Evaluation the kill rate and mutant selection window of danofloxacin against Actinobacillus pleuropneumoniae in a peristaltic pump model.

BACKGROUND: Actinobacillus pleuropneumoniae is a serious pathogen in pigs. The abundant application of antibiotics has resulted in the gradual emergence of drugresistant bacteria, which has seriously affected treatment of disease. To aid measures to prevent the emergence and spread of drug-resistant bacteria, herein, the kill rate and mutant selection window (MSW) of danofloxacin (DAN) against A. pleuropneumoniae were evaluated. METHODS: For the kill rate study, the minimum inhibitory concentration (MIC) was tested using the micro dilution broth method and time-killing curves of DAN against A. pleuropneumoniae grown in tryptic soy broth (TSB) at a series drug concentrations (from 0 to 64 MIC) were constructed. The relationships between the kill rate and drug concentrations were analyzed using a Sigmoid Emax model during different time periods. For the MSW study, the MIC99 (the lowest concentration that inhibited the growth of the bacteria by ≥ 99%) and mutant prevention concentration (MPC) of DAN against A. pleuropneumoniae were measured using the agar plate method. Then, a peristaltic pump infection model was established to simulate the dynamic changes of DAN concentrations in pig lungs. The changes in number and sensitivity of A. pleuropneumoniae were measured. The relationships between pharmacokinetic/pharmacodynamic parameters and the antibacterial effect were analyzed using the Sigmoid Emax model. RESULTS: In kill rate study, the MIC of DAN against A. pleuropneumoniae was 0.016 µg/mL. According to the kill rate, DAN exhibited concentration-dependent antibacterial activity against A. pleuropneumoniae. A bactericidal effect was observed when the DAN concentration reached 4-8 MIC. The kill rate increased constantly with the increase in DAN concentration, with a maximum value of 3.23 Log10 colony forming units (CFU)/mL/h during the 0-1 h period. When the drug concentration was in the middle part of the MSW, drugresistant bacteria might be induced. Therefore, the dosage should be avoided to produce a mean value of AUC24h/MIC99 (between 31.29 and 62.59 h. The values of AUC24h/MIC99 to achieve bacteriostatic, bactericidal, and eradication effects were 9.46, 25.14, and > 62.59 h, respectively. CONCLUSION: These kill rate and MSW results will provide valuable guidance for the use of DAN to treat A. pleuropneumoniae infections.

Revealing the material basis and mechanism for the inhibition of intestinal peristalsis by Zingiber officinale Roscoe through integrated metabolomics, serum pharmacochemistry, and network pharmacology.

Abnormal relaxation and contraction of intestinal smooth muscle can cause various intestinal diseases. Diarrhea is a common and important public health problem worldwide in epidemiology. Zingiber officinale Roscoe (fresh ginger) has been found to treat diarrhea, but the material basis and mechanism of action that inhibits intestinal peristalsis remain unclear. Metabolomics and serum pharmacology were used to identify differential metabolites, metabolic pathways, and pharmacodynamic substances, and were then combined with network pharmacology to explore the potential targets of ginger that inhibit intestinal peristalsis during diarrhea treatment, and the targets identified were verified using molecular docking and molecular dynamic simulation. We found that 25 active components of ginger (the six most relevant components), 35 potential key targets (three core targets), 40 differential metabolites (four key metabolites), and four major metabolic pathways were involved in the process by which ginger inhibits intestinal peristalsis during diarrhea treatment. This study reveals the complex mechanism of action and pharmacodynamic material basis of ginger in the inhibition of intestinal peristalsis, and this information helps in the development of new Chinese medicine to treat diarrhea and lays the foundation for the clinical application of ginger.

Resource utilization of wastepaper and bentonite: Cu(II) removal in the aqueous environment.

Contamination of heavy metals has always been a pressing concern. The dry-wet alternately treated carboxymethylcellulose bentonite (DW-CB) was successfully prepared by intercalating bentonite (BT) with carboxymethyl cellulose (CMC) obtained by solvent processes using enzymatically digested wastepaper as cellulosic raw material, and the adsorption capacity of Cu2+ on DW-CB in aqueous solution was investigated. A 98.18 ± 2.31 % removal efficiency was achieved by 4 g/L of DW-CB after 8 h in a solution containing 100 mg/L of Cu2+, which were 4.1 times and 1.5 times of that of BT and adsorbent prepared without alternating dry-wet process, respectively. The introduction of -COOH groups during the preparation of DW-CB enhanced the electrostatic interaction between DW-CB and Cu2+, which was the main driving force for Cu2+ removal. The pseudo-first-order kinetic model and Langmuir model better described the adsorption process and adsorption capacity of Cu2+ on DW-CB. DW-CB still showed high removal of Cu2+ (19.61 ± 0.99 mg/g) in the presence of multiple metal ions, while exhibiting the potential for removal of Zn2+, Mg2+ and K+, especially Mg2+ (22.69 ± 1.48 mg/g). However, the interactions of organics with Cu2+ severely affected the removal of Cu2+ by DW-CB (removal efficiency: 17.90 ± 4.17 % - 95.33 ± 0.27 %). In this study, an adsorbent with high targeted adsorption of Cu2+ was prepared by utilizing wastepaper and BT, which broadened the way of wastepaper resource utilization and had good economic and social benefits.

A neural network paradigm for modeling psychometric data and estimating IRT model parameters: Cross estimation network.

This paper presents a novel approach known as the cross estimation network (CEN) for fitting the datasets obtained from psychological or educational tests and estimating the parameters of item response theory (IRT) models. The CEN is comprised of two subnetworks: the person network (PN) and the item network (IN). The PN processes the response pattern of individual respondent and generates an estimate of the underlying ability, while the IN takes in the response pattern of individual item and outputs the estimates of the item parameters. Four simulation studies and an empirical study were comprehensively and rigorously conducted to investigate the performance of CEN on parameter estimation of the two-parameter logistic model under various testing scenarios. Results showed that CEN effectively fit the training data and produced accurate estimates of both person and item parameters. The trained PN and IN adhered to AI principles and acted as intelligent agents, delivering commendable evaluations for even unseen patterns of new respondents and items.

Extracellular vesicles-transmitted long non-coding RNA MTUS2-5 promotes proliferation and vascularization of human vascular endothelial cells in patients with Budd-Chiari syndrome.

The high rates of misdiagnosis and untreated mortality with regard to Budd-Chiari syndrome (BCS) indicated the need to screen effective biomarkers. The aim of this study was to explore the function of extracellular vesicles (EVs) in patients with BCS as well as associated mechanisms. First, differentially expressed long non-coding RNAs (lncRNAs) from EVs separated from serum between BCS and healthy controls were screened using microarray analysis. Second, the proliferation, migration and tube formation of human vascular endothelial cells (HUVECs) were detected after EVs treatment, along with vascular endothelial growth factor (VEGF) levels and inflammatory factors from the cell supernatant. Last, the overexpressed lncRNA was transfected into the cells to further explore the mechanisms involved. Extracellular vesicles of BCS patients have significantly higher levels of lncRNA MTUS2-5 than healthy controls. Apparently, treatment with EVs from BCS or the ones transfected with plasmids that overexpress lncRNA MTUS2-5 enhances proliferation, migration and angiogenesis capacity. The results were considerably better than those obtained from treatment with EVs from healthy controls or transfection with the normal control plasmid, which also elevated the level of VEGF and inflammatory factors. Furthermore, FOS and PTGS2 were potentially regulated by the lncRNA MTUS2-5 transmitted by EVs. The lncRNA MTUS2-5 in EVs plays an important role in angiogenesis in the Budd-Chiari syndrome.

Broadband near-infrared luminescence in erbium ion single-doped tellurite glass for optical amplification.

This Letter proposes a simple approach for the realization of a broadband near-infrared (NIR) luminescence source in erbium ion single-doped tellurite glass, which is bent on tailoring the network structure. Under the collective action of multiple broadening mechanisms and fluorescence capture, broadband fluorescence with a full width at half maximum (FWHM) of 132 nm (1500-1632 nm) was achieved. To the best of our knowledge, this is the largest FWHM reported for erbium single-doping of tellurite glass materials. Meanwhile, this fiberglass exhibits excellent thermal stability and high visible to NIR transmittance. Furthermore, a novel equivalent five-level Stark splitting model is proposed that can effectively explain the spectrum broadening. This study is beneficial for the further development of broadband optical amplification.

ErF3 microcrystals controllably deposited in perfluoride glass for upconversion red emission.

To the best of our knowledge, this paper first reports ErF3 microcrystals controllably deposited in perfluoride glass using phase-separation engineering techniques. The sample exhibited strong upconversion red-light emission owing to the small distance between Er3+ ions and low phonon energy (585 cm-1). The sample has a high red/green ratio of up to 18.6, which, to our knowledge, is the highest reported value in Er3+-doped fluoride glass ceramics. Furthermore, the sample has a long fluorescence lifetime (3.18 ms @660 nm), good color saturation (0.6255,0.3707), and good thermal stability (Δ E=0.31e V). Therefore, this sample has the potential for application across multiple fields, such as color display, visible laser, and lighting.

Synthesis and Bioevaluation of 2-Styrylquinoxaline Derivatives as Tau-PET Tracers.

This study focused on designing and evaluating Tau-PET tracers for noninvasive positron emission computed tomography (PET) imaging of neurofibrillary tangles (NFTs), a hallmark pathology of Alzheimer's disease (AD). The tracers were synthesized with a 2-styrylquinoxaline scaffold and varying lengths of FPEG chains. The compound [18F]15, which had two ethoxy units, showed high affinity for recombinant K18-Tau aggregates (Ki = 41.48 nM) and the highest selectivity versus Aß1-42 aggregates (8.83-fold). In vitro autoradiography and fluorescent staining profiles further validated the binding of [18F]15 or 15 toward NFTs in brain sections from AD patients and Tau-transgenic mice. In normal ICR mice, [18F]15 exhibited an ideal initial brain uptake (11.21% ID/g at 2 min) and moderate washout ratio (2.29), and micro-PET studies in rats confirmed its ability to penetrate the blood-brain barrier with the peak SUV value of 1.94 in the cortex. These results suggest that [18F]15 has the potential to be developed into a useful Tau-PET tracer for early AD diagnosis and evaluation of anti-Tau therapeutics.

Impact of Nursing Interventions Targeting Vital Signs and Complication Risk on Perioperative Parameters and Complication Rates in Aortic Dissection Patients.

Objective: This study aimed to investigate the impact of nursing interventions targeting vital signs and complication risk on perioperative outcomes and complications in patients diagnosed with aortic dissection. Methods: This retrospective study included patients presenting to our emergency department with acute chest pain as the primary complaint. Inclusion criteria encompassed identifiable chest pain symptoms, documented occurrence time and a time from symptom onset to blood collection of ≤ 24 hours. The cases of aortic dissection were selected from April 2018 to April 2022 and were diagnosed as major arterial dissection based on the Chinese Expert Consensus on the Criteria for the Diagnosis and Treatment of Aortic Dissection. The control group received conventional nursing care for aortic dissection, while the observation group received a nursing plan incorporating vital signs monitoring and addressing complication risk in addition to standard care. Results: All 120 enrolled patients successfully recovered and were discharged from the hospital. Age, body weight, operation time, anesthesia time, preoperative albumin levels, hypersensitive C-reactive protein (hs-CRP), and interleukin-6 (IL-6) showed no statistically significant differences between the two groups (P > .05). However, 24 hours post-operation, the observation group exhibited significantly lower IL-6 levels compared to the control group (P < .001), with no significant differences in hs-CRP levels (P > .05). Postoperative albumin levels in both aortic dissection groups significantly decreased compared to pre-surgery levels (P < .001) without statistical group differences (P > .05). Compared to controls, the observation group had reduced intraoperative sufentanil dosage, postoperative tracheal catheter extubation time, hospital stay, and costs (P < .001). No anastomotic complications occurred, and edema incidence was lower in the observation group (P = .021), with no significant differences in other complications (P > .05). Conclusions: Nursing interventions improve aortic dissection patient outcomes, reduce complications, and warrant broader clinical use.

Gut Microbial-Derived Metabolites as Immune Modulators of T Helper 17 and Regulatory T Cells.

The gut microbiota and its derived metabolites greatly impact the host immune system, both innate and adaptive responses. Gut dysbiosis and altered levels of microbiota-derived metabolites have been described in several immune-related and immune-mediated diseases such as intestinal bowel disease, multiple sclerosis, or colorectal cancer. Gut microbial-derived metabolites are synthesized from dietary compounds ingested by the host or host-produced metabolites, and additionally, some bacterial products can be synthesized de novo. In this review, we focus on the two first metabolites families including short-chain fatty acids, indole metabolites, polyamines, choline-derived compounds, and secondary bile acids. They all have been described as immunoregulatory molecules that specifically affect the adaptive immune system and T helper 17 and regulatory T cells. We discuss the mechanisms of action and the consequences in health and diseases related to these gut microbial-derived metabolites. Finally, we propose that the exogenous administration of these molecules or other compounds that bind to their immunoregulatory receptors in a homologous manner could be considered therapeutic approaches.

Preparation and application of metal-modified biochar in the purification of micro-polystyrene polluted aqueous environment.

Microplastics (MPs) have already spread across the globe and have been found in drinking water and human tissues. This may pose severe threats to human health and water environment. Therefore, this study accurately evaluated the removal effect of metal-modified biochar on polystyrene microplastics (PS-MPs) (1.0 µm) in the water environment using a high-throughput fluorescence quantification method. The results indicated that Fe-modified biochar (FeBC) and Fe/Zn-modified biochar (Fe/ZnBC) had good removal efficiencies for PS-MPs under the dosage of 3 g/L, which were 96.24% and 84.77%, respectively. Although pore effects were observed (such as "stuck", "trapped"), the electrostatic interaction was considered the main mechanism for the adsorption of PS-MPs on metal-modified biochar, whereas the formation of metal-O-PS-MPs may also contribute to the adsorption process. The removal efficiency of PS-MPs by FeBC was significantly reduced under alkaline conditions (pH = 9 and 11) or in the presence of weak acid ions (PO43-, CO32-, HCO3-). A removal efficiency of 72.39% and 78.33% of PS-MPs was achieved from tap water (TW) and lake water (LW) using FeBC when the initial concentration was 20 mg/L. However, FeBC had no removal effect on PS-MPs in biogas slurry (BS) and brewing wastewater (BW) due to the direct competitive adsorption of high concentrations of chemical oxygen demand (COD). The findings of this study highlighted that metal-modified biochar had a potential application in purifying tap water or lake water which contaminated by MPs.

[Chemical constituents and mechanism of Chuanzhi Tongluo Capsules based on UPLC-Q-Exactive Orbitrap-MS and network pharmacology].

The chemical constituents of Chuanzhi Tongluo Capsules were analyzed and identified using ultra-high performance liquid chromatography-quadrupole/electrostatic field orbitrap high-resolution mass spectrometry(UPLC-Q-Exactive Orbitrap-MS) to clarify the pharmacological substance basis. In addition, network pharmacology was employed to explore the mechanism of Chuanzhi Tongluo Capsules in the treatment of cerebral infarction. Gradient elution was performed using acetonitrile and 1% acetic acid in water as the mobile phase. Mass spectrometry was performed in positive and negative ion modes. Xcalibur 4.2 software was used for compound analysis, including accurate mass-to-charge ratio and MS/MS fragment information, combined with the comparison of reference standards and literature data. A total of 152 compounds were identified, including 32 organic acids, 35 flavonoids and their glycosides, 33 diterpenes, 13 phthalides, 12 triterpenes and triterpene saponins, 23 nitrogen-containing compounds, and 4 other compounds, and their fragmentation patterns were analyzed. SwissTargetPrediction, GeneCards, DAVID, and other databases were used to predict and analyze the core targets and mechanism of Chuanzhi Tongluo Capsules. Protein-protein interaction(PPI) network topology analysis identified 10 core targets, including TNF, VEGFA, EGFR, IL1B, and CTNNB1. KEGG enrichment analysis showed that Chuanzhi Tongluo Capsules mainly exerted their effects through the regulation of lipid and atherosclerosis, glycoproteins in cancer, MicroRNAs in cancer, fluid shear stress, and atherosclerosis-related pathways. Molecular docking was performed between the key constituents and core targets, and the results demonstrated a strong binding affinity between the key constituents of Chuanzhi Tongluo Capsules and the core targets. This study comprehensively elucidated the chemical constituents of Chuanzhi Tongluo Capsules and explored the core targets and mechanism in the treatment of cerebral infarction based on network pharmacology, providing a scientific reference for the study of the pharmacological substance basis and formulation quality standards of Chuanzhi Tongluo Capsules.

Effects of dexmedetomidine on cognitive dysfunction and neuroinflammation via the HDAC2/HIF-1α/PFKFB3 axis in a murine model of postoperative cognitive dysfunction.

Inhibition of histone deacetylase (HDAC) may be a useful approach in the treatment of disorders characterized by cognitive dysfunction. Dexmedetomidine (DEX), an α2-adrenoceptor (α2-AR) agonist, has demonstrated neuroprotective effects. Here, we attempted to investigate the protective effects of DEX on postoperative cognitive dysfunction (POCD) involving HDAC2. Male C57BL/6 mice were selected to develop a POCD model, where HDAC2, HIF-1α, and PFKFB3 expression was quantified. DEX was administered before POCD modeling. Then the cognitive function of POCD mice was evaluated with the open field and Y-maze tests. Meanwhile, lipopolysaccharide (LPS) was employed to induce BV-2 microglial cells to simulate the inflammatory response. The contents of TNF-α, IL-6, and IL-10 were measured by enzyme-linked immunosorbent assay (ELISA) in mouse serum and BV-2 cell supernatant. Abundant expression of HDAC2, HIF-1α, and PFKFB3 was confirmed in POCD mice (p < 0.05). Cognitive dysfunction in POCD mice could be alleviated following pharmacological inhibition of HDAC2 by FK228 (p < 0.05). Mechanistically, HDAC2 upregulated HIF-1α and PFKFB3 and promoted the secretion of inflammatory factors in LPS-exposed BV-2 cells (p < 0.05). DEX attenuated neuroinflammation and the resulting cognitive dysfunction by decreasing HDAC2 expression and HIF-1α-dependent PFKFB3 upregulation in POCD mice (p < 0.05). In conclusion, DEX-regulated HDAC2 may play an inhibitory role in mice with POCD through regulation of the HIF-1α/PFKFB3 axis.

Study on phenolic acids of Lonicerae japonicae Flos based on ultrahigh performance liquid chromatography-tandem mass spectrometry combined with multivariate statistical analysis.

Lonicerae japonicae Flos, a traditional Chinese medicine, has the function of evacuating heat and detoxifying. To promote the optimization of Lonicerae japonicae Flos germplasms and improve the quality of medicinal materials, 55 batches of five Lonicerae japonicae Flos germplasms with the same origin were collected during different periods, a UHPLC-TOF-MS method was established, and 22 kinds of phenolic acids were found and qualitatively analysed. Seventeen phenolic acids were selected for quantitative analysis by UHPLC-QqQ-MS/MS, and the quantitative results were analysed by principal component analysis, orthogonal partial least squares-discriminant analysis, and partial least squares discriminant analysis. The contents of phenolic acids in periods S1-S6 were found to be significantly different. There were also significant differences in the accumulation of phenolic acids in Lonicerae japonicae Flos during different growth periods. Ferulic acid, 5-O-caffeoylquinic acid, and caffeic acid were determined to be important components to distinguish the different growth periods of Lonicerae japonicae Flos. There were significant differences in the phenolic acid content of different germplasms of Lonicerae japonicae Flos, and the total amount of 17 phenolic acids and total acids (chlorogenic acid, 3,5-di-O-caffeoylquinic acid, and 4,5-di-O-caffeoylquinic acid) in "Hua Jin No. 6" was highest, so the quality of "Hua Jin No. 6" was better than that of the four other germplasms. In addition, chlorogenic acid methyl ester and caffeic acid were the smallest markers in combination to distinguish the five germplasms of Lonicerae japonicae Flos.

Aperture measurement based on a conic invariant.

With the advantages of low cost, universal applicability, and in situ detection, the conic invariant of the tested aperture diameter was obtained by ellipse geometric fitting on the aperture surface. The world coordinate system was established, and the transformation relationship between the world coordinate system and the camera coordinate system was obtained by the calibration. The improved Candy algorithm and coordinate transformation relationship could be used to project the sub-pixel coordinates of the aperture edge onto the aperture surface. Then, the ellipse geometric fitting was performed on the aperture edge curve surface to obtain the conic invariant. Finally, the conic invariant was used to measure the aperture diameter on the test bench.

Photochemical Disulfide-Ene Modification Enhances Protein Sequencing and Disulfide Mapping by Mass Spectrometry.

A new photochemical disulfide-ene reaction system capable of alkylating protein disulfide bonds in seconds has been established. The system is simple, containing acetone and isopropanol for disulfide reduction under 254 nm UV irradiation and norbornene as a highly efficient alkylation reagent. Enhanced characterization of disulfide-rich proteins with significantly shortened analysis time is demonstrated by coupling the reaction online with mass spectrometry.

The Photocatalysis-Enhanced TiO2@HPAN Membrane with High TiO2 Surface Content for Highly Effective Removal of Cationic Dyes.

The elimination of dye pollutants from wastewater is a significant concern that has prompted extensive research into the development of highly efficient photocatalytic membranes. A novel method was proposed to prepare photocatalysis-enhanced poly(acrylonitrile-methyl acrylate) (PAN-based) membranes in this study. In detail, the blended membrane containing SiO2@TiO2 nanoparticles with a shell-core structure was first prepared via thermal-induced phase separation. The SiO2 nanoshells were dissolved, and the released TiO2 nanoparticles migrated to the membrane surface during a simple hydrolysis process, which prevents the TiO2 nanoparticles from directly contacting or interacting with the polymer matrix. The hydrogen bonds bind the exposed TiO2 with the PAN membrane surface, resulting in the formation of the TiO2@HPAN hybrid membrane. The photocatalytic efficiency of the TiO2@HPAN membrane doubled compared with that of nonhydrolyzed membranes. In the presence of UV light, the hybrid membrane can degrade 99.8% of methylene blue solution in less than 2 h, compared to only 86.1% for the blended membranes. Further, the TiO2@HPAN membrane showed excellent photocatalytic activity for cationic dyes due to electrostatic attraction. Moreover, the high-flux recovery rate and recycling stability of the TiO2@HPAN membrane lead to an excellent antifouling property. The facile preparation method proposed in this work shows extraordinary potential for the development of highly efficient selective photocatalytic materials for cationic dyes to be used in wastewater treatment applications.

Discovery of Diphenoxy Derivatives with Flexible Linkers as Ligands for ß-Amyloid Plaques.

The highly rigid and planar scaffolds with π-conjugated systems have been widely considered to be indispensable for ß-amyloid (Aß) binding ligands. In this study, a library of diphenoxy compounds with different types of more flexible linkers as Aß ligands were synthesized and evaluated. Most of them displayed good affinity (Ki < 100 nM) for Aß1-42 aggregates, and some ligands even showed values of Ki less than 10 nM. Structure-activity relationship analysis revealed that modification on the linkers or substituents tolerated great flexibility, which challenged the long-held belief that rigid and planar structures are exclusively favored for Aß binding. Three ligands were labeled by iodine-125, and they exhibited good properties in vitro and in vivo, which further supported that this flexible scaffold was potential and promising for the development of Aß imaging agents.

Study on steroidal saponins in crude and stir-fried Fructus Tribuli by ultra-high-performance liquid chromatography-mass spectrometry coupled with multivariate statistical analysis.

Fructus Tribuli is a traditional Chinese medicine used clinically for many years. Crude Fructus Tribuli and stir-fried Fructus Tribuli are recorded in the Pharmacopoeia of the People's Republic of China. However, the differences between steroidal saponins in crude Fructus Tribuli and stir-fried Fructus Tribuli have not been compared. In this study, ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry along with multivariate statistical analysis was developed to discriminate the chemical profiles and identify the steroidal saponins of crude Fructus Tribuli and stir-fried Fructus Tribuli. Additionally, an ultra-high-performance liquid chromatography triple-quadrupole mass spectrometer was used for the simultaneous quantification of nine major steroidal saponins to analyze the variations between crude Fructus Tribuli and stir-fried Fructus Tribuli. Finally, a total of 30 steroidal saponins whose structures or contents changed significantly after processing were found and identified. The mechanism of structural transformations deduced indicated that during the stir-frying of Fructus Tribuli, C-22 hydroxy furostanol saponins were converted to the corresponding furostanol saponins containing C-20-C-22 double bonds by dehydroxylation and deglycosylation reactions that occurred in the spirostanol saponins causing the generation of steroidal sapogenins. This study was successfully applied to the global analysis of crude Fructus Tribuli and stir-fried Fructus Tribuli. The results of this research will be beneficial to explore the processing mechanism of Fructus Tribuli.

Analysis of variations in the contents of steroidal saponins in Fructus Tribuli during stir-frying treatment.

Just as natural saponins transform into aglycones, secondary glycosides and their derivatives using biotransformation technology, steroidal saponins may also undergo similar transformation after stir-frying. The purpose of this study was to elucidate the variations and the reasons for these variations in the contents of steroidal saponins in Fructus Tribuli (FT) during a stir-frying treatment. Stir-fried FT was processed in different time-temperature conditions. An UHPLC-MS/MS method was established and fully validated for quantitative analysis. In addition, the simulation processing products of tribuluside A, terrestroside B, terrestrosin K, terrestrosin D and 25R-tribulosin were determined by qualitative analysis using UHPLC-Q-TOF-MS. The established UHPLC-MS/MS method provides a rapid, flexible, and reliable method for the quality assessment of FT. The present study revealed that furostanol saponins with a C22-OH group could transform into corresponding furostanol saponins with a C-20-C-22 double bond (FSDB) via dehydroxylation. Additionally, FSDB could be successively converted into its secondary glycosides via a deglycosylation reaction. The transformation of spirostanol saponins into corresponding aglycones via deglycosylation led to a decrease in spirostanol saponins and an increase in aglycones. The results of this research provided scientific evidence of variation and structural transformation among steroidal saponins. These findings might be helpful for elucidating the processing mechanism of FT.