The fabrication of a gold nanoelectrode-nanopore nanopipette for dopamine enrichment and multimode detection.

It is important to further improve the electrophysiology and electrochemistry techniques of neurotransmitter detection. Here, we report the development of multifunctional nanopipette-based integrated approaches for the detection of neurotransmitters. We successfully fabricated a nanopipette with two independent functional units at the apex, a nanopore and a gold nanoelectrode (GNE). The GNE shows good electrochemical response to dopamine (DA). Furthermore, both the nanopore and nanoelectrode can effectively enrich DA but not ascorbic acid by electrical means. The enriched DA is then detected and analysed with an obviously improved signal-to-noise ratio by electrochemical methods and surface-enhanced Raman spectroscopy (SERS). In addition, with the addition of silver nanoparticles during enrichment, up to 10 times increase of the Raman intensity of DA can be observed.

The effect of ethanol extract of Glycyrrhiza uralensis on the voltage-gated sodium channel subtype 1.4.

To investigate the inhibitory effect of Glycyrrhiza uralensis (G. uralensis) and its monomeric compounds on Nav1.4 voltage-gated sodium channels (VGSCs) and analyze the relationship between the content of its marker compounds and the inhibitory rate. Based on this study, we found that 4 mg/ml ethanol extract of G. uralensis at 30%, 50%, 70% and 90% (v/v) exhibited 77.00 ± 0.03%, 34.75 ± 0.09%, 100.00 ± 0.01% and 2.00 ± 0.01% inhibitory rates on INav1.4 respectively, and 8 mg/ml ethanol extract of G. uralensis at 30%, 50%, 70% and 90% (v/v) exhibited 99.00 ± 0.01%, 97.10 ± 0.02%, 100.00 ± 0.01% and 17.00 ± 0.04% inhibitory rates on INav1.4 respectively. Isoliquiritigenin, echinatin, liquiritin and glycyrrhizic acid exhibited higher inhibitory rates of 39.98 ± 4.55%, 33.20 ± 1.61%, 22.62 ± 0.30% and 20.54 ± 4.82% respectively. However, liquiritigenin, formononetin, neoisoliquiritin and glycyrrhetinic acid exhibited lower inhibitory rates of less than 20%. Further, liquiritin apioside, isoliquiritin and neoliquiritin exhibited almost no effect on INav1.4. These findings showed that glycyrrhizic acid reached a maximum concentration of 49.15 µg/ml, while echinatin had the lowest concentration. The ethanol extract of G. uralensis has significant inhibitory effects on Nav1.4 VGSCs. This may be an important mechanism in the treatment of gastrocnemius spasm and could guide further research regarding material basis and mechanism of the treatment of gastrocnemius spasm with peony and licorice decoction.

Screening and Identification of the Metabolites in Rat Plasma and Urine after Oral Administration of Areca catechu L. Nut Extract by Ultra-High-Pressure Liquid Chromatography Coupled with Linear Ion Trap-Orbitrap Tandem Mass Spectrometry.

Areca catechu L. nut, a well-known toxic traditional herbal medicine, has been widely used to treat various diseases in China and many other Asian countries for centuries. However, to date the in vivo absorption and metabolism of its multiple bioactive or toxic components still remain unclear. In this study, liquid chromatography coupled with tandem mass spectrometry was used to analyze the major components and their metabolites in rat plasma and urine after oral administration of Areca catechu L. nut extract (ACNE). A total of 12 compounds, including 6 alkaloids, 3 tannins and 3 amino acids, were confirmed or tentatively identified from ACNE. In vivo, 40 constituents, including 8 prototypes and 32 metabolites were identified in rat plasma and urine samples. In summary, this study showed an insight into the metabolism of ACNE in vivo, which may provide helpful chemical information for better understanding of the toxicological and pharmacological profiles of ACNE.

Cascade strategy for glucose oxidase-based synergistic cancer therapy using nanomaterials.

Nanomaterial-based cancer therapy faces significant limitations due to the complex nature of the tumor microenvironment (TME). Starvation therapy is an emerging therapeutic approach that targets tumor cell metabolism using glucose oxidase (GOx). Importantly, it can provide a material or environmental foundation for other diverse therapeutic methods by manipulating the properties of the TME, such as acidity, hydrogen peroxide (H2O2) levels, and hypoxia degree. In recent years, this cascade strategy has been extensively applied in nanoplatforms for ongoing synergetic therapy and still holds undeniable potential. However, only a few review articles comprehensively elucidate the rational designs of nanoplatforms for synergetic therapeutic regimens revolving around the conception of the cascade strategy. Therefore, this review focuses on innovative cascade strategies for GOx-based synergetic therapy from representative paradigms to state-of-the-art reports to provide an instructive, comprehensive, and insightful reference for readers. Thereafter, we discuss the remaining challenges and offer a critical perspective on the further advancement of GOx-facilitated cancer treatment toward clinical translation.

Screening of Lactiplantibacillus plantarum with High Stress Tolerance and High Esterase Activity and Their Effect on Promoting Protein Metabolism and Flavor Formation in Suanzhayu, a Chinese Fermented Fish.

In this study, three Lactiplantibacillus plantarum, namely 3-14-LJ, M22, and MB1, with high acetate esterase activity, acid, salt, and high-temperature tolerance were selected from 708 strains isolated from fermented food. Then, L. plantarum strains MB1, M22, and 3-14-LJ were inoculated at 107 CFU/mL in the model and 107 CFU/g in actual Suanzhayu systems, and the effects during fermentation on the physicochemical properties, amino acid, and volatile substance were investigated. The results showed that the inoculated group had a faster pH decrease, lower protein content, higher TCA-soluble peptides, and total amino acid contents than the control group in both systems (p < 0.05). Inoculation was also found to increase the production of volatile compounds, particularly esters, improve the sour taste, and decrease the bitterness of the product (p < 0.05). L. plantarum M22 was more effective than the other two strains in stimulating the production of isoamyl acetate, ethyl hexanoate, and ethyl octanoate. However, differences were discovered between the strains as well as between the model and the actual systems. Overall, the isolated strains, particularly L. plantarum M22, have good fermentation characteristics and have the potential to become excellent Suanzhayu fermenters in the future.

Impact of metabolic stress induced by diets, aging and fasting on tissue oxygen consumption.

OBJECTIVE: Alterations in mitochondrial function play an important role in the development of various diseases, such as obesity, insulin resistance, steatohepatitis, atherosclerosis and cancer. However, accurate assessment of mitochondrial respiration ex vivo is limited and remains highly challenging. Using our novel method, we measured mitochondrial oxygen consumption (OCR) and extracellular acidification rate (ECAR) of metabolically relevant tissues ex vivo to investigate the impact of different metabolic stressors on mitochondrial function. METHODS: Comparative analyses of OCR and ECAR were performed in tissue biopsies of young mice fed 12 weeks standard-control (STD), high-fat (HFD), high-sucrose (HSD), or western diet (WD), matured mice with HFD, and 2year-old mice aged on STD with and without fasting. RESULTS: While diets had only marginal effects on mitochondrial respiration, respiratory chain complexes II and IV were reduced in adipose tissue (AT). Moreover, matured HFD-fed mice showed a decreased hepatic metabolic flexibility and prolonged aging increased OCR in brown AT. Interestingly, fasting boosted pancreatic and hepatic OCR while decreasing weight of those organs. Furthermore, ECAR measurements in AT could indicate its lipolytic capacity. CONCLUSION: Using ex vivo tissue measurements, we could extensively analyze mitochondrial function of liver, AT, pancreas and heart revealing effects of metabolic stress, especially aging.

Quantitative Determination of 7 Saikosaponins in Xiaochaihu Granules Using High-Performance Liquid Chromatography with Charged Aerosol Detection.

Bupleuri Radix (Chaihu, in Chinese) is the principal drug in Xiaochaihu granules (XGs) that is a famous Chinese medicine preparation in China. Since previous analytical methods have not focused on the multiactive saikosaponins of Chaihu, it is difficult to effectively control the quality of XG on the market. In this manuscript, the simultaneous determination of 7 saikosaponins (saikosaponins C, I, H, A, B2, G, and B1) in XG by HPLC with charged aerosol detection (CAD) and confirmation by LC-Q-Orbitrap HRMS were described. The saikosaponins were purified on an SPE cartridge and determined on a Waters CORTECTS C18 column (4.6 mm × 150 mm, 2.7 µm) by gradient elution using 0.01% acetic acid aqueous solution and acetonitrile. The results showed good linearity with the r 2 values higher than 0.998 for all analytes. The average recoveries at three different concentration levels ranged from 80% to 109% and the intraday and interday precision (relative standard deviations, RSD%) were in the range of 1.0%∼1.9% and 1.4%∼2.1%, respectively. The established HPLC-CAD method was subsequently applied to 15 batches of XG to investigate the batch-to-batch consistency and controllability. The proposed method could potentially be used for the quality control of XG and also be helpful in the quality evaluation of Chaihu and its related preparations.

Lipase Addition Promoted the Growth of Proteus and the Formation of Volatile Compounds in Suanzhayu, a Traditional Fermented Fish Product.

This work investigated the effect of lipase addition on a Chinese traditional fermented fish product, Suanzhayu. The accumulation of lactic acid and the decrease of pH during the fermentation were mainly caused by the metabolism of Lactobacillus. The addition of lipase had little effect on pH and the bacterial community structure but promoted the growth of Proteus. The addition of lipase promotes the formation of volatile compounds, especially aldehydes and esters. The formation of volatile compounds is mainly divided into three stages, and lipase had accelerated the fermentation process. Lactobacillus, Enterococcus and Proteus played an important role not only in inhibition of the growth of Escherichia-Shigella, but also in the formation of flavor. This study provides a rapid fermentation method for the Suanzhayu process.

Evaluation on the concentration change of paeoniflorin and glycyrrhizic acid in different formulations of Shaoyao-Gancao-Tang by the tri-level infrared macro-fingerprint spectroscopy and the whole analysis method.

As a kind of common prescriptions, Shaoyao-Gancao-Tang (SGT) contains two Chinese herbs with four different proportions which have different clinical efficacy because of their various components. In order to investigate the herb-herb interaction mechanisms, we used the method of tri-level infrared macro-fingerprint spectroscopy to evaluate the concentration change of active components of four SGTs in this research. Fourier transform infrared spectroscopy (FT-IR) and Second derivative infrared spectroscopy (SD-IR) can recognize the multiple prescriptions directly and simultaneously. 2D-IR spectra enhance the spectral resolution and obtain much new information for discriminating the similar complicated samples of SGT. Furthermore, the whole analysis method from the analysis of the main components to the specific components and the relative content of the components may evaluate the quality of TCM better. Then we concluded that paeoniflorin and glycyrrhizic acid were the highest proportion in active ingredients in SGT-12:1 and the lowest one in SGT-12:12, which matched the HPLC-DAD results. It is demonstrated that the method composed by the tri-level infrared macro-fingerprint spectroscopy and the whole analysis can be applicable for effective, visual and accurate analysis and identification of very complicated and similar mixture systems of traditional Chinese medicine.

Development of a stability- indicating HPLC method for simultaneous determination of ten related substances in vonoprazan fumarate drug substance.

Vonoprazan fumarate is a novel potassium-competitive acid blocker for the treatment of acid-related diseases. In the present study, a simple, fast, and economic reversed-phase liquid chromatography (LC) method was developed for the analysis of ten related substances (raw materials, by-products and degradants) in vonoprazan fumarate. The optimized separation was performed on a Phenomenex Kinetex EVO C18 (250mm×4.6mm, 5.0µm) column. The mobile phase consisted of (A) 0.03M sodium phosphate buffer (pH adjusted to 6.5) - methanol - acetonitrile (72:25:3, v/v/v) and (B) 0.03M sodium phosphate buffer (pH adjusted to 6.5) - acetonitrile (30:70, v/v). Detection of the analytes was conducted at 230nm using a UV detector. The stability-indicating ability of this method was demonstrated by carrying out forced degradation studies. Vonoprazan underwent significant degradation when subjected to alkaline and oxidative stress conditions, while the drug proved to be stable to acidic, thermal and photolytic degradation. The degradants did not interfere with the detection of vonoprazan fumarate and its impurities. The performance of this method was validated in accordance to the regulatory guidelines recommended by the International Conference on Harmonisation (ICH) and this validation included specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision and robustness. The method proposed in this paper could be applied for process development as well as quality assurance of vonoprazan in bulk drug, since no monograph is available in official compendia.

Development of a validated HPLC method for the quantitative determination of trelagliptin succinate and its related substances in pharmaceutical dosage forms.

Trelagliptin succinate is a dipeptidyl peptidase IV (DPP-4) inhibitor which is used as a new long-acting drug for once-weekly treatment of type 2 diabetes mellitus (DM). In the present study, a rapid, sensitive and accurate high-performance liquid chromatography (HPLC) method was developed and validated for separation and determination of trelagliptin succinate and its eight potential process-related impurities. The chromatographic separation was achieved on a Waters Xselect CSH™ C18 (250mm×4.6mm, 5.0µm) column. The mobile phases comprised of 0.05% trifluoroacetic acid in water as well as acetonitrile containing 0.05% trifluoroacetic acid. The compounds of interest were monitored at 224nm and 275nm. The stability-indicating capability of this method was evaluated by performing stress test studies. Trelagliptin succinate was found to degrade significantly in acid, base, oxidative and thermal stress conditions and only stable in photolytic degradation condition. The degradation products were well resolved from the main peak and its impurities. In addition, the major degradation impurities formed under acid, base, oxidative and thermal stress conditions were characterized by ultra-high-performance liquid chromatography coupled with linear ion trap-Orbitrap tandem mass spectrometry (UHPLC-LTQ-Orbitrap). The method was validated to fulfill International Conference on Harmonisation (ICH) requirements and this validation included specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision and robustness. The developed method in this study could be applied for routine quality control analysis of trelagliptin succinate tablets, since there is no official monograph.

Identification of the Major Components of Buddleja officinalis Extract and Their Metabolites in Rat Urine by UHPLC-LTQ-Orbitrap.

Buddleja officinalis Maxim, one of the most popular herbal medicines in China, is widely prescribed for curing eye diseases for centuries. In this study, the major components of B. officinalis extract (BOE) and their metabolites in rat urine were detected and identified by ultra-high-pressure liquid chromatography coupled with linear ion trap-orbitrap tandem mass spectrometry (UHPLC-LTQ-Orbitrap). A total of 19 compounds, including 8 flavonoids and 11 phenylethanoid glycosides, were confirmed or tentatively identified from BOE. In vivo, 33 components, including 3 prototypes and 30 metabolies, were confirmed or tentatively identified in rat urine samples. The metabolic pathways of different types of compounds were also proposed. This study would effectively narrow the range of potentially bioactive constituents of BOE and shed light to its action mechanism.