Wheat germ, a byproduct of the wheat milling industry, as a beneficial source of anti-aging polyamines: A quantitative comparison of various forms

Polyamines have received a lot of attention since the 1990s because of their anti-aging, anti-chronic disease, and proliferative effects. Wheat germ was reported as one of the natural sources of high polyamine, especially spermidine. The current study used three types of wheat germ: group A was industrially separated germ from whole grain, group B was the commercially available germinated wheat germ, and group C was manually separated wheat germ from germinated grain. The polyamine content of putrescine, spermidine, and spermine has been determined using a simplified isocratic LC-MS/MS method. An optimized extraction procedure was performed on all seven samples for obtaining a polyamine-enriched extract. The three dominant carbomylated polyamines were identified by analyzing the extracted samples in order to determine their relative abundance. Wheat germ powders contain the highest amount of polyamines (220-337 μg/g) of which spermidine is one of the most important. Germinated wheat grains, on the other hand, contain the least amount of this polyamine. The commercially available separated wheat germs are suggested as a good nutrition source of these polyamines.

Development and Validation of an Innovative Analytical Approach for the Quantitation of Tris(Hydroxymethyl)Aminomethane (TRIS) in Pharmaceutical Formulations by Liquid Chromatography Tandem Mass Spectrometry

A novel COVID-19 vaccine (BriLife®) has been developed by the Israel Institute for Biological Research (IIBR) to prevent the spread of the SARS-CoV-2 virus throughout the population in Israel. One of the components in the vaccine formulation is tris(hydroxymethyl)aminomethane (tromethamine, TRIS), a buffering agent. TRIS is a commonly used excipient in various approved parenteral medicinal products, including the mRNA COVID-19 vaccines produced by Pfizer/BioNtech and Moderna. TRIS is a hydrophilic basic compound that does not contain any chromophores/fluorophores and hence cannot be retained and detected by reverse-phase liquid chromatography (RPLC)-ultraviolet (UV)/fluorescence methods. Among the few extant methods for TRIS determination, all exhibit a lack of selectivity and/or sensitivity and require laborious sample treatment. In this study, LC−mass spectrometry (MS) with its inherent selectivity and sensitivity in the multiple reaction monitoring (MRM) mode was utilized, for the first time, as an alternative method for TRIS quantitation. Extensive validation of the developed method demonstrated suitable specificity, linearity, precision, accuracy and robustness over the investigated concentration range (1.2−4.8 mg/mL). Specifically, the R2 of the standard curve was >0.999, the recovery was >92%, and the coefficient of variance (%CV) was <12% and <6% for repeatability and intermediate precision, respectively. Moreover, the method was validated in accordance with strict Good Manufacturing Practice (GMP) guidelines. The developed method provides valuable tools that pharmaceutical companies can use for TRIS quantitation in vaccines and other pharmaceutical products.

Identification and Determination of 1,3-Thiazinane-4-carboxylic Acid in Human Urine-Chromatographic Studies

It is well established that homocysteine (Hcy) and its thiolactone (HTL) are reactive towards aldehydes in an aqueous environment, forming substituted thiazinane carboxylic acids. This report provides evidence that Hcy/HTL and formaldehyde (FA) adduct, namely 1,3-thiazinane-4-carboxylic acid (TCA) is formed in vivo in humans. In order to provide definitive proof, a gas chromatography-mass spectrometry (GC-MS) based method was elaborated to identify and quantify TCA in human urine. The GC-MS assay involves chemical derivatization with isobutyl chloroformate (IBCF) in the presence of pyridine as a catalyst, followed by an ethyl acetate extraction of the obtained isobutyl derivative of TCA (TCA-IBCF). The validity of the method has been demonstrated based upon United States Food and Drug Administration recommendations. The assay linearity was observed within a 1-50 µmol L-1 range for TCA in urine, while the lowest concentration on the calibration curve was recognized as the limit of quantification (LOQ). Importantly, the method was successfully applied to urine samples delivered by apparently healthy volunteers (n = 15). The GC-MS assay may provide a new analytical tool for routine clinical analysis of the role of TCA in living systems in the near future.

Structural elucidation of dipeptides displaying limited mass spectral information by liquid chromatography-electrospray ionization-tandem mass spectrometry

Small peptides, such as dipeptides, have attracted attention in many research fields because of their important biological functions and potential roles as disease biomarkers. However, the identification of many of them by implementation of liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) is a challenging task. This is because many dipeptides display limited mass spectral information in LC-ESI-MS/MS analyses, which leads to unavoidable ambiguity in determinations of their structures. In this study, two useful analytical techniques were developed for the structural elucidation of 10 representative dipeptides exhibiting a dominant/single product ion in the ESI-MS/MS spectra of the protonated molecules [M + H]⁺ . Structural elucidation was obtained instantaneously through LC-ESI-MS/MS fragmentation of the accompanying sodium adducts [M + Na]⁺ or alternatively by "in-vial" chemical derivatization with isobutyl chloroformate. The sodium adducts and the resulting carbamate derivatives altered the charge distribution occurring during ESI-MS/MS fragmentation, enabling detailed structural elucidation and unambiguous identification of such dipeptides at ng/ml levels. These quick, simple, and easy techniques can be implemented to identify various dipeptides or confirm their identities without the need for complex sample handling.

Challenges in the identification process of phenidate analogues in LC-ESI-MS/MS analysis: Information enhancement by derivatization with isobutyl chloroformate

A new analytical technique for the structural elucidation of four representative phenidate analogues possessing a secondary amine residue, which leads to a major/single amine-representative fragment/product ion at m/z 84 both in their GC-EI-MS and LC-ESI-MS/MS spectra, making their identification ambiguous, was developed. The method is based on "in vial" chemical derivatization with isobutyl chloroformate in both aqueous and organic solutions, followed by liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS/MS). The resulting carbamate derivatives promote rich fragmentation patterns with full coverage of all substructures of the molecule, enabling detailed structural elucidation and unambiguous identification of the original compounds at low ng/mL levels.

Convenient synthesis of collagen-related tripeptides for segment condensation

Chromatography is a common step in the solution-phase synthesis of typical peptides, as well as peptide fragments for subsequent coupling on a solid support. Combining known reagents that form readily separable byproducts is shown to eliminate this step, which wastes time and other resources. Specifically, activating carboxyl groups with isobutyl chloroformate or as pentafluorophenyl esters and using N-methyl morpholine as a base enable chromatography-free synthetic routes in which peptide products are isolated from byproducts by facile evaporation, extraction, and trituration. This methodology was used to access tripeptides related to collagen, such as Fmoc-Pro-Pro-Gly-OH and Fmoc-Pro-Hyp(tBu)-Gly-OH, in a purity suitable for solid-phase segment condensation to form collagen mimetic peptides.

Kinetic evaluation of the solvolysis of isobutyl chloro- and chlorothioformate esters

The specific rates of solvolysis of isobutyl chloroformate (1) are reported at 40.0 °C and those for isobutyl chlorothioformate (2) are reported at 25.0 °C, in a variety of pure and binary aqueous organic mixtures with wide ranging nucleophilicity and ionizing power. For 1, we also report the first-order rate constants determined at different temperatures in pure ethanol (EtOH), methanol (MeOH), 80% EtOH, and in both 97% and 70% 2,2,2-trifluoroethanol (TFE). The enthalpy (ΔH(≠)) and entropy (ΔS(≠)) of activation values obtained from Arrhenius plots for 1 in these five solvents are reported. The specific rates of solvolysis were analyzed using the extended Grunwald-Winstein equation. Results obtained from correlation analysis using this linear free energy relationship (LFER) reinforce our previous suggestion that side-by-side addition-elimination and ionization mechanisms operate, and the relative importance is dependent on the type of chloro- or chlorothioformate substrate and the solvent.