Hydrophilic interaction liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry for determination of nuclear and cytoplasmatic contents of nucleotides, nucleosides and their nucleobases in food yeasts

An on-line SPE-LC-MS/MS method for quantification of nucleobases and nucleosides present in biological fluids

Solid phase extraction (SPE) and liquid chromatographic (LC) separation of nucleobases and nucleosides are challenging due to the high hydrophilicity of these compounds. Herein we report a novel on-line SPE-LC-MS/MS method for their quantification after pre-column derivatization with chloroacetaldehyde (CAA). The method proposed is selective and sensitive with limits of detection at the nano-molar level. Analysis of urine and saliva samples by using this method is demonstrated. Adenine, guanine, cytosine, adenosine, guanosine, and cytidine were found in the range from 0.19 (guanosine) to 1.83 μM (cytidine) in urine and from 0.015 (guanosine) to 0.79 μM (adenine) in saliva. Interestingly, methylation of cytidine was found to be significantly different in urine from that in saliva. While 5-hydroxymethylcytidine was detected at a very low level (<0.05 μM) in saliva, it was found to be the most prominent methylated cytidine in urine at a high level of 3.33 μM. Since on-line SPE is deployed, the proposed LC-MS/MS quantitative assay is convenient to carry out and offers good assay accuracy and repeatability.

Nucleoside Analogs: A Review of Its Source and Separation Processes

Nucleoside analogs play a crucial role in the production of high-value antitumor and antimicrobial drugs. Currently, nucleoside analogs are mainly obtained through nucleic acid degradation, chemical synthesis, and biotransformation. However, these methods face several challenges, such as low concentration of the main product, the presence of complex matrices, and the generation of numerous by-products that significantly limit the development of new drugs and their pharmacological studies. Therefore, this work aims to summarize the universal separation methods of nucleoside analogs, including crystallization, high-performance liquid chromatography (HPLC), column chromatography, solvent extraction, and adsorption. The review also explores the application of molecular imprinting techniques (MITs) in enhancing the identification of the separation process. It compares existing studies reported on adsorbents of molecularly imprinted polymers (MIPs) for the separation of nucleoside analogs. The development of new methods for selective separation and purification of nucleosides is vital to improving the efficiency and quality of nucleoside production. It enables us to obtain nucleoside products that are essential for the development of antitumor and antiviral drugs. Additionally, these methods possess immense potential in the prevention and control of serious diseases, offering significant economic, social, and scientific benefits to the fields of environment, biomedical research, and clinical therapeutics.

Extraction of Nucleotides from Dietary Supplements by Newly Synthesized Adsorbents

The aim of the study was the synthesis and application of novel adsorbents for the extraction of nucleotides from dietary supplements. Three different adsorbents modified with a silane containing two amine groups and various dicarboxylic acids were synthesized and characterized using various instrumental techniques. Next, different solvents were tested for their adsorption and desorption of five nucleotides. The results showed that the efficiency of both processes depends on the conditions used and the type of dicarboxylic acid bound to the surface of the adsorbent. The best results were obtained for succinic acid. The most effective adsorption occurred for water acidified with acetic acid to pH 4.5, while the highest recoveries (85-102%) with high reproducibility were obtained for 10 mM ammonium acetate at pH 9. The nucleotide extraction was performed simply by changing the charge at the adsorbent surface, providing the possibility of electrostatic attraction and repulsion between the adsorbent and nucleotides. Moreover, the sorption capacity of the obtained materials was also determined, which was essential for their use in extracting nucleotides from real samples by dispersive extrusion to the solid phase. The new adsorbents and the developed extraction method were successfully applied to isolate nucleotides from two different dietary supplements with different compositions (one of them with yeast strains). The method is simple and reproducible; no organic solvents or high-concentration inorganic salts are used (it is environmentally friendly). The entire process is performed in one centrifuge tube and is cheaper compared with methods used so far.

A comparison of hydrophilic interaction liquid chromatography and capillary electrophoresis for the metabolomics analysis of human serum

Cationic, anionic, zwitterionic and, partially polar metabolites are very important constituents of blood serum. Several of these metabolites underpin the core metabolism of cells (e.g., Krebs cycle, urea cycle, proteins synthesis, etc.), while others might be considered ancillary but still important to grasp the status of any organism through blood serum analysis. Due to its wide chemical diversity, modern metabolomics analysis of serum is still struggling to provide a complete and comprehensive picture of the polar metabolome, due to the limitations of each specific analytical method. In this study, two metabolomics-based analytical methods using the most successful techniques for polar compounds separation in human serum samples, namely hydrophilic interaction liquid chromatography (HILIC) and capillary electrophoresis (CE), are evaluated, both coupled to a high-resolution time-of-flight mass spectrometer via electrospray ionization (ESI-Q-TOF-MS). The performance of the two methods have been compared using five terms of comparison, three of which are specific to metabolomics, such as (1) compounds' detectability (2) Pezzatti score (Pezzatti et al. 2018), (3) intra-day precision (repeatability), (4) ease of automatic analysis of the data (through a common deconvolution alignment and extrapolation software, MS-DIAL, and (5) time & cost analysis. From this study, HILIC-MS proved to be a better tool for polar metabolome analysis, while CE-MS helped identify some interesting variables that gave it interest in completing metabolome coverage in metabolomics studies. Finally, in this framework, MS-DIAL demonstrates for the first time its ability to process CE data for metabolomics, although it is not designed for it.

Integrated LC-MS and network pharmacology methods to screen quantitative indicators in the Hippocampus histrix Kaup and method transfer

Hippocampus histrix Kaup is a popular marine medicine with high medicinal and healthcare values. In this study, liquid chromatography-mass spectrometry (LC-MS) analysis combined with network pharmacological method was used to screen for suitable quantitative indicators for the quality control of H. histrix Kaup. Firstly, an LC-MS analytical method for the simultaneous determination of 12 nucleosides in extracts of H. histrix Kaup was established. And then, a network pharmacological method incorporated target prediction, protein-protein interaction network, components-targets network, and targets-pathways network was performed to screen for quantitative indicators. Finally, the developed LC-MS method was transferred to liquid chromatographs to improve the generalizability of the method. All 12 nucleotides were authenticated in extracts of H. histrix Kaup by comparing with the standards. The optimal chromatographic separation conditions are as follows: the chromatographic separation was achieved on an Acquire BEH-C18 column (2.1 mm * 100 mm, 1.7 µm) and gradient elution was performed using methanol solution and buffer (0.30% formic acid and 10 mmol/L ammonium acetate) as mobile phase at a flow rate of 0.15 mL/min and an acquisition wavelength of 260 nm. Network pharmacology results showed that adenosine, and uridine show excellent pharmacological activity. Integration the content, correlation, chromatographic separation, and pharmacological activity of each compound in H. histrix Kaup, uridine and adenosine were tentatively determined as quantitative indicators for quality control in H. histrix Kaup. The established LC-MS method was successfully transferred to liquid chromatographs, and the method is stable and reliable for the quality control of H. histrix Kaup. This developed integrated strategy was successfully used to screen quantitative indicators in the H. histrix Kaup.