Isomeric Compounds Research Articles

Rapid and efficient LC-MS/MS diagnosis of inherited metabolic disorders: a semi-automated workflow for analysis of organic acids, acylglycines, and acylcarnitines in urine.

The analysis of organic acids in urine is an important part of the diagnosis of inherited metabolic disorders (IMDs), for which gas chromatography coupled with mass spectrometry is still predominantly used. Ultra-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for urinary organic acids, acylcarnitines and acylglycines was developed and validated. Sample preparation consists only of dilution and the addition of internal standards. Raw data processing is quick and easy using selective scheduled multiple reaction monitoring mode. A robust standardised value calculation as a data transformation together with advanced automatic visualisation tools are applied for easy evaluation of complex data. The developed method covers 146 biomarkers consisting of organic acids (n=99), acylglycines (n=15) and acylcarnitines (n=32) including all clinically important isomeric compounds present. Linearity with r2>0.98 for 118 analytes, inter-day accuracy between 80 and 120 % and imprecision under 15 % for 120 analytes were achieved. Over 2 years, more than 800 urine samples from children tested for IMDs were analysed. The workflow was evaluated on 93 patient samples and ERNDIM External Quality Assurance samples involving a total of 34 different IMDs. The established LC-MS/MS workflow offers a comprehensive analysis of a wide range of organic acids, acylcarnitines and acylglycines in urine to perform effective, rapid and sensitive semi-automated diagnosis of more than 80 IMDs.

Simple isocratic RP-UHPLC-MS methods for the determination of steviols and its glycosides: Quality control perspectives

Stevia is well-known for its unique non-caloric intense sweetness and recognising as one of the most acceptable sweeteners. Therefore, quality control and metabolite profiling perspectives, two isocratic reverse-phase UPLC-PDA-ELSD-MS methods were developed to determine nine diterpene glycosides (method A) and isomeric compounds (steviol and isosteviol; method B). Both the methods were validated and found as per the ICH guidelines for accuracy (recovery), precision (Intraday, interday, and intermediate precision), linearity, and regression coefficient (r2), ruggedness (eluent concentration ± 2 mM, column oven temperature ± 3 °C and retention time), and system suitability (theoretical plate count, asymmetric factor, injection precision and resolution). LOD for steviol and its glycosides were found between 0.92 and 5.22 μg/mL while LOQ were 2.78–18.29 μg/mL, respectively. Validated methods had shown only the presence of steviol glycosides in Stevia rebaudina samples while LC-ESI-MS/MS revealed the identification of 46 different class of molecules. These methods will be helpful to monitor quality in Stevia production and its derived products.

In-situ FTIR investigation of isomerisation of cis-butadiene rubber during the vulcanization

The physical properties of cis-butadiene rubber (BR) have been shown to be critically dependent on its stereoregularity. In this work, the evolution process and influencing factors of cis-trans isomerisation of BR based on the conventional formulation system during its vulcanization process are systematically investigated using in-situ Fourier transform infrared spectroscopy (FTIR) technology. The results show that the isomerisation occurs in the BR compound with sulphur vulcanization system in both non-isothermal and isothermal vulcanization processes because of the polysulfide bonds formed by sulphur in the system, and it is more obvious than that with dicumyl peroxide (DCP) vulcanization system. The degree of isomerisation shows a positive correlation with the sulphur dosage and can reach 10% with 3 phr sulphur. Experiments also prove that zinc oxide (ZnO) and antioxidants have a significant inhibitory effect on the isomerisation during the vulcanization. The isomerisation degree of BR/ZnO-4 is reduced by half compared to that of BR/ZnO-0. The effect of antioxidant poly (1,2-dihydro-2,2,4-trimethyl-quinoline) (RD) is greater than that of N-1,3-dimethylbutyl-N′-phenyl-p-phenylenediamine (6PPD) due to its higher activity. The isomerisation of BR compound in the vulcanization is not affected significantly by the accelerator types. Besides, the isomerisation degree of Nd-BR with higher chain regularity is lower than that of Ni-BR with the same vulcanization system. The investigation above provides new perspectives and inspirations for the optimization of formula and scientific analysis on the structure-property relationship of BR composite.

Synthesis of Two Series of Isomeric Triazolo-Triazine Fused Energetic Salts: High Thermal Stability, Insensitivity, and High Performances

In recent years, the safety of energetic materials has attracted more and more attention. How to design and synthesize heat-resistant and insensitive energetic materials has become an urgent problem to be solved. In this work, two series of energetic salts based on isomeric triamino triazolo-triazine fused-ring compounds were designed and synthesized by incorporating oxygen-rich anions (such as NO3– or ClO4–) with nitrogen-rich energetic cations. All of the new compounds were fully characterized by infrared (IR) spectroscopy, nuclear magnetic resonance (NMR), elemental analysis, and differential scanning calorimetry (DSC). Decomposition temperatures (Td) of isomeric perchlorate salts 3 and 9 are 315 and 364 °C, respectively. Their different properties, densities and molecular stabilities are rationally explained based on crystal structures and packing patterns. Meanwhile, perchlorate 9 has the highest decomposition temperature and good detonation performance (D = 8485 m s–1, P = 27.7 GPa), which is superior to HNS and PYX and suggests that it could be applied as a heat-resistant insensitive explosive.

Preparation of human milk fat substitute and improvement of its oxidative stability

1,3-Dioleoyl-2-palmitoylglycerol (OPO) was synthesized by enzymatic interesterification using palm stearin rich in tripalmitin (PPP) and ethyl oleate. Enzymatic interesterification parameters such as temperature, water content, enzyme load, and substrate molar ratio were optimized. High contents of C52 (primarily OPO and its isomeric compounds) production (46.7%) and sn-2 palmitic acid (PA) content of 75.3% were detected. In addition, OPO-human milk fat substitute (HMFS) was blended with coconut, soybean, algal and microbial oils at a weight ratio of 0.70:0.18:0.11:0.004:0.007 to simulate fatty acids in human milk fat (HMF) according to the mathematical model. The main and important fatty acids in the Final-HMFS were within the ranges of those present in HMF. The Final-HMFS could promote the absorption of fats and minerals and the development of retina tissues in infants. The mixture of L-ascorbyl palmitate (L-AP) and vitamin E (VE) resulted in a synergistic antioxidant effect both in OPO-HMFS and OPO-HMFS emulsions. This finding has great significance in improving the quality and extending shelf-life of HMFS.

Potential Role of Oleanolic and Ursolic Acids from Food and Plant Materials as Natural Ingredients for the Cosmetic Industry: A Review

Cosmeceuticals have emerged as health and beauty aid products that integrate active ingredients from natural sources. Phytochemicals have prevailed in this market as an effective alternative toward different skin conditions. This is mainly due to the increasing demand for natural products that overcome the side effects of conventional treatments. Alopecia, acne, and skin aging are prevalent skin-related conditions worldwide. These conditions are characterized by high levels of inflammatory biomarkers and oxidative stress conditions. Oleanolic and ursolic acids are two biologically active pentacyclic triterpenoid isomeric compounds. They have shown strong potential for the prevention and treatment of diverse skin-related conditions through their effective antioxidant and anti-inflammatory capacity. This review presents the latest available information on the biological potential of oleanolic and ursolic acids, highlighting their cosmeceutical potential. In the pursuit of a better understanding of their potential as natural ingredients of dermatological relevance, graphical analysis is provided to propose the molecular mechanisms involved in the effects of each skin-related condition.

Separation of diarylethene-based photoswitchable isomeric compounds by high-performance liquid chromatography and supercritical fluid chromatography.

Diarylethene-based photoswitches have become very popular over the last few decades for potential applications in chemistry, materials science, and biotechnology due to their unique physical and chemical properties. We report the isomeric separation of a diarylethene-based photoswitchable compound using high-performance liquid chromatography. The separated isomers were characterized by ultraviolet-visible spectroscopy and mass spectrometry confirmed the isomeric nature of the compounds. The isomers were purified by preparative high-performance liquid chromatography, providing fractionated samples to study the isomers individually. A total amount of 13mg of an isomer of interest was fractionated from a solution of 0.4mg/ml of the isomeric mixture. Because the preparative high-performance liquid chromatographic method required large quantities of solvent, we explored the use of supercritical fluid chromatography as an alternative separation mode which, to the best of our knowledge, is the first time this technique is used to separate diarylethene-based photoswitchable compounds. Supercritical fluid chromatography provided faster analysis times while maintaining sufficient baseline resolution for the separated compounds and consuming less organic solvent in the mobile phase compared to high-performance liquid chromatography. It is proposed that the supercritical fluid chromatographic method be upscaled and used in future fractionation of the diarylethene isomeric compounds, becoming a more environmentally benign approach for compound purification.

Molecular and Structural Characterization of Isomeric Compounds in Atmospheric Organic Aerosol Using Ion Mobility-Mass Spectrometry.

Secondary organic aerosol (SOA) formed through multiphase atmospheric chemistry makes up a large fraction of airborne particles. The chemical composition and molecular structures of SOA constituents vary between different emission sources and aging processes in the atmosphere, which complicates their identification. In this work, we employ drift tube ion mobility spectrometry with quadrupole time-of-flight mass spectrometry (IM-MS) detection for rapid gas-phase separation and multidimensional characterization of isomers in two biogenic SOAs produced from ozonolysis of isomeric monoterpenes, d-limonene (LSOA) and α-pinene (PSOA). SOA samples were ionized using electrospray ionization (ESI) and characterized using IM-MS in both positive and negative ionization modes. The IM-derived collision cross sections in nitrogen gas (DTCCSN2 ) for individual SOA components were obtained using multifield and single-field measurements. A novel application of IM multiplexing/high-resolution demultiplexing methodology was employed to increase sensitivity, improve peak shapes, and augment mobility baseline resolution, which revealed several isomeric structures for the measured ions. For LSOA and PSOA samples, we report significant structural differences of the isomer structures. Molecular structural calculations using density functional theory combined with the theoretical modeling of CCS values provide insights into the structural differences between LSOA and PSOA constituents. The average DTCCSN2 values for monomeric SOA components observed as [M + Na]+ ions are 3-6% higher than those of their [M - H]- counterparts. Meanwhile, dimeric and trimeric isomer components in both samples showed an inverse trend with the relevant values of [M - H]- ions being 3-7% higher than their [M + Na]+ counterparts, respectively. The results indicate that the structures of Na+-coordinated oligomeric ions are more compact than those of the corresponding deprotonated species. The coordination with Na+ occurs on the oxygen atoms of the carbonyl groups leading to a compact configuration. Meanwhile, deprotonated molecules have higher DTCCSN2 values due to their elongated structures in the gas phase. Therefore, DTCCSN2 values of isomers in SOA mixtures depend strongly on the mode of ionization in ESI. Additionally, PSOA monomers and dimers exhibit larger DTCCSN2 values (1-4%) than their LSOA counterparts owing to more rigid structures. A cyclobutane ring is present with functional groups pointing in opposite directions in PSOA compounds, as compared to noncyclic flexible LSOA structures, forming more compact ions in the gas phase. Lastly, we investigated the effects of direct photolysis on the chemical transformations of selected individual PSOA components. We use IM-MS to reveal structural changes associated with aerosol aging by photolysis. This study illustrates the detailed molecular and structural descriptors for the detection and annotation of structural isomers in complex SOA mixtures.

Multicomponent Anti-Kasha’s Rule Emission from Nanotubular Metal–Organic Frameworks for Selective Detection of Small Molecules

The peak photoluminescence (PL) of conventional fluorophores is independent of the excitation wavelength (called Kasha's rule), while the search of metal-organic framework materials with the so-called anti-Kasha's rule emission remains very limited. Herein, we report the observation of anti-Kasha's rule emission in a multicomponent PL three-dimensional nanotubular metal-organic framework (abbr. MOF-NT), [Zn(μ-L)(μ-bix)]n·0.33nH2O [H2L = biphenyl-3,5-dicarboxylic acid; bix = 1,4-bis(imidazole-1-ylmethyl)benzene]. The MOF-NT crystalline sample represents a notable example of strong excitation-dependent fluorescence from the ultraviolet to the visible spectral region. Moreover, by virtue of electronic flexibility and high PL efficiency, MOF-NT shows a discriminative PL response between isomeric nitroaromatic compounds. The work demonstrated the intrinsic anti-Kasha's rule emission in the crystalline-state MOF materials, providing new visions for the development of advanced solid-state emissive materials.

Triacylglycerols hydrolysis and hydroxy- and epoxy-fatty acids release during lactic fermentation of plant matrices: An extensive study showing inter- and intra-species capabilities of lactic acid bacteria

This study aims to show that lactic fermentation by selected starters can enrich plant matrices with hydroxy- and oxo-fatty acids. The behavior of 31 lactic acid bacteria strains was investigated during the fermentation of Persian walnut, which was selected as a model growth substrate due to its inherent lipids content. The content of the following free fatty acids increased in the majority of the fermented walnut samples: linoleic, α-linolenic, palmitic, and oleic acids. The increase of diacylglycerols and, especially, monoacylglycerols levels in fermented walnuts confirmed that strain-specific bacterial lipolytic activities hydrolyzed triacylglycerols during walnut fermentation. Twelve hydroxylated or epoxidized derivatives arising from oleic, linoleic, and linolenic fatty acids, in five groups of isomeric compounds, were also identified. In addition to the better-known lactobacilli, certain strains of Weissella cibaria, Leuconostoc mesenteroides, and Enterococcus faecalis emerged for their lipolytic activities and ability to release hydroxy- and epoxy-fatty acids during walnut fermentation.

Total Syntheses of Nominal and Actual Prorocentin.

The dinoflagellate-derived polyether prorocentin is a co-metabolite of the archetypical serine/threonine phosphatase inhibitor okadaic acid. Whereas a structural relationship cannot be missed and a biosynthetic link was proposed, it is currently unknown whether there is any parallel in the bioactivity profile of these natural products. However, it was insinuated in the past that the structure assigned to prorocentin might need to be revised. Indeed, re-examination of the published spectra cast doubts as to the constitution of the fused/spirotricyclic BCD-ring system in the core. To clarify this issue, a flexible synthesis blueprint was devised that allowed us to obtain the originally proposed structure as well as the most plausible amended structure. The key to success was late-stage gold-catalyzed spirocyclization reactions that furnished the isomeric central segments with excellent selectivity. The lexicon of catalytic transformations used to make the required cyclization precursors comprised a titanium-mediated ester methylenation/metathesis cascade, a rare example of a gold-catalyzed allylic substitution, and chain extensions via organocatalytic asymmetric aldehyde propargylation. A wing sector to be attached to the isomeric cores was obtained by Krische allylation, followed by a superbly selective cobalt-catalyzed oxidative cyclization of the resulting di-unsaturated alcohol with the formation of a 2,5-trans-disubstituted tetrahydrofuran; the remaining terminal alkene was elaborated into an appropriate handle for fragment coupling by platinum-catalyzed asymmetric diboration/oxidation. The assembly of the different building blocks to the envisaged isomeric target compounds proved that the structure of prorocentin needs to be revised as disclosed herein.

Differentiation between Isomeric 4,5-Functionalized 1,2,3-Thiadiazoles and 1,2,3-Triazoles by ESI-HRMS and IR Ion Spectroscopy.

A large variety of 1,2,3-thiadiazoles and 1,2,3-triazoles are used extensively in modern pure and applied organic chemistry as important structural blocks of numerous valuable products. Creation of new methods of synthesis of these isomeric compounds requires the development of reliable analytical tools to reveal the structural characteristics of these novel compounds, which are able to distinguish between isomers. Mass spectrometry (MS) is a clear choice for this task due to its selectivity, sensitivity, informational capacity, and reliability. Here, the application of electrospray ionization (ESI) with ion detection in positive and negative modes was demonstrated to be useful in structural studies. Additionally, interconversion of isomeric 4,5-functionalized 1,2,3-triazoles and 1,2,3-thiadiazoles was demonstrated. Application of accurate mass measurements and tandem mass spectrometry in MS2 and MS3 modes indicated the occurrence of gas-phase rearrangement of 1,2,3-triazoles into 1,2,3-thiadiazoles under (+)ESI-MS/MS conditions, independent of the nature of substituents, in line with the reaction in the condensed phase. Infrared multiple photon dissociation (IRMPD) spectroscopy enabled the establishment of structures of some of the most crucial common fragment ions, including [M+H-N2]+ and [M+H-N2-RSO2]+ species. The (-)ESI-MS/MS experiments were significantly more informative for the sulfonyl alkyl derivatives compared to the sulfonyl aryl ones. However, there was insufficient evidence to confirm the solution-phase transformation of 1,2,3-thiadiazoles into the corresponding 1,2,3-triazoles.

Geochemistry of Late Permian coals from the Moxinpo mine, Chongqing, Southwestern China: Emphasis on petrology, minerals, and organic matter

The indicative significance of organic matter in fossil fuels, particularly polycyclic aromatic compounds (PACs), is a current research hotspot. Petrology, minerals, and organic matter in Late Permian coals from the Moxinpo (MXP) mine located in Chongqing, southwestern China, were analyzed to evaluate the coal rank, coal-forming material source and thermal maturity of organic matter, and sedimentary environment of the peat swamp. Vitrinite and inertinite were dominated by collotelinite, collodetrinite, inertodetrinite, fusinite, and semifusinite. Owing to the high maturity of the coals, liptinite was not observed under the microscope. Clay (kaolinite) and pyrite were the primary minerals in the MXP coals, followed by calcite, quartz, trace amounts of anatase, gypsum, xenotime, and bastnaesite. The minerals in the MXP coals were authigenic primarily in the epigenetic stage. The extract yield of organic matter in coals was low (0.30%), and the saturated and aromatic fractions accounted for approximately 60% of the extractable organic matter. Low ratios of saturated to aromatic compounds reflected the terrestrial higher plants input and high maturity level of the coals. The extracted yield in the host rock samples was much lower than in the coals, while the proportion of saturated hydrocarbons was relatively high. The marine-continental transitional sedimentary environment, distribution of n-alkanes, ∑ C21−/∑ C22+, and pristane (Pr)/n-C17 vs. phytane (Ph)/n-C18 indicated that the organic matter originated from the input of terrestrial higher plants and was accompanied by the contribution of marine lower phytoplankton and aquatic organisms. The coal-forming environment of the coal seam was reductive according to the Pr/Ph and sulfur-containing compounds of dibenzothiophenes and benzonaphthothiophenes. The thermodynamic stability controls the presence of polycyclic aromatic hydrocarbons in extractable organic matter. Isomeric compounds with high stability had higher concentrations, such as 2-methylnaphthalene, 2,6 + 2,7-DMN, 4- methylbiphenyl, and 2- methylphenanthrene.

Supramolecular Isomerism of Coordination Compounds Based on the in Situ Formed [V2O3]4+ Core: Discrete and Chain-like Architectures

Supramolecular Isomerism of Coordination Compounds Based on the in Situ Formed [V2O3]4+ Core: Discrete and Chain-like Architectures

Next Challenges for the Comprehensive Molecular Characterization of Complex Organic Mixtures in the Field of Sustainable Energy.

The conversion of lignocellulosic biomass by pyrolysis or hydrothermal liquefaction gives access to a wide variety of molecules that can be used as fuel or as building blocks in the chemical industry. For such purposes, it is necessary to obtain their detailed chemical composition to adapt the conversion process, including the upgrading steps. Petroleomics has emerged as an integral approach to cover a missing link in the investigation bio-oils and linked products. It relies on ultra-high-resolution mass spectrometry to attempt to unravel the contribution of many compounds in complex samples by a non-targeted approach. The most recent developments in petroleomics partially alter the discriminating nature of the non-targeted analyses. However, a peak referring to one chemical formula possibly hides a forest of isomeric compounds, which may present a large chemical diversity concerning the nature of the chemical functions. This identification of chemical functions is essential in the context of the upgrading of bio-oils. The latest developments dedicated to this analytical challenge will be reviewed and discussed, particularly by integrating ion source features and incorporating new steps in the analytical workflow. The representativeness of the data obtained by the petroleomic approach is still an important issue.

Critical assessment of chromatographic metadata in publicly available metabolomics data repositories

IntroductionThe structural identification of metabolites represents one of the current bottlenecks in non-targeted liquid chromatography-mass spectrometry (LC–MS) based metabolomics. The Metabolomics Standard Initiative has developed a multilevel system to report confidence in metabolite identification, which involves the use of MS, MS/MS and orthogonal data. Limitations due to similar or same fragmentation pattern (e.g. isomeric compounds) can be overcome by the additional orthogonal information of the retention time (RT), since it is a system property that is different for each chromatographic setup.ObjectivesIn contrast to MS data, sharing of RT data is not as widespread. The quality of data and its (re-)useability depend very much on the quality of the metadata. We aimed to evaluate the coverage and quality of this metadata from public metabolomics repositories.MethodsWe acquired an overview on the current reporting of chromatographic separation conditions. For this purpose, we defined the following information as important details that have to be provided: column name and dimension, flow rate, temperature, composition of eluents and gradient.ResultsWe found that 70% of descriptions of the chromatographic setups are incomplete (according to our definition) and an additional 10% of the descriptions contained ambiguous and/or incorrect information. Accordingly, only about 20% of the descriptions allow further (re-)use of the data, e.g. for RT prediction. Therefore, we have started to develop a unified and standardized notation for chromatographic metadata with detailed and specific description of eluents, columns and gradients.ConclusionReporting of chromatographic metadata is currently not unified. Our recommended suggestions for metadata reporting will enable more standardization and automatization in future reporting.

Flavonols, lignans and diacetylenes from leaves of Hydrocotyle leucocephala Cham. & Schltdl. and aerial parts of H. bonariensis Comm. ex Lam

Chemical investigation of ethyl acetate and n-butanol fractions from methanol extracts from leaves of Hydrocotyle leucocephala Cham. & Schltdl. and aerial parts of H. bonariensis Comm. ex Lam. resulted in the identification of 6 compounds and a putative identification of 12 more, including thirteen glycosylated flavonols (1–13), two dibenzylbutyrolactone lignans (14 and 15) and three diacetylenes (16–18) based on UPLC-ESI-QToF-MS/MS analysis in the positive and negative ionization modes. In the case of compounds 3, 14–18, their structures were confirmed by analysis of NMR spectra. Compounds 5, 7, 10–12 or isomeric compounds of them were identified for the first time in this genus. The obtained results contribute with chemotaxonomy of Hydrocotyle since flavonoids, dibenzylbutyrolactone lignans, and diacetylenes were characterized, in consonance with other species previously investigated.

Complementary Mass Spectral Analysis of Isomeric O-bearing Organic Compounds and Fragmentation Differences through Analog Techniques for Spaceborne Mass Spectrometers

Mass spectrometers on board spacecraft typically use either impact ionization or electron ionization (EI) as ion sources. Understanding the similarities and differences in the spectral signatures and fragmentation patterns produced by different techniques in mass spectrometry could elucidate the composition of organic compounds. Here we present a comparison between the mass spectra obtained through laser-induced liquid beam ion desorption (LILBID; proven to simulate the impact ionization mass spectra of ice grains) and EI mass spectra of pairs of low-mass, isomeric aldehydes and ketones. Our comparison confirms that EI produces more fragmentation of carbonyl compounds, particularly aldehydes, than LILBID. We find protonated molecular ions [M+H]+ in LILBID but molecular ions [M]+ in EI spectra. From the evaluated species, LILBID generally produces oxygen-carrying fragment ions (e.g., [CHO]+ and [C2H3O]+) in the mass ranges 26–30 and 39–44 u, while in EI, most ions in these ranges correspond to hydrocarbon fragments. The LILBID spectra additionally show mostly protonated oxygen-bearing fragments [CH3O]+ and [C2H5O]+ at m/z 31 and 45, less commonly observed in EI spectra. We observe a decrease in the relative intensities of cation fragment mass lines between m/z 26 and 33 and an increase between m/z 39 and 45, with an increasing carbon number for ketones and aldehydes with LILBID and EI, respectively. Our study provides a basis for complementary compositional analysis to identify the structural properties of organic species in a space environment using different spaceborne mass spectrometers (e.g., SUrface Dust Analyzer and MAss Spectrometer for Planetary EXploration) on board NASA’s future Europa Clipper space mission.

Commelina benghalensis (Wandering Jew) Linn exhibits abortifacient potentials and hepatotoxicity in pregnant Wistar rats via elevating indicators of oxidative stress and activating proinflammatory cytokines

Ethnopharmacological relevanceCommelina benghalensis Linn is a perennial plant with upright stems reaching a height of 1 m. Its stem is commonly used to induce abortion in traditional medicine. However, there are insignificant scientific data to evaluate such a claim. Aim of the studyThe study was conducted to determine the abortifacient and toxicological potential of ethanol extract of Commelina benghalensis Linn stem (EECBS) via selected proinflammatory and oxidative stress biomarkers in pregnant Wistar rats. Materials and methodsTo determine the phytochemicals responsible for EECBS's toxicity and abortifacient effects, high-performance liquid chromatography–photodiode array detection (HPLC-PDA) and gas chromatography-mass spectrometry (GC-MS) was used. The abortion rate was determined by monitoring the markers of reproductive system failure in the experimental model. To assess rat hepatotoxicity, biochemical markers and immunohistopathological parameters were used. ResultsResults demonstrated the presence of isomeric benzene-mesitylene compounds in EECBS. Also, EECBS significantly altered the markers of liver function and oxidative damage while eliciting a significantly reduced (P < 0.05) number of live fetuses, number of corpora lutea, progesterone, estradiol, and luteinizing hormone, whereas the number of dead fetuses percentage vaginal opening, and post-implantation loss increased significantly (P < 0.05). Estrogenicity studies indicated a significant (P < 0.05) increase in uterine weight, uterine glucose, and ALP dose-dependently. Moreover, EECBS also caused a vaginal hemorrhage preceding the parturition. Also, EECBS treatment significantly increased levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and significantly elevated the expression of COX-2 protein in the liver. ConclusionThe current investigation established Commelina benghalensis Linn stem's abortifacient activity. Continuous use, on the other hand, may cause liver damage in pregnant rats by disrupting antioxidant defense mechanisms, promoting the production of pro-inflammatory cytokines, and increasing COX-2 expression. Hence, caution should be excised while consuming this plant's stem for medication purposes, especially during the gestational period.

Developing intrinsic halogen-free and phosphorus-free flame retardant biobased benzoxazine resins with superior thermal stability and high strength

Endowing intrinsic halogen-free and phosphorus-free flame retardant biobased benzoxazine resins (biobased content > 50 %) with ultrahigh thermal stability and high strength is still an important and challenging issue. Herein, starting from citraconic anhydride and para-aminophenol or ortho-aminophenol, two isomeric phenolic compounds containing citraconimide groups, pCI and oCI, were designed and synthesized, each of which then reacted with furfurylamine and paraformaldehyde to synthesize novel para-functionalized benzoxazine monomer (pCI–fa) or ortho-functionalized benzoxazine monomer (oCI–fa). Results show that pCI–fa and oCI–fa have excellent processability, represented by low melting point (pCI–fa: 150.0 °C, oCI–fa: 127.7 °C) and low curing temperature (pCI–fa: 217.6 °C, oCI–fa: 205.5 °C); moreover, interestingly, there is no Diels-Alder reaction between citraconimide and furan groups. The cured resin from pCI–fa or oCI–fa, coded as poly(pCI–fa) or poly(oCI–fa), has outstanding thermal resistance, tensile properties and flame retardancy. Especially, poly(pCI-fa) has better integrated performance than poly(oCI–fa), and the initial thermal decomposition temperature (Tdi) of poly(pCI-fa) is as high as 391 °C, obviously higher than the those of all halogen-free and phosphorus-free flame retardant biobased benzoxazine resins (the biobased content > 50 %) reported in SCI database by 3 August 2022. The mechanism behind the integrated performances was discussed.