Although numerous studies have been conducted on ginger extracts and fractions, the data on the pharmacological activity of single constituents of
are still insufficient. To assess the antidementia ...properties of the plant, a thin layer chromatography (TLC)-based bioautography acetylcholinesterase inhibitory assay was performed on the
diethyl ether extract. It led to the recognition of three active inhibitors among volatile constituents of the plant:
-curcumene (A),
-sesquiphellandrene (B) and
zingiberene (C). The identification of the components was possible thanks to the application of a TLC-HPLC-MS interface analysis of active zones and the GC-MS qualitative analysis of the tested samples. Based on the obtained results, the influence of several extraction techniques (hydrodistillation-HD, pressurized liquid extraction or accelerated solvent extraction-ASE, shaking maceration-SM, supercritical fluid extraction-SFE, and ultrasound-assisted extraction-UAE) on the recovery of the active metabolites from plant material was assessed to deliver enriched extracts. As a result, HD and SFE, were found to be the most efficient methods to recover the volatile components and the concentrations of A, B, and C reached 0.51 ± 0.025, 0.77 ± 0.045, and 1.67 ± 0.11 percent, respectively. Only HD and SFE were found to recover monoterpene hydrocarbons from the plant matrix. The remaining techniques provided extracts rich in more complex constituents, like sesquiterpenes.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Affinity monolith chromatography (AMC) is a liquid chromatographic technique that utilizes a monolithic support with a biological ligand or related binding agent to isolate, enrich, or detect a ...target analyte in a complex matrix. The target‐specific interaction exhibited by the binding agents makes AMC attractive for the separation or detection of a wide range of compounds. This article will review the basic principles of AMC and recent developments in this field. The supports used in AMC will be discussed, including organic, inorganic, hybrid, carbohydrate, and cryogel monoliths. Schemes for attaching binding agents to these monoliths will be examined as well, such as covalent immobilization, biospecific adsorption, entrapment, molecular imprinting, and coordination methods. An overview will then be given of binding agents that have recently been used in AMC, along with their applications. These applications will include bioaffinity chromatography, immunoaffinity chromatography, immobilized metal‐ion affinity chromatography, and dye‐ligand or biomimetic affinity chromatography. The use of AMC in chiral separations and biointeraction studies will also be discussed.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
This review is an overview of the recent advances of gas chromatography in essential oil analysis; in particular, it focuses on both the new stationary phases and the advanced analytical methods and ...instrumentations. A paragraph is dedicated to ionic liquids as gas chromatography stationary phases, showing that, thanks to their peculiar selectivity, they can offer a complementary contribution to conventional stationary phases for the analysis of complex essential oils and the separation of critical pairs of components. Strategies to speed‐up the analysis time, thus answering to the ever increasing request for routine essential oils quality control, are also discussed. Last but not least, a paragraph is dedicated to recent developments in column miniaturization in particular that based on microelectromechanical‐system technology in a perspective of developing micro‐gas chromatographic systems to optimize the energy consumption as well as the instrumentation dimensions. A number of applications in the essential oil field is also included.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The use of micro, capillary, and nano liquid chromatography systems for forensic analysis has excellent potential. In a field where sample size is often limited, several studies have presented the ...viability of capillary columns with microflow and nanoflow, and when using mass spectrometric analysis limits of detection can be improved. Reduction in flow rates result in significant reduction in operating costs. Recent advances in miniaturized liquid chromatography systems also aim at in‐laboratory and on‐site detection, which have already been applied to forensic drug cases. This critical review will discuss the advantages, disadvantages, and applicability of microflow and nano liquid chromatography. In this regard, included in this article is a discussion of some promising areas not yet applied to forensic research.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•An overview of the current status of the topic is provided.•Different modes of polymer chromatography are discussed.•Guidelines are given to select appropriate strategies for separation ...problems.•Potentials and limitations are discussed.
Most heterogeneities of polymers with respect to different structural features cannot be resolved by only size exclusion chromatography (SEC), the most frequently applied mode of polymer chromatography. Instead, methods of interaction chromatography became increasingly important. However, despite the increasing applications the principles and potential of polymer interaction chromatography are still often unknown to a large number of polymer scientists. The present review will explain the principles of the different modes of polymer chromatography. Based on selected examples it will be shown which separation techniques can be successfully applied for separations with respect to the different structural features of polymers.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Aims
To isolate a novel endophytic bacterium from Panax ginseng that could have excellent properties in converting ginsenoside Rb1 to ginsenoside Rg3.
Methods and Results
Based on a 16S rDNA gene ...sequence, the strain named GE 17‐7 was identified as Burkholderia sp. This strain has shown the highest activity in converting ginsenoside Rb1 to 20(S)‐ginsenoside Rg3. During the biotransformation of ginsenoside Rb1, the final metabolite was identified by nuclear magnetic resonance analysis and the transformation pathway of ginsenoside Rb1 was also identified by thin‐layer chromatography and high performance liquid chromatography analysis in this study.
Conclusions
We have successfully isolated a β‐glucosidase‐producing endophytic bacterium GE 17‐7 from P. ginseng. Ginsenoside Rg3 was produced by strain GE 17‐7 from ginsenoside Rb1 via ginsenoside Rd.
Significance and Impact of the Study
This is the first report of the conversion of major ginsenoside Rb1 into minor ginsenoside Rg3 by fermentation with Burkholderia sp. endophytic bacteria in P. ginseng. These results suggest a new preparation method for ginsenoside Rg3 using strain GE 17‐7 in the pharmaceutical industry.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Momilactones A (MA) and B (MB) are the active phytoalexins and allelochemicals in rice. In this study, MA and MB were purified from rice husk of
cv. Koshihikari by column chromatography, and ...purification was confirmed by high-performance liquid chromatography, thin-layer chromatography, gas chromatography-mass spectrometry, liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS), and ¹H and
C nuclear magnetic resonance analyses. By in vitro assays, both MA and MB exerted potent inhibition on α-amylase and α-glucosidase activities. The inhibitory effect of MB on these two key enzymes was greater than that of MA. Both MA and MB exerted greater α-glucosidase suppression as compared to that of the commercial diabetic inhibitor acarbose. Quantities of MA and MB in rice grain were 2.07 ± 0.01 and 1.06 ± 0.01 µg/dry weight (DW), respectively. This study was the first to confirm the presence of MA and MB in refined rice grain and reported the α-amylase and α-glucosidase inhibitory activity of the two compounds. The improved protocol of LC-ESI-MS in this research was simple and effective to detect and isolate MA and MB in rice organs.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Biopharmaceutical separations require tremendous amounts of optimization to achieve acceptable product purity. Typically, large volumes of reagents and biological materials are needed for testing ...different parameters, thus adding to the expense of biopharmaceutical process development. This study demonstrates a versatile and customizable microscale column (µCol) for biopharmaceutical separations using immobilized metal affinity chromatography (IMAC) as an example application to identify key parameters. µCols have excellent precision, efficiency, and reproducibility, can accommodate any affinity, ion‐exchange or size‐exclusion‐based resin and are compatible with any high‐performance liquid chromatography (HPLC) system. µCols reduce reagent amounts, provide comparable purification performance and high‐throughput, and are easy to automate compared with current conventional resin columns. We provide a detailed description of the fabrication methods, resin packing methods, and µCol validation experiments using a conventional HPLC system. Finite element modeling using COMSOL Multiphysics was used to validate the experimental performance of the µCols. In this study, µCols were used for improving the purification achieved for granulocyte colony stimulating factor (G‐CSF) expressed using a cell‐free CHO in vitro translation (IVT) system and were compared to a conventional 1 ml IMAC column. Experimental data revealed comparable purity with a 10‐fold reduction in the amount of buffer, resin, and purification time for the μCols compared with conventional columns for similar protein yields.
Biopharmaceutical separations require tremendous amounts of optimization to achieve acceptable product purity. Typically, large volumes of reagents and biological materials are needed for testing different parameters, thus adding to the expense of biopharmaceutical process development. This study demonstrates a versatile and customizable microscale column (µCol) for biopharmaceutical separations using immobilized metal affinity chromatography (IMAC) as an example application to identify key parameters
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The absolute configuration of the naturally occurring isomers of 6beta-benzoyloxy-3alpha-tropanol (1) has been established by the combined use of chiral high-performance liquid chromatography with ...electronic circular dichroism detection and optical rotation detection. For this purpose (±)-1, prepared in two steps from racemic 6-hydroxytropinone (4), was subjected to chiral high-performance liquid chromatography with electronic circular dichroism and optical rotation detection allowing the online measurement of both chiroptical properties for each enantiomer, which in turn were compared with the corresponding values obtained from density functional theory calculations. In an independent approach, preparative high-performance liquid chromatography separation using an automatic fraction collector, yielded an enantiopure sample of OR(+)-1 whose vibrational circular dichroism spectrum allowed its absolute configuration assignment when the bands in the 1100-950 cm-1 region were compared with those of the enantiomers of esters derived from 3alpha,6beta-tropanediol. In addition, an enantiomerically enriched sample of 4, instead of OR(±)-4, was used for the same transformation sequence, whose high-performance liquid chromatography follow-up allowed their spectroscopic correlation. All evidences lead to the OR(+)-(1S,3R,5S,6R) and OR(-)-(1R,3S,5R,6S) absolute configurations, from where it follows that samples of 1 isolated from Knightia strobilina and Erythroxylum zambesiacum have the OR(+)-(1S,3R,5S,6R) absolute configuration, while the sample obtained from E. rotundifolium has the OR(-)-(1R,3S,5R,6S) absolute configuration.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•This review compares the kinetic performance of modern LC and SFC approaches.•The upper pressure limit of monolithic columns should be extended to 400–600bar.•Columns packed with superficially ...porous particles are very powerful in both LC and SFC.•Modern SFC systems still need to be optimized (lower σext2 and higher ΔPmax).
In the last few years, there have been a lot of advances in the field of liquid chromatography (LC) and supercritical fluid chromatography (SFC). The intent of this review is to summarize the available approaches including the use of high mobile phase temperature, extended system upper pressure limit, fully porous particles down to sub-2μm, superficially porous particles (SPP) from 1.3 to 5μm, as well as first and second generations silica-based monoliths.
Increasing the mobile phase temperature in LC is one of the most attractive strategies to decrease analysis time, while it is not always the best way to achieve very high plate count. Silica-based monoliths available since 2000, may be more competitive if the upper pressure limit of the column can be extended to 400–600bar (modification of the PEEK cladding). Extending the system pressure in UHPLC beyond 1000bar is a powerful strategy to increase the maximal achievable efficiency in LC, but its impact on throughput remains limited and frictional heating effects should be considered with care. Modern columns packed with SPP introduced in 2007 are attractive in both LC and SFC. Stationary phases packed with 5 and 1.3μm SPP are currently the most promising strategies for high resolution and high throughput separations in LC, respectively. In SFC, columns packed with 2.7μm SPP particles represent a good compromise between throughput and resolution.
Finally, to attain the highest possible kinetic performance in SFC, there is a need to further reduce extra-column band broadening (system dispersion, σext2) down to 10μL2 or less. In addition, the system upper pressure limit should be extended to ∼800bar, to have a sufficient flexibility, particularly when working with a mobile phases containing a relatively high amount of organic solvent (e.g. 20–40% MeOH).
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
PDF
