1.High-performance liquid chromatographic enantioseparation of cyclic β-aminohydroxamic acids on zwitterionic chiral stationary phases based on Cinchona alkaloids.
Lajkó G1, Orosz T2, Grecsó N1, Fekete B3, Palkó M3, Fülöp F3, Lindner W4, Péter A2, Ilisz I5. Anal Chim Acta. 2016 May 19;921:84-94. doi: 10.1016/j.aca.2016.03.044. Epub 2016 Apr 7.
Cyclic β-aminohydroxamic acid enantiomer pairs were stereoselectively separated by high-performance liquid chromatography on the recently developed Cinchona alkaloid-based zwitterionic chiral stationary phases Chiralpak ZWIX(+)™, ZWIX(-)™, ZWIX(+A) and ZWIX(-A). The results of variation of the applied chromatographic conditions, such as the bulk solvent composition, the concentrations and ratio of the acid and base additives, the presence of water as mobile phase additive and the counter-ion concentration furnished a better understanding of the retention mechanism. A thermodynamic study in the temperature range 5-50 °C revealed enthalpy-controlled enantiodiscrimination in all cases. The structure-selectivity relationships clearly indicated the importance of the strereochemistry of the functional groups. From an enantiorecognition aspect, the diexo position of the functional groups always proved more favorable than the diendo position. The elution sequence was determined in all cases and was found to reversed when ZWIX(+)™ was changed to ZWIX(-)™ or ZWIX(+A) to ZWIX(-A).
2.Facilitation of Hippocampal Kindling and Exacerbation of Kindled Seizures by Intra-CA1 Injection of Quinine: A Possible Role of Cx36 Gap Junctions.
Etemadi F1,2, Sayyah M1, Gholami Pourbadie H1, Babapour V2. Iran Biomed J. 2016 Apr 25.Pii-IBJ-A-10-49-6. [Epub ahead of print]
BACKGROUND: GABAergic interneurons in the hippocampal CA1 area are mutually communicated by gap junctions (GJs) composed of connexin36 (Cx36). We examined the role of Cx36 in CA1 in manifestation of kindled seizures and hippocampal kindling in rats.
3.Regulation of Adipogenesis by Quinine through the ERK/S6 Pathway.
Ning X1, He J2, Shi X3, Yang G4. Int J Mol Sci. 2016 Apr 13;17(4). pii: E504. doi: 10.3390/ijms17040504.
Quinine is a bitter tasting compound that is involved in the regulation of body weight as demonstrated in in vivo animal models and in vitro models of the adipogenic system. Arguments exist over the positive or negative roles of quinine in both in vivo animal models and in vitro cell models, which motivates us to further investigate the functions of quinine in the in vitro adipogenic system. To clarify the regulatory functions of quinine in adipogenesis, mouse primary preadipocytes were induced for differentiation with quinine supplementation. The results showed that quinine enhanced adipogenesis in a dose dependent manner without affecting lipolysis. The pro-adipogenic effect of quinine was specific, as other bitter tasting agonists had no effect on adipogenesis. Moreover, the pro-adipogenic effect of quinine was mediated by activation of ERK/S6 (extracellular-signal-regulated kinase/Ribosomal protein S6) signaling. Knockdown of bitter taste receptor T2R106 (taste receptor, type 2, member 106) impaired the pro-adipogenic effect of quinine and suppressed the activation of ERK/S6 signaling.
4.Quinine-Catalyzed Asymmetric Synthesis of 2,2'-Binaphthol-Type Biaryls under Mild Reaction Conditions.
Moliterno M1, Cari R1, Puglisi A1, Antenucci A1, Sperandio C1, Moretti E1, Di Sabato A1, Salvio R2,3, Bella M4. Angew Chem Int Ed Engl. 2016 Apr 20. doi: 10.1002/anie.201601660. [Epub ahead of print]
Simple quinine as an organocatalyst mediates the addition of various naphthols to halogenated quinones to afford non-C2 -symmetrical, axially chiral biaryl products, which are promising compounds as chiral ligands and organocatalysts. The rotational barrier required to have two distinct atropisomers has been evaluated in the products generated from the addition of naphthols to various quinones by means of DFT calculations and HPLC. The use of halogenated quinones as reagents was necessary to have configurationally stable enantiomeric products which can be obtained in good yield and stereoselectivity. These compounds have also been prepared in gram quantities and recrystallized to near enantiopurity.
