scholarly journals Chiral Alkaloid Analysis

2021 ◽  
Author(s):  
Ngoc Van Thi Nguyen ◽  
Kim Ngan Huynh Nguyen ◽  
Kien Trung Nguyen ◽  
Kyeong Ho Kim ◽  
Hassan Y. Aboul-Enein
Keyword(s):  
Liquid Chromatography ◽  
Plant Growth ◽  
Stationary Phases ◽  
Racemic Mixture ◽  
Theoretical Studies ◽  
Chiral Compounds ◽  
First Choice ◽  
Wide Range ◽  
Plant Growth Stimulants ◽  
Or Applications

Alkaloids are distributed in plant kingdom and play important role in protection, germination as well as plant growth stimulants. Most of them are chiral compounds and are clinically administered as the racemic mixture, even though its enantiomers have been known to exert different pharmacological activity. Liquid chromatography using chiral stationary phases (CSP) proved to be an essential tool with a wide range of applications, including analysis of the stereochemistry of natural compounds. This review gives an overview of chiral separation alkaloids that were used in theoretical studies and/or applications in recent years. It shows the possibilities of polysaccharide CSPs have now also been established as the first-choice of chiral phases for enantiomer separation.

scholarly journals Liquid Chromatography Study on Atenolol--Cyclodextrin Inclusion Complex

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Shailesh M. Buha ◽  
Girin A. Baxi ◽  
Pranav S. Shrivastav
Keyword(s):  
Liquid Chromatography ◽  
Complex Formation ◽  
Inclusion Complex ◽  
Stationary Phases ◽  
Inclusion Complexation ◽  
Dispersion Interactions ◽  
Column Temperature ◽  
Retention Factors ◽  
Wide Range ◽  
London Dispersion

Inclusion complex formation of atenolol with -cyclodextrin (-CD) has been investigated by HPLC on different stationary phases, by varying pH and concentration of -CD added as an additive in the mobile phase over a wide range of column temperature. Stationary phases of different polarity and hydrophobicity were evaluated to find the best conditions for complex formation. The optimum conditions for inclusion complexation were achieved on YMC ODS-AQ C18 ( mm, 5 μ) analytical column. The apparent formation constant () of the complex as evaluated by liquid chromatography using retention factors () was  M−1 at 25°C. The stoichiometry of the complex was 1 : 1 as is evident from the straight line plot of 1/ versus -CD concentration. The formation of inclusion complex was essentially enthalpy (−42.12 kJ/mol) driven and the binding forces included hydrophobic, van der Waals-London dispersion interactions. The enthalpy-entropy compensation criterion was used to prove the inclusion phenomena.

scholarly journals The impact of chirality on the analysis of alkaloids in plant

Pharmacia ◽  
2021 ◽  
Vol 68 (3) ◽  
pp. 643-656
Author(s):  
Ngoc-Van Thi Nguyen ◽  
Kim-Ngan Huynh Nguyen ◽  
Kien Trung Nguyen ◽  
Kyeong Ho Kim ◽  
Hassan Y. Aboul-Enein
Keyword(s):  
Pharmacological Activity ◽  
Enantiomeric Composition ◽  
Chiral Analysis ◽  
Racemic Mixture ◽  
Theoretical Studies ◽  
Chiral Compounds ◽  
Points Of View ◽  
The Impact

Most of the alkaloids are chiral compounds and are clinically administered as the racemic mixture, even though its enantiomers have been known to exert different pharmacological activity. The determination of the enantiomeric composition of alkaloid-containing plants is subject to severe attention from pharmacological and toxicological points of view. This review gives an overview of the chiral analysis of alkaloids that were used in theoretical studies and applications for plants in recent years.

scholarly journals Liquid Chromatographic Enantioseparations Utilizing Chiral Stationary Phases Based on Crown Ethers and Cyclofructans

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4648
Author(s):  
Róbert Berkecz ◽  
Gábor Németi ◽  
Antal Péter ◽  
István Ilisz
Keyword(s):  
Liquid Chromatography ◽  
Crown Ethers ◽  
High Performance ◽  
Structural Characteristics ◽  
Stationary Phases ◽  
Chiral Stationary Phases ◽  
Food Samples ◽  
Chiral Compounds ◽  
Amine Compounds ◽  
Liquid Chromatographic

Natural compounds can exist in different forms, where molecules possessing chirality play an essential role in living organisms. Currently, one of the most important tasks of modern analytical chemistry is the enantioseparation of chiral compounds, in particular, the enantiomers of compounds having biological and/or pharmaceutical activity. Whether the task is to analyze environmental or food samples or to develop an assay for drug control, well-reproducible, highly sensitive, stereoselective, and robust methods are required. High-performance liquid chromatography best meets these conditions. Nevertheless, in many cases, gas chromatography, supercritical fluid chromatography, or capillary electrophoresis can also offer a suitable solution. Amino acids, proteins, cyclodextrins, derivatized polysaccharides, macrocyclic glycopeptides, and ion exchangers can serve as efficient selectors in liquid chromatography, and they are quite frequently applied and reviewed. Crown ethers and cyclofructans possessing similar structural characteristics and selectivity in the enantiodiscrimination of different amine compounds are discussed less frequently. This review collects information on enantioseparations achieved recently with the use of chiral stationary phases based on crown ethers or cyclofructans, focusing on liquid chromatographic applications.

The Stabilizing Effect of Pre-Equilibria: A Trifluoromethyl Complex as CF2 Reservoir in Catalytic Olefin Difluorocarbenation

2020 ◽  
Author(s):  
Thomas Louis-Goff ◽  
Huu Vinh Trinh ◽  
Eileen Chen ◽  
Arnold L. Rheingold ◽  
Christian Ehm ◽  
...  
Keyword(s):  
High Selectivity ◽  
Side Reactions ◽  
Theoretical Studies ◽  
Attractive Feature ◽  
Catalyst Recovery ◽  
Wide Range ◽  
Stabilizing Effect ◽  
Experimental And Theoretical Studies

A new, efficient, catalytic difluorocarbenation of olefins to give 1,1-difluorocyclopropanes is presented. The catalyst, an organobismuth complex, uses TMSCF<sub>3</sub> as a stoichiometric difluorocarbene source. We demonstrate both the viability and robustness of this reaction over a wide range of alkenes and alkynes, including electron-poor alkenes, to generate the corresponding 1,1-difluorocyclopropanes and 1,1-difluorocyclopropenes. Ease of catalyst recovery from the reaction mixture is another attractive feature of this method. In depth experimental and theoretical studies showed that the key difluorocarbene-generating step proceeds through a bismuth non-redox synchronous mechanism generating a highly reactive free CF<sub>2</sub> in an endergonic pre-equilibrium. It is the reversibility when generating the difluorocarbene that accounts for the high selectivity, while minimizing CF<sub>2</sub>-recombination side-reactions.

Analysis of Aromatic Amines in Industrial Wastewater by Capillary Gas Chromatography-Mass Spectrometry

2000 ◽  
Vol 35 (2) ◽  
pp. 245-262 ◽  
Author(s):  
Francis I. Onuska ◽  
Ken A. Terry ◽  
R. James Maguire
Keyword(s):  
Gas Chromatography ◽  
Aromatic Amines ◽  
Methylene Chloride ◽  
Solid Phase ◽  
Stationary Phases ◽  
Gas Chromatography Mass Spectrometry ◽  
Substituted Anilines ◽  
Environmental Media ◽  
Solid Phase Extraction Cartridge ◽  
Wide Range

Abstract The analysis of aromatic amines, particularly benzidines, at trace levels in environmental media has been difficult because of the lack of suitable deactivated capillary column stationary phases for gas chromatography. This report describes the use of an improved type of column as well as a method for the analysis of anilines and benzidines in water, wastewater and sewage samples. Extraction procedures are applicable to a wide range of compounds that are effectively partitioned from an aqueous matrix into methylene chloride, or onto a solid-phase extraction cartridge. The extracted analytes are also amenable to separation on a capillary gas chromatographic column and transferable to the mass spectrometer. These contaminants are converted to their N-trifluoroacetyl derivatives. Aniline and some substituted anilines, and 3,3’-dichlorobenzidine and benzidine were determined in 24-h composite industrial water, wastewater, primary sludge and final effluent samples at concentrations from 0.03 up to 2760 µg/L.

Phytochemical, Analytical and Medicinal Studies of Holoptelea integrifolia Roxb. Planch - A Review

2019 ◽  
Vol 5 (4) ◽  
pp. 270-277 ◽  
Author(s):  
Vijay Kumar ◽  
Simranjeet Singh ◽  
Ragini Bhadouria ◽  
Ravindra Singh ◽  
Om Prakash
Keyword(s):  
Liquid Chromatography ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
High Performance ◽  
Biologically Active ◽  
Toxicological Studies ◽  
Wide Range ◽  
Layer Chromatography

Holoptelea integrifolia Roxb. Planch (HI) has been used to treat various ailments including obesity, osteoarthritis, arthritis, inflammation, anemia, diabetes etc. To review the major phytochemicals and medicinal properties of HI, exhaustive bibliographic research was designed by means of various scientific search engines and databases. Only 12 phytochemicals have been reported including biologically active compounds like betulin, betulinic acid, epifriedlin, octacosanol, Friedlin, Holoptelin-A and Holoptelin-B. Analytical methods including the Thin Layer Chromatography (TLC), High-Performance Thin Layer Chromatography (HPTLC), High-Performance Liquid Chromatography (HPLC) and Liquid Chromatography With Mass Spectral (LC-MS) analysis have been used to analyze the HI. From medicinal potency point of view, these phytochemicals have a wide range of pharmacological activities such as antioxidant, antibacterial, anti-inflammatory, and anti-tumor. In the current review, it has been noticed that the mechanism of action of HI with biomolecules has not been fully explored. Pharmacology and toxicological studies are very few. This seems a huge literature gap to be fulfilled through the detailed in-vivo and in-vitro studies.

scholarly journals Growth Promotion or Osmotic Stress Response: How SNF1-Related Protein Kinase 2 (SnRK2) Kinases Are Activated and Manage Intracellular Signaling in Plants

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1443
Author(s):  
Yoshiaki Kamiyama ◽  
Sotaro Katagiri ◽  
Taishi Umezawa
Keyword(s):  
Protein Kinase ◽  
Plant Growth ◽  
Osmotic Stress ◽  
Protein Function ◽  
Intracellular Signaling ◽  
Growth Promotion ◽  
Research Field ◽  
Dependent Manner ◽  
Related Protein ◽  
Wide Range

Reversible phosphorylation is a major mechanism for regulating protein function and controls a wide range of cellular functions including responses to external stimuli. The plant-specific SNF1-related protein kinase 2s (SnRK2s) function as central regulators of plant growth and development, as well as tolerance to multiple abiotic stresses. Although the activity of SnRK2s is tightly regulated in a phytohormone abscisic acid (ABA)-dependent manner, recent investigations have revealed that SnRK2s can be activated by group B Raf-like protein kinases independently of ABA. Furthermore, evidence is accumulating that SnRK2s modulate plant growth through regulation of target of rapamycin (TOR) signaling. Here, we summarize recent advances in knowledge of how SnRK2s mediate plant growth and osmotic stress signaling and discuss future challenges in this research field.

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