Stereoselective interactions of profen stereomers with human plasma proteins using nano solid phase micro membrane tip extraction and chiral liquid chromatography

Determination of the epitopic peptides of fig mosaic virus and the single-chain variable fragment antibody by mass spectrometry

The study of antibody-antigen interactions, through epitope mapping, enhances our understanding of antibody neutralization and antigenic determinant recognition. Epitope mapping, employing monoclonal antibodies and mass spectrometry, has emerged as a rapid and precise method to investigate viral antigenic determinants. In this report, we propose an approach to improve the accuracy of epitopic peptide interaction rate recognition. To achieve this, we investigated the interaction between the nucleocapsid protein of fig mosaic virus (FMV-NP) and single-chain variable fragment antibodies (scFv-Ab). These scFv-Ab maintain high specificity similar to whole monoclonal antibodies, but they are smaller in size. We coupled this with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The experimental design involved using two different enzymes to digest FMV-NP separately. The resulting peptides were then incubated separately with the desired scFv-Ab at different incubation times and antibody concentrations. This allowed us to monitor the relative rate of epitopic peptide interaction with the antibody. The results demonstrated that, at a 1:1 ratio and after 2 h of interaction, the residues 122-136, 148-157, and 265-276 exhibited high-rate epitopic peptide binding, with reductions in peak intensity of 78%, 21%, and 22%, respectively. Conversely, the residues 250-264 showed low-rate binding, with a 15% reduction in peak intensity. This epitope mapping approach, utilizing scFv-Ab, two different enzymes, and various incubation times, offers a precise and dependable analysis for monitoring and recognizing the binding kinetics of antigenic determinants. Furthermore, this method can be applied to study any kind of antigens.

Strategies for chiral separation: from racemate to enantiomer

Chiral separation has become a crucial topic for effectively utilizing superfluous racemates synthesized by chemical means and satisfying the growing requirements for producing enantiopure chiral compounds. However, the remarkably close physical and chemical properties of enantiomers present significant obstacles, making it necessary to develop novel enantioseparation methods. This review comprehensively summaries the latest developments in the main enantioseparation methods, including preparative-scale chromatography, enantioselective liquid-liquid extraction, crystallization-based methods for chiral separation, deracemization process coupling racemization and crystallization, porous material method and membrane resolution method, focusing on significant cases involving crystallization, deracemization and membranes. Notably, potential trends and future directions are suggested based on the state-of-art "coupling" strategy, which may greatly reinvigorate the existing individual methods and facilitate the emergence of cross-cutting ideas among researchers from different enantioseparation domains.

Nano solid phase micro membrane tip and electrochemical methods for vanillin analysis in chocolate samples

A polymer-based nanosensor and electrochemical methods were developed for the quantitative analysis of vanillin. The sample preparation was done using nano solid phase micro membrane tip extraction (NSPMMTE). A novel poly(phenylalanine)/TiO2/CPE sensor was built as the working electrode for the first time for the analysis of the vanillin substance. The electrochemical behavior and analytical performance of vanillin were examined in detail by cyclic voltammetry (CV) and differential pulse stripping voltammetry (DPSV) techniques via the oxidation process. The optimized modules of the DPSV technique that affected the vanillin peak current and peak potential were pH, pulse amplitude, step potential, and deposition time. The electroactive surface areas of bare CPE, TiO2/CPE, and poly(phenylalanine)/TiO2/CPE electrodes were found to be 0.135 cm2, 0.155 cm2, and 0.221 cm2, respectively. The limit of detection (LOD) was 32.6 μg/L in the 0.25-15.0 mg/L working range at pH 7.0. The selectivity of the proposed DPSV method for the determination of vanillin on the modified electrode was investigated in the presence of various organic and inorganic substances, and the determination of vanillin with high recovery was achieved with less than 5% relative error. The analytical application was applied in chocolate samples and the DPSV method was found highly efficient, reproducible, and selective.

Enantioseparation and mechanism study on baclofen by capillary electrophoresis and molecular modeling

Enantioselective analysis of chiral drugs plays a significant role in chemistry, biology and pharmacology. Baclofen, an antispasmodic chiral drug, has been widely studied due to the obvious differences in toxicity and medical activity between enantiomers. Herein, a simple and efficient method for separation of baclofen enantiomers by capillary electrophoresis was established without complicated sample derivatization and expensive instruments. Then, the molecular modeling and density functional theory were used to simulate and investigate the chiral resolution mechanism of electrophoresis, the calculated intermolecular forces were directly presented by visualization softwares. Moreover, the theoretical and experimental electronic circular dichroism (ECD) spectra of ionized baclofen were compared, and the configuration of dominant enantiomer in the nonracemic mixture can be determined by ECD signal intensity, which was proportional to the electrophoresis peak area difference of the corresponding enantiomer excess experiments. In this way, the peak order identification and configuration quantification of baclofen enantiomers in electrophoretic separation were successfully achieved without relying on a single standard.

The Target Determination and the Mechanism of Action of Chiral-Antimalarial Drugs: A Docking Approach

Due to an undecided target and the prescription of chiral-aminoquinolines (chloroquine, primaquine and quinacrine) in the racemic form, the mechanism of action as well as the reason of causing side effects become unclear. Based on computationally evaluated literature data, the things determined theoretically were (i) the target of aminoquinolines during antimalarial activity, (ii) the mechanism of action of chiral-aminoquinolines and (iii) biologically active enantiomers of aminoquinolines. For the presented study, the enantiomeric binding affinities of aminoquinolines with all the targets claimed by other scientists were calculated, and then used in interpretation with the help of many investigations done/observed by others. The results were very interesting based on which, a new and acceptable mechanism of action of chiral-aminoquinolines during malaria curing step, is given for the first time. The current docking study not only resolves the questionable point about a definite target of aminoquinolines but also makes the mechanism of action understandable.

On the applicability of functional-group symmetry-adapted perturbation theory and other partitioning models for chiral recognition - the case of popular drug molecules interacting with chiral phases

The applicability of symmetry-adapted perturbation theory (SAPT) and functional-group SAPT (F-SAPT) to study chiral recognition is investigated on an example of three popular chiral drug molecules: ibuprofen, norepinephrine, and baclofen, interacting with phenethylamine or proline - two molecules that are often used as chiral phases in chromatography. The comparison of the F-SAPT with the interacting quantum atoms (IQA) approach is also provided. Accurate estimation of energetic differences of the non-covalent intermolecular complexes composed of two chiral molecules is a necessary prerequisite for the possibility of a prediction of the chiral recognition. The SAPT method with interacting molecules described on the density functional theory level provides accurate total interaction energies, while the F-SAPT approach is the most useful in determining which functional groups are responsible for strengthening or weakening of the interaction between chiral molecules. The largest difference in the interaction energies has been calculated for the baclofen-phenethylamine and norepinephrine-phenethylamine pairs, while the smallest for the ibuprofen-proline and baclofen-proline ones. In most cases, the intermolecular interaction is found to be composed of a strong directional hydrogen bond, which was stabilized by two or more weaker non-covalent interactions between groups (in accordance with the phenomological three-point rule), but in several cases more subtle factors are responsible for larger stability of one diastereoisomer, like the stabilization of the conformation involving two noninteracting functional groups attached to a chiral atom through intramolecular attraction. Additionally, the simulated IR spectra were analyzed for all pairs of diastereoisomeric complexes and the red- and blue-shifts of characteristic bond vibrations were discussed in the context of inter-group interactions.

Role of Unani Medicines in Cancer Control and Management

Background:

Cancer is a havoc and killer disease. Several ways including allopathic chemotherapy have been used in the cancer treatment. Allopathic chemotherapy has several limitations and side effects. Unani medicine is also one of the therapies to cure cancer.

Objective:

In this type of treatment, herbal drugs are used for the treatment and prevention of cancer. The main attractive thing about herbal drug is no side effect as compared to allopathic chemotherapy.

Methods:

Actually, herbal drugs are the extracts of medicinal plants. The plant extracts are obtained by crushing and heating the main part of the plants; showing anticancer activity. The main plants used in the treatment of cancer are oroxylum indicum, dillenia indica, terminalia arjuna etc.

Results:

Mainly the cancers treated are of digestive system, breast, cervical, brain, blood, bone, lungs, thyroid, uterine, bladder, throat etc.

Conclusion:

The present review article discusses the importance of Unani system of medicine for the treatment of cancer. Besides, the future perspectives of Unani medicine in cancer treatment are also highlighted.