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Lipid metabolism plays a crucial role in maintaining bone homeostasis, particularly in osteoclasts (OCs) formation. Here, we found that the expression level of FATP2, a transporter for long-chain and very-long-chain fatty acids, was significantly upregulated during OC differentiation and in the bone marrow of mice fed a high-fat diet (HFD). Notably, the use of FATP2 siRNA or a specific inhibitor (Lipofermata) resulted in significant inhibition of OC differentiation, while only slightly affecting osteoblasts. In pathological models of bone loss induced by LPS or ovariectomy, in vivo treatment with Lipofermata was able to rescue the loss of bone mass by inhibiting OC differentiation. RNA sequencing revealed that Lipofermata reduced fatty acid β-oxidation and inhibited energy metabolism, while regulating ROS metabolism to decrease ROS production, ultimately inhibiting OC differentiation. Treatment with Lipofermata, either in vivo or in vitro, effectively rescued the overactivation of OCs, indicating that FATP2 regulated OC differentiation by modulating fatty acid uptake and energy metabolism. These findings suggested that targeting FATP2 may represent a promising therapeutic approach for pathological osteoporosis. Lay Summary: The inhibition of osteoclastogenesis by Lipofermata, a FATP2 inhibitor, was achieved through the reprogramming of energy metabolism and regulation of ROS levels. In both pathological bone loss and HFD-induced osteoporosis models, the expression levels of FATP2 were significantly upregulated, and Lipofermata demonstrated potential therapeutic effects in the pathological bone loss model. Graphical Abstract [ABSTRACT FROM AUTHOR]

Peroxynitrite (ONOO−) is a potent bio-oxidant involved in many physiological and pathological processes; however, most of the pathological effects associated with ONOO−in vivo are still ambiguous. Herein, we designed and synthesized two near-infrared ratiometric fluorescent probes, Ratio-A and Ratio-B, for the detection and biological evaluation of ONOO−. The recognition unit diene in the probes could be specifically cleaved by ONOO− with a 94-fold enhancement in the ratiometric fluorescence signal. By imaging ONOO− in immune stimulated cells and acute inflammation mice model using Ratio-A, we investigated the fluctuations of ONOO− levels in a rheumatoid arthritis (RA) model of mice. Ratio-A could be applied for the effective imaging of RA and could rapidly evaluate the response of the RA treatment with methotrexate (MTX). Thus, Ratio-A can be considered as a promising tool for pathological diagnosis and the therapeutic assessment of a wide range of diseases including RA. [ABSTRACT FROM AUTHOR]

A novel switchable solvent liquid-phase microextraction technique, based on the solidification of floating organic droplets (SS-LPME-SFO), was developed for the pretreatment of aqueous samples. In this process, octanoic acid was selected as the extractant due to its low density, moderate melting point, and ability to switch between hydrophilic and hydrophobic characteristics. This technique has been successfully applied in the enrichment of five polycyclic aromatic hydrocarbon monohydroxy metabolites (OH-PAHs) in urine samples. Furthermore, a HPLC-FLD detection procedure was established to analyze the samples. A series of parameters affecting the extraction were systematically studied. Under the optimal conditions, all analytes showed good linearity within the studied range, and the values of the correlation coefficient (R2) were higher than 0.99. The limits of detection (LODs) and the limits of quantitation (LOQs) were within the range of 0.018–0.076 μg L−1 and 0.059–0.25 μg L−1, respectively. The method also achieved good recoveries, ranging between 88.5% and 102.5%. Overall, the method is highly cost-effective, environmentally-friendly, fast and efficient. This study proposes an efficient extraction method for the analysis of most organic pollutants in complex environmental aqueous phases. [ABSTRACT FROM AUTHOR]

A sensitive method was developed for the simultaneous detection of four nitrofuran (NF) metabolites (3-amino-2-oxazolidinone (AOZ), semicarbazide (SEM), 3-amino-morpholinomethyl-2-oxazolidinone (AMOZ) and 1-aminohydantoin (AH)) in marine products. Samples were derivatized using 7-(diethylamino)-2-oxochromene-3-carbaldehyde (DAOC) under the assistance of a microwave within 20 min, followed by analysis by high performance liquid chromatography–fluorescence detection (HPLC-FLD). These NF metabolite derivatives were completely separated on a reversed-phase Eclipse XDB-C18 column within 10 min at specific excitation and emission wavelengths (λex = 450 and λem = 510 nm). Excellent linearity (R ＞ 0.998) of all NF metabolite compounds was achieved with the limits of detection (LODs) and the limits of quantitation (LOQs) in the range of 0.22–0.29 μg kg−1 and 0.69–0.95 μg kg−1, respectively. Satisfactory recoveries ranging from 91.39–104.93% were obtained for all the NF metabolites. This method was successfully applied for the identification and quantitation of the NF metabolites in marine products. Furthermore, the proposed method should have powerful potential in the analysis of AOZ, AH, AMOZ and SEM in foodstuffs. [ABSTRACT FROM AUTHOR]

In this study, a simple analytical method for the determination of γ‐aminobutyric acid, gabapentin, and baclofen by using high‐performance liquid chromatography with fluorescence detection was developed. An amidogen‐reactive fluorescence labeling reagent, 4‐(carbazole‐9‐yl)‐benzyl chloroformate was first used to sensitively label these analytes. The completed labeling of these analytes can be finished rapidly only within 5 min at the room temperature (25°C) to form 4‐(carbazole‐9‐yl)‐benzyl chloroformate labeled fluorescence derivatives. These labeled derivatives expressed strong fluorescence property with the maximum excitation and emission wavelengths of 280 and 380 nm, respectively. The labeled derivatives were analyzed using a reversed‐phase Eclipse SB‐C18 column within 10 min with satisfactory shapes. Excellent linearity (R2 > 0.995) for all analytes was achieved with the limits of detection and the limits of quantitation in the range of 0.25−0.35 and 0.70−1.10 μg/L, respectively. The proposed method was used for the simultaneous determination of γ‐aminobutyric acid and its analogs in human serum with satisfactory recoveries in the range of 94.5–97.5%. [ABSTRACT FROM AUTHOR]

Abstract A rapid and efficient method for extraction of 12 phenoxy carboxylic acids (PCAs) in environmental water samples was established based on metal–organic framework MIL-101 assisted dispersive solid phase extraction (DSPE). 12 PCAs were labeled by d 0 -10-methyl-2-(piperazin-1-ylsulfonyl)anthracen-9(10H)-one(d 0 -MASPz) and d 3 -10-methyl-2-(piperazin-1-ylsulfonyl)anthracen-9(10H)-one(d 3 -MASPz), allowing each analyte to have an isotope internal standard. A stable isotope-coded strategy for the detection of 12 PCAs was developed under optimized extraction conditions and UHPLC-MS/MS conditions. All PCAs analytes were in good linearity in the concentration range of 5–1000 ng/L, and the calibration function was verified by the Mandel fitting test with a 95% confidence level. The LODs and LOQs were estimated by the IUPAC's recommendations. The LODs ranged from 0.18 to 0.88 ng/L, and LOQs ranged from 0.59 to 2.90 ng/L. The intra-day and inter-day precision in three spiked levels (5, 50 and 100 ng/L) were in the range of (1.40 ± 0.14) %– (2.76 ± 0.12) % and (2.60 ± 0.26) %– (3.83 ± 0.32) %, respectively. The developed method has been successfully applied to the determination of PCAs in environmental water samples with recoveries ranging from 95.3% to 105.5%. All of the precision and recovery analyses were done in triplicate. Graphical abstract Scheme of dispersive solid phase extraction and relative quantification fx1 Highlights • The MOF material MIL-101 was first used as adsorbent to enrich PCAs from environmental water samples. • An isotope-coded strategy for determination of PCAs was developed, allowing each analyte to have an isotope internal standard. • PCAs in environmental water samples were quantified on the basis of isotope-coded strategy by UHPLC-MS/MS. [ABSTRACT FROM AUTHOR]

Urinary aromatic diamines are exposure biomarkers of diisocyanate which are highly irritating to skin, mucosa and the upper respiratory system. In this study, a highly sensitive and selective high-performance liquid chromatography-fluorescence detection (HPLC-FLD) method was developed for determination of three aromatic diamines, 4,4′-methylenedianiline (MDA), 2,4-toluenediamine (4TDA) and 2,6-toluenediamine (6TDA) exposed to corresponding diisocyantes in human urine. The whole idea is based on an intramolecular excimer-forming fluorescence derivatization using 4-(1-pyrene)butanoyl chloride (PBC), followed by performing HPLC-FLD analysis.The resulting polypyrene-labeled derivatives of these aromatic diamines provided intramolecular excimer fluorescence at the emission wavelength of 475 nm wavelengths, which was shifted markedly to the higher emission wavelengths as compared with the wavelengths of the pyrene monomer. Under this condition, interferences such as amino acids and biogenic monoamines gave no peaks. It was found that using PBC derivatization, it was possible to improve the sensitivity and selectivity toward aromatic diamines. The limits of detection (LODs) were in the range of 0.30–0.52 ng/L, while the limits of quantitation (LOQs) between 1.05 and 1.63 ng/L. The intraday and interday precision was in the range of 3.6–4.5% and 4.1–5.7%, respectively. The proposed method was successfully applied to the quantitation of these exposure biomarkers in human urine samples. [ABSTRACT FROM AUTHOR]

A new fluorescence labeling reagent 1-(4-(1 H-phenanthro[9,10-d]imidazol-2-yl)phenyl)-1 H-pyrrole-5-dione (PIPD) used for the sensitive determination of thiols in food samples has been successfully prepared. Thiols were extracted by a gas purge microsyringe extraction (GP-MSE) device. The derivatization of PIPD with thiols could be finished within 10 minutes at 35 °C in weak alkaline condition, and the corresponding derivatives showed excellent fluorescence properties with excitation and emission wavelengths of 264 nm and 396 nm, respectively. The eight thiol derivatives could be easily separated on normal reversed phase column because of the introduction of highly hydrophobic PIPD unit into the target analytes. It is the first time that GP-MSE has been applied to the extraction of a wide range of thiols in food samples with only a small amount of methanol (0.5 mL) needed. The limits of detection (LODs) were in the range of 0.19-0.98 µg/kg, while the recoveries were in the range of 85.6%-97.1% with relative standard deviations (RSDs) < 4.98%. Good linearities were observed for all analytes with correlation coefficients of higher than >0.9995.GRAPHICAL ABSTRACT [ABSTRACT FROM AUTHOR]

A rapid and sensitive reversed-phase high performance liquid chromatography– fluorescence-mass spectrometer (RP-HPLC–FLD-MS) method based on pre-column derivatization using 2-(5-benzoacridine)ethyl-p-toluenesulfonate (BAETS) as labelling reagent has been developed for simultaneous determination of five triterpenic acids (asiatic acid (AA), maslinic acid (MA), corosolic acid (CA), oleanolic acid (OA), and betulinic acid (BA). The presented method was validated for linearity (correlation coefficient R2 > 0.9994), precision (RSD 2.1%–3.9%) and reproducibility (RSD 0.01%–2.1%). The limits of detection (LODs) and the limits of quantitation LOQs were within the range of 0.71–1.02 ng mL−1and 2.28–3.24 ng mL−1, respectively. The proposed method was successfully applied to simultaneously determine five triterpenic acids of fourCorydalisplants and showed satisfactory reproducibility and credibility. Moreover, several main parameters affecting extraction procedure and derivatization efficiency were investigated by response surface methodology (RSM), respectively. Triterpenic acid content in fourCorydalisplants was measured according to the established method and the results indicated that triterpenic acid contents were various in different organs and herbs. [ABSTRACT FROM AUTHOR]

Caragana korshinskii Kom. (CK), one of afforestation tree species, is widely planted in northwest region of China. To compare the constituents as references for further utilization of CK, C. microphyll Lam. (CM) and C. jubata L. (CJ), been used as traditional Chinese medicine, were taken into consideration. To obtain more information on CK for further utilization, a sensitive and stable pre-column derivatization method for the analysis of fatty acids (FAs) was established using a novel labeling reagent 2-(5H-benzo[a]-carbazol-11(6H)-yl)ethyl hydrazine-carboxylate (BCEHC) by HPLC with fluorescence detector. The derivatives exhibit predominant fluorescence property at excitation and emission wavelengths of 330 nm and 380 nm, respectively. 16 derivatives of FAs including 13 saturated FAs and 3 unsaturated FAs are separated on a reversed-phase column with gradient elution within 30 min. The validation of method indicated that all FAs were given excellent linear responses with good linear coefficient of correlation being equal to or greater than 0.9985. The limits of detection (LODs) at a signal-to-noise ratio of 3 varied from 63.12 to 116.21 ng L −1 . The developed method was successfully applied to determine the contents of free FAs (FFAs) in flowers, leaves and bark of CK and the samples were extracted by a green and simple method of gas purge microsyringe extraction. The results show that the contents of linoleic acid and linolenic acid are high in flowers and leaves while the bark is rich in linoleic acid. The total content of FFAs in all parts of CK is higher than that of CM. The distribution of FFAs in plants is obviously different even in the congeneric among different species. [ABSTRACT FROM AUTHOR]

A new fluorescent labeling reagent, benzimidazo[2,1- b]quinazolin-12(6 H)-one-5-ethyl- p-toluenesulfonate (BQETS) was designed and synthesized, and it was successfully applied to the determination of fatty acids with liquid chromatography. BQETS can easily and quickly label fatty acids within 20 min at 90 °C in dimethylformamide with KCO as catalyst. The derivatives exhibit high stability and strong fluorescence with excitation and emission wavelengths of 247 and 401 nm, respectively. The 24 derivatives of fatty acids were completely separated by gradient elution on a Hypersil GOLD C18 column. Excellent linear responses for all fatty acids were observed with correlation coefficients of >0.9991. The method also showed good sensitivity and precision, with limits of detection in the 0.0024-0.0206 μg g range and relative standard deviations ≤9.6 %. This is the first time that BQETS fluorescent probe and its applications for the determination of fatty acids have been reported. Moreover, this is the first report on the comparison of free fatty acids composition in the above-ground part of Coriandrum sativum L. from different habitats in China. [ABSTRACT FROM AUTHOR]

Hippophae rhamnoidesL., a fruit which is rich in natural chemical ingredients, has become an important raw material of health food, medicine, and cosmetics. In the present work, a method using 2-(5-benzoacridine)ethyl-p-toluenesulfonate as pre-column derivatization reagent with high sensitivity, selectivity, and short separation time was developed to analyze triterpenic acids (TTAs) inH. rhamnoidesL. by HPLC with fluorescence detection and simultaneously confirmed by post-column atmospheric pressure chemical ionization-mass spectrometry. The method was validated by linearity, limits of detection (LODs) and lower limits of quantification (LLOQs), precision, and accuracy. Good linear correlations were observed for all TTAs with correlation coefficients greater than 0.9996. LODs and LLOQs were in the range of 1.71–2.14 and 7.45–8.23 ng mL−1, respectively. The method was successfully employed to analyze TTAs inH. rhamnoidesL. from various origins in the Qinghai–Tibetan plateau with trace amount of samples within 15 min. A systemic mapping of the TTAs inH. rhamnoidesL. of different origins was established. The results indicated thatH. rhamnoidesL. is rich in TTAs, especially in oleanolic and ursolic acids, and the content of TTAs varies across origins. This work will support the research on pharmaceutical applications ofH. rhamnoidesL. and provide information for quality control. [ABSTRACT FROM PUBLISHER]

A novel fluorescence method using 2-(7-methyl-1H-pyrazolo-[3,4-b] quinoline-1-yl) ethyl-4-methyl benzenesulfonate as the labeling reagent was established for high-performance liquid chromatography determination of fatty acids. The conditions were optimized, including the identity of the organic solvent, identity, and amount of catalyst, amount of derivatization reagent, derivatization temperature, and derivatization time. The results indicated that quantitative yields of derivative were obtained with a five-fold molar excess of reagent at 90°C for 30 min using 25 mg of potassium carbonate as the catalyst. Atmospheric pressure chemical ionization mass spectrometry results indicated that collision-induced dissociation of protonated fatty acid derivatives produced fragments atm/z228.2,m/z210.2, andm/z183.8. The method was validated in terms of linearity, limits of detection, limits of quantification, precision, and accuracy, and the results showed that the method exhibited excellent sensitivity, selectivity, and reproducibility. Limits of detection and limits of quantification were in the ranges of 0.52–2.34 ng mL−1and 1.23–6.63 ng mL−1, respectively. This method was successfully applied to the determination of fatty acids in sarcocarps, seeds, and leaves ofNitraria tangutorumBobr.,Nitraria sibiricaPall., andNitraria roborowskiiKom. The results indicated that the main components were oleic, linoleic, linolenic, and hexadecanoic acids. However, the composition of fatty acids in the tissues varied considerably. [ABSTRACT FROM AUTHOR]

A new fluorescent labeling reagent has been developed for the determination of fatty acids (FAs) by HPLC with fluorescence detection. The derivatization conditions including the amount of derivatization reagent, temperature, and type of catalyst were investigated, the results indicated that the reaction proceeded within 30 min at 90°C in the presence of K2CO3 catalyst. The maximal yield was obtained with a four- to fivefold molar reagent excess. The derivatives exhibited strong fluorescence with an excitation maximum at λex = 245 nm and an emission maximum at λem = 410 nm. Twenty-five FA derivatives were well separated by RP-HPLC on a Hypersil BDS C8 column in combination with gradient elution. All FAs were found to give excellent linear responses with correlation coefficients >0.9992. The method gave a low LOQ of 0.85-5.5 ng/mL (S/N of 10). The developed method was employed to analyze free FAs (FFAs) composition in pomegranate samples without any purification. FFAs in samples were doubly identified by HPLC retention time and protonated molecular ion corresponding to m/ z [M+H]+. This newly developed method allows a highly sensitive determination of trace FFAs from pomegranate and other foodstuffs. [ABSTRACT FROM AUTHOR]

A new fluorescence labeling reagent 2-(12-benzo[ b]acridin-5(12 H)-yl)-acetohydrazide (BAAH) has been designed for fatty acids labeling. Eleven fatty acids containing seven saturated and four unsaturated fatty acids were used to evaluate the analytical potential of this reagent. The labeling reaction of BAAH with fatty acids was completed at 85 °C for 60 min using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC·HCl) as the condensing agent. Separation of the derivatized fatty acids was carried out on a reversed-phase Thermo Hypersil Gold C18 column (4.6 mm × 250 mm, 5 μm) in combination with a gradient elution with a good baseline resolution. The fluorescence excitation and emission wavelengths were set at λ 280 and λ 510 nm, respectively. The identification was carried out by the online APCI-MS in positive-ion detection mode. Linear correlation coefficients for all fatty acid derivatives were of >0.9994. Detection limits, at a signal-to-noise ratio of 3:1, were 3.89-12.5 nmol L for the labeled fatty acids. The developed method was successfully applied to the accurate determination of fatty acids in five traditional Chinese herbs with satisfactory results. [ABSTRACT FROM AUTHOR]

Sample pretreatment is a critical and essential step in almost all analytical procedures, especially for the analysis of biological and environmental samples with complex matrices. Dopamine molecules can easily self-polymerize under weak alkaline conditions, leading to a facile deposition of polydopamine (PDA) coatings on various surfaces. Since 2011, PDA chemistry has undergone significant expansion in its applications and is becoming one of the most attractive areas within the materials field. Here, recent advancements in the use of PDA-derived adsorbents for sample pretreatment were reviewed, with especial focus on surface modification strategies, extraction modes, and application fields. In addition, prospects of PDA-derived adsorbents for sample pretreatment are also proposed. [ABSTRACT FROM AUTHOR]

Mechanistically, S1P deficiency impeded COP II-mediated transport vesicles formation, which leads to proteins retention in the endoplasmic reticulum (ER) and subsequently ER distension. ER distension increased the contact between the ER and mitochondria, disrupting ER-to-mitochondria calcium flow, resulting in mitochondrial dysfunction and energy metabolism disturbance. Finally, using 2-APB to inhibit calcium ion channels and the senolytic drug dasatinib and quercetin (D + Q) partially rescued the aging and degenerative phenotypes caused by S1P deficiency. In conclusion, our findings suggest that S1P is a critical factor in causing IVDD in the process of aging and highlight the potential of targeting S1P as a therapeutic approach for age-related IVDD.