Search Results (137)

Lactic acid is a widely used component in cosmetics such as hair care products. High concentration of lactic acid or inappropriate enantiomeric form can have a negative impact on the skin. This study focuses on the development of methods of analysis for the separation, enantioseparation and determination of lactic acid in cosmetics and the confirmation of its enantiomeric form. Achiral reversed-phase high-performance liquid chromatography (RP-HPLC) on a C18 stationary phase and hydrophilic interaction liquid chromatography (HILIC) on an amino-propyl stationary phase, combined with diode array detection (DAD; 210 nm), were applied for analysis. Chiral HPLC-DAD on a teicoplanin-based stationary phase was an effective method for verification of the enantiomeric form, confirming L-lactic acid in tested samples. The complex samples were treated by solid-phase extraction using an anion-exchange adsorbent. Recovery studies showed good results, 76.1–91.8% (RSD ≤ 5.0%). The methods provide linearity of response in the concentration ranges tested (R² > 0.996). This study demonstrated several approaches to the HPLC-DAD determination of lactic acid and proposed an effective sample preparation procedure. Developed methods were rapid, simple and applicable in the routine analysis of cosmetics for monitoring the safety of products. Full article

Monohalogen-substituted (F-, Cl-, Br-) phenylethylamine derivates are a valuable class of chiral compounds, e.g., for C-C-coupling reactions, which are the basis for multiple pharmaceuticals and resolving agents. Here, the solid phase behavior of the underlying phenylethylamine derivates, especially of the corresponding hydrochloride salts, is highly relevant as those compounds are often applied in enantiopure form during the production processes. In this study, the solid phase behavior of 20 synthesized chiral phenylethylamine hydrochloride derivates (both enantiomers and racemates) was investigated including detailed information regarding melting behavior, powder X-ray diffraction data and the type of the chiral system present. Further, the binary melt phase diagram of a found conglomerate system and two novel enantiomer crystal structures were determined. This study is aimed at revealing structure–phase behavior relationships for the 20 monohalogen-substituted compounds investigated as well as providing basic solid–phase-related data required for later crystallization-based enantioseparation processes. Full article

The synthesis and phase behavior of two liquid crystalline racemates containing four aromatic rings, differing in the number of methylene groups, were reported. These materials form smectic phases, as was confirmed by dielectric spectroscopy. The mesomorphic properties of the studied racemates were compared with those of the appropriate (S) enantiomers previously synthesized. Since these materials are racemic mixtures, they were subjected to chiral separation by high-performance liquid chromatography. This research was conducted on two chiral columns based on polysaccharides. We identified optimal conditions that enable the baseline separation of these racemates, which can be scaled up for preparative purposes. Then, there is no need for repeated synthesis of chiral equivalents. Full article

In addition to well-known traditional synthetic illicit drugs like cocaine, amphetamines, and heroin, an increasing number of new psychoactive substances (NPS) are appearing on the global drug market. Among them, cathinones represent a prominent class. These amphetamine-like compounds contain a stereogenic center, resulting in the possible presence of two enantiomers. Pure enantiomers of cathinone derivatives are not commonly available, and their production is cost-intensive. Thus, there is very little knowledge about the possible distinct effects of single enantiomers of cathinones. The objective of this study was to evaluate the stability of a set of eight cathinone derivatives, namely 3-methylethcathinone, 3-methylmethcathinone, 4-methylethcathinone, 4-methylmethcathinone, ethylone, 3,4-trimethylene-α-ethylaminovalerophenone, 3,4-tetramethylene-α-pyrrolidinovalerophenone, and 3,4-trimethylene-α-pyrrolidinobutiophenone, over a six-month period. Any racemization that may have occurred under different storage and solution conditions was monitored and compared. Pure enantiomeric fractions were collected on a multi-milligram scale using semi-preparative HPLC under isocratic normal-phase conditions. A Phenomenex Lux^® i-Cellulose-5, 5 μm 250 × 10 mm column containing cellulose tris(3,5-dichlorophenylcarbamate) served as the chiral selector. The tests showed that aqueous conditions, pH, temperature, chemical structure, sunlight, and oxygen influence compound stability. The long-term storage of cathinone derivative enantiomers was found to be optimal as solids under deep-freezing conditions or in a slightly acidified solvent where they are protected from air and light. Full article

Chemical complexity is not a nuisance to be minimized in origin of life research, it is an enabling condition. This second edition of the Special Issue on the Origin of Life in Chemically Complex Messy Environments gathers contributions that embrace multicomponent mixtures, dynamic geochemical settings, and nonequilibrium processes. The papers collected here survey surface hydrothermal routes to reactive nitriles, groundwater evolution of alkaline lakes, and transition metal sulfide-driven amino acid and amide formation without cyanide. They report one pot nucleoside and nucleotide synthesis from formamide over cerium phosphate, review non aqueous organophosphorus pathways, and probe peptide rich mixtures and formose type networks under serpentinization associated minerals. The issue also advances conceptual frameworks, including atmospheric photochemical signatures for biosignature discrimination, the role of chiral mineral surfaces in enantioseparation, and computational simulations of the origin of LUCA. Together, these studies position messy chemistry as a crucible that turns chemical diversity and environmental heterogeneity into routes toward organization and function. Full article

Chiral materials have shown promising application prospects across various disciplines in recent years due to their unique structural asymmetry and the resulting chiral dependence in optical, electrical, and biomedical applications. However, the existing literature lacks a unified summary of its applications in different fields. This review systematically introduces the applications of chiral materials in optics, electricity, quantum science, and biomedicine. Based on circular dichroism and chiral inversion aggregation-induced emission, chiral materials enable efficient circularly polarized light emission/detection, advancing chiral perovskite and spin light-emitting diodes. In quantum science, in-depth studies of the chiral-induced spin-selectivity effect and chiral topological superconductors support spintronic devices and quantum computing. They facilitate the development of high-efficiency energy conversion devices and high-performance chiral electrochemical sensors. In biomedicine, they excel in enantioseparation, targeted drug delivery, and theranostics. In the future, chiral materials will develop towards multi-functional integration, intelligent response, and high-performance devices. Their in-depth applications in three-dimensional display technology, low-power spin storage devices, green catalytic systems, and precision medicine will provide innovative solutions to energy, environmental, and health challenges. Full article

Tetrahydroprotoberberine alkaloids (THPBs) are bioactive natural products bearing stereogenic centers that frequently exhibit enantiomer-specific pharmacological effects. Xylopinine (XPN), a representative THPB, shows cytotoxic, antimicrobial, and antimalarial activity in vitro, and displays pronounced stereoselectivity in vivo, with the naturally occurring (S)-enantiomer emphasizing the need for reliable enantioselective analysis. In this study, we present the synthesis of racemic XPN from norlaudanosine, and its first comprehensive cyclodextrin-assisted capillary electrophoresis screening dedicated to the enantioseparation of XPN. Sulfated- and sulfobutyl-ether-β-cyclodextrin (S-β-CyD, SBE-β-CyD) provided efficient resolution (R_s > 3), while heptakis-(6-deoxy-6-(2-carboxyethyl)thio)-β-CyD (subetadex, SBX) yielded outstanding separation (R_s > 9). The enantiomer migration order was consistently R,S, except when using SBE-β-CyD, which showed the inverse sequence. Chiral HPLC using a Chiralpak AD column in polar organic mode with methanol modified with 0.1% diethylamine as mobile phase enabled the semi-preparative isolation of XPN enantiomers, with the (S)-enantiomer exceeding 95% purity. The absolute configuration was confirmed by circular dichroism spectroscopy. ¹H NMR titration and 2D rotating-frame nuclear Overhauser effect correlation spectroscopy (ROESY) consistently revealed multi-site recognition of XPN by SBX, supporting the inclusion of both aromatic rings (A and D). Full article

Deep eutectic solvents (DESs) represent a versatile and sustainable class of solvents, characterized by their low volatility, favorable biodegradability, and the ability to tailor their viscosity, polarity, and hydrogen-bonding capacity through the choice of their individual components. These characteristics have established them as powerful media in various analytical extraction and separation processes. This review presents a critical evaluation of the expanding role of DESs within the field of capillary electromigration techniques, summarizing key advancements from 2019 to mid-2025. We synthesize the current literature to delineate the benefits, persistent challenges, and future prospects of integrating DESs into capillary electrophoresis (CE)-based analytical workflows. Specifically, it systematically documents the following: (i) the diverse types of DESs employed in electrophoretic separations, (ii) proposed mechanisms underlying their influence on chiral compound resolution, and (iii) their utilization as separation media and pseudostationary phases (PSP) in capillary electromigration systems. By critically assessing their advantages and drawbacks, this review aims to provide a comprehensive perspective on the application of DESs in modern capillary electromigration techniques. Full article

Chiral liquid chromatography (cLC) using chiral stationary phases (CSPs) has become a crucial technique for separating enantiomers. Understanding enantiomeric discrimination is essential for improving chromatographic conditions and elucidating chiral molecular recognition; the computational methods are extremely helpful for this. To assess the relevance of the association of these two approaches and to analyze the current trends, in this review, a systematic analysis of the scientific literature was performed, covering recently published works (from 2015 to January 2025) on enantioseparation by cLC using CSPs and computational studies. CSPs based on polysaccharides and Pirkle-type were the most described (accounting for 52% and 14% of the studies, respectively). Regarding the computational methods, molecular docking and molecular dynamics (MD) were the most reported (accounting for 50% and 25% of the studies, respectively). In the articles surveyed, a significant growth in research concerning both cLC enantioseparation and computational studies is evident, emphasizing the benefit of the synergy between these two approaches. Full article

The separation of three proton pump inhibitors (omeprazole, lansoprazole, and rabeprazole) as exemplified molecules containing chiral sulfoxide groups was investigated in polar organic liquid chromatographic mode on seven different polysaccharide stationary phases (Chiralcel OD and OJ; Chiralpak AD, AS, and IA; Lux Cellulose-2 and -4). Different alcohols, such as methanol, ethanol, 1-propanol, 2-propanol, and their combinations, were used as eluents. After method optimization, semi-preparative enantioseparation was successfully applied for the three proton pump inhibitors to collect the individual enantiomers. A detailed investigation was conducted into elution order reversal, thermodynamic parameters, the effect of eluent mixtures, and the hysteresis of retention time and selectivity. Using Chiralpak AS, containing the amylose tris[(S)-α-methylbenzylcarbamate] chiral selector, the separation of the investigated enantiomers was achieved in all four neat eluents, with methanol providing the best results. In many cases, a reversal of the enantiomer elution order was observed. In addition to chiral-selector-dependent reversal, eluent-dependent reversal was also observed. Notably, even replacing methanol with ethanol altered the enantiomer elution order. Both enthalpy- and entropy-controlled enantioseparation were also observed in several cases; however, temperature-dependent elution order reversal was not. The hysteresis of retention and selectivity was further investigated on amylose-type columns in methanol–2-propanol and methanol–ethanol eluent mixtures. The phenomenon was observed on all amylose columns regardless of the eluent mixtures employed. Hystereticity ratios were calculated and used to compare the hysteresis behaviors of different systems. Multivariate statistical analysis revealed that Chiralpak AS exhibited the most distinct enantioselective behavior among the tested columns, likely due to the absence of a direct connection between the carbamate moiety and the aromatic substituent. The present study aided in understanding the mechanisms leading to enantiomer recognition, which is crucial for developing new chiral stationary phases and chiral HPLC method development in general. Full article

The paper proposes a putative prebiotic scenario leading to homochirality in the RNA world. In this scenario, racemic ribose, the only chiral moiety in RNA, was enantioseparated (in its pyranose form) on a chiral surface formed by the adsorption of (prochiral) nucleobases (NBs) on a mineral or metal. Purine bases (adenine and guanine) are more likely candidates for this process than pyrimidine bases because they have more H-bond donors and acceptors. Another possible candidate surface for the enantioseparation of ribose would be formed by the adsorption of nucleobase pairs, e.g., guanine–cytosine (GC). Interactions of ribose molecules with hydrogen bond donors and acceptors of NBs or NB pairs (located on the surface) enforced the orientation of ribose molecules in two directions perpendicular to each other and parallel to the surface. Consequently, the energy of interactions of enantiomers of the sugar with the surface was not the same. Thus, a solvent moving along the surface caused the enantiomers of ribose to move with different rates, resulting in the enantioseparation of ribose in a chromatography-like process. The same process would also separate ribose from other monosaccharides in the mix. Hydrogen bonding between nucleobases was also pivotal in the formation of large homochiral domains on the surfaces. Full article

New psychoactive substances (NPSs) are emerging narcotics or psychotropics that pose a public health risk. The most commonly reported NPSs are synthetic cannabinoids and synthetic cathinones. Synthetic cannabinoids mimic the effects of Δ9-tetrahydrocannabinol (Δ9-THC), often with greater potency, while synthetic cathinones act as stimulants, frequently serving as cheaper alternatives to amphetamines, 3,4-methylenedioxymethamphetamine (MDMA) and cocaine. While some synthetic cannabinoids exhibit chirality depending on their synthesis precursors, synthetic cathinones are intrinsically chiral. Biotargets can recognize and differentiate between enantiomers, leading to distinct biological responses (enantioselectivity). Understanding these differences is crucial; therefore, the development of enantioresolution methods to assess the biological and toxicological effects of enantiomer is necessary. This work systematically compiles enantioselectivity studies and enantioresolution methods of synthetic cannabinoids and synthetic cathinones, following PRISMA guidelines. The main aim of this review is to explore the impact of chirality on these NPSs, improving our understanding of their toxicological behavior and evaluating advances in analytical techniques for their enantioseparation. Key examples from both groups are presented. This review highlights the importance of continuing research in this field, as demonstrated by the differing properties of synthetic cannabinoid and synthetic cathinone enantiomers, which are closely linked to variations in biological and toxicological outcomes. Full article

Since the 1990s, cannabis has experienced a gradual easing of access restrictions, accompanied by the expansion of its legalization and commercialization. This shift has led to the proliferation of cannabis-based products, available as cosmetics, food supplements, and pharmaceutical dosage forms. Consequently, there has been a growing demand for reliable and reproducible extraction techniques alongside precise analytical methods for detecting and quantifying cannabinoids, both of which are essential for ensuring consumer safety and product quality. Given the variability in extraction and quantification techniques across laboratories, significant attention has recently been directed toward method validation. Validated methods ensure precise cannabinoid measurement in cannabis-based products, supporting compliance with dosage guidelines and legal limits. Thus, this review highlights recent advancements in these areas, with a particular focus on High-Performance Liquid Chromatography (HPLC) coupled with Ultraviolet (UV) detection, as it is considered the gold standard for cannabinoid analysis included in cannabis monographs present in several pharmacopeias. The research focused on studies published between January 2022 and December 2024, sourced from PubMed, Scopus, and Web of Science, that employed an HPLC-UV analytical technique for the detection of phytocannabinoids. Additionally, the review examines cannabinoid extraction techniques and the validation methodologies used by the authors in the selected papers. Notably, ultrasound extraction has emerged as the most widely utilized technique across various matrices, with Deep Eutectic Solvents (DESs) offering a promising, efficient, and environmentally friendly extraction alternative. Analytical chromatographic separations continue to be predominantly conducted using C18 reversed-phase columns. Nevertheless, in recent years, researchers have explored various stationary phases, particularly to achieve the enantioseparation of cannabinoids. Full article

Broccoli, a highly valued Brassica vegetable, is renowned for its rich content of bioactive substances, including glucosinolates, phenolic compounds, vitamins, and essential minerals. Glucosinolates (GSLs), secondary plant metabolites, are particularly abundant in broccoli. The global consumption of broccoli has increased due to its high nutritional value. This review examines the essential bioactive compounds in broccoli and their biological properties. Numerous in vitro and in vivo studies have demonstrated that broccoli exhibits various biological activities, including antioxidant, anticancer, antimicrobial, anti-inflammatory, anti-obesity and antidiabetic effects. This review analyzes several aspects of the chemical and biological activity of GSLs and their hydrolysis products, isothiocyanates such as sulforaphane, as well as phenolic compounds. Particular emphasis is placed on sulforaphane’s chemical structure, the reactivity of its isothiocyanate fraction (-NCS), and given the different behavior of SFN enantiomers, a wide and detailed review of the chemical synthesis methods described, by microbial oxidation, or using a chiral ruthenium catalyst and more widely using chiral auxiliaries for synthesizing sulforaphane enantiomers. In addition, the methods of chiral resolution of racemates by HPLC are reviewed, explaining the different chiral fillers used for this resolution and a third section on resolution using the formation of diastereomeric complexes and subsequent separation on achiral columns. Additionally, this review highlights the presence of antimicrobial peptides in broccoli, which have shown potential applications in food preservation and as natural alternatives to synthetic antibiotics. The antimicrobial peptides (AMPs) derived from broccoli target bacterial membranes, enzymes, oxidative stress pathways and inflammatory mediators, contributing to their effectiveness against a wide range of pathogens and with potential therapeutic applications. Full article

For a long time, D-amino acids remained unexplored in mammalian physiology. The technological advances in enantioseparation over the past 50 years have revealed that D-amino acids not only exist in human tissues and fluids but also play important roles in neurotransmission, immune regulation, and cellular proliferation. The present review provides a comprehensive assessment of the role of D-amino acids in cancer, including their endogenous and exogenous production pathways, along with the analytical methodologies used for detection and quantification, from liquid chromatography to biosensors. These methods have underlined how altered levels of D-amino acids can be helpful in early detection, progression, or response to treatment in several malignancies, including gastric, hepatic, colorectal, or breast cancer. The present review also explores how manipulation of D-amino acids can regulate cell proliferation, their mechanisms in cancer regulation, including the modulation of N-methyl-D-aspartate (NMDA) receptors and the production of hydrogen sulphide (H₂S), and the role of specific D-amino acids in cancer onset, immune defence, and protection against chemotherapy-induced toxicity. Finally, several underexplored research directions are outlined, such as potential correlations with gut microbiota composition, the impact of processed food consumption, and the integration of multiomics strategies. Full article