Chemical Papers最新文献

A novel, rapid, selective, ultrasensitive, and ultra-reproducible spectrofluorometric nanoassay was designed for the L-methionine quantification. A carbon dot with a %QY as high as 95% was prepared using a solvent-free ultrafast method and used as the label-free nanoprobe. The nanoprobe was characterized for size, morphology, elemental composition, optical properties, and quantum efficiency. Afterward, the nanoprobe was utilized for quantification of L-methionine in biological samples, revealing an ultra-wide linear range of 0.0–140.0 nm with a LOD as low as 0.65 nM. Besides, the developed method showed ultra-reproducibility with an inter-week assay, of RSD = 2.7% and high repeatability with a RSD as low as 1.0%. The mechanistic studies proved the simultaneous formation of two complexes between CDs and L-methionine, resulting in high sensitivity, selectivity, and stability of the sensor. Moreover, a binding constant as high as 1.4 × 10⁺⁶ M⁻¹, number of binding sites of 1.5, and a ∆G of − 35.1 was obtained for interaction between CDs and L-methionine. Finally, the developed method was utilized for analysis of the methionine content of human serum samples for both healthy and patients with homocystinuria for proving its possible application in homocystinuria diagnosis, showing highly accurate and reproducible results. Consequently, the proposed nanoassay can be applied for clinical practical applications toward homocystinuria diagnosis.

Althaea officinalis L. has been widely used traditionally as an herbal tea and for the treatment of cough, mucous membrane irritation, colds, and inflammation. Parts of the plant extracts were analyzed using HPLC-DAD and HPLC-MS/MS. The total phenolic content, radical scavenging activities, and enzyme inhibitions (urease and xanthine oxidase) of the extracts were determined spectroscopically. The main molecules of this plant and their 3D structures were built using the LigPrep module of Schrödinger Maestro 11.5 with the OPLS3 force field. Additionally, these molecules were analyzed for various physical descriptors and pharmaceutically relevant properties for ADME prediction using the QikProp tool of the Schrodinger Suite. Through HPLC-DAD-MS analysis, abundant compounds such as hesperidin, epigallocatechin, myricetin, and apigenin-7-glucoside were detected in the extracts. Moreover, the methanol extracts from the flowers showed a higher inhibition effect on xanthine oxidase (XO). In silico results indicated that the thirteen molecules exhibited strong inhibitory activity toward XO. However, according to the ADME results, the overall compounds, except for rutin and hesperidin, displayed low values of violations of Lipinski's rule of five and predicted pharmacokinetic parameters. They also exhibited drug-likeness features with minimal violations. The HPLC-DAD-MS/MS analysis of the extracts from Althaea officinalis revealed a rich phenolic content in this plant. These therapeutic and preventive compounds may be worth considering for isolation and further exploration as natural remedies.

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Guanidinium benzilate (GBA) and benzylammonium benzilate (BABA) have been prepared from guanidinium carbonate and benzylamine/benzilic acid (BA). GBA has inter-ionic, intraionic and intermolecular hydrogen bondings giving a three-dimensional supramolecular assembly. The carboxylate ion is present in the resonance form with C–O distances of 1.242 and 1.246 Å in GBA, whereas the C–O distances being 1.262 and 1.245 Å in BABA. In BABA, an inverted dimer with inter-ionic hydrogen bonding exist as a dimer with supramolecular assembly due to intermolecular hydrogen bonding between the ion pairs. So the counter cation decides the resonance form of the carboxylate ion, hydrogen-bonding network and the disposition of the phenyl rings in the benzilate and benzyl moiety. The IR, ¹H NMR and ¹³C NMR spectral data have been interpreted using the crystal structure data and by the comparison between the two similar derivatives. Both the compounds show the formation of the ammonium benzilate or methylammonium benzilate moiety which decompose leaving no residue. Both the compounds exhibit the emission at 442 nm (blue) and 547.2 nm (green) on excitation at 257 nm. Chromaticity indicated excellent emission characteristics of both GBA and BABA which is necessary for OLED applications.

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