Chromatographic Method Research Articles

Silica Gel Chromatographic Methods for Identification, Isolation and Purification of Gossypol Acetic Acid.

Several cottonseed varieties are cultivated in different countries. Each variety produces a different amount of gossypol as a natural toxic compound. The rising interest in cottonseed products (oil and feed) increases the demand for establishing simple methods for gossypol detection. Silica gel-based methods are ideal for its isolation, purification, and characterization. Silica gel-based methods are variants and can be used as simple methods for tracking plants' compounds. In this study, gossypol was isolated, characterized, and purified as gossypol acetic acid in the form of yellow crystals. Methods used for its characterization were TLC, preparative TLC, silica gel column, UV/IR spectrophotometer, and HPLC (robust spherical silica gel). A comparative study between its amount in both the Egyptian and Chinese varieties was performed. Under the experimental conditions, the Egyptian's cottonseed contains 8.705 gm/kg, while the Chinese's cottonseed contains 5.395 gm/kg. The TLC used in this study proved to be fast, accurate, and inexpensive. It can be used for gossypol acetic acid evaluation and quantification. Additionally, using TLC as a pre-purification step will give a pre-judgment for the sample's purity and quality. This step will protect the expensive HPLC silica gel-based column from any unexpected impurities. During each step, the silica gel itself could be simply removed by paper filtration. Collectively, the different silica gel-based methods as well as the other used methods are recommended for better Gossypol acetic acid isolation, purification, and characterization, as well as for maintaining HPLC columns.

Heptaellipside A, a rare new 2,28-bidesmosidic lupane-type saponin from the leaves of Heptapleurum ellipticum

For the first time, phytochemical constituents of the leaves of Heptapleurum ellipticum were investigated. One rare new 2,28-bidesmosidic lupane-type saponin, named heptaellipside A (1), along with four other lupane-type analogs (2–5) were purified by combining differently chromatographic methods. All of the separated compounds (1–5) were communicated for the first time from H. ellipticum. The structures of them were definitely illustrated following extensive and comprehensive UV/VIS, FTIR, HRMS/ESI, and NMR techniques. Further, all isolated compounds were evaluated for their α-glucosidase and α-amylase inhibition. As the results, compound 3 respectively exhibited stronger in both inhibitory activities against α-glucosidase and α-amylase (IC50 values of 15.53 and 26.93 μM), than the acarbose standard (IC50 values of 214.50 and 143.48 μM).

Isotope dilution with isotopically labeled biomass: An effective alternative for quantitative metabolomics

BackgroundState-of-the-art quantitative metabolomics relies on isotope dilution using internal standards (IS) derived from fully 13C labeled biomass. By spiking samples and external standards with known amounts of IS, the spike characterization demands are kept to a minimum. In fact, it is sufficient to experimentally assess the isotopic enrichment of the IS. This study develops the yeast derived IS toolbox further, (1) by characterizing the concentration levels of hydrophilic metabolites in a yeast fermentation batch and (2) by exploring the analytical figures of merit of one-point IS versus multipoint external calibration using IS, the established gold-standard for quantitative metabolomics. ResultsIndependent reverse isotope dilution experiments using different chromatographic methods over a period of several months, delivered a list of 83 13C-labeled metabolites with fully characterized concentration and their uncertainty, covering 5 orders of magnitude, from the nanomolar to the low millimolar range. The 13C-labeled yeast-derived IS showed excellent intermediate stability with 92 % of molecules showing inter-method RSDs ≤30 % (75 % of molecules showed RSDs ≤15 %) over a timeframe of five months. One-point internal standardization with the characterized labeled biomass achieved figures of merit equivalent to multipoint calibrations for the majority of metabolites. SignificanceThe proposed calibration workflow rationalizes time and standard expenditure and is particularly beneficial for laboratories dealing with wide-target assays and small analysis batches. The present assessment serves as a seminal study for further developments of the concept towards absolute quantification from archive high-resolution MS data of U13C-biomass-spiked samples and the implementation of quick biomass recalibration with each experiment, promising seamless transition between internal standards derived from different fermentation batches.

Amarissinin F and its 16-epimer, two neo-clerodane diterpenoids from Salvia amarissima containing a 5-hydroxy-furan-2(5H)-one with MDR modulatory activity in cancer cells

Amarissinin F (1) and its 16-epimer (2) are two neo-clerodane diterpenoids isolated from the leaves and flowers of Salvia amarissima that occur as an unresolved epimeric mixture by chromatographic methods. The molecular structures of these compounds were deduced by the extensive analyses of their HRESIMS and their 1D/2D NMR data. Both compounds co-exist in the solid state as confirmed by single-crystal X-ray diffraction. In solution, both isolates appeared as the major compounds, which was corroborated by derivatization with Mosher reagents. However, the 1H and 13C NMR spectra demonstrated evidence for epimerization at C-20 and the possible interconversion of the 16-hydroxy-15,16-furanone to a 15-hydroxy-16,15-furanone, which was supported by a variable temperature 1H NMR analysis. The absolute configuration of compounds 1 and 2 was established by single-crystal X-ray diffraction and NMR. The cytotoxic effects of the isolated epimeric mixture (1 and 2) against a set of human cancer cells and the MDR modulatory activity in resistant MCF-7 breast cancer cells were explored.

Development and Validation of Stability Indicating Liquid Chromatographic Method for Vandetanib: Application to Degradation Studies by LC-MS

Objective: The central goal of this research was to formulate and validate a stability-demonstrating assay approach using reverse-phase high-performance liquid chromatography (RP-HPLC) for the assessment of vandetanib, its primary degradation products, and their respective degradation pathways, which were identified and characterized using liquid chromatography-electrophore spray ionization-mass spectrometry (LC-ESI-MS).Methods: The method was designed and developed by employing a Grace C18 column (250 x 4.6 mm x4.0 μm) and deploying a mixture of methanol and 0.1% formic acid in H2O (in a proportion of 90:10, v/v) as the mobile phase, with a flow rate maintained at 1-mL/min. The analytes were detected at a wavelength of 249 nm. Additionally, vandetanib was subjected to various stress conditions, including acidic, alkaline, oxidative, thermal, and photolytic degradation, to unearth the degradation paths for the principal degradation products.Results: The approach was meticulously formulated and validated to ensure robustness, linearity, precision, accuracy, and linear regression analysis data. A high correlation coefficient of 0.9985 was obtained in the 2 to 12 μg/mL concentration range, demonstrating a robust linear relationship. Moreover, the limit of detection (LoD) and the limit of quantification (LoQ) were found to be 0.166 and 0.503 μg/mL, respectively. In the stress degradation studies, we noticed that vandetanib degraded in alkaline and acidic mediums. The liquid chromatography-mass spectrometry (LC-MS) technique was used to characterize the degradation products.Conclusion: The devised method demonstrated itself to be quick, sensitive, precise, accurate, and robust for the vandetanib analysis, thereby facilitating its routine testing.

Development and Validation of HPTLC for the Determination of Gefitinib HCl in Tablet Dosage Form

A simple, high-performance thin-layer chromatography (HPTLC) method of gefitinib HCl in pharmaceutical formulation was developed. Separation was done on TLC aluminum plates precoated by silica gel 60GF254 (20 × 20 cm) with 200 μm layer depth. With UV detection set to 254nm, chromatography was conceded out by the mobile phase of dichloromethane and methanol (9:1, v/v). Linearity was found to range of 50 to 300 ng/spot and, the correlation coefficient was found to be 0.99 and the Rf value was found to be 0.46. The system’s suitability was considered to ascertain the performance of ascertaining quality performance of the developed chromatographic method. The method’s accuracy, precision, and specificity were all verified against the International Council of Harmonization (ICH) standards. Application of the approach to the determination of gefitinib in tablet form was successful.

Analytical QbD for the optimization of a multimode HPLC method for the investigation of hydrochlorothiazide, diltiazem and propranolol release from 3D printed formulation

Since 3D printing technology is an emerging field in pharmaceutical technology, the present study aimed at the development of a mixed-mode liquid chromatographic method for the separation and determination of hydrochlorothiazide, diltiazem, and propranolol to investigate their in-vitro release performance from 3D printed tablets. Due to the unique properties of the mixed-mode stationary phase, the three drugs were separated in less than 8 min under isocratic elution. Method development was accomplished following the Analytical Quality by Design principles and was evaluated using risk assessment and multivariate analysis. The influences of critical method parameters on critical method attributes (were screened using a 2-level fractional factorial design and subsequently optimized through a central composite design. The method operable design region was approved by the establishment of a robust zone using Monte Carlo simulation and capability analysis. The validation of the HPLC method was performed based on the total error concept. The relative bias was varied between ─ 11.6 % and 10.5 % and the RSD values for repeatability and intermediate precision were below 4.4 % in all cases. The limits of detection (LOD) ranged between 0.17 – 0.90 μg/mL and were adequate for the specific application. The developed method was successfully applied to the analysis of the studied drugs in in-vitro drug release samples obtained from 3D-printed tablets combining the above-mentioned active pharmaceutical ingredients (APIs).

Development of an organic polymer monolith column for the nano liquid chromatography fast analysis of monoclonal antibody in infusion bags prepared in a hospital pharmacy.

Poly(butyl methacrylate-co-ethylene dimethacrylate) monolith was in situ prepared in a liquid chromatography capillary column with a 75 μm internal diameter. This monolith offered high permeability (5.3 ± 10-14m2) and good peak capacity (140 for a 15 cm column length at 300 nl/min with a 20 min gradient time). This is exemplified by its separation ability in reversed mode for subunit analysis of monoclonal antibodies after IdeS digestion (middle-up analysis). The potential of this column was also illustrated for the fast analytical control of therapeutic monoclonal antibodies in standardized infusion bags prepared in advance in a pharmacy department. Linearity analysis revealed the column's capability for accurate quantification analysis of the different dose bandings (in mg) of monoclonal antibodies in <2min. In addition, lifetime analysis data indicated that the column can be highly reproducible and has a long lifetime with stable and low back pressure. The variations observed on the peak shape and area between unstressed (intact) and stressed monoclonal antibodies indicated that our nano liquid chromatographic method was stability indicating. In addition, using a gradient elution mode, the presence of minor components in the infusion bags was visualized.

Validation of Commercial Formulation of Difenoconazole Using HPLC Equipped with Dad

Effective, selective, precise, and accurate liquid chromatographic analytical methods for the determination of difenoconazole fungicide in the formulation have been optimized and validated to meet the accreditation requirements, the performance characteristics of the analytical method were validated which is also one of the basic requirements of ISO Standard 17025:2017, for the rapid determination of difenoconazole by HPLC-DAD. The used method involves the extraction of the substances by sonication of the sample with acetonitrile, followed by dilution in acetonitrile, and direct injection on a liquid chromatography system. For the analysis LC system from Agilent Technologies 1290 Infinity II was used. Good separation was achieved on a Luna C18 column (3µm, 100°A, 3x150mm) with a guard column (C18 4x2.0mm I.D), an isocratic mobile elution consisting of acetonitrile and water acidified 0.075% with formic acid (85:15, v/v), at a flow rate of 0.7 ml/minute and UV detection at 220 nm. The column temperature was 25⁰C, injected volume was 1 μL. The analysis duration was 10 minutes (the retention time of difenoconazole and 4 – Hydroxybenzoic acid – methyl ester was 1.846 and 1.135 minutes, respectively. The linearity within the concentration range of 750-125 µg mL-1, with the internal standard at a concentration of 250 µg mL-1 with an average correlation coefficient (R2) of 0.9998. We have considered precision, repeatability, and selectivity in the validation.

Synchronized Assessment of Lobeglitazone Sulfate and Metformin Hydrochloride in Tablet by Robust, High-performance Thin-layer Chromatographic Method

Background: A combination of fixed-doses containing 0.5 mg lobeglitazone sulfate and 1000 mg metformin hydrochloride has demonstrated efficacy in enhancing glycemic control in diabetes. Aim: The projected work aimed to establish and validate a high-performance thin-layer chromatographic methodology for the quantification of both drugs in tablet formulations. Objective: The task involves creating and validating a method in accordance with ICH guidelines to quantify two particular drugs in tablet formulations accurately. Methods: The high-performance thin-layer chromatographic analysis utilized aluminum plates layered with silica gel 60F254, and the solvent system consisted of acetonitrile, 1 M ammonium acetate (methanol), toluene, and triethyl amine (1.5:2.5:4:0.2 v/v/v/v), followed by densitometric scanning at 237 nm. Results: The methodology exhibited linearity in the range of 100-1500 ng/band for lobeglitazone sulfate and 1000-15000 ng/band for metformin hydrochloride, with correlation coefficients of 0.9991 and 0.9992, correspondingly. Exceptional sensitivity was observed, with detection limits of 8.17 ng/band for lobeglitazone sulfate and 271.34 ng/band for metformin hydrochloride, along with quantification limits of 24.75 ng/band for lobeglitazone sulfate and 822.24 ng/band for metformin hydrochloride. The method demonstrated precision (% relative standard deviation of peak area &lt;360;2) and accuracy (recovery between 96 and 103%). Conclusion: The suggested methodology is fit for the concurrent quantification of both drugs in tablet formulations, making it applicable for routine quality control assessments in laboratories.

Establishment of an immunolateral chromatographic quantitative method for the detection of alternariol based on quantum dot fluorescent nanospheres in fruit

Alternariol (AOH) is a metabolic product of Alternaria, which has various toxic effects on humans and animals and its pollution is increasingly being discovered in fruits, vegetables, and grains. At present, the detection of AOH is mainly achieved through high-performance liquid chromatography-mass spectrometry and immunological methods. However, there is currently a lack of fast detection methods for on-site use. Considering the unique advantages of immunological testing methods, this study developed an immunolateral chromatographic quantitative method for detecting AOH using quantum dot fluorescent nanospheres (QDFNs) as signal amplification materials. The detection range of AOH is 5.2–4798 μg/kg, 50 % inhibiting concentration (IC50) is 156.4 μg/kg, limit of detection (LOD) value is 2.32 μg/kg, and limit of quantification (LOQ) value is 6.96 μg/kg. The recovery rates of AOH in tomato and strawberry were 95.27%–111.63% and 88.43%–96.22%, respectively. In brief, the developed approach has good accuracy and repeatability and can be used for the detection of AOH.

Inhibitory effects of compounds isolated from Geranium wilfordii on IL-4 production and β-hexosaminidase release in RBL-2H3 cells

This study aimed to investigate the anti-allergic activity of compounds isolated from Geranium wilfordii Maxim. and to suggest potential therapeutic agents for allergies. Nine compounds were isolated from an ethanolic G. wilfordii extract using chromatographic methods and identified chemically and by spectroscopic analysis. These compounds were identified using reported literature data as brevifolin carboxylic acid (1), chlorogenic acid (2), corilagin (3), ellagic acid (4), geraniol (5), kaempferol 3-O-dirhamnoside (6), kaempferol 3-O-neohesperidoside (7), protocatechuic acid (8), and gallic acid (9). All nine identified compounds were assessed for including IL-4 mRNA expression and β-hexosaminidase release in RBL-2H3 cells stimulated with PMA/ionomycin or IgE + DNP-BSA. IL-4 gene expression assay showed that corilagin (3) potently inhibited IL-4 production, and β-hexosaminidase release assay showed that protocatechuic acid (8) markedly reduced histamine release. The study shows that of the nine compounds isolated from G. wilfordii, corilagin (3), and protocatechuic acid (8) are potential treatments for allergy-related diseases.

Effect of diastereoisomeric composition on the chromatographic retention of phosphorothioated oligonucleotides using three different liquid chromatography systems

To increase understanding of the interactions and effects of the diastereoisomeric character of phosphorothioate (PS) oligonucleotides on chromatographic retention, three chromatographic methods [in-series reversed phase-strong anion exchange (RP-SAX), ion pair-reversed phase and metal ion complexation chromatography (MICC)] were applied to the characterization of stereo-enriched compounds. Chromatographic systems are widely available, amenable to routine applications, and simple to deploy in comparison to more advanced instrumentation (e.g., 31P NMR) and procedures (e.g., enzymatic digestion). Analogous diastereoisomeric distribution profiles were obtained by RP-SAX and IP-RP based on their common mechanism of separation involving the combination of hydrophobic and electrostatic interactions. Similar linear relationships between retention time (tR) and the numbers of stereo random, Rp, and Sp PS linkages were obtained with both methods. Sp-enriched diastereoisomers were retained longer than stereo random and Rp-enriched diastereoisomers. MICC produced much broader diastereoisomeric peak distributions than the other two methods due to its more complicated nature of interaction. Average mass spectra showed a smaller number of Ag ions (1-7) complex with early eluting diastereoisomers than with later eluting diastereoisomers (which complex between 6-12 Ag ions). A higher late-to-early peak UV area ratio was obtained for a sample containing 10 Sp linkages vs one containing 10 Rp linkages pointing to the tendency of the Sp diastereoisomers for increased interactions which could be explained by structures with more open or stretched configurations. Consideration of the peak shapes of the MICC distributions led to comparable hierarchical cluster analysis (HCA) classification to that produced by the IP-RP method, indicating a good orthogonality between the two methods. Preliminary analysis of the data using partial least squares showed that it should be possible to determine the diastereoisomeric composition of PS oligonucleotides from chromatographic data following appropriate data training.

A Complementary Multitechnique Approach to Assess the Bias in Molecular Weight Determination of Lignin by Derivatization-Free Gel Permeation Chromatography.

The growing interest in lignin valorization in the past decades calls for analytical techniques for lignin characterization, ranging from wet chemistry techniques to highly sophisticated chromatographic and spectroscopic methods. One of the key parameters to consider is the molecular weight profile of lignin, which is routinely determined by size-exclusion chromatography; however, this is by no means straightforward and is prone to being hampered by considerable errors. Our study expands the fundamental understanding of the bias-inducing mechanisms in gel permeation chromatography (GPC), the magnitude of error originating from using polystyrene standards for mass calibration, and an evaluation of the effects of the solvent and type of lignin on the observed bias. The developed partial least-squares (PLS) regression model for lignin-related monomers revealed that lignin is prone to association mainly via hydrogen bonding. This hypothesis was supported by functional group-based analysis of the bias as well as pulse field gradient (pfg) diffusion NMR spectroscopy of model compounds in THF-d8. Furthermore, although the lack of standards hindered drawing conclusions based on functionalities, direct infusion electrospray ionization mass spectrometry indicated that the relative bias decreases considerably for higher molecular weight species. The results from pfg-diffusion NMR spectroscopy on whole lignin samples were comparable when the same solvents were used in both experiments; in addition, the comparison between results obtained by pfg-diffusion NMR in different solvents gives some additional insights into the aggregation.

Synthesis and Isolation of Phenol- and Thiol-Derived Epicatechin Adducts Prepared from Avocado Peel Procyanidins Using Centrifugal Partition Chromatography and the Evaluation of Their Antimicrobial and Antioxidant Activity.

Polyphenols from agro-food waste represent a valuable source of bioactive molecules that can be recovered to be used for their functional properties. Another option is to use them as starting material to generate molecules with new and better properties through semi-synthesis. A proanthocyanidin-rich (PACs) extract from avocado peels was used to prepare several semi-synthetic derivatives of epicatechin by acid cleavage in the presence of phenol and thiol nucleophiles. The adducts formed by this reaction were successfully purified using one-step centrifugal partition chromatography (CPC) and identified by chromatographic and spectroscopic methods. The nine derivatives showed a concentration-dependent free radical scavenging activity in the DPPH assay. All compounds were also tested against a panel of pathogenic bacterial strains formed by Listeria monocytogenes (ATCC 7644 and 19115), Staphylococcus aureus (ATCC 9144), Escherichia coli (ATCC 11775 and 25922), and Salmonella enterica (ATCC 13076). In addition, adducts were tested against two no-pathogenic strains, Limosilactobacillus fermentum UCO-979C and Lacticaseibacillus rhamnosus UCO-25A. Overall, thiol-derived adducts displayed antimicrobial properties and, in some specific cases, inhibited biofilm formation, particularly in Listeria monocytogenes (ATCC 7644). Interestingly, phenolic adducts were inactive against all the strains and could not inhibit its biofilm formation. Moreover, depending on the structure, in specific cases, biofilm formation was strongly promoted. These findings contribute to demonstrating that CPC is a powerful tool to isolate new semi-synthetic molecules using avocado peels as starting material for PACc extraction. These compounds represent new lead molecules with antioxidant and antimicrobial activity.

Surface-enhanced Raman scattering sensor based on cysteine-mediated nucleophilic addition reaction for detection of patulin

Fruits are susceptible to fungal infection and propagation during storage and transportation, and carry toxic metabolites of fungi. Patulin (PAT) is a primary mycotoxin contaminant in fruits and their products, with neurotoxicity, teratogenicity and carcinogenicity. The current chromatographic methods have limitations such as time-consuming, high-cost and the need for professional training. For rapid and sensitive detection of PAT, a surface-enhanced Raman scattering (SERS) method based on nucleophilic addition reaction was described in this paper. 4-aminothiophenol (4-ATP), silver ion, and cysteine (Cys) were successively attached to the surface of the Au-core-Ag-shell nanoparticles to form SERS sensors. PAT reacted with Cys to form a complex covering the surface of the sensor, attenuating the Raman signal from 4-ATP. Combined with the chemometrics algorithms, the hidden spectral information can be extracted effectively. Among these algorithms, the ant colony optimization partial least squares (ACO-PLS) model demonstrated the best predictive performance (Rc = 0.9985, RMSEC = 0.0494). The recovery rate of PAT was 96.58 ∼ 101.74 % with the RSD ≤ 1.42 %. HPLC was used to verify the applicability of this SERS method, and the results indicated that the SERS method was consistent with the HPLC method (p = 0.283 > 0.05). Furthermore, the SERS sensor was not subject to interference from ochratoxins A, alternariol, and the PAT structural analogues. Consequently, the proposed SERS sensor can realize rapid and highly selective detection of PAT, providing a new strategy for the rational design of SERS sensor based on chemical reaction for indirect detection of harmful substances.

Two protocols for the detection of oleaginous bacteria using Oil Red O

The selection of oleaginous bacteria, potentially applicable to biotechnological approaches, is usually carried out by different expensive and time-consuming techniques. In this study, we used Oil Red O (ORO) as an useful dye for staining of neutral lipids (triacylglycerols and wax esters) on thin-layer chromatography plates. ORO could detect minimal quantities of both compounds (detection limit, 0.0025 mg of tripalmitin or 0.005 mg of cetylpalmitate). In addition, we developed a specific, rapid, and inexpensive screening methodology to detect triacylglycerol-accumulating microorganisms grown on the agar plate. This staining methodology detected 9/13 strains with a triacylglycerol content higher than 20% by cellular dry weight. ORO did not stain polyhydroxyalkanoates-producing bacteria. The four oleaginous strains not detected by this screening methodology exhibited a mucoid morphology of their colonies. Apparently, an extracellular polymeric substance produced by these strains hampered the entry of the lipophilic dye into cells. The utilization of the developed screening methodology would allow selecting of oleaginous bacteria in a simpler and faster way than techniques usually used nowadays, based on unspecific staining protocols and spectrophotometric or chromatographic methods. Furthermore, the use of ORO as a staining reagent would easily characterize the neutral lipids accumulated by microorganisms as reserve compounds.Key points• Oil Red O staining is specific for triacylglycerols• Oil Red O staining is useful to detect oleaginous bacteria• Fast and inexpensive staining to isolate oleaginous bacteria from the environment

A rapid and accurate liquid chromatographic method for hemp compliance testing

A liquid chromatography ultraviolet (LC-UV) method, which used methanol as the organic solvent for both extraction and separation, was developed for hemp compliance testing. While published methods occasionally used methanol for separation, all of them used gradient elution which would cause baseline drifts and a subsequent high limit of quantification (LOQ), and only eight or less cannabinoids were included. Our method was characterized by a baseline separation of Δ9-tetrahydrocannabinol (Δ9-THC) and Δ9-tetrahydrocannabinolic acid (Δ9-THCA) among nineteen cannabinoids in ten minutes and a calibration between 0.04 to 50 µg/mL, making it the most effective method validated so far. However, a reproducible separation of Δ9-THCA could not be achieved with the common formate buffer system, presumably due to its adsorption onto the C18 column which could be prevented by either using acetonitrile in the organic solvent that was widely undertaken by published methods or adding 0.1 % (v/v) trifluoroacetic acid in the aqueous solvent that was achieved only in this study. While similar problems were not reported by published methods, it was speculated that the problem could be common for all C18 columns, more or less, as the stationary phase in this study was di-isobutyl-n-octadecyl-silane without any polar imbedded moieties. Additionally, while quantification of Δ9-THC at 230 nm achieved good specificity, quantification of Δ9-THCA required 269 nm for acceptable specificity, which was verified by electrospray ionization time-of-flight mass spectrometry (ESI/TOFMS), indicating no false quantification and identification of Δ9-THC and Δ9-THCA, despite the observation of ten matrix peaks in the LC-UV chromatograms and identification of three untargeted/unknown cannabinoids by ESI/TOFMS in ten samples.

Dicerandrol C Suppresses Proliferation and Induces Apoptosis of HepG2 and Hela Cancer Cells by Inhibiting Wnt/β-Catenin Signaling Pathway.

Overwhelming evidence points to an aberrant Wnt/β-catenin signaling as a critical factor in hepatocellular carcinoma (HCC) and cervical cancer (CC) pathogenesis. Dicerandrol C (DD-9), a dimeric tetrahydroxanthenone isolated from the endophytic fungus Phomopsis asparagi DHS-48 obtained from mangrove plant Rhizophora mangle via chemical epigenetic manipulation of the culture, has demonstrated effective anti-tumor properties, with an obscure action mechanism. The objective of the current study was to explore the efficacy of DD-9 on HepG2 and HeLa cancer cells and its functional mechanism amid the Wnt/β catenin signaling cascade. Isolation of DD-9 was carried out using various column chromatographic methods, and its structure was elucidated with 1D NMR. The cytotoxicity of DD-9 on HepG2 and HeLa cells was observed with respect to the proliferation, clonality, migration, invasion, apoptosis, cell cycle, and Wnt/β-catenin signaling cascade. We found that DD-9 treatment significantly reduced tumor cell proliferation in dose- and time-dependent manners in HepG2 and HeLa cells. The subsequent experiments in vitro implied that DD-63 could significantly suppress the tumor clonality, metastases, and induced apoptosis, and that it arrested the cell cycle at the G0/G1 phase of HepG2 and HeLa cells. Dual luciferase assay, Western blot, and immunofluorescence assay showed that DD-9 could dose-dependently attenuate the Wnt/β-catenin signaling by inhibiting β-catenin transcriptional activity and abrogating β-catenin translocated to the nucleus; down-regulating the transcription level of β-catenin-stimulated Wnt target gene and the expression of related proteins including p-GSK3-β, β-catenin, LEF1, Axin1, c-Myc, and CyclinD1; and up-regulating GSK3-β expression, which indicates that DD-9 stabilized the β-catenin degradation complex, thereby inducing β-catenin degradation and inactivation of the Wnt/β-catenin pathway. The possible interaction between DD-9 and β-catenin and GSK3-β protein was further confirmed by molecular docking studies. Collectively, DD-9 may suppress proliferation and induce apoptosis of liver and cervical cancer cells, possibly at least in part via GSK3-β-mediated crosstalk with the Wnt/β-catenin signaling axis, providing insights into the mechanism for the potency of DD-9 on hepatocellular and cervical cancer.

New improved radiometabolite analysis method for [18F]FTHA from human plasma: a test-retest study with postprandial and fasting state

BackgroundFatty acid uptake can be measured using PET and 14-(R,S)‐[18F]fluoro‐6‐thia‐heptadecanoic acid ([18F]FTHA). However, the relatively rapid rate of [18F]FTHA metabolism significantly affects kinetic modeling of tissue uptake. Thus, there is a need for accurate chromatographic methods to analyze the unmetabolized [18F]FTHA (parent fraction). Here we present a new radiometabolite analysis (RMA) method, with comparison to a previous method for parent fraction analysis, and its use in a test-retest clinical study under fasting and postprandial conditions. We developed a new thin-layer chromatography (TLC) RMA method for analysis of [18F]FTHA parent fraction and its radiometabolites from plasma, by testing stationary phases and eluent combinations. Next, we analyzed [18F]FTHA, its radiometabolites, and plasma radioactivity from subjects participating in a clinical study. A total of 17 obese or overweight participants were dosed with [18F]FTHA twice under fasting, and twice under postprandial conditions and plasma samples were obtained between 14 min (mean of first sample) and 72 min (mean of last sample) post-injection. Aliquots of 70 plasma samples were analyzed using both methods, enabling head-to-head comparisons. We performed test-retest and group comparisons of the parent fraction and plasma radioactivity.ResultsThe new TLC method separated seven [18F]FTHA radiometabolite peaks, while the previous method separated three. The new method revealed at least one radiometabolite that was not previously separable from [18F]FTHA. From the plasma samples, the mean parent fraction value was on average 7.2 percentage points lower with the new method, compared to the previous method. Repeated [18F]FTHA investigations on the same subject revealed reproducible plasma SUV and parent fractions, with different kinetics between the fasted and postprandial conditions.ConclusionsThe newly developed improved radio-TLC method for [18F]FTHA RMA enables accurate parent fraction correction, which is required to obtain quantitative data for modelling [18F]FTHA PET data. Our test-retest study of fasted and postprandial conditions showed robust reproducibility, and revealed clear differences in the [18F]FTHA metabolic rate under different study settings.Trial registrationEudraCT No: 2020-005211-48, 04Feb2021; and Clinical Trials registry NCT05132335, 29Oct2021, URL: https://classic.clinicaltrials.gov/ct2/show/NCT05132335.