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Background Type 2 diabetes mellitus (T2DM) intricately involves disrupted lipid metabolism. Exosomes emerge as carriers of biomarkers for early diagnosis and monitoring. This study aims to identify lipid metabolites in serum exosomes for T2DM diagnosis. Methods Serum samples were collected from newly diagnosed T2DM patients and age and body mass index−matched healthy controls. Exosomes were isolated using exosome isolation reagent, and untargeted/targeted liquid chromatography−tandem mass spectrometry (LC-MS/MS) was used to identify and validate altered lipid metabolites. Receiver operating characteristic curve analysis was used to evaluate the diagnostic value of candidate lipid metabolites. Results Serum exosomes were successfully isolated from both groups, with untargeted LC-MS/MS revealing distinct lipid metabolite alterations. Notably, phosphatidylethanolamine (PE) (22:2(13Z,16Z)/14:0) showed stable elevation in T2DM-serum exosomes. Targeted LC-MS/MS confirmed significant increase of PE (22:2(13Z,16Z)/14:0) in T2DM exosomes but not in serum. PE (22:2(13Z,16Z)/14:0) levels not only positively correlated with hemoglobin A1C levels and blood glucose levels, but also effectively distinguished T2DM patients from healthy individuals (area under the curve = 0.9141). Conclusion Our research sheds light on the importance of serum exosome lipid metabolites in diagnosing T2DM, providing valuable insights into the complex lipid metabolism of diabetes. [ABSTRACT FROM AUTHOR]

Triadica cochinchinensis honey (TCH) is collected from the nectar of the medicinal plant T. cochinchinensis and is considered the most important honey variety in southern China. TCH has significant potential medicinal properties and commercial value. However, reliable markers for application in the authentication of TCH have not yet been established. Herein, a comprehensive characterization of the botanical origin and composition of TCH was conducted by determining the palynological characteristics and basic physicochemical parameters. Liquid chromatography tandem-mass spectrometry (LC-MS/MS) was used to investigate the flavonoid profile composition of TCH, T. cochinchinensis nectar (TCN) and 11 other common varieties of Chinese commercial honey. (−)-Gallocatechin gallate (GCG) was identified as a reliable flavonoid marker for TCH, which was uniquely shared with TCN but absent in the other 11 honey types. Furthermore, the authentication method was validated, and an accurate quantification of GCG in TCH and TCN was conducted. Overall, GCG can be applied as a characteristic marker to identify the botanical origin of TCH. [ABSTRACT FROM AUTHOR]

Red dragon fruit is gaining popularity globally due to its nutritional value and bioactive components. The study aimed to assess the phytochemical, nutritional composition, antioxidant, antibacterial, and cytotoxic properties of extracts from the South Chinese red dragon fruit peel, flesh, and seeds. Extract fractions with increasing polarity (ethyl acetate50 values ranging from 3.25–8.30 μg/mL. The flesh MT and ET extract fractions demonstrated substantial inhibitory effects, with MIC50 ranging 73.62–98.85 μg/mL, against several multidrug-resistant bacteria. Cytotoxicity assays revealed no adverse effects of the crude extract fractions on human keratinocytes (HaCaT) cells (from adult human skin). Liquid chromatography with tandem mass spectrometry (LC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS) analyses unveiled a wide array of compounds with known and unknown antibacterial and antioxidant activities. Thereafter, pharmacological property screening and molecular docking were performed. The results identified four active compounds, baicalein, quercetin, morin, and isorhamnetin, which demonstrated strong binding affinity with the selected target proteins and complied with most of the pharmacological parameters. In conclusion, this study provides essential information on the key nutrients present in the peel, flesh, and seeds of the red dragon fruit from Southern-China. Furthermore, it highlights the potential of ET and MT fractions, which contain compounds with promising antibacterial properties. [ABSTRACT FROM AUTHOR]

Nifedipine is a potent antihypertensive medication classified as a dihydropyridine calcium channel blocker. The objective of this trial was to assess the bioequivalence of a 30‐mg nifedipine controlled‐release tablet and a reference drug in a cohort of healthy Chinese individuals. Two independent open‐label, randomized, single‐dose, crossover studies were conducted, 1 under fasting conditions (N = 44, with 1 participant dropping out midway) and the other under fed conditions (N = 44, with 4 participants dropping out midway). Plasma concentrations of nifedipine were determined using liquid chromatography‐mass spectrometry, and pharmacokinetic (PK) parameters were calculated using noncompartmental analysis with Phoenix WinNonlin 8.0 software. In both fasting and fed studies, reasonable bioequivalence was observed for the PK parameters of both the test product and the reference drug. A good safety profile was demonstrated for both the test product and reference drug, with no serious adverse events reported, and both were similarly well tolerated. An important observation with food coadministration was that systemic exposure to nifedipine (based on area under the curve, AUC0‐∞) was reduced by approximately 12%. The bioequivalence of the test product and reference drug under fasting/fed conditions in healthy subjects in China was demonstrated by the study results. [ABSTRACT FROM AUTHOR]

Mycotoxins often contaminate rice, which are the secondary metabolites of fungi. Ustiloxins, a type of mycotoxin that has often been overlooked, pose a significant risk to human health. Therefore, identifying and controlling the pollution of ustiloxins in rice is required. In this study, we examined the natural contamination of rice with ustiloxins and their link to climate conditions. A total of 300 paddy samples were collected from six regions in southern China, and concentrations of ustiloxins A, B, C, D, and F were analyzed by liquid chromatography–tandem mass spectrometry (LC-MS/MS). Results showed that the occurrence of ustiloxins A, B, C, D, and F in paddies was found to be 55.7%, 41.3%, 29.0%, 93.7%, and 96.7%, respectively. Ustiloxin A had the highest mean (177.8 µg/kg) and maximum (3620.9 µg/kg) concentration, followed, in order, by ustiloxins C, B, D, and F. Furthermore, ustiloxin levels were significantly different depending on their origin, with the highest concentration in rice from Changde and Yueyang. And the regional difference in ustiloxins was related to the diversity of climate. A positive correlation between ustiloxin occurrence and mean humidity and precipitation was found in July and August of different regions, while mean temperature indicated a negative dependence. This is an essential survey of the contamination of rice with ustiloxins throughout southern China. The influence of climatic conditions on ustiloxins contamination was evaluated for the first time in our study. Overall, the rice samples examined in this study exhibited a high distribution of ustiloxins, suggesting that regulatory limits and the establishment of maximum allowable levels of ustiloxins in rice are necessary. This study provides a basis and guidance for the pollution situation and control strategy of ustiloxins in China. [ABSTRACT FROM AUTHOR]

Herbal medicines are widely used for clinical purposes worldwide. These herbs are susceptible to phytopathogenic fungal invasion during the culturing, harvesting, storage, and processing stages. The threat of fungal and mycotoxin contamination requires the evaluation of the health risks associated with these herbal medicines. In this study, we collected 138 samples of 23 commonly used herbs from 20 regions in China, from which we isolated a total of 200 phytopathogenic fungi. Through morphological observation and ITS sequencing, 173 fungal isolates were identified and classified into 24 genera, of which the predominant genera were Fusarium (27.74%) and Alternaria (20.81%), followed by Epicoccum (11.56%), Nigrospora (7.51%), and Trichocladium (6.84%). Quantitative analysis of the abundance of both Fusarium and Alternaria in herbal medicines via RT-qPCR revealed that the most abundant fungi were found on the herb Taraxacum mongolicum, reaching 300,000 copies/μL for Fusarium and 700 copies/μL for Alternaria. The in vitro mycotoxin productivities of the isolated Fusarium and Alternaria strains were evaluated by using liquid chromatography–tandem mass spectrometry (LC-MS/MS), and it was found that the Fusarium species mainly produced the acetyl forms of deoxynivalenol, while Alternaria species mainly produced altertoxins. These findings revealed widely distributed fungal contamination in herbal medicines and thus raise concerns for the sake of the quality and safety of herbal medicines. [ABSTRACT FROM AUTHOR]

Background: Geographical factors affect the nutritional, therapeutic and commercial values of fruits. Dragon fruit (Hylocereus spp) is a popular fruit in Asia and a potential functional food with diverse pharmacological attributes. Although it is produced in various localities, the information related to the altitudinal variation of dragon fruit nutrients and active compounds is scarce. Hence, this study aimed to investigate the variations in metabolite profiles of H. polyrhizus (variety Jindu1) fruit pulps from three different altitudes of China, including Wangmo (WM, 650 m), Luodian (LD, 420 m), and Zhenning (ZN, 356 m). Jindu1 is the main cultivated pitaya variety in Guizhou province, China. Results: The LC-MS (liquid chromatography-mass spectroscopy)-based widely targeted metabolic profiling identified 645 metabolites, of which flavonoids (22.64%), lipids (13.80%), phenolic acids (12.40%), amino acids and derivatives (10.39%), alkaloids (8.84%), and organic acids (8.37%) were dominant. Multivariate analyses unveiled that the metabolite profiles of the fruit differed regarding the altitude. Fruits from WM (highest altitude) were prime in quality, with higher levels of flavonoids, alkaloids, nucleotides and derivatives, amino acids and derivatives, and vitamins. Fruits from LD and ZN had the highest relative content of phenolic acids and terpenoids, respectively. We identified 69 significantly differentially accumulated metabolites across the pulps of the fruits from the three locations. KEGG analysis revealed that flavone and flavonol biosynthesis and isoflavonoid biosynthesis were the most differentially regulated. It was noteworthy that most active flavonoid compounds exhibited an increasing accumulation pattern along with the increase in altitude. Vitexin and isovitexin were the major differentially accumulated flavonoids. Furthermore, we identified two potential metabolic biomarkers (vitexin and kaempferol 3-O-[2-O-β-D-galactose-6-O-a-L-rhamnose]-β-D-glucoside) to discriminate between dragon fruits from different geographical origins. Conclusion: Our findings provide insights into metabolic changes in dragon fruits grown at different altitudes. Furthermore, they show that growing pitaya at high altitudes can produce fruit with higher levels of bioactive compounds, particularly flavonoids. [ABSTRACT FROM AUTHOR]

Bitespiramycin, has been shown to have a therapeutic effect against respiratory tract inflammation, including a potential effect against COVID-19. A current clinical trial in China showed that bitespiramycin was an effective treatment for severe pneumonia and intracranial infection. However, there is lack of an analytical method to elucidate the distribution of bitespiramycin. In this study, a highly sensitive, rapid and reliable UPLC–MS/MS method was developed to comprehensively characterize the bitespiramycin distribution in various bio-samples, which is significantly improved upon the published work. A rapid sample preparation method was developed by using n-butanol as the solvent to extract bitespiramycin from different bio-samples. The extract was then directly analyzed by UPLC–MS/MS coupled with an alkaline-resistant column after centrifugation which avoids the time-consuming concentration process under nitrogen and redissolution. The method was employed to accurately quantify bitespiramycin and its metabolites in rat plasma, tissues, and human cerebrospinal fluid. Notably, the presence of bitespiramycin and its metabolites was identified for the first time in various rat organs including brain, testis, bladder and prostate as well as in human cerebrospinal fluid. This newly developed approach shows great promise for drug distribution assays including other antibiotics and can help elucidate the ADME of bitespiramycin. [ABSTRACT FROM AUTHOR]

In view of the defects in the previous detection of cuaminosulfate, which only focused on the analysis of copper ions, there is currently no analysis method available to determine the actual state of cuaminosulfate as chelated or bound. In order to investigate the dissipation and terminal residues in soil and watermelon of cuaminosulfate for food safety and environmental risk, a highly effective technique was developed to detect cuaminosulfate residues in watermelon and soil, and field experiments were conducted in China. After single-factor experiments, residual cuaminosulfate in samples was extracted by pure water, purified using a liquid–liquid approach combined with a dispersive solid-phase extraction, and detected by liquid chromatography tandem mass spectrometry (LC-MS/MS). The Box–Behnken design (BBD) study was used to find the optimal solutions for the time of liquid–liquid purification, the amount of extraction solvent, and the amounts of cleanup sorbents for the analytical method. The average recovery of the method was in the range of 80.0% to 101.1%, the average relative standard deviation (RSD) was 5.3–9.9%, and the detection limit was lower than 0.05 mg/kg. The BBD study not only improved the extraction rate of the method, but also saved time and was operated easily. The final residues of cuaminosulfate in watermelon at different sampling intervals were all lower than 0.05 mg/kg under field conditions. The cuaminosulfate in soils dissipated following exponential kinetics, with half-life values in the range of 9.39 to 12.58 days, which varied by different locations. Based on the validated method, food safety residues and soil residues can be determined rapidly and accurately. [ABSTRACT FROM AUTHOR]

Pesticide residues in rice have attracted widespread public attention in recent years. This research aimed to monitor the residues of 17 pesticides and their 3 metabolites in 120 samples of rice and rice flour collected from markets in China using the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) pretreatment method combined with high-performance liquid chromatography-tandem mass spectrometry (HPLC–MS/MS). The monitoring results showed that isoprothiolane, tricyclazole, fenoxanil, and tebuconazole were detected in the rice samples, with detection frequencies of 33.3%, 17.5%, 8.3%, and 2.5%, and concentrations ranging from 0.02 to 0.1 mg/kg (median = 0.04), 0.01 to 0.17 mg/kg (median = 0.14), 0.04 to 0.06 mg/kg (median = 0.05), and 0.01 to 0.02 mg/kg (median = 0.01), respectively. The residues of these four pesticides were all below their corresponding maximum residue levels (MRLs) set by China. Additionally, isoprothiolane, tricyclazole, fenoxanil, and tebuconazole were detected in rice flour samples, with detection frequencies of 74.2%, 55.0%, 5.0%, and 2.5%, and concentrations ranging from 0.01 to 0.1 mg/kg (median = 0.04), 0.01 to 0.04 mg/kg (median = 0.02), 0.01 to 0.06 mg/kg (median = 0.03), and 0.02 to 0.04 mg/kg (median = 0.03), respectively. Furthermore, the chronic dietary intake risk (HQc), the acute dietary intake risk (HQa), and cumulative dietary risk (HI) for all the detected pesticides were evaluated and found well below 100%, indicating that the dietary intake risks would not pose potential health risks. [ABSTRACT FROM AUTHOR]

In this study, the transfer rates of nine pesticides with different water solubility (imidaclothiz, acetamiprid, thiamethoxam, imidacloprid, clothianidin, carbendazim, pyraclostrobin, phoxim and etoxazole) from dry tea to infusion were carefully determined using the liquid-chromatography-tandem mass spectrometry (LC-MS/MS). The obtained results show that the transfer of each pesticide from tea spiked with the pesticides to the infusion ranged from 4.54% (etoxazole) to 58.0% (acetamiprid) under the traditional brewing condition in China, which indicates that transfer of pesticides was dependent on their water solubilities. Increases in infusion time resulted in increased transfer within 30 min. However, there was little influence of infusion time on transfer rates after 30 min. When the infusion temperature was between 50 and 100°C, the transfer rates of acetamiprid, thiamethoxam, imidacloprid, carbendazim, pyraclostrobin, phoxim and etoxazole increased with temperature, while transfer rates for imidaclothiz and clothianidin decreased with increasing temperature. After three infusions, the transfer rates of imidaclothiz, thiamethoxam, acetamiprid, and clothianidin were >70%. Our results provide a basis for the rational use of pesticides in tea gardens and a reasonable evaluation of dietary exposure levels of pesticide residues in brewed tea. [ABSTRACT FROM AUTHOR]

Alternaria mycotoxins are a class of important, agriculture-related hazardous materials, and their contamination in ruminant feeds and products might bring severe toxic effects to animals and even human beings. To control these hazardous compounds, a reliable and sensitive LC-MS/MS (liquid chromatography–tandem mass spectrometry) method was established for simultaneous determination of six target Alternaria mycotoxins in ruminant feeds, including ALT (Altenuene), AME (Alternariol Monomethyl Ether), AOH (Alternariol), ATX-Ι (Altertoxins I), TeA (Tenuazonic Acid), and TEN (Tentoxin). This developed analytical method was used for the determination of the presence of these substances in cattle and sheep feeds in Xinjiang Province, China. The results revealed that Alternaria mycotoxins are ubiquitously detected in feed samples. Especially, AME, AOH, TeA, and TEN are the most frequently found mycotoxins with a positive rate over 40% and a concentration range of 4~551 µg/kg. The proposed method could be applied for exposure investigation of Alternaria mycotoxins in ruminant feeds and for the reduction in the health risk to animals and even consumers. [ABSTRACT FROM AUTHOR]

Licorice (Glycyrrhiza uralensis Fisch) is a natural plant resource widely used as a food and herbal medication in China. Glycycoumarin (GCM) is a major coumarin in licorice that possesses several biological activities. However, little is known about its pharmacokinetic profile. The present study aimed to describe the oral absorption, tissue distribution, and excretion of GCM in rats. Free (parent drug) and/or total (parent drug plus the glucuronidated metabolite) GCM in biological samples was quantified before and after the hydrolysis reaction with ß-glucuronidase using a reliable LC-MS/MS method. The results indicated that GCM was rapidly absorbed and transformed into its conjugated metabolites after administration. Free GCM plasma concentrations after i. v. (10 mg/kg) administration quickly decreased with an average t1/2,λz of 0.71 h, whereas the totalGCMconcentration reduced slowly with a t1/2, λz of 2.46 h. The area under the curve of glucuronidated metabolites was approximately four-times higher than that of free GCM. Presumably, because of hepatic and/or intestinal tract first-pass metabolism, GCM exhibited a poor bioavailability of 9.22%, as estimated from its total plasma concentration. Additionally, GCM was distributed rapidly and widely in various tissues except the brain. The liver had the highest concentration; further, GCM was promptly eliminated from test tissues after intraperitoneal (20 mg/kg) administration, but only a small amount of GCM was excreted via bile and urine. Overall, GCM is absorbed and rapidly transformed into its conjugated metabolites with low bioavailability; further, it is distributed in various tissues, except the brain. These pharmacokinetic results are helpful for better understanding the characteristics and pharmacological effects of GCM. [ABSTRACT FROM AUTHOR]

Tetrodotoxin (TTX) inhibits neurotransmission in animals, and there is no specific antidote. In clinical practice in China, Althaea rosea (A. rosea flower) extract has been used to treat TTX poisoning. In this work, the efficacy of the ethyl acetate fraction extract of A. rosea flower in treating TTX poisoning in rats was investigated. A high-performance liquid chromatography–tandem mass spectrometry (LC-MS/MS) method was developed to determine nine neurotransmitters in rat brain tissue, including γ-aminobutyric acid (GABA), dopamine (DA), 5-hydroxytryptamine (5-HT), noradrenaline (NE), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 5-hydroxyindole-3-acetic acid (5-HIAA), epinephrine (E), and tyramine (Tyn). The detoxifying effect of A. rosea flower was verified by comparing the changes in neurotransmitters' content in brain tissue before and after poisoning in rats. The assay was performed in multiple reaction monitoring mode. The quantification method was performed by plotting an internal-standard working curve with good linearity (R2 > 0.9941) and sensitivity. Analyte recoveries were 94.04–107.53% (RSD < 4.21%). Results indicated that the levels of 5-HT, DA, E, and NE in the brains of TTX-intoxicated rats decreased, whereas the levels of GABA, Tyn, and 5-HIAA showed an opposite trend, and HVA and DOPAC were not detected. The levels of all seven neurotransmitters returned to normal after the gavage administration of ethyl acetate extract of A. rosea flower to prove that the ethyl acetate extract of A. rosea flower had a therapeutic effect on TTX poisoning. The work provided new ideas for studies on TTX detoxification. [ABSTRACT FROM AUTHOR]

Cullen corylifolium has been used to treat bronchial asthma, vitiligo, nephritis and leucopenia from ancient times in China. However, its chemical composition has not been fully understood. In this study, both LC-MS and GC-MS were used to identify the chemical composition in C. corylifolium. Consequently, 31 compounds were qualified by LC-MS/MS, 8 representative compounds of which were quantified, 62 compounds including hydrocarbons, terpenoids and coumarins were identified by GC-MS. Among a total of 93 compounds, 32 compounds (8 by LC-MS/MS and 24 by GC-MS) are undocumented for this herb. Our results will provide a crucial foundation for further studies related to its pharmaceutical activities and quality control. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to describe the vitamin D status and its distribution in different age groups, sexes, seasons, and provinces of a large Chinese population. Methods: This study retrospectively analyzed 1,528,685 results of serum 25-hydroxyvitamin D (25(OH)D) in the central laboratory of KingMed Diagnostics. The samples were from the individuals aged 0–119 years old in 30 provinces of China. Serum 25(OH)D was measured by an accurate commercial liquid chromatography-tandem mass spectrometry (LC–MS/MS) method from January 2017 to December 2019. The subjects were stratified by age, sex, the season of blood collection, and the province of residence. Results: The median 25(OH)D concentration was 25.5 ng/mL (interquartile range (IQR) 18.7–32.7 ng/mL) in males and 20.8 ng/mL (IQR 14.4–28.2 ng/mL) in females. Overall, the median 25(OH)D concentration decreased with age in both males and females. Males had a 0.2–2.4 ng/mL higher median 25(OH)D concentration than females in different age groups. Vitamin D deficiency (25(OH)D < 15 ng/mL for the individuals under 14 years old; < 20 ng/mL for the individuals over 14 years old) was found in 21.3% of males and 43.6% of females. Significant seasonal variation of serum 25(OH)D concentrations was repeatedly observed in 3 years, with median concentration higher in summer (25.3 ng/mL (IQR 19.3–31.9 ng/mL)) and lower in winter (18.5 ng/mL (IQR 12.3–26.6 ng/mL)). Vitamin D status varied by province. The median 25(OH)D concentration was the highest in Hainan (31.0 ng/mL (IQR 24.9–39.2 ng/mL)) and the lowest in Qinghai (14.4 ng/mL (IQR 9.6–20.0 ng/mL)). 25(OH)D2 was detected in 12.2% of the results, and no significant seasonal variation was observed. Conclusion: In China, vitamin D deficiency is prevalent in the population participating in clinical vitamin D measurement. Age and sex differences in vitamin D levels were observed in our study. Seasonal variation and provincial differences are important aspects of serum vitamin D status. 25(OH)D2 cannot be ignored entirely in clinical measurement practice in China. [ABSTRACT FROM AUTHOR]

This study presents the contents of α-methylenecyclopropylglycine, a potentially toxic amino acid, in the peel, pulp and seed fractions of two well-known litchi varieties, namely Shahi and China, over a span of three harvest-seasons. For analysing α-methylenecyclopropylglycine, an LC-MS/MS-based method was validated. The method-accuracies fell within 75–110 % (RSD, <15 %) at 0.1 mg/kg (LOQ) and higher levels. A comparative evaluation of the results in peel, pulp and seed at 30 days before harvest (DBH), 15-DBH, and edible-ripe stage revealed that α-methylenecyclopropylglycine content increased as the litchi seeds grew towards maturity, regardless of the cultivar. In arils, at maturity, the concentration of α-methylenecyclopropylglycine ranged from not-detected to 11.7 μg/g dry weight. The Shahi cultivar showed slightly higher α-methylenecyclopropylglycine content in comparison to China litchi. This paper presents the first known analysis of combined seasonal data on different fruit components at various growth stages for the two chosen litchi cultivars grown in India. • An LC-MS/MS method optimised for estimation of α-methylenecyclopropylglycine in litchi • MCPG was quantified in peel, seed and aril of China and Shahi litchi at 3 growth stages • MCPG in litchi aril ranged between 0 and 11.7 μg/g DW • Shahi litchi showed slightly higher MCPG content over China cultivar • Ripe arils showed higher MCPG over unripe in Shahi cultivar [ABSTRACT FROM AUTHOR]

Houttuyniae herba, the Saururaceae plant Houttuynia cordata Thunb., has multiple therapeutic effects, including clearing heat, eliminating toxins, reducing swelling, discharging pus, and relieving stagnation. It has a long history as an edible and medicinal plant in China. Phytochemical studies show that the main constituents include volatile oil, flavonoids, and alkaloids. Aristolactam is a major alkaloid with a structure similar to toxic aristolochic acids. However, there has been no systematic study on aristolochic acids and alkaloids in Houttuyniae herba. Therefore, in this study, an LC–MS/MS method was developed to simultaneously detect seven alkaloids and five aristolochic acids in Houttuyniae herba from different origins. Six alkaloids (O-demethyl nornucifrine, N-nornucifrine, aristololactam AII, aristololactam FI, aristololactam BII, cepharadione B) were found and quantitatively determined in 75 batches of samples. Meanwhile, no aristolochic acids or aristololactams were found in Houttuyniae herba at a limit of detection (LOD) of ≤4 ng/mL. The method developed was fully validated in terms of LOD, limit of quantification (LOQ), linearity, precision, accuracy, and stability. These data clarify the content of the above safety-related components in Houttuyniae herba and provide a reference for further research into its safety. [ABSTRACT FROM AUTHOR]

Pesticide residues in food have become an important factor seriously threatening human health. Therefore, this study was conducted to determine the pesticide residues in fruits and vegetables commonly found in Fujian, China, with the aim of constructing a simple and rapid method for pesticide residue monitoring. We collected 5607 samples from local markets and analyzed them for the presence of 45 pesticide residues. A fast, easy, inexpensive, effective, robust, and safe (QuEChERS) multi-residue extraction method followed by liquid chromatography equipped with triple-quadrupole mass spectrometry (LC-MS/MS) was successfully established. This 12-min-long analytical method detects and quantifies pesticide residues with acceptable validation performance parameters in terms of sensitivity, selectivity, linearity, the limit of quantification, accuracy, and precision. The linear range of the calibration curves ranged from 5 to 200 mg/L, the limits of detection for all pesticides ranged from 0.02 to 1.90 μg/kg, and the limits of quantification for the pesticides were 10 μg/kg. The recovery rates for the three levels of fortification ranged from 72.0% to 118.0%, with precision values (expressed as RSD%) less than 20% for all of the investigated analytes. The results showed that 726 (12.95%) samples were contaminated with pesticide residues, 94 (1.68%) samples exceeded the maximum residue limit (MRL) of the national standard (GB 2763-2021, China), 632 (11.23%) samples were contaminated with residues below the MRL, and 4881 (87.05%) samples were pesticide residue-free. In addition, the highest number of multiple pesticide residues was observed in bananas and peppers, which were contaminated with acetamiprid, imidacloprid, pyraclostrobin, and thiacloprid. [ABSTRACT FROM AUTHOR]

Lipophilic phycotoxins (LPTs) are toxic and lipophilic secondary metabolites produced by toxic microalgae, which pose a serious threat to marine shellfish culture industries. LPTs were systematically investigated in bottom seawater, suspended particulate matter (SPM), sediment, and sediment porewater of Laizhou Bay, a typical mariculture bay in China, to understand the chemical diversity and environment behaviors of LPTs in the benthic environments. Okadaic acid (OA), pectenotoxin-2 (PTX2), dinophysistoxin-1 (DTX1), azaspiracid-2 (AZA2), gymnodimine (GYM), pectenotoxin-2 seco acid (PTX2 SA), 7-epi- pectenotoxin-2 seco acid (7-epi-PTX2 SA), 13-desmethylspirolide C (SPX1), yessotoxin (YTX) and homo YTX (h-YTX) were detected in the benthic environment of Laizhou Bay in spring, indicating that LPTs are rich in chemical diversity. OA and PTX2 were dominant in bottom seawater and porewater; PTX2 and PTX2 SA were dominant in SPM; and PTX2 and AZA2 were dominant in sediments, but AZA2 was present in sediments only. At the bottom seawater-SPM interface, the average proportion of LPTs in the dissolved phase (DP) (84.35%) was significantly higher than in the particulate phase (PP) (15.65%), indicating that LPTs were mainly distributed to the DP in the bottom seawater. At the sediment-porewater interface, a considerable variation exists in the partitioning behavior of different groups of LPTs, with abundant PTX2 and OA in DP, while the AZA2 and YTX group of LPTs were present in PP. The concentration of total lipophilic phycotoxins (∑LPTs) in the bottom seawater ranged from 8.07 ng L -1 to 37.11 ng L -1 , with an average of 22.63 ng L -1 , showing that the spatial distribution characteristics of ∑LPTs of the northern farshore are higher than in the southern nearshore. Concentrations of ∑LPTs in sediment and porewater ranged from 1.51 ng kg -1 -32.67 ng kg -1 (mean: 17.32 ng kg -1 ) and 17.32 ng L -1 -226.54 ng L -1 (mean: 88.72 ng L -1 ), respectively. Notably, the concentration of ∑LPTs in porewater is significantly higher than in bottom and surface seawater, indicating that the potential harm of LPTs to benthos needs more attention., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Vitamin D deficiency has been a critical global health issue within the pediatric population. Closed-off management brought about by the COVID-19 pandemic has drastically impacted outdoor activities and sunlight exposure, however, whether it indirectly further exacerbated the vitamin D deficiency has not been largely investigated, especially among children in China. The purpose of this study was to evaluate 25(OH)D concentrations in children before and during the COVID-19 lockdown and to analyze the factors influencing their vitamin D status., Methods: A cross-sectional survey included children aged 1-6 years from Han Zhong Central Hospital in the southern Shanxi Province of China. This study examined healthy children from a pediatric health care department over two periods: before COVID-19 (March 2019-February 2020), and during COVID-19 (March 2020-February 2021). Total 25(OH)D concentrations were compared between the two observation periods. Vitamin D status was determined by 25(OH)D concentrations: deficient (<20 ng/ml), insufficient (20-29 ng/ml), and sufficient (30-100 ng/ml)., Results: The study involved 6,780 children, with 52.8% being 1-year-olds, 23.1% being 2-year-olds, and 24.1% being 3 to 6-year-olds. Boys and girls were 52.8 and 47.2%, respectively. The actual prevalence of deficiency in vitamin D nutritional status among children was 2.8%, with 87.1% of cases in those aged 3 to 6 years. Vitamin D insufficiency was 18.3%, affecting 54.8% of the same demographic. The average of 25(OH)D concentration were 38.2 ± 9.8 ng/ml, significantly varying by age and season. 25(OH)D concentrations decreased with age, from 42.3 ± 8.8 ng/ml at 1-year-olds to 37.4 ± 8.2 ng/ml at 2-year-olds, and further to 30.2 ± 8.1 ng/ml at 3 to 6-year-olds. Seasonal variations showed that 25(OH)D concentrations were higher in spring (38.7 ± 10.1 ng/ml), summer (38.7 ± 10.0 ng/ml), and fall (38.6 ± 9.2 ng/ml) in comparison to winter (36.0 ± 9.8 ng/ml). Additionally, the concentrations of 25(OH)D in spring exhibited a decrease during the COVID-19 pandemic (37.9 ± 10.3 ng/ml) in comparison to the pre-pandemic measurements (39.3 ± 9.9 ng/ml) ( p  = 0.008), while winter concentrations increased from (35.1 ± 10.4 ng/ml) to (37.9 ± 10.3 ng/ml) during the pandemic ( p  = 0.002)., Conclusion: The research indicated that vitamin D deficiency is uncommon among Chinese children, with 25(OH)D concentrations experiencing a notable decline in those aged 3-6 years. The findings suggested a potential need for tailored supplementation strategies and possibly higher doses for this age group, along with monitoring 25(OH)D concentrations to evaluate supplementation effectiveness. COVID-19-related restrictions minimally affected children's 25(OH)D concentrations, revealing the nutritional implications of the pandemic., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2025 Qiao, Wang, Ma and Hu.)

Cystatin C (CysC) belongs to the cysteine protease inhibitor superfamily and is produced by all nucleated cells in the body in very stable amounts independent of age, sex, diet, and muscle mass. CysC is considered an ideal biomarker for assessing glomerular filtration rate (GFR) compared to traditional biomarkers for assessing GFR, such as creatinine. However, CysC is not sufficiently utilized for GFR assessment by clinicians, probably for various reasons such as insufficient understanding among clinicians or a lack of standardized quantitative methods. This review discusses and analyzes the aforementioned issues from the perspective of laboratory technicians., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.)

Fish-killing events caused by haptophyte Prymnesium parvum have been reported in aquatic environments worldwide. This haptophyte could produce diverse prymnesins (PRMs) that harm to aquatic organisms like fishes. In this study, the components of prymnesins in the strain of P. parvum (NMBjih029) isolated from the coast of Ningbo city, China, were elucidated by a high-resolution mass spectrometer (HRMS), and the influence of nitrate levels and salinity on growth and toxin production of P. parvum were also explored. Results showed that the P. parvum produced C-type prymnesins with structure variations in saturation, chlorination, and sugar modifications. The growth and toxin production were significantly affected by nitrate levels in the batch cultures. At the lowest level of nitrate (N:P = 4:1), growth of P. parvum was inhibited but toxin quotas per cell increased up to approximately 4 times of that in control group (N:P = 16:1) during the exponential growth stage. Growth of P. parvum was not obviously affected by different salinities, but the biosynthesis of prymnesins increased with decreasing salinity from 32 to 14 in the culture media. The proportion of high chlorination of prymnesins (tetrachloride) increased in P. parvum under nitrogen limitation stress and low salinity. And the toxin quotas per cell also markedly increased with the extension of culture period in P. parvum under nitrogen limitation and different salinity conditions. This study provides some important cues for toxin profile and environmental impacts on the biosynthesis of prymnesins in the strain of P. parvum isolated from Chinese aquatic environments., Competing Interests: Declaration of competing interest The authors declare no conflict of interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Donkeys are indispensable livestock in China because they have transport function and medicinal value. With the popularization of artificial insemination on donkeys, semen cryopreservation technology has gradually become a research hotspot. Seminal plasma is a necessary medium for transporting sperm and provides energy and nutrition for sperm. Seminal plasma metabolites play an important role in the process of sperm freezing, and also have an important impact on sperm motility and fertilization rate after freezing and thawing. In this study, liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis was used to compare the metabolic characteristics of seminal plasma of high freezability (HF) and low freezability (LF) male donkeys. We identified 672 metabolites from donkey seminal plasma, of which 33 metabolites were significantly different between the two groups. Metabolites were identified and categorized according to their major chemical classes, including homogeneous non‐metal compounds, nucleosides, nucleotides, and analogues, organosulphur compounds, phenylpropanoids and polyketide, organoheterocyclic compounds, organic oxygen compounds, benzenoids, organic acids and derivatives, lipids and lipid‐like molecules, organooxygen compounds, alkaloids and derivatives, organic nitrogen compounds. The results showed that the contents of phosphatidylcholine, piceatannol and enkephalin in donkey semen of HF group were significantly higher than those of LF group (p <.05), while the contents of taurocholic and lysophosphatidic acid were significantly lower than those of LF group (p <.05). The different metabolites were mainly related to sperm biological pathway response and oxidative stress. These metabolites may be considered as candidate biomarkers for different fertility in jacks. [ABSTRACT FROM AUTHOR]

This study assessed the presence of the genotoxic impurity 1-methyl-4-nitrosopiperazine (MNP) in 27 batches of rifampicin capsules obtained from 11 manufacturers in China. While they were below the temporary limit of 5 ppm set by the US Food and Drug Administration, the observed levels (0.33–2.36 ppm) exceeded the acceptable threshold of 0.16 ppm. Building upon preliminary findings and degradation experiments, we concluded that MNP is a by-product of the oxidative degradation of rifampicin or is introduced via oxidation or nitrosation during the synthesis process involving 1-methyl-4-aminopiperazine. The pathways of MNP formation were confirmed in this study. Furthermore, we observed that the addition of antioxidants, sealed storage, and selection of dominant crystal forms can aid in controlling MNP levels. • Changes in MNP content were observed after rifampicin degradation. • Oxidation and nitrosation reactions are critical conditions for MNP formation. • Selection dominant crystal forms of rifampicin can aid in controlling MNP levels. • Adding antioxidants can help control MNP generation after rifampicin degradation. [ABSTRACT FROM AUTHOR]

Nitroaromatic compounds (NACs) in ambient particles are of great concern due to their adverse effects on human health and climate. However, investigations on the characteristics and potential sources of NACs in Southwest China are still scarce. In this study, a field sampling campaign was carried out in the winter of 2022 at a suburban site in Mianyang, Southwest China. A direct injection liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to rapidly determine 10 NACs in fine particulate matter (PM 2.5) extracts. The method was sensitive for the quantification of the NACs, with a limit of quantification (LOQ) in the range of 0.092–0.52 ng mL−1. Then, the developed method was applied to determine the concentrations of nitrophenols (NPs), nitrocatechols (NCs), nitrosalicylic acids (NSAs), and nitronaphthol in PM 2.5 in Mianyang. The average concentration of total NACs was 78.2 ± 31.2 ng m−3, with daily concentrations ranging from 20.7 to 127.9 ng m−3. Among the measured NACs, 4-nitrocatechol was the most abundant, accounting for 57.8% of the NACs in winter. The five NPs compounds together contributed to 14% of the NACs, which was lower than in other Chinese cities due to the warm climate in winter in Southwest China. NSAs and nitronaphthol each accounted for less than 5% of the NACs. Three major sources of NACs were identified based on the principal component analysis, including vehicle emissions, biomass burning, and secondary formation. The significant correlation between individual NACs and NO 2 supported their secondary formation sources. The good correlation between NPs and cloud amount further suggested that gas-phase oxidation was the possible NPs formation mechanism. Our findings revealed the important role of nitrocatechols in NACs in Southwest China, implying that more measures should be taken to control biomass burning and aromatic volatile organic compounds emissions to reduce the level of NACs. [Display omitted] • Development of a direct injection LC-MS/MS method for quantification of 10 NACs in PM 2.5 extracts. • 4-nitrocatechol was the most abundant species, accounting for 58% of measured NACs. • Vehicle emission, biomass burning, and secondary formation were potential sources. [ABSTRACT FROM AUTHOR]

A popular and widely used combination therapy of leflunomide (LEF) and Tripterygium glycosides tablets (TGTS) has become a valuable clinical tool in China for the treatment of rheumatoid arthritis. This regimen has not been evaluated either in terms of interaction or toxicity, even given the rising concerns about LEF's prolonged elimination half-life and TGT's narrow therapeutic index, in addition to the current trend of using high doses of LEF. Thus, this study determines the potential adverse drug reactions between these two medicines. Reliable validated LC-MS/MS methods were used for the determination of teriflunomide (TER, the only active metabolite of LEF), and the main components of TGT: wilforlide A, wilforgine, wilfortrine, wilfordine, and wilforine. The results obtained from this investigation, as paralleled with the control groups, revealed that the Cmax and AUC0-t of TER were significantly decreased with separate co-administration, as the Cmax and AUC0-t were 30.17 ± 1.55 μg/mL and 24.47 ± 2.50 μg/mL, 374.55 ± 15.54 μg h/mL and 336.94 ± 21.19 μg h/mL, respectively (p < 0.05). Meanwhile, the pharmacokinetic profiles of the main components of TGT have also been affected by separate co-administration in rats. Therefore, herb–drug interactions between LEF and TGT have been proven. [ABSTRACT FROM AUTHOR]

Background: Hair antiretroviral concentrations are an objective and non-invasive measure of adherence to long-term antiretroviral therapy (ART) and can further predict virologic outcomes among people living with HIV/AIDS (PLWH). Zidovudine, one of the mainstream antiretrovirals in China, has been verified to have high reliability in adherence assessment, especially for its hair concentrations. However, data are limited in its predicting virologic outcomes. Therefore, this study aimed to characterize whether hair zidovudine concentrations can predict virologic suppression among Chinese PLWH compared with hair lamivudine concentrations and two self-reported measures, the overall frequency of adherence behaviors and percentage adherence. Methods: This cross-sectional study randomly recruited 564 PLWH currently treated with zidovudine, lamivudine, and other ART agents (efavirenz, nevirapine, or lopinavir/ritonavir) in Guangxi, China. Hair antiretroviral concentrations were determined using the LC-ESI+-MS/MS method. Receiver operating characteristic (ROC) curves were used to estimate the optimal classification thresholds of hair concentrations of zidovudine and lamivudine, and the two self-reported measures. Based on those optimal classification thresholds, logistic regression was used to examine whether those four adherence measures can predict virologic suppression (HIV-1 RNA < 200 copies/mL). Results: ROC curves demonstrated good classification performance for association with virologic suppression of zidovudine with the optimal threshold at 58 pg/mg and lamivudine at 255 pg/mg but no self-reported measures. PLWH with hair zidovudine concentrations > 58 pg/mg had an adjusted odds ratio (aOR) of 43.191 (95% confidence interval (CI) = 10.171‒183.418, p < 0.001) for virologic suppression. Hair lamivudine concentrations were also associated with virologic suppression (aOR = 10.656, 95% CI = 3.670‒30.943, p < 0.001). However, two self-reported measures did not predict virologic suppression (aORs = 1.157 and 2.488, ps > 0.149). Conclusion: Hair zidovudine concentrations can be served as an alternative tool for clinically predicting virologic suppression among PLWH in China. [ABSTRACT FROM AUTHOR]

Zhuang Medicine Jin-mu Granules (ZMJG) are prescriptions derived from the Zhuang nationality, which is the largest minority among 56 ethnic groups in China. They have been widely used in the treatment of chronic pelvic inflammatory disease (CPID) in Guangxi Zhuang Autonomous Region for clearing away heat and toxins, removing dampness and poisoning. CPID is a common gynecological disease of female reproductive organs and surrounding tissues and is characterized by persistent and recurrent symptoms, causing serious physical and psychological damage to the patient. Preliminary research found that ZMJG have beneficial effects on CPID model rats, but the metabolic mechanism underlying their protective effects is unclear. In this study, we used the strategy of combining network pharmacology, pharmacodynamic, and metabolomic approaches to investigate the molecular mechanisms and potential targets of ZMJG for the treatment of CPID. First, a network diagram of "medicinal materials-components-targets-pathways" based on network pharmacology was constructed to obtain a preliminary understanding of the biologically active compounds and related targets of ZMJG and clarify their molecular mechanism in CPID. Subsequently, the in vivo efficacy of ZMJG was verified in a rat model. Furthermore, we analyzed the corresponding metabolomics profile to explore the differentially induced metabolic markers and elucidate the metabolic mechanism by which ZMJG treat CPID. The results show that the therapeutic effect of ZMJG on CPID is mediated through multiple pathways, metabolic pathways, and multi-component multi-target modes, providing a detailed theoretical basis for the development and clinical application of ZMJG and a new research idea for the treatment of CPID in Chinese medicine. [ABSTRACT FROM AUTHOR]

A simple and sensitive liquid chromatography-tandem mass spectrometry method was developed for the determination of thidiazuron (TDZ), a plant growth regulator, in soil, tobacco leaf (fresh, cured), stem, and root. The detection limits of TDZ ranged from 0.03 μg/kg to 0.15 μg/kg, and the limits of quantification ranged from 0.1 − 0.5 μg/kg. The average recoveries of TDZ in soil, tobacco leaf (fresh, cured), stem, and root were between 75.39% and 98.51% with intra-day relative standard deviations (RSDs) between 1.06% and 4.91% and inter-day RSDs between 1.49% and 7.52%. The valid method was used to determine the amount of TDZ residues in tobacco and soil samples under open field and laboratory conditions. Field experiments were carried out in six agricultural sites of China, and the results showed that the half-lives of TDZ were 9.76 − 12.60 days and 2.04 − 4.81 days in soil and fresh tobacco leaves, respectively. The terminal concentration of TDZ in cured tobacco leaves was <0.50−7.46 μg/kg. Foliage spray and root irrigation experiments were conducted under laboratory conditions. The results indicated that TDZ can be transferred upward and downward in tobacco plants. The transfer factor (TF) of the root irrigation was approximately 10 times of TF of the foliage spray. [ABSTRACT FROM AUTHOR]

It has been widely reported that the key biomarkers of homocysteine metabolic pathways have emerged as markers or independent risk factors for cardiovascular disease and many other diseases. To improve the accuracy of evaluation in China, we establish the reference intervals of serum homocysteine (Hcy), cysteine (Cys), and methionine (Met) in apparently healthy Chinese adults. We examined 1553 subjects aged ≥20 years who underwent Hcy metabolic pathway tests, in the Chaoyang Central Hospital between January 2019 and December 2020. The serum Hcy, Cys, and Met levels were simultaneously determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Multiple regression analysis was performed to identify sources of variation. A nonparametric method was used to establish the reference intervals. Gender differences were observed in Hcy and Met, with higher levels in males. Reference intervals for males were 6.09–17.00 μmol/L (Hcy) and 19.31–33.68 μmol/L (Met); conversely, the reference intervals for females were 4.61–14.61 μmol/L (Hcy) and 16.16–30.35 μmol/L (Met). The serum Cys reference intervals were seen to be gender-independent, but age-dependent reference intervals were needed; those for Cys were 188.85–334.27 μmol/L, 200.48–340.66 μmol/L, and 216.03–349.67 μmol/L in <40, 40–50, and ≥50 years, respectively. By this study, the gender- or age-specific reference intervals of Hcy, Cys, and Met that were matched with the Chinese population were established, providing valuable references for clinical work and laboratory researches. [ABSTRACT FROM AUTHOR]

Ganpu tea is a novel type of beverage produced from Pu-erh tea stuffed in the pericarp of Citrus reticulata "Chachi". It has gained considerable popularity in China owing to its inviting flavor and health effects. However, the in vivo metabolites of Ganpu tea, which may contribute to its overall health effects, are still unclear. In the present work, rat urine and feces samples were collected after oral administration of Ganpu tea extract (GTE), and then subjected to ultra-high-performance liquid chromatography/quadrupole-time-of-flight tandem mass spectrometry (UHPLC-Q-TOF-MS/MS)-based metabolite profiling. As a result, 27 prototype compounds and 41 metabolites derived from caffeic acid, gallic acid, p -coumaric acid, xanthine, catechin, polymethoxyflavone, (PMF) flavanone, and flavone were identified in rat urine and feces. Based on the detected metabolites, the ingested prototype compounds derived from Ganpu tea were found to undergo extensive phase II metabolism in rats, especially and sulfation. These results will be valuable for interpreting the health effects of Ganpu tea. [ABSTRACT FROM AUTHOR]

Sirolimus (SRL) is commonly used in transplant patients to prevent organ transplant rejection. The current guidelines recommend to perform SRL therapeutic drug monitoring regularly to improve treatment outcomes and avoid adverse effects. Consequently, a precise and accurate method for determining SRL is crucial in clinical practice. Currently, liquid chromatography-tandem mass spectrometry (LC-MS/MS) and immunoassays have been widely adopted for determining SRL concentrations. However, previous studies have shown that immunoassays exhibit a positive bias compared to LC-MS/MS. As the new updated version of the EMIT-based Viva-E® System (SVPS), this study aims to compare SRL blood concentrations measured by the SVPS and LC-MS/MS. The residual whole-blood samples obtained from transplant patients were simultaneously analyzed using the SVPS and LC-MS/MS, respectively. The correlation between the two assays was analyzed using the linear regression analysis and Deming linear regression. The Pearson correlation coefficient and Intraclass correlation coefficient (ICC) analysis were executed. The Paired Wilcoxon test and Bland-Altman analysis were performed to assess the concordance between the two methods. The SVPS considerably increased SRL concentration value by 46.62 % as compared to the LC-MS/MS method. When SRL concentrations measured by the SVPS were above 4.0 ng/mL, there was no significant difference between the corrected SVPS concentrations after using the Deming linear regression equation, indicating their interchangeability. Given the significant disparities observed between EMIT and LC-MS/MS, it is crucial to indicate the methodology and instruments in both TDM reports and future clinical guidelines. Our study also provides the conversion formulas between the SVPS and LC-MS/MS, which can be applied as a reference for different clinical centers., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The National Medical Products Administration has authorized sodium oligomannate for treating mild-to-moderate Alzheimer's disease. In this study, an LC-MS/MS method was developed and validated to quantitate sodium oligomannate in different biomatrices. The plasma pharmacokinetics, tissue distribution, and excretion of sodium oligomannate in Sprague-Dawley rats and beagle dogs were systematically investigated. Despite its complicated structural composition, the absorption, distribution, metabolism, and excretion profiles of the oligosaccharides in sodium oligomannate of different sizes and terminal derivatives were indiscriminate. Sodium oligomannate mainly crossed the gastrointestinal epithelium through paracellular transport following oral administration, with very low oral bioavailability in rats (0.6%–1.6%) and dogs (4.5%–9.3%). Absorbed sodium oligomannate mainly resided in circulating body fluids in free form with minimal distribution into erythrocytes and major tissues. Sodium oligomannate could penetrate the blood-cerebrospinal fluid (CSF) barrier of rats, showing a constant area under the concentration-time curve ratio (CSF/plasma) of approximately 5%. The cumulative urinary excretion of sodium oligomannate was commensurate with its oral bioavailability, supporting that excretion was predominantly renal, whereas no obvious biliary secretion was observed following a single oral dose to bile duct-cannulated rats. Moreover, only 33.7% (male) and 26.3% (female) of the oral dose were recovered in the rat excreta within 96 h following a single oral administration, suggesting that the intestinal flora may have ingested a portion of unabsorbed sodium oligomannate as a nutrient. [Display omitted] • ADME profiles of sodium oligomannate oligosaccharides were indiscriminate. • An LC-MS/MS method was developed and validated for the ADME study of sodium oligomannate. • Sodium oligomannate was absorbed through paracellular transport with very low BA. • Approximately 5% of sodium oligomannate penetrated the blood–CSF barrier of rats. • The absorbed drug was excreted through the kidney; unabsorbed drug was excreted in feces. [ABSTRACT FROM AUTHOR]

A total of 1338 samples were analyzed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to study the toxin profiles of lipophilic marine toxins in bivalve mollusks collected from the southeast coast of China from 2017 to 2020. The most abundant toxin was HomoYTX, followed progressively by YTX and PTX2. Low proportions of OA, DTX-1, and DTX-2 were found. No AZA1, AZA2, and AZA3 were quantified above limit of quantitation (LOQ). The highest concentrations of HomoYTX, YTX, PTX2, OA, DTX-1, and DTX-2 were 429, 98.0, 40.3, 33.0, 22.6, and 26.5 μg/kg, respectively. Mussels (Mytilus galloprovincialis, Perna viridis), scallop (Chlamys farreri) and clam (Atrina pectinate) accumulated higher toxin levels than clams (Sinonovaculla Constricta, Ruditapes philippinarum), oyster (Crassostrea gigas) and scallop (Arca granosa). Homo YTX and PTX2 levels reached the maximum in July and June, respectively, and the OA-group peaked in August. The results provide a reliable basis for monitoring marine toxins and protecting the health of aquatic consumers. [Display omitted] • This work reported the lipophilic toxin profiles and contents in Shellfish from Southeastern China in 2017–2020. • The predominant lipophilic toxins were yessotoxins and pectenotoxins. • Mussel (Mytilus galloprovincialis) and scallop (Chlamys farreri) accumulated higher toxin levels than other shellfish. • Yessotoxins reached a maximum level in July, and pectenotoxins reached the maximum in June. [ABSTRACT FROM AUTHOR]

Bovis Calculus Artifactus (BCA) is the main substitute for natural Calculus bovis, a traditional drug in China used to treat high fever, convulsion, and sore throat. The effect of BCA on cytochrome P450 (CYP) activities is unknown. This study was to investigate the effect of BCA on eight rat hepatic microsomal CYPisozymes to evaluate the potential drug interactions using the cocktail approach. Metabolites of the eight isoform probe substrates of CYP isozymes were quantified by LC-MS/MS. The method was validated by incubating known CYP inhibitors α-naphthoflavone (CYP1A2), thiotepa (CYP2B1), quercetin (CYP2C7), sulfaphenazole (CYP2C6), ticlopidine (CYP2C11), quinidine (CYP2D1), ketoconazole (CYP3A1),4-methylpyrazole (CYP2E1) with individual probe substrate and rat liver microsomes. The formation rates of the corresponding metabolites of the eight probe substrates were determined to evaluate the activity of each isozyme. The results showed that BCA has different degrees of inhibitory effect on four CYP450 isoforms (CYP2C6, CYP2C11, CYP2D1, CYP3A1) (p < 0.05), but no significant influence on CYP1A2, 2B1, 2C7 or 2E1 (p > 0.05). Attention should be paid to the BCA-drug interactions by careful monitoring and appropriate dosage adjustments in the concurrent use of the drugs which are metabolized by CYP1A2, CYP2C19, and CYP3A4. Abbreviations: BCA, bovis calculus artifactus; CYP, cytochrome P450; DDIs, drug-drug interactions; ESI, electrospray ionization; MRM, multiple reaction monitoring; NBC, Natural Bovis Calculus; QC, quality control; T CM, traditional Chinese medicine. [ABSTRACT FROM AUTHOR]

A new method for the determination of 26 legacy and emerging per- and polyfluoroalkyl substances (PFASs) in marine sediment pore water was developed using online solid phase extraction coupled with liquid chromatography-tandem mass spectrometry. The proposed method requires only about 1 mL of pore water samples. Satisfactory recoveries of most target PFASs (83.55–125.30 %) were achieved, with good precision (RSD of 1.09–16.53 %), linearity (R 2 ≥ 0.990), and sensitivity (MDLs: 0.05 ng/L–5.00 ng/L for most PFASs). Subsequently, the method was applied to determine PFASs in the sediment pore water of five mariculture bays in the Bohai and Yellow Seas of China for the first time. Fifteen PFASs were detected with total concentrations ranging from 150.23 ng/L to 1838.48 ng/L (mean = 636.80 ng/L). The ∑PFASs and PFOA concentrations in sediment pore water were remarkably higher than those in surface seawater (tens of ng/L), indicating that the potential toxic effect of PFASs on benthic organisms may be underestimated. PFPeA was mainly distributed in pore water, and the partition of PFHpA (50.99 %) and PFOA (49.01 %) was almost equal in the solid and liquid phases. The proportions of all other PFASs partitioned in marine sediments were significantly higher than those in pore water. [Display omitted] • A convenient method for the detection of PFASs in marine sediment pore water was developed. • Only about 1 mL of actual sediment pore water is needed to determine various PFASs. • High levels of PFASs were detected in pore water from five mariculture bays of China. • Different PFASs exhibit varying partitioning behaviors at the sediment–pore water interface. • Great attention should be paid to PFASs in the sediment pore water of mariculture areas. [ABSTRACT FROM AUTHOR]

In this study, we describe a dispersive liquid-liquid microextraction strategy for bongkrekic acid (BA) purification, enrichment, and liquid chromatography coupled with mass spectrometry (LC-MS/MS) analysis. Bongkrekic acid (BA) was an important toxin that could cause liver and kidney damages, or even death. Furthermore, there were several food poisoning incidents occurred by BA in many countries including Indonesia, China, and so on. A rapid, simple and reliable determination of BA in plasma was of great value in the clinical diagnosis and treatment of poisoning patients. In this study, we describe a dispersive liquid-liquid microextraction strategy for purification and enrichment of BA followed by liquid chromatography tandem mass spectrometry (LC-MS/MS). The BA (pKa value was 4.15) in the plasma samples were dispersed and extracted by methanol, dichloromethane and 0.1% phosphoric acid solution successively, in which the proper ratios and the dosages were all optimized in this study. The conditions for ionization source and the extracting conditions for BA were also optimized. The matrix effect ranged from 95.0% to 102%, indicating matrix effects may be negligible. The feasibility of the extraction method was tested by analysis of BA in plasma samples. The mean recoveries for BA determination were achieved between 88.3% and 98.4%. The LOD and LLOQ for BA were 3.7 and 10 µg L−1, respectively. The proposed method is fast and simple, and highly sensitive for testing BA in plasma. [ABSTRACT FROM AUTHOR]

Actinidia arguta (Sieb. et Zucc.) is abundant of vitamin C and bioactive compounds with high antioxidant activities. In this study, eight wild A. arguta accessions from different areas in Northeast China were collected. Some bioactive compounds were extracted from leaves, petioles and fruits of different germplasms for constituent analysis and non-enzymatic antioxidant assay. Liquid chromatography with tandem mass spectrometry (LC–MS/MS) was used to detect the flavonoid compounds. The results showed that the highest vitamin C content was found in young apical leaves of 'CBS-6' (7.47 mg/g fresh weight), and the highest soluble sugar content was in fruits of 'CJ-1' (196.52 mg/g fresh weight) and the highest total phenolic content and total flavonoids content were in young apical leaves of 'CBS-11' (3.48 mg/g fresh weight) and of 'CBS-3' (2.00 mg/g fresh weight), respectively. Ten flavonoid compounds including kaempferol, isorhamnetin and quercetin were detected in leaves, petioles and fruits. The total content of flavonoids was highest in young apical leaves (10219.84 µg/g) and the lowest in fruits (78.75 µg/g). Based on the comparison of the contents of several bioactive compounds, the two accessions 'CJ-1' and 'CBS-8' stood out; the young leaves had the strongest antioxidant activity among different tissues based on the non-enzymatic antioxidant assay. These results highlighted the radical-scavenging potential in vitro of A. arguta leaves as a major source of phenolics and vitamin C as well as flavonoids. It provided a theoretical basis for the utilization of leaves of A. arguta. Supplemental data for this article is available online at https://doi.org/10.1080/13102818.2021.1908166. Supplemental data for this article can be accessed online at . [ABSTRACT FROM AUTHOR]

In Korea and China, ilaprazole is a widely used proton pump inhibitor in the treatment of gastric ulcers. In this study, a specific and sensitive LC-MS/MS method has been developed and validated for the quantification of ilaprazole enantiomers in the rat plasma, using R -lansoprazole as the internal standard. The enantioseparation was achieved on a CHIRALPAK AS-RH column (4.6 mm × 150 mm, i.d. 5 μm), with a mobile phase composed of 10 mM ammonium acetate aqueous solution and acetonitrile (60:40, V/V), at a flow-rate of 0.5 mL/min. The method was validated over the concentration range of 0.5–300 ng/mL for both, R - and S -ilaprazole. The lower limit of quantification was 0.5 ng/mL for both enantiomers. The relative standard deviation (RSD) of intra- and inter-day precision of R -ilaprazole and S -ilaprazole was less than 10.9%, and the relative error accuracy (RE) ranged from −0.5%–2.0%. Finally, the method was successfully evaluated in rats in a stereoselective pharmacokinetic study of the ilaprazole racemate. Image 1 • The enantioseparation of ilaprazole enantiomers was achieved on Chiralpak AS-RH column. • The LC-MS/MS was specific and sensitive. • The PK profiles of ilaprazole enantiomers showed significant difference. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the fate, terminal residues and risk assessment of spirotetramat and its four metabolites in pineapple and pineapple pulp samples. To achieve this goal, a simple, efficient and sensitive method based on QuEChERS technique was developed using LC-MS/MS. The limit of quantification was 0.01 mg/kg for all the target analytes with the average recoveries ranging from 77% to 109%. The validated method was successfully applied to investigate the fate and terminal residue of spirotetramat and its four metabolites in pineapple and pineapple pulp samples in China. The dissipation dynamics of spirotetramat in pineapple were investigated according to first-order kinetics and the calculated half-lives were 4.6 and 2.3 days in the two sampling locations. After two or three applications at the doses of 80 to120 mg a.i./kg, the highest spirotetramat residue (sum of spirotetramat and its four metabolites) that detected in pineapple and pineapple pulp samples were 0.203 and 0.064 mg/kg. The dietary risk assessment of spirotetramat in pineapple was assessed by risk quotients and the calculated risk quotient value was found to be far below 100%, indicating a low health risk to the consumers. As there was no recommended MRL value in pineapple in China, these results should be useful for safe and reasonable usage of spirotetramat in pineapple in China. [ABSTRACT FROM AUTHOR]

To investigate the presence of nitenpyram in kiwifruit, a field experiment was conducted in six kiwifruit producing regions in China. A modified quick, easy, cheap, effective, rugged and safe method (QuEChERS) method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the determination of nitenpyram in kiwifruit. Quantitative detection was performed by LC-MS/MS in multiple reaction monitoring (MRM) mode under positive-ion electrospray ionisation. The proposed method is linear and accurate in the range of 0.005 to 4.5 μg/mL. The recovery of nitenpyram was satisfactory (71.96–96.67%) with reasonable RSDs (9.83 %) for 0.01–4.5 mg/kg spiked levels. The limit of quantification (LOQ) was 0.01 mg/kg for nitenpyram. Nitenpyram degraded rapidly in kiwifruit with a half-life <4 days. Residues of nitenpyram were <0.01 − 0.54 mg/kg in kiwifruit 7, 14 and 21 days after spraying at six sites. [ABSTRACT FROM AUTHOR]

Artificial per- and polyfluoroalkyl substances (PFASs) are widely distributed in the environment and are potentially harmful to human health. This study assessed the matrix effect of different shellfish on LC-MS analysis and the recoveries of PFASs in purified extracts purified by adding ENVI-Carb graphitized carbon black. Total 76 samples were collected from coastal cities of the Bohai Sea and South China Sea in China. Results showed that the signal response of perfluorocarboxylic acid increased with the length of fluorocarbon chains. ENVI-Carb can mitigate the shellfish matrix effects for analysis of PFASs. Ten PFASs components were detected in shellfish samples at concentrations ranging from 1.3 to 8.5 ng/g wet weight. The PFOA and PFHxS were the dominant components, and PFOA, PFTrDA and PFNA were detected at high rates of 58–93%. The highest levels of ∑PFASs were accumulated in clams, while the lowest levels were found in mussels. The dietary risk assessment indicated that PFASs potentially threaten human health via consumption of clam products in the Bohai Sea region. This study will improve the understanding of the contamination status and the dietary risk of PFASs in shellfish products along the coasts of Bohai Sea and South China Sea in China. [Display omitted] • Shellfish matrix has obvious effects on the MS signals of the isotope PFASs. • ENVI-Carb purification can mitigate the interference of shellfish matrix effect. • The PFOA and PFHxS were the dominant components in shellfish samples. • PFASs may pose a risk to human health via the consumption of clams in the Bohai Sea. [ABSTRACT FROM AUTHOR]

The objective of this study was to analyze the concentration of PAEs and conduct a risk assessment focusing on their potential non-carcinogenic and carcinogenic effects as endocrine-disrupting chemicals. In this research, a method of quantifying eight PAEs in fruit juice samples was established through the utilization of dispersive solid-phase extraction (dSPE) and Liquid Chromatography coupled with Tandem Mass Spectrometry (LC-MS/MS). While he method recoveries for the samples ranged from 92.21 % to 96.74 %, the RSDs for the eight analytes in the samples ranged from 4.22 % to 6.64 %. Additionally, LODs ranging from 0.34 to 1.88 ng/mL and LOQs ranging from 1.17 to 6.27 ng/mL were determined. Utilizing this methodology, the assessment of PAE concentrations was carried out in 48 fruit juice samples. The results showed that PAEs were detectable in the fruit juice samples, but all tested compounds remained below the specific migration limits set by the EU (30 mg/kg for BBP, 1.5 mg/kg for DEHP, 0.3 mg/kg for DBP, and 9 mg/kg for DINP and DIDP). Among the analyzed PAEs, DINP (26.94 ± 3.25 ng/mL), DEP (7.07 ± 7.59 ng/mL), and DEHP (3.48 ± 1.02 ng/mL) were found to be the most prevalent plasticizers in the fruit juices. Health risk assessments were conducted by calculating Hazard Quotient (HQ) and Hazard Index (HI) values based on the consumption patterns of different age groups. The findings indicated that the values for DEHP, DINP, DEP, and DBP were all below 1, indicating negligible non-carcinogenic health risks associated with the consumption of fruit juices across all age groups. Moreover, the dietary intake levels of each PAE were found to be below the values established by the EFSA for TDI., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Objective: We aimed to describe the 25-hydroxyvitamin D (25(OH)D) status of southern Chinese individuals by a high-accuracy liquid chromatography tandem mass spectrometry (LC-MS/MS) method which can trace to reference measurement procedure. Materials and methods: From January 2018 to June 2019, a total of 4775 southern Chinese individuals were evaluated in our study. The serum levels of parathyroid hormone (PTH) were detected simultaneously in 162 cases. 25(OH)D was determined by LC-MS/MS, and PTH was detected using routine automated analysers. The distribution of the concentration, prevalence and seasonal variability of 25(OH)D in males and females of different age groups were studied. Results: The mean 25(OH)D concentration in our study was 32.57 ng/mL (4.20–101.40 ng/mL). The global 25(OH)D concentration in males was higher than that in females of different age group. The prevalence of vitamin D deficiency (< 20 ng/mL) in females (16.65%) was higher than that in males (6.83%). The prevalence of vitamin D deficiency (< 20 ng/mL) was most common in winter (22.98% of all women and 15.49% of all men). 25(OH)D concentrations were higher in those from whom blood samples were collected in summer and autumn than in winter and spring. 25(OH)D2 was detected in 672 serum samples (14.07%). In addition, there was a negative correlation between the concentrations of 25(OH)D and serum PTH (r = − 0.149, P < 0.05). Conclusion: Our study demonstrated that the average serum 25(OH)D concentration in southern Chinese individuals was higher than that in other Chinese cohorts by a high-accuracy LC-MS/MS method. The global 25(OH)D concentration in males was higher than that in females of different ages, and the prevalence of vitamin D deficiency in females was higher than that in males. Seasonal change was an important aspect of 25(OH)D concentration in young and middle-aged people but became less relevant for that in older subjects. 25(OH)D2 detection was of minor practical significance in our study. In addition, we also found that there was a negative correlation between the serum levels of 25(OH)D and PTH in southern Chinese individuals. [ABSTRACT FROM AUTHOR]

• A comprehensive LC–MS/MS method for the simultaneous determination of 17 aryl-OPEs. • Five aryl-OPEs were analyzed for the first time using LC–MS/MS. • Methanol provided better baseline separation of aryl-OPEs isomers than did acetonitrile. • The LOQ of the method was lower than that of some previous methods. • Elevated concentrations of AO168 = O were observed in all the indoor dust samples. Aryl organophosphate esters (aryl-OPEs) have gained increasing interest over the past few years since a growing number of emerging aryl-OPEs were identified in the environmental media. The currently available analytical methods for aryl-OPEs are usually tailored to detect a very limited number of aryl-OPEs and have inadequate sensitivity for several emerging aryl-OPEs. In this work, a comprehensive and sensitive method for the quantitative analysis of 17 aryl-OPEs in indoor dust samples by liquid chromatography-tandem mass spectrometry (LC–MS/MS) was developed and validated. The method allows for the determination of four traditional and thirteen emerging aryl-OPEs, which compose almost all the environmentally relevant aryl-OPEs that have been identified. For the first time, 2-isopropylphenyl diphenyl phosphate (2IPPDPP), 2,4-diisopropylphenyl diphenyl phosphate (24DIPPDPP), bis(2-isopropylphenyl) phenyl phosphate (B2IPPPP), bis(4- tert -butylphenyl) phenyl phosphate (B4tBPPP), and 2-naphthalenyl phosphate (NDPHP) were analyzed using LC–MS/MS. With a systematic optimization of the MS/MS parameters, chromatographic separation conditions, and sample preparation procedures, the target aryl-OPEs in the indoor dust were well separated within 13 min in one analytical run, with limits of quantification ranging from 0.09 to 3.2 ng g−1. Compared with the previously published methods, this method obtained a better sensitivity for most aryl-OPEs. The validated method was applied to 12 indoor dust samples that were collected from residential houses in Guangzhou, China. Both the traditional and emerging aryl-OPEs were frequently detected in the samples, except for NDPHP, with ∑aryl-OPEs ranging from 90 to 33,800 ng g−1. In particular, elevated concentrations of the newly identified tris(2,4-di- tert -butylphenyl) phosphate (AO168 = O) were observed in all the indoor dust samples. To our knowledge, these are the first reported data of AO168 = O levels in the environment media from China. These data indicate that AO168 = O is a ubiquitous pollutant that was previously overlooked and merits further investigation in the environment. [ABSTRACT FROM AUTHOR]

An efficient, sensitive, simple and fast method for the simultaneous determination of oxine-copper and pyraclostrobin in citrus fruit was developed and validated. The method uses ethylene diamine tetra-acetic acid as a competitive ligand to convert oxine-copper to soluble 8-hydroxyquinoline for analysis by QuEChERS and LC-MS/MS. Linear relationships were determined with correlation coefficients ranging from 0.9904 to 0.9998. The limits of detection for the analytes were 0.012–0.8 μg kg−1, and the limits of quantitation were 0.04–2.6 μg kg−1 in citrus. The average recoveries were 79.1–114.9% with relative standard deviations of less than 7.4%. The analyses of dissipation indicated that the half-lives of oxine-copper and pyraclostrobin were 1.94–3.67 and 1.79–2.48 days and the terminal residues were <0.08–8.99 and <0.02–1.90 mg kg−1, respectively. The risk quotients of oxine-copper and pyraclostrobin were 0.026–0.199 and 0.003–0.022, respectively. This risk assessment provides a reference for the safe and reasonable use of oxine-copper and pyraclostrobin and may help to establish maximum residue limits for these pesticides in China. [ABSTRACT FROM AUTHOR]

Phosphonate is an important phosphorous species in the effluent of wastewater treatment plant (WWTP), contributing to eutrophication and interfering with phosphate removal in WWTP. It is particularly difficult to determine phosphonates in samples of complex solution chemistry, resulting in very limited information on their presence in environmental matrices. Herein, we proposed a sensitive method based on liquid chromatography tandem mass spectrometry (LC-MS/MS) to determine six quantitatively most important phosphonates even at the ng/L level, i.e., 2-phosphonobutane-1,2,4-tricarboxylic acid, 1-hydroxyethane 1,1-diphosphonic acid, nitrilotris(methylene phosphonic acid), ethylenediamine tetra(methylene phosphonic acid), hexamethylenediamine tetra(methylene phosphonic acid) and diethylenetriamine penta(methylene phosphonic acid). Trimethylsilyldiazomethane (TMSCHN 2) derivatization of the target phosphonates is pre-requisite since it could greatly increase the sensitivity up to 2-3 orders of magnitude over direct analysis of the virgin ones. The sample pretreatment methods (including ion exchange and solid phase extraction(SPE)), the derivatization procedures, and the LC-MS/MS conditions were systematically optimized. The limits of quantitation for the six phosphonates in the background of tap water ranged from 1.4 μg/L to 57 μg/L for direct analysis, and from 5.0 ng/L to 200 ng/L for SPE enabled pre-concentration analysis, respectively. The reliability of the proposed method was successfully validated by analysis of authentic water samples collected from one river and three WWTPs (0.088–7200 μg/L phosphonates) with satisfactory recoveries (72–126%). To the best of knowledge, this is the first report on quantification of phosphonates in environmental samples in China. Image 1 • LC-MS/MS method for determination of phosphonates with LOD at ng/L level. • TMSCHN 2 pre-methylation enhanced MS intensity by 2–3 orders of magnitude. • SPE is required for authentic samples containing trace phosphonates (at ng/L level). • Phosphonates of 0.011–2200 μg P/L was determined in wastewater and river waters. • The first study in China on phosphonate analysis in authentic water samples. [ABSTRACT FROM AUTHOR]

• A novel LC–MS/MS method for bioanalysis of Da-Huang-Xiao-Shi decoction (DHXSD). • Multiple compounds of DHXSD were simultaneously monitored in plasma. • Monitoring 13 prototypes and their glucuronide/sulfate metabolites. • Challenge of structual diversity and various linear ranges of compounds was overcome. • The pharmacokinetic characteristics of DHXSD were studied for the first time Da-Huang-Xiao-Shi decoction (DHXSD), a traditional Chinese medicinal formula, has been used mainly to treat jaundice for more than 1700 years in China. In this study, we developed a rapid, sensitive, and accurate LC–MS/MS method to simultaneously determine multiple, potentially bioactive compounds of DHXSD, including five alkaloids (berberine, phellodendrine, palmatine, jatrorrhizine, and magnoflorine), five anthraquinones (rhein, aloe-emodin, emodin, chrysophanol, and physcion), two iridoid glycosides (geniposide and genipin 1-gentiobioside), and one iridoid aglycone (genipin) in rat plasma. Plasma samples collected from rats were treated immediately with 5% acetic acid to avoid the degradation of genipin. After protein precipitation with acetonitrile containing 5% acetic acid, the compounds were reconstituted in acetonitrile–water (50:50, v/v) solution containing 6.5% formic acid and separated on the ACQUITY™ UPLC BEH C 18 column (2.1 × 100 mm; 1.7 μm) using a mobile phase composed of 2 mM ammonium formate in water (solvent A) and acetonitrile (solvent B) at a flow rate of 0.3 mL/min. Quantitation was performed on a Triple Quand 5500 tandem mass spectrometer coupled with an electrospray ionization (ESI) source. Multiple reaction monitoring (MRM) was used to quantify compounds in positive and negative ion modes. The method validation results showed that the specificity, linearity, precision and accuracy, recovery, matrix effect, and stability of the 13 compounds met the requirements for their quantitation in biological samples. This newly established method was successfully used in a pharmacokinetic study on rats orally treated with DHXSD. Besides, glucuronide and sulfate metabolites were also determined in rat plasma after hydrolysis. This is the first method developed for the simultaneous quantification of multiple compounds of DHXSD in vivo. Our study provides relevant information on the pharmacokinetics of DHXSD and the relationship between the compounds of DHXSD and their therapeutic effects. [ABSTRACT FROM AUTHOR]

Gynura procumbens is commonly consumed as a vegetable and has been approved as an ingredient for food and dietary supplements in China. However, Gynura species are known to contain toxic pyrrolizidine alkaloids (PAs) and the PA profiles in G. procumbens are not known. This study was to extract and enrich PA from G. procumbens or health care products using PCX solid-phase extraction (SPE) cartridges identify the main PAs in the herb and to develop an liquid chromatography–mass spectrometry (LC-MS/MS) method for assaying the PA contents in the plant and its derived products. Upon using multiple reaction monitoring (MRM) acquisition together with comparison to the characteristics of mass fragmentations and retention times of reference standards, 11 PAs were identified as the main PAs in the plant. After clean-up and enrichment with PCX solid-phase extraction (SPE) cartridges, which resulted in better PA recoveries than either C18 or SCX cartridges, the LC-MS/MS method was subjected to validation in terms of linearity, repeatability, limits of quantification (LOQ) and recovery. The validated method was applied to quantify PAs in 12 plant samples and 7 commercial finished products. The total amounts of targeted PAs were found to vary from 15.6 to 848 μg/kg in the herbs and from 9.9 μg/kg to 33.9 mg/kg in the commercial products. The present work was the first to demonstrate that G. procumbens contained PAs in the herb and its derived products and the PA contents might exceed the daily dose limits in food and herbal medicinal products proposed by the European Medicines Agency (i.e. 0.35 μg PA per day for 50 kg adult). [ABSTRACT FROM AUTHOR]