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Analysis of Essential Oils
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Adriana Arigò, Mariosimone Zoccali, Danilo Sciarrone, Peter Q. Tranchida, Paola Dugo, Luigi Mondello
The advantage on the application of Es-GC lies mainly in its high separation efficiency and sensitivity, simple detection, unusually high precision and reproducibility, and also the need for a small amount of sample. Moreover, its main use is related with the characterization of the enantiomeric composition and the determination of the enantiomeric excess (ee) and/or ratio (ER) of chiral research chemicals, intermediates, metabolites, flavors and fragrances, drugs, pesticides, fungicides, herbicides, pheromones, etc. Information on ee or ER is of great importance to characterize natural flavor and fragrance materials, such as essential oils, since the obtained values are useful tools, or even “fingerprints,” for the determination of their quality, applied extraction technique, geographic origin, biogenesis, and also authenticity (Dugo et al., 1992).
On Biocatalysis as Resourceful Methodology for Complex Syntheses: Selective Catalysis, Cascades and Biosynthesis
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
Andreas Sebastian Klein, Thomas Classen, Jörg Pietruszka
Enzymes are often associated with the term “green chemistry” because they are natural, biological degradable and so on. However, it must be considered that enzymes are usually used in aqueous solutions causing downstream challenges: energy consuming evaporation or salt/solvent contaminated wastewater. These drawbacks may be taken into account if the synthesis profits from an enzyme’s selectivity, which is in many cases much higher than the selectivity of competing chemical catalysts. Enzymes may install chemical moieties by their chemoselectivity and may bypass step-intensive protective strategies. Stereogenic centers might be installed with high selectivity by means of asymmetric synthesis or the enantiomeric excess can be increased to pharmaceutical relevance by means of kinetic resolution.
Investigation of the enantioselectivity of acetylcholinesterase and butyrylcholinesterase upon inhibition by tacrine-iminosugar heterodimers
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2023
I. Caroline Vaaland, Óscar López, Adrián Puerta, Miguel X. Fernandes, José M. Padrón, José G. Fernández-Bolaños, Magne O. Sydnes, Emil Lindbäck
No obvious enantioselectivity of eeAChE and eqBuChE was observed for the three pairs of enantiomeric inhibitors included in this study. In addition, no preferential inhibitory activity trend was found for the enantiomers incorporating a DAB or LAB moiety. For instance, 9a is a ca. 4-fold more potent eeAChE inhibitor than its enantiomer 9b, whereas 10b is a ca. 4-fold more potent eeAChE inhibitor than its enantiomer 10a. For the enantiomeric pair 11a and 11b, we observed essentially equal eeAChE inhibitory activities. These observations indicate that the impact on the eeAChE inhibitory potency of our heterodimers by switching between a DAB and LAB moiety is small compared to the contribution from the tacrine ring.
Chemical composition, enantiomeric analysis and anticholinesterase activity of Lepechinia betonicifolia essential oil from Ecuador
Published in Pharmaceutical Biology, 2022
James Calva, Luis Cartuche, Salomé González, José Vinicio Montesinos, Vladimir Morocho
Essential oils (EO) are a mixture of complex volatile compounds, synthesised by various parts of the plant (Akthar et al. 2014), they have an aromatic nature due to a mixture of multiple chemical substances, including terpenes, aldehydes, alcohols, esters, phenolics, ethers, and ketones (Degenhardt et al. 2009). The chemical composition of an EO can vary from species to species and even due to different ecological conditions and is responsible for a plant’s sensorial and biological properties (Perrino et al. 2021). Variation also depends on the part collected and employed for extraction as well as the mode of culturing (Santo-Gómes and Fernandes-Ferreria 2001), ecotypes (subpopulations genetically differentiated) (Barra 2009), management conditions as post-harvesting, processing and extraction method that can affect the types and amounts of compounds detected (Zhang and Guo 2020). Furthermore, several components in an EO are chiral compounds, often occurring as pure enantiomers or in an enantiomeric excess and, seldom, in racemic form (Finefield et al. 2012).
Stereoselective pharmacokinetics and tissue distribution of levodropropizine after administration of pure levodropropizine and the rac-dropropizine to Sprague–Dawley rats
Published in Xenobiotica, 2020
Bhavesh Babulal Gabani, Umesh Todmal, Neeraj Kumar Saini, Vinod A. Balakrishna, Suresh P. Sulochana, Ashok Timmapuram, Mohd Zainuddin, Narayanan Balaji, Praharaj Shuvranshu, Nuggehally R. Srinivas, Ramesh Mullangi
Hundred milligrams of rac-dropropizine was dissolved in 4 mL of mobile phase and loaded on preparative Chiralpak IA column (250 × 20 mm; 5 μm) using n-hexane:ethanol with 0.1% diethyl amine (80:20, v/v) as a mobile phase at a flow-rate of 18 mL/min on an Agilent 1260 Infinity Prep HPLC instrument (Agilent Technologies, Palo Alto, CA). The first eluted enantiomer was LDP (confirmed with retention time of the pure LDP procured from Combi-Blocks) and the later was DDP. Chiral purity of both the enantiomers was checked in Analytical Chemistry Department, Jubilant Biosys and found that the purity was >99% (ee: 99.95%).