including several chemical shift reassignments for dilatrin (6), is reported. In addition this is one of the few reports to discuss the isolation of new phenylphenalenones from an Australian medicinal plant. The crude extract of both the bulbaceous and aerial components of the plant exhibited varying degrees of antibacterial, antifungal, and antiviral activity, and only the bulbs displayed potent cytotoxic activity.
Publisher: Elsevier BV
Date: 03-2018
Publisher: MDPI AG
Date: 22-11-2016
DOI: 10.3390/MD14110214
Publisher: Elsevier BV
Date: 06-2013
DOI: 10.1016/J.FOODCHEM.2012.12.024
Abstract: Exposure of a Chardonnay wine to light from a mercury vapour l under controlled temperature conditions showed that colour enhancement was dependent on bottle colour. The increase in colouration was Antique Green<French Green<Arctic Blue<Flint, in agreement with the transmission characteristics of each bottle type. Xanthylium pigments were identified as one component contributing to the observed enhancement of colour. The presence of oxygen was shown to be a critical factor to initiate the formation of these xanthylium pigments during light exposure. Without temperature control, wine colour development was highest in Antique Green and lowest in Flint. This alternate order reflects the ability of the darker bottles to retain heat longer than lighter coloured ones as confirmed by surface temperature decay rates. Specific pigments contributing to the wine colour enhancement in uncontrolled temperature/light exposure experiments could not be identified, although tentative evidence was obtained for the presence of flavan-3-ol based compounds. The different bottle glass surfaces did not influence the rate of loss of dissolved oxygen or oxidation of ascorbic acid. The potential to develop the results obtained in this study to identify markers for light and/or temperature exposure of white wines is discussed.
Publisher: Springer Science and Business Media LLC
Date: 30-07-2015
Publisher: Springer Science and Business Media LLC
Date: 06-01-2021
DOI: 10.1186/S13007-020-00702-5
Abstract: Enzyme assays have widespread applications in drug discovery from plants to natural products. The appropriate use of blanks in enzyme assays is important for assay baseline-correction, and the correction of false signals associated with background matrix interferences. However, the blank-correction procedures reported in published literature are highly inconsistent. We investigated the influence of using different types of blanks on the final calculated activity/inhibition results for three enzymes of significance in diabetes and obesity α-glucosidase, α-amylase, and lipase. This is the first study to examine how different blank-correcting methods affect enzyme assay results. Although assays targeting the above enzymes are common in the literature, there is a scarcity of detailed published protocols. Therefore, we have provided comprehensive, step-by-step protocols for α-glucosidase-, α-amylase- and lipase-inhibition assays that can be performed in 96-well format in a simple, fast, and resource-efficient manner with clear instructions for blank-correction and calculation of results. In the three assays analysed here, using only a buffer blank underestimated the enzyme inhibitory potential of the test s le. In the absorbance-based α-glucosidase assay, enzyme inhibition was underestimated when a s le blank was omitted for the coloured plant extracts. Similarly, in the fluorescence-based α-amylase and lipase assays, enzyme inhibition was underestimated when a substrate blank was omitted. For all three assays, method six [ R aw D ata - ( Su bstrate + Sa mple B lank)] enabled the correction of interferences due to the buffer, s le, and substrate without double-blanking, and eliminated the need to add substrate to each s le blank. The choice of blanks and blank-correction methods contribute to the variability of assay results and the likelihood of underestimating the enzyme inhibitory potential of a test s le. This highlights the importance of standardising the use of blanks and the reporting of blank-correction procedures in published studies in order to ensure the accuracy and reproducibility of results, and avoid overlooked opportunities in drug discovery research due to inadvertent underestimation of enzyme inhibitory potential of test s les resulting from unsuitable blank-correction. Based on our assessments, we recommend method six [RD − (Su + SaB)] as a suitable method for blank-correction of raw data in enzyme assays.
Publisher: Elsevier BV
Date: 08-2017
Publisher: MDPI AG
Date: 16-04-2012
Publisher: Wiley
Date: 09-02-2013
DOI: 10.1002/BIT.24844
Publisher: American Chemical Society (ACS)
Date: 25-03-2011
DOI: 10.1021/JF104897Z
Abstract: The potential for iron(III) tartrate to act as a photoactivator in light-induced oxidative degradation of white wine is described. Using a tartaric-acid-based model wine system containing 5 mg/L iron, exposure to light from a xenon arc l led to the oxidative degradation of tartaric acid and the production of glyoxylic acid. The critical wavelength of light for the degradation process was found to be below 520 nm. No glyoxylic acid was formed in the absence of iron and/or light. Flint glass offered little protection from the light-induced photodegradation of tartaric acid. Antique Green glass offered more protection but did not stop the photodegradation process.
Publisher: Elsevier BV
Date: 05-2021
Publisher: Springer Science and Business Media LLC
Date: 03-06-2014
Publisher: MDPI AG
Date: 08-04-2020
DOI: 10.3390/JCM9041061
Abstract: Among the major neurodegenerative disorders (NDDs), Alzheimer’s disease (AD) and Parkinson’s disease (PD), are a huge socioeconomic burden. Over many centuries, people have sought a cure for NDDs from the natural herbals. Many medicinal plants and their secondary metabolites are reported with the ability to alleviate the symptoms of NDDs. The major mechanisms identified, through which phytochemicals exert their neuroprotective effects and potential maintenance of neurological health in ageing, include antioxidant, anti-inflammatory, antithrombotic, antiapoptotic, acetylcholinesterase and monoamine oxidase inhibition and neurotrophic activities. This article reviews the mechanisms of action of some of the major herbal products with potential in the treatment of NDDs according to their molecular targets, as well as their regional sources (Asia, America and Africa). A number of studies demonstrated the beneficial properties of plant extracts or their bioactive compounds against NDDs. Herbal products may potentially offer new treatment options for patients with NDDs, which is a cheaper and culturally suitable alternative to conventional therapies for millions of people in the world with age-related NDDs.
Publisher: Elsevier BV
Date: 12-2012
DOI: 10.1016/J.FOODCHEM.2012.07.068
Abstract: Pigmentation enhancement in a Chardonnay wine with high flavan-3-ol concentration was examined by irradiating the wine under controlled conditions. Heating the wine in darkness required temperatures in excess of 50°C before enhanced pigmentation became apparent. It was found that ultraviolet and, to a lesser extent, low wavelength visible light contributed to pigment production. The development of pigmentation depended on wine bottle glass colour: Flint>Arctic Blue>French Green>Antique Green. This is in agreement with the transmission characteristics of the bottles with even the darkest (Antique Green) allowing the transmission of some ultraviolet light. Riboflavin, when added to the wine, degraded rapidly when exposed to radiation <400 nm. The degradation of riboflavin and the onset of colour development depended on the actual amounts as well as the ratio of riboflavin to flavan-3-ol, suggesting that a complex series of reactions are occurring. A degradation product of riboflavin may be contributing to the increase in absorbance in the visible region observed during light exposure.
Start Date: 08-2023
End Date: 08-2028
Amount: $4,958,927.00
Funder: Australian Research Council
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