Untargeted metabolomics based on ultra-high performance liquid chromatography-mass spectrometry/MS reveals the lipid-lowering mechanism of taurine in hyperlipidemia mice.

Introduction: Taurine has a prominent lipid-lowering effect on hyperlipidemia. However, a comprehensive analysis of the effects of taurine on endogenous metabolites in hyperlipidemia has not been documented. This study aimed to explore the impact of taurine on multiple metabolites associated with hyperlipidemia. Methods: The hyperlipidemic mouse model was induced by high-fat diet (HFD). Taurine was administered via oral gavage at doses of 700 mg/kg/day for 14 weeks. Evaluation of body weight, serum lipid levels, and histopathology of the liver and adipose tissue was performed to confirm the lipid-lowering effect of taurine. Ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS)-based metabonomics analyses of serum, urine, feces, and liver, coupled with multivariate data analysis, were conducted to assess changes in the endogenous metabolites. Results and discussion: Biochemical and histological examinations demonstrated that taurine administration prevented weight gain and dyslipidemia, and alleviated lipid deposition in the liver and adipose tissue in hyperlipidemic mice. A total of 76 differential metabolites were identified by UPLC-MS-based metabolomics approach, mainly involving BAs, GPs, SMs, DGs, TGs, PUFAs and amino acids. Taurine was found to partially prevent HFDinduced abnormalities in the aforementioned metabolites. Using KEGG database and MetaboAnalyst software, it was determined that taurine effectively alleviates metabolic abnormalities caused by HFD, including fatty acid metabolism, sphingolipid metabolism, glycerophospholipid metabolism, diacylglycerol metabolism, amino acid metabolism, bile acid and taurine metabolism, taurine and hypotaurine metabolism. Moreover, DGs, GPs and SMs, and taurine itself may serve as active metabolites in facilitating various anti-hyperlipidemia signal pathways associated with taurine. This study provides new evidence for taurine to prevent hyperlipidemia.

High-performance liquid chromatography (HPLC) as a means of assessing the presence of uric acid in archeological human remains: Challenges and future directions.

OBJECTIVES: This research aimed to replicate the Swinson, D., Snaith, J., Buckberry, J., & Brickley, M. (2010). High performance liquid chromatography (HPLC) in the investigation of gout in paleopathology. International Journal of Osteoarchaeology, 20, 135-143. https://doi.org/10.1002/oa.1009 method for detecting uric acid in archeological human remains to investigate gout in past populations and to improve the original High Performance Liquid Chromatography-ultraviolet (HPLC-UV) method by using HPLC-mass spectrometry (HPLC-MS), a more sensitive, compound-specific detection method. MATERIALS AND METHODS: We used reference samples of uric acid to create a dilution series to assess the limits of quantification and detection. Samples from individuals with and without gout lesions were taken from foot bones and ribs from the English cemeteries of Tanyard, Hickleton, Gloucester, and Lincoln. RESULTS: We could not replicate the results of Swinson and colleagues using HPLC-UV. Tests using a dilution series of uric acid showed HPLC-MS was approximately 100× more sensitive than HPLC-UV, with the additional benefit of being compound specific. A newly developed hydrophilic interaction chromatography (HILIC) method improved retention characteristics. Fourteen samples from eight individuals, five with skeletal lesions consistent with gout, were analyzed with the final method. None showed evidence of uric acid despite the newly developed method's improved sensitivity and specificity. DISCUSSION: The lack of detectable uric acid extracted from these samples suggests that (1) urate crystals were not present in any of the bone samples, regardless of gout status; (2) urate crystals did not survive these specific archeological conditions; or (3) the concentration of uric acid in our bone extracts was low, and thus larger samples would be required.

Clean-DM1, a Korean Polyherbal Formula, Improves High Fat Diet-Induced Diabetic Symptoms in Mice by Regulating IRS/PI3K/AKT and AMPK Expressions in Pancreas and Liver Tissues.

OBJECTIVE: To investigate the effects of Clean-DM1 (C-DM1), a polyherbal formulation of Radix Scrophulariae, Radix Astragali, Rhizoma Atractylodis, and Radix Salviae Miltiorrhizae, on high-fat diet (HFD)-induced diabetes mice. METHODS: The information about active components of C-DM1 extract and molecular mechanism was obtained from network pharmacology analysis. Main compounds of C-DM1 extract by high performance liquid chromatography-mass spectrometry (HPLC-MS) analysis were conducted for quality control. For in vivo study, mice were induced diabetes by HFD for 12 weeks. The mice in the normal group (Nor) were maintained with a regular diet and treated with saline by gavage. The HFD model mice were randomly divided into 3 groups, including a HFD diabetic model group, a C-DM1 extract-administered group (C-DM1, 500 mg/kg), and metformin-administered groups (Met, 500 mg/kg), 8 mice in each group. Food intake, body weight (BW), and fasting blood glucose (FBG) levels were recorded weekly for 4 weeks. After 4 weeks of treatment, alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood glucose, low-density lipoprotein cholesterol (LDL-C) were determined using an automated clinical chemistry analyzer, and homeostatic model for assessing insulin resistance (HOMA-IR) levels and oral glucose tolerance test (OGTT) were detected. The histopathological changes of liver and pancreatic tissues were observed by hematoxylin-eosin staining. Insulin receptor substrate (IRS)/phosphatidylinositol 3 kinase (PI3K)/ protein kinase B (AKT) and adenosine 5'-monophosphate-activated protein kinase (AMPK) expressions in liver and pancreas tissues were detected by Western blot analysis. RESULTS: HPLC-MS identified dihydroisotanshinone, dihydroisotanshinone I, cryptotanshinone, harpagoside, and atractyloside A in C-DM1 extract. The administration of C-DM1 extract significantly decreased body weight, calorie intake, and the levels of blood glucose and insulin in the diabetic mice (P<0.05 or P<0.01). The C-DM1 extract administration improved the impaired glucose tolerance and insulin resistance in the diabetic mice and significantly decreased the levels of LDL-C, ALT and AST (P<0.01). The C-DM1 extract inhibited the histopathological changes of fatty liver and hyperplasia of pancreatic islets in the diabetic mice. The C-DM1 extract significantly increased the phosphorylation of IRS, AKT, and AMPK and the expression of PI3K in pancreas and liver tissues (P<0.05 or P<0.01), which was consistent with the analysis results of network pharmacology. CONCLUSION: C-DM1 extract improved diabetes symptoms in long-term HFD-induced mice by regulation of IRS/PI3K/AKT and AMPK expressions in pancreas and liver tissues, suggesting that C-DM1 formulation may help prevent the progression of T2DM.

The Breakdown of Blood-Labyrinth Barrier Makes it Easier for Drugs to Enter the Inner Ear.

PURPOSE: This study aimed to investigate dynamic change of permeability of blood-labyrinth barrier (BLB) after noise exposure and its effect on the drug delivery efficiency of systemic administration. METHODS: Gadopentetate dimeglumine (Gd-DTPA) and dexamethasone (DEX) were used as tracers, and magnetic resonance imaging (MRI) and immunofluorescence were used to observe the change of the BLB after strong noise exposure in guinea pigs. High-performance liquid chromatography-mass spectrometry (LC-MS) was used to observe the effect of the breakdown of BLB after noise exposure on the drug delivery efficiency of intravenous DEX. The guinea pigs were divided into 6 groups: normal group (N), 1, 3, 5, 8, and 12 days after noise exposure groups (P1, P3, P5, P8, P12), with 5 animals in each group. RESULTS: The BLB changes dynamically after noise exposure. Increased permeability of the blood-endolymph barrier, the endolymph-perilymph barrier, and the blood-nerve barrier was observed at days 1-3, 1-5, and 1-8, respectively, after noise exposure in guinea pigs. Higher drug concentration in the cochlear tissue was obtained by intravenous administration of DEX in guinea pigs during the time window of increased permeability of the BLB. CONCLUSION: After noise exposure, the increased BLB permeability makes it easier for drugs to enter the inner ear from blood. In guinea pigs, 1-8 days after strong noise exposure, the drug delivery efficiency of systemic administration increased. After 8 days, the efficiency gradually returned to normal level. 1-8 days after noise exposure may be the best intervention time for systemic administration. LEVEL OF EVIDENCE: NA Laryngoscope, 134:2377-2386, 2024.

Analysis of Differences in Secondary Metabolites from Dendrobium nobile Stems Cultivated on Epiphytic Rocks in Different Growth Years Based on Metabolomics / 中国实验方剂学杂志

ObjectiveTo study the changing characteristics of secondary metabolic compounds accumulated in Dendrobium nobile stems at different growth years， a simulated wild stone plant， in order to provide a theoretical basis for rational planning of the harvesting period of D. nobile. MethodUltra-high performance liquid chromatography-mass spectrometry（UPLC-MS/MS） was used to detect and analyze the secondary metabolites in the stems of 1-year-old， 2-year-old， and 3-year-old D. nobile. The mass spectrometry data were processed using Analyst 1.6.3 software， and all samples were subjected to principal component analysis（PCA）， cluster heat map analysis， partial least squares-discriminant analysis（PLS-DA）， and differential secondary metabolites were screened based on variable importance in projection（VIP） values>1， fold change（FC）≥2 and FC≤0.5. Then differential secondary metabolites were identified based on relative molecular weight， fragmentation ions and mass spectrometry database， and enriched pathways were identified based on the Kyoto Encyclopedia of Genes and Genomes（KEGG） database. ResultA total of 1 317 secondary metabolites were identified in the stems of D. nobile at three growth stages， with flavonoids， phenolic acids， alkaloids and terpenoids accounting for 76.55% of the total. Compared with the 1-year-old stems of D. nobile， 289 differential secondary metabolites were identified in the 2-year-old stems， of which 255 were up-regulated and 34 were down-regulated， 682 differential secondary metabolites were identified in the 3-year-old stems， of which 502 were up-regulated and 180 were down-regulated. Compared to the 2-year-old stems， the 3-year-old stems had 602 differential secondary metabolites， with 405 up-regulated and 197 down-regulated. As the growth stage of D. nobile increased， the top 10 up-regulated differential metabolites mainly included flavonoids， phenolic acids， phenylpropanoids and terpenoids， such as kaempferol derivatives， asperulosidic acid， apigenin derivatives， chrysoeriol derivatives， isorhamnetin derivatives， taxifolin derivatives， quercetin derivatives. KEGG enrichment analysis showed significant enrichment of secondary metabolites in the flavonoid biosynthesis， flavone， and flavonol biosynthesis， secondary metabolite biosynthesis， and phenylpropanoid biosynthesis pathways with the increase of growth years. ConclusionWith the increase of the growth years， the levels of secondary metabolites such as flavonoids， phenolic acids， phenylpropanoids and terpenoids in the wild-grown D. nobile have been significantly enhanced. In practical production， grading based on different growth years can be carried out to improve the medicinal and economic values of D. nobile.

Urine levels of estrogen and its metabolites in premenopausal middle-aged women with different degrees of obesity and their correlation with glucose and lipid metabolism.

Objectives: To determine the levels of estrogen and estrogen metabolites in the urine of premenopausal women with obesity and their correlation with glucose and lipid metabolism. Methords: 135 premenopausal women were selected from the same area. According to the body mass index (BMI), they were divided into four different groups. High performance liquid chromatography-mass spectrometry (HPLC/MS) was adopted to detect the concentrations of estrogen and estrogen metabolites in the urine. The influencing factors of BMI were analyzed, the correlation between the urinary degrees of estrogen and estrogen metabolites and glucose and lipid metabolism levels was assessed. Results: (1) The concentrations of 17ß-estradiol (E2), estrone (E1), 16α-hydroxyestrone (16α-OHE1) and 2-hydroxyestrone (2-OHE1) gradually increased with increasing BMI (p < 0.05). (2) Stepwise regression analysis displayed that the concentrations of E2, 16α-OHE1 and 2-OHE1 in urine were significantly positively correlated with BMI (p < 0.05). (3) The concentrations of E2, E1, 16α-OHE1, 2-OHE1 and 16α-OHE1/2-OHE1 in urine were greatly positively related to fasting insulin (FIN), Triglyceride (TG), Total Cholesterol (TC) and Low-density lipoprotein (LDL) (p < 0.05). And they were greatly negatively related to High-density lipoprotein (HDL) (p < 0.05). Conclusions: Early screening can reflect the degree of obesity and glucose and lipid metabolism disorders in premenopausal middle-aged women, thereby providing guidance for improving the prognosis of obese women.

Structural characteristics, component interactions and functional properties of gelatins from three fish skins extracted by five methods.

Fish skin gelatin is an important functional product used in food, medicine and other industries. However, the structure and function of gelatins extracted with different methods differ significantly, thus limiting its production and application. This study used dry-salting, wet-salting, pepsin, acid and heat methods to extract gelatins from the skins of tilapia, grass carp and sea perch. Then, their structural characteristics (micro- and ultra-structure, amyloid-like fibril, etc.) and functional properties (viscosity, emulsifying performance, antioxidant abilities, etc.) were analyzed, and interaction between gelatin components were also explored. According to the results, the gelatins extracted with dry-salting and wet-salting methods had better reticular structure, larger fiber length/height, and higher viscosity properties, emulsifying and antioxidant capacity. The gelatin extracted by applying heat has the highest gel strength, and the gelatin extracted using pepsin had better thermal stability, water absorption capacity, and fat absorption capacity. Further analysis of component interaction showed that 11 types of collagens detected in the gelatins might promote the conversion of collagen to gelatin through self-assembly ability. The co-assembly of different types of collagens enhanced the properties of gelatin. Decorin had a positive effect on gelatin network structure, but Metallopeptidase inhibited the formation of network structure. Different methods can produce personalized gelatin products according to specific needs. The mining of component interaction would reveal the mechanism of gelatin formation and promote the development of gelatin synthetic biology.

Analysis of Metabolites and Metabolic Pathways of Three Chinese Jujube Cultivar.

Most studies on metabolites in jujube fruits focus on specific types of metabolites, but there are only a few comprehensive reports on the metabolites in jujube fruits. In order to understand the variance of metabolites in fruits of different jujube varieties. The objective of this study was to explore the metabolic components of jujube fruit by comparing three cultivars, namely Linyi LiZao (LZ), Jiaocheng SuantianZao (STZ), and Xianxian Muzao (MZ). The metabolites present in the fruits of these three cultivars were evaluated and compared. The results revealed the detection of 1059 metabolites across the three jujube varieties, with each cultivar exhibiting distinct metabolic characteristics. Notably, MZ exhibited a higher abundance of six metabolite classes, namely amino acids and derivatives, flavonoids, lipids, organic acids, phenolic acids, and terpenoids, compared to LZ. Conversely, LZ exhibited higher concentrations of alkaloids, lignans, coumarins, nucleotides, and their derivatives compared to the other two cultivars. In terms of STZ, its content of amino acids and derivatives, lignans and coumarins, organic acids, and phenolic acids was largely similar to that of LZ. However, the content of alkaloids, nucleotides, and their derivatives, and terpenoids was significantly higher in STZ compared to LZ. Additionally, STZ exhibited lower levels of flavonoids and lipids compared to LZ. Moreover, MZ was found to be less nutritionally rich than STZ, except for lignans and coumarins, as it displayed lower levels of all the metabolites. KEGG pathway enrichment analysis revealed six significantly different metabolic pathways (p < 0.05) between LZ and MZ, including arginine and proline metabolism, sphingolipid metabolism, flavonoid biosynthesis, glutathione metabolism, glycerophospholipid metabolism, and cysteine and methionine metabolism. The metabolites in STZ and MZ exhibited three significantly different pathways (p < 0.05), primarily associated with flavonoid biosynthesis, arginine and proline metabolism, and sphingolipid metabolism. The significantly differential metabolites between LZ and STZ were observed in the phenylpropionic acid biosynthesis pathway and the ubiquinone and other terpenoid-quinone biosynthesis pathways. LZ showed a closer relationship with STZ than with MZ. STZ and LZ exhibited higher medicinal values, while LZ had lower acidity and MZ displayed better antioxidant activity. This study presents the first thorough analysis of metabolites in LZ, STZ, and MZ cultivars, which can serve as a theoretical basis for quality analysis, functional research, and classification processing of jujube fruit.

Rapidly and accurately screening histidine decarboxylase inhibitors from Radix Paeoniae alba using ultrafiltration-high performance liquid chromatography/mass spectrometry combined with enzyme channel blocking and directional enrichment technique.

Histidine Decarboxylase (HDC), an unique enzyme responsible for the synthesis of histamine, which is an important mediator in allergy. Inhibition of HDC activity to decrease histamine production is one way to alleviate allergic symptoms. Traditional Chinese medicines (TCMs) with reported anti-allergy effect is one of important source to search for natural HDC inhibitor. Ultrafiltration combined with high-performance liquid chromatography/mass spectrometry (UF-HPLC/MS) is an effective method for screening HDC inhibitor from TCMs. Nevertheless, false-positive and false-negative results caused by the non-specific binding and the neglection of the trace active compounds are major problems in this method. In this study, an integrated strategy that combined UF-HPLC/MS with enzyme channel blocking (ECB) technique and directional enrichment (DE) technique was developed to seek natural HDC inhibitors from Radix Paeoniae alba (RPA), and at the same time, to reduce false-positive and false-negative results. HDC activity was detected to determine the validity of the screened compounds by RP-HPLC-FD in vitro. Molecular docking was applied to assay the binding affinity and binding sites. As a result, three compounds were screened from low content components of RPA after the DE. Among them, two non-specific compounds were eliminated by ECB, and the specific compound was identified as catechin, which has obvious HDC inhibition activity with IC50 0.52 mM. Furthermore, gallic acid (IC50 1.8 mM) and paeoniflorin (IC50>2 mM) from high content components of RPA were determined having HDC inhibitory activity. In conclusion, the integrated strategy of UF-HPLC/MS combined with ECB and DE technique is an effective mode for rapid and accurate screening and identification of natural HDC inhibitors from TCMs.

Quality Markers' Discovery and Quality Evaluation of Jigucao Capsule Using UPLC-MS/MS Method.

Jigucao capsules (JGCC) have the effects of soothing the liver and gallbladder and clearing heat and detoxification. It is a good medicine for treating acute and chronic hepatitis cholecystitis with damp heat of the liver and gallbladder. However, the existing quality standard of JGCC does not have content determination items, which is not conducive to quality control. In this study, serum pharmacochemistry technology and UNIFI data processing software were used to identify the blood prototype components and metabolites under the condition of the obvious drug effects of JGCC, and the referenced literature reports and the results from in vitro analysis of JGCC in the early stage revealed a total of 43 prototype blood components and 33 metabolites in JGCC. Quality markers (Q-markers) were discovered, such as abrine, trigonelline, hypaphorine and isoschaftoside. In addition, ultra-high-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-QQQ-MS) was used to determine the active ingredients in JGCC. The components of quantitative analysis have good correlation in the linear range with R2 ≥ 0.9993. The recovery rate is 93.15%~108.92% and the relative standard deviation (RSD) is less than 9.48%. The established UPLC-MS/MS quantitative analysis method has high sensitivity and accuracy, and can be used for the quality evaluation of JGCC.

Fungicide Dissipation Kinetics and Dietary Exposure Risk Assessment in Squash Fruit and Leaf.

The dissipation behavior and dietary exposure risk assessment of four fungicides (dimethomorph, mandipropamid, myclobutanil, and metalaxyl) was performed in fruits and leaves of squash grown under greenhouse conditions. Squash fruit and leaf samples were randomly collected at 0, 3, 5, 7, and 14 days after the last pesticide application. Analysis was performed using ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). The quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was used for sample preparation. Recovery rates at two spiked levels (0.01 and 0.1 mg/kg) were found to be in the range of 76.4%-101.9% for the analyzed pesticides and their relative standard deviations were ≤4%. Pesticide half-lives were 2.1 and 4.9 days for dimethomorph, 4.6 and 8.1 days for mandipropamid, 4.7 and 8.2 days for myclobutanil, and 2.7 and 5 days for metalaxyl in squash fruit and leaf, respectively. Regarding the total surveyors, hazard quotient values for squash fruit and leaf were ≤1.03 × 10-3 and ≤2.39 × 10-3, respectively. These values in the case of true consumers were ≤3.14 × 10-3 and ≤3.91 × 10-1, respectively.

Ionic Liquid-Dispersive Micro-Extraction and Detection by High Performance Liquid Chromatography-Mass Spectrometry for Antifouling Biocides in Water.

A simple analytical method was developed and evaluated for the determination of two antifouling biocides using an ionic liquid-dispersive liquid-liquid micro-extraction (IL-DLLME) and a high-performance liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) analysis. Irgarol 1051 and Sea-Nine 211 were extracted from deionized water, lake water, and seawater using IL 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIm][PF6]) and ethyl acetate as the extraction solvent and the dispersion solvent. Several factors were considered, including the type and volume of extraction and dispersive solvent, IL amount, sample pH, salt effect, and cooling temperature. The developed method resulted in a recovery range of 78.7-90.3%, with a relative standard deviation (RSD, n = 3) less than 7.5%. The analytes were enriched greater than 40-fold, and the limits of detection (LOD) for two antifouling biocides were 0.01-0.1 µg L-1. The method was effectively applied for the analysis of real samples of freshwater as well as samples of seawater.

Microsampling and enantioselective liquid chromatography coupled to mass spectrometry for chiral bioanalysis of novel psychoactive substances.

In this paper, the development of efficient enantioselective HPLC methods for the analysis of five benzofuran-substituted phenethylamines, two substituted tryptamines, and three substituted cathinones is described. For the first time, reversed-phase (eluents made up with acidic water-methanol solutions) and polar-ionic (eluent made up with an acetonitrile-methanol solution incorporating both an acidic and a basic additive) conditions fully compatible with mass spectrometry (MS) detectors were applied with a chiral stationary phase (CSP) incorporating the (+)-(18-crown-6)-tetracarboxylic acid chiral selector. Enantioresolution was achieved for nine compounds with α and RS factors up to 1.32 and 5.12, respectively. Circular dichroism (CD) detection, CD spectroscopy in stopped-flow mode and quantum mechanical (QM) calculations were successfully employed to investigate the absolute stereochemistry of mephedrone, methylone and butylone and allowed to establish a (R)<(S) enantiomeric elution order for these compounds on the chosen CSP. Whole blood miniaturized samples collected by means of volumetric absorptive microsampling (VAMS) technology and fortified with the target analytes were extracted following an optimized protocol and effectively analysed by means of an ultra-high performance liquid chromatography-MS system. By this way a proof-of-concept procedure was applied, demonstrating the suitability of the method for quali-quantitative enantioselective assessment of the selected psychoactive substances in advanced biological microsamples. VAMS microsamplers including a polypropylene handle topped with a small tip of a polymeric porous material were used and allowed to volumetrically collect small aliquots of whole blood (10 µL) independently from its density. Highly appreciable volumetric accuracy (bias, in the -8.7-8.1% range) and precision (% CV, in the 2.8-5.9% range) turned out.

Study of degradation of norfloxacin antibiotic and their intermediates by natural solar photolysis.

In this work, the photolysis of the antibiotic norfloxacin (NOR) and the formation of its photodegradation products were studied using UV and solar radiation. Their extraction was also assessed in Milli-Q water and secondary effluents from a wastewater treatment plant. The photolysis of NOR was chromatographically monitored. The structure of each degradation product is related to the reaction of NOR with reactive oxygen species (ROS), as confirmed using radical quenchers and mass spectrometry. Additionally, the feasibility of extracting NOR and its degradation products was assessed using a commercial solid phase extraction system. Photolysis results showed the formation of five degradation products, generated under exposure to both types of radiation. The decays in NOR concentrations for the solar and UV treatments were adjusted to pseudo first-order kinetics with apparent constant values of ksolar = 1.19 × 10-3 s-1 and kUV = 3.84 × 10-5 s-1. Furthermore, the superoxide radical was the main participant species in the formation of the degradation products P3, P4, and P5. Species P1 and P2 do not need this radical for their formation. The presence of NOR in water opens the possibility of its photolysis by solar radiation. This work contributes to the understanding of the mechanisms that mediate its photodegradation, in addition to studying potential options for its determination and its photodegradation products in the sample treatment.

Intraluminal deposits: A rare cause of glaucoma drainage implant total obstruction.

PURPOSE: To report the unforeseen complication of total obstruction of a glaucoma drainage implant (GDI) tube lumen by white deposit material and to present a preliminary report identifying the composition of this material. METHODS: Two subjects with a high IOP due to total obstruction of a GDI tube were reviewed. Both patients had a long history with brinzolamide and timolol maleate eye drops. The GDI tube was swept with a 5-0 polypropylene suture stent in order to open the tube. The intraluminal solid sample was successfully collected from the implant tube in one patient. High-performance liquid chromatography-mass spectrometry (HPLC-MS) was used to determine the origin of the intraluminal sample. RESULTS: Intraluminal deposits containing components of antiglaucoma drugs e.g., timolol and brinzolamide are a rare cause of total obstruction of GDI tubes. CONCLUSIONS: Our study describes a new cause of total obstruction GDI tubes. The long-term use of timolol maleate and brinzolamide and their presence in the intraluminal solid sample collected from the blocked GDI tube suggest that the glaucoma medication may have a role in the pathogenesis. However, the exact mechanism is unknown and requires further studies.

Fluorinated magnetic porous carbons for dispersive solid-phase extraction of perfluorinated compounds.

Novel magnetic and fluorinated porous carbons (M-FPCs) with high fluorine content, large pore volume and specific surface area were first prepared by carbonizing and further fluorinating Fe-Zr bimetal-organic frameworks. The M-FPCs exhibit excellent adsorption performance toward perfluorinated compounds (PFCs), and the maximal adsorption capacity ranges from 518.1 to 919.3 mg g-1 for various PFCs. Based on this property, an environmental analytical method of dispersive solid-phase extraction (DSPE) using M-FPCs as adsorbents coupled with ultra-high-performance liquid chromatography-mass spectrometry (UPLC-MS) was developed for the detection of trace PFCs. The linear range was as wide as 10-200 ng L-1, and low limit of detection (0.02-0.16 ng L-1) and good precision (relative standard deviation less than 6.11% for intra-day and inter-day) were achieved. This method was applied to the detection of trace PFCs in environmental water and soil samples with satisfactory results.

Rapid identification, quantitation, and antioxidant activity evaluation of the components in Guanxin Shutong capsule with liquid chromatography and mass spectrometry.

Guanxin Shutong capsule (GSC) is a traditional Chinese medicinal prescription used in the treatment of coronary heart disease (CHD) and angina pectoris in clinic. However, the chemical profile of GSC is still uncovered, which hindered the progress of pharmacological study and clinical application. Herein, high performance liquid chromatography (HPLC) together with high resolution mass spectrometry (HR-MS) techniques were employed to analyze the quality consistency and to identify chemical components in GSC. As a result, a total of 111 compounds were tentatively annotated. Quantitative analysis based on HPLC-ultraviolet detection (UV) was performed for 6 main components and fingerprints of 10 different batches of GSC were established. The developed method was validated for linearity, precision, repeatability, stability, and recovery. The quality evaluation and similarity analysis of the 10 batches were also performed. Furthermore, in vitro antioxidant activity assays demonstrated that GSC exhibited potential DPPH and hydroxyl radical scavenging capacities. Especially, salvianolic acids showed the strongest free radical scavenging capacities, which might be the main component for quality control of GSC.

Evaluation of the antioxidant characteristics of craft beer with green tea.

The addition of green tea as antioxidants to beer can improve the beer's flavor stability by protecting against staling during storage. To analyze the effect of different green teas on the flavor stability of beer, we developed an approach to rapidly evaluate their antioxidant activity. Ten types of craft beer were produced by adding different kinds of green tea during brewing, and their antioxidant activity and phenolic profiles were evaluated. The results showed remarkable variations in antioxidant activity and antioxidative compound contents, which were considerably higher in green tea beers than in non-tea beer (p < 0.05). A comprehensive evaluation function was developed to evaluate the total antioxidant activity of beers using principal component analysis. The highest total antioxidant activity was observed in Taiping Houkui beer, with a comprehensive evaluation score of 2.53. Pearson correlation analysis suggested that (-)-epigallocatechin gallate, (-)-epicatechin gallate, and (-)-epigallocatechin were strongly correlated with the total antioxidant activity of green tea beers (p < 0.01). The summation of their contents represented more than 60% of the total phenolic content of the teas, which can be used to predict the total antioxidant activity of green tea beers. PRACTICAL APPLICATION: Flavor stability is of prime concern for brewers, and flavor aging is increasingly becoming the limiting factor in beer shelf life. The application of green tea as antioxidants in beer can improve the flavor stability by protecting against beer staling during storage. The analytical method developed in this study will contribute to the rapid comparison of the effect of different green teas on the flavor stability of beer. Furthermore, the research findings demonstrate the potential benefits of green teas to beer flavor stability, which is of considerable importance in promoting the development and consumption of green teas.

Simultaneous determination and quality evaluation of 16 compounds in Ligustri Lucidi Fructus covering different regions and processed products using ultra-high-performance liquid chromatography-mass spectrometry.

A quantitative analysis method and a chemical pattern recognition method were developed to evaluate raw Ligustri Lucidi Fructus (LLF) from different regions and different processed products. In this study, a comprehensive strategy using ultra-high-performance liquid chromatography-mass spectrometry quantitative analysis method was established for the simultaneous determination of 16 components in 47 batches of LLF covering 19 regions belonging to 8 provinces and 24 batches of different processed products (steamed LLF without auxiliary material, wine-steamed LLF, salt-steamed LLF, and vinegar-steamed LLF). The results of this study indicated that the proposed method was reliable and accurate for the rapid analysis proved by detection limit, quantification limit, precision, and accuracy. Furthermore, principal component analysis and hierarchical cluster analysis were employed to analyze the experimental data, showing that the best-quality samples of 47 batches of raw LLF were S47 (Lantian, Shaanxi), S39 (Pingyang-2, Shandong), S38 (Pingyang-1, Shandong), and S45 (Lingbao, Henan), whereas the worst-quality samples were S7-S16 (Huzhou, Zhejiang). In 24 batches of processed products, the best-quality samples were S48 (salt steamed 2 h), S60 (wine steamed 2 h), and S61 (wine steamed 4 h). Meanwhile, the heat map showed that the contents of triterpenoid saponins, including C16 (ursolic acid), C15 (oleanic acid), and C14 (maslinic acid), were higher than those of other compounds in 71 batches of samples. These results suggested that the quality of raw LLF in the central and northern regions was better than that in the southern regions, and regarding the processed products, different auxiliary materials had little effect on the quality of LLF, but steaming time of 2 h was appropriate. Briefly, this study proposed a multiparameter quantitative analysis method for the overall quality control of raw LLF samples covering different regions in China and different processed LLF.

UHPLC-Orbitrap study of the first phase tacrine in vitro metabolites and related Alzheimer's drug candidates using human liver microsomes.

Tacrine was the first drug used in the therapy of Alzheimer's disease (AD) and is one of the leading structures frequently pursued in the drug discovery of novel candidates for tackling AD. However, because tacrine has been withdrawn from the market due to its hepatotoxicity, ascribed to specific metabolites, concerns are high about the toxicity profile of newly developed compounds related to tacrine. From the point of view of drug safety, the formation of metabolites must be uncovered and analyzed. Bearing in mind that the main culprit of tacrine hepatotoxicity is its biotransformation to hydroxylated metabolites, human liver microsomes were used as a biotransformation model. Our study aims to clarify phase I metabolites of three potentially non-toxic tacrine derivatives (7-methoxytacrine, 6-chlorotacrine, 7-phenoxytacrine) and to semi-quantitatively determine the relative amount of individual metabolites as potential culprits of tacrine-based hepatotoxicity. For this purpose, a new selective UHPLC-Orbitrap method has been developed. Applying UHPLC-Orbitrap method, two as yet unpublished tacrine and 7-methoxytacrine monohydroxylated metabolites have been found and completely characterized, and the separation of ten dihydroxylated tacrine and 7-methoxytacrine metabolites was achieved for the first time. Moreover, the structures of several new metabolites of 7-phenoxytacrine and 6-chlorotacrine have been identified. In addition, the relative amount of these newly observed metabolites was determined. Based on the results and known facts about the toxicity of tacrine metabolites published so far, it appears that 7-phenoxytacrine and 6-chlorotacrine could be substantially less hepatotoxic compared to tacrine, and could potentially pave the way for metabolically safe molecules applicable in AD therapy.