Lysine Methyltransferase 5A Promotes the Progression of Growth Hormone Pituitary Neuroendocrine Tumors through the Wnt/ß-Catenin Signaling Pathway.

INTRODUCTION: Growth hormone (GH) secreting pituitary adenoma is considered one of the most harmful types of Pituitary Neuroendocrine Tumors (PitNETs). Our previous research has found that high expression of Lysine methyltransferase 5A (KMT5A) is closely related to the proliferation of PitNETs. The aim of this study was to investigate the role and molecular mechanism of KMT5A in the progression of GH PitNETs. METHODS: Immunohistochemistry, qRT-PCR, and Western blot (WB) were used to assess the expression levels of KMT5A in human normal pituitary and GH PitNETs, as well as in rat normal pituitary and GH3 cells. Additionally, we utilized RNA interference technology and treatment with a selective KMT5A inhibitor to decrease the expression of KMT5A in GH3 cells. CCK-8, EdU, flow cytometry (FCM), clone formation, and WB assay were further employed to evaluate the impact of KMT5A on the proliferation of GH3 cells in vitro. A xenograft model was established to evaluate the role of KMT5A in GH PitNETs progression in vivo. RESULTS: KMT5A was highly expressed in GH PitNETs and GH3 cells. Moreover, the reduction of KMT5A expression led to inhibited growth of GH PitNETs and increased apoptosis of tumor cells, as indicated by the findings from CCK-8, EdU, clone formation, and FCM assays. Additionally, WB analysis identified the Wnt/ß-catenin signaling pathway as a potential mechanism through which KMT5A promotes GH PitNETs progression. CONCLUSION: Our research suggests that KMT5A may facilitate the progression of GH PitNETs via the Wnt/ß-catenin signaling pathway. Therefore, KMT5A may serve as a potential therapeutic target and molecular biomarker for GH PitNETs.

The evaluation of hepatoprotective effects of flavonoids from Scorzonera austriaca Wild against CCl4-induced acute liver injury in vitro and in vivo.

Scorzonera austriaca Wild is a traditional herbal medicine; however, little is known with regard to the effect of flavonoids from S. austriaca (FSA) on liver injury induced by Carbon tetrachloride (CCl4), especially the mechanism remains unknown. Therefore, our paper was designed to investigate the hepatoprotective effect of FSA against CCl4-induced acute liver injury in vitro and in vivo, with focus on its potential mechanism. The purity of FSA prepared by using polyporous resin column chromatography could reach 94.5%, and seven flavonoid compounds in FSA were identified by using LC-ESI-MS analysis. In vivo results showed that FSA markedly decreased the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and malonaldehyde (MDA) and increased the contents of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Furthermore, in vivo and in vitro results confirmed that FSA could inhibit inflammatory response, as evidenced by decreasing the levels of tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) through inactivating toll-like receptor-4/nuclear factor-κB (TLR4/NF-κB) signaling pathway. FSA activated autophagy by increasing the ratio of LC3B-II/I and decreasing the protein level of p62 so as to exert its hepatoprotective effect. In general, these evidences suggested that FSA is likely to serve as a potential material for the drugs against chemical hepatic injury.

Ginsenoside Rg3 attenuates cisplatin-induced kidney injury through inhibition of apoptosis and autophagy-inhibited NLRP3.

The NOD-like receptor family pyrin domain-containing (NLRP3) inflammasomes is centrally implicated in cisplatin (CP)-induced kidney injury. Autophagy is critical for inhibiting production of NLRP3 protein that effectively reduces the inflammatory response. Ginsenoside Rg3 (SY), an active component extracted from ginseng, is reported to protect against CP-induced nephrotoxicity. However, the mechanisms underlying renoprotection by SY have not been established to date. Our results indicate that SY attenuated CP-induced apoptosis and damage in vivo and in vitro, as evidenced by increased cell viability, decreased the proportion of late apoptotic cells, elevated mitochondrial membrane potential, and ameliorated histopathological damage of the kidney. SY ameliorated CP-induced human renal tubular (HK-2) cells and kidney injury through upregulation of LC3II/I and beclin-1, inhibition of p62, NLRP3, ASC, caspase-1, and interleukin-1ß. However, blockade of autophagy by 3-methyladenine reversed the suppression of SY on NLRP3 inflammasome activation and the protection of SY on HK-2 cells. Our collective results support the utility of SY as a therapeutic agent that effectively protects against CP-induced kidney injury by activating the autophagy-mediated NLRP3 inhibition pathway.

Calycosin ameliorates doxorubicin-induced cardiotoxicity by suppressing oxidative stress and inflammation via the sirtuin 1-NOD-like receptor protein 3 pathway.

The limitation of doxorubicin (DOX), which is widely used for the treatment of solid tumors and hematologic malignancies, is a vital problem in clinical application. The most serious of limit factors is cardiotoxicity. Calycosin (CA), an isoflavonoid that is the major active component in Radix astragali, has been reported in many bioactivities including antitumor, anti-inflammatory, and cardioprotection. The aim of the study was to investigate the effects and mechanisms of CA on DOX-induced cardiotoxicity in vitro and in vivo. CA increased H9c2 cell viability and reduced apoptosis induced by DOX via Bcl-2, Bax, and the PI3K-Akt signaling pathway. Moreover, CA prevented DOX-induced oxidative stress in cells by decreasing the generation of reactive oxygen species. Similarly, oxidative stress was inhibited by CA through the increased activities of antioxidant enzymes such as glutathione peroxidase, catalase, and superoxide dismutase and decreased the levels of aspartate aminotransferase, lactate dehydrogenase, and malondialdehyde in vivo. Furthermore, the levels of sirtuin 1 (Sirt1)-NOD-like receptor protein 3 (NLRP3) and related proteins were ameliorated by CA in cells and in mice hearts. When H9c2 cells were treated by Ex527 (Sirt1 inhibitor), the effect of CA on expressions of NLRP3 and thioredoxin-interacting protein was suppressed. In conclusion, the results suggested that CA might be a cotreatment with DOX to ameliorate cardiotoxicity by Sirt1-NLRP3 pathway.

XingNaoJing injection ameliorates cerebral ischaemia/reperfusion injury via SIRT1-mediated inflammatory response inhibition.

Context: XingNaoJing injection (XNJ), extracted from a traditional compound Chinese medicine Angong niuhuang pill, is well known for treating stroke in the clinic, but the specific effects and mechanisms remain unclear.Objective: We investigated the mechanistic basis for the protective effect of XNJ on cerebral ischaemia/reperfusion (I/R) injury.Materials and methods: Five groups of 10 SD rats underwent 2 h of middle cerebral artery occlusion (MCAO) followed by 24 h reperfusion. XNJ at 10 and 15 mL/kg was intraperitoneally administered 24 h before ischaemia and at the onset of reperfusion respectively. The silent information regulator 1 (SIRT1) inhibitor EX527 was intracerebroventricularly injected 0.5 h before reperfusion. Cerebral infarction size, neurological scores, morphological changes, and expression levels of inflammatory mediators and SIRT1 were measured. Furthermore, human brain microvascular endothelial cells (HBMECs) were subjected to 3 h oxygen and glucose deprivation (OGD) followed by 24 h reoxygenation to mimic cerebral I/R in vitro. EX527 pre-treatment occurred 1 h before OGD. SIRT1 and inflammatory mediator levels were analyzed.Results: Both XNJ doses significantly decreased cerebral infarct area (40.11% vs. 19.66% and 9.87%) and improved neurological scores and morphological changes. Inflammatory mediator levels were remarkably decreased in both model systems after XNJ treatment. XNJ also enhanced SIRT1 expression. Notably, the SIRT1 inhibitor EX527 attenuated the XNJ-mediated decrease in inflammation in vivo and in vitro.Conclusions: XNJ improved cerebral I/R injury through inhibiting the inflammatory response via the SIRT1 pathway, which may be a useful target in treating cerebral I/R injury.

Retrospective study of budesonide in children with eosinophilic gastroenteritis.

BACKGROUND: The effectiveness of budesonide (BUD), a locally active steroid, on eosinophilic gastroenteritis (EGE) is not well understood. This study is to retrospectively evaluate the efficacy of BUD in children with EGE. METHODS: Forty-four children, diagnosed with EGE, were enrolled from 2013 to 2017 in our center. According to patients' preference, all the patients were treated with dietary elimination (DE) and montelukast therapy, or combined with prednisone (PRED)/BUD. Patients' clinical manifestations, treatments, and outcomes were reviewed from the medical records. Twenty-four patients (7 PRED, 7 BUD, 10 DE) received therapy for ≥8 weeks, followed by repeat endoscopy and biopsies. Histological response was defined as <20 eos/hpf (eosinophils per high-power field). RESULTS: Significant number of patients in DE+PRED (6/7, 85.7%) and DE+BUD (6/7, 85.7%) groups achieved histological response than in the DE group (3/10.30%) (p = 0.024). Mean post-treatment peak eos/hpf in the DE+PRED group was 16.57 ± 6.85 vs. 10.00 ± 5.07 in the DE+BUD group vs. 36.60 ± 24.57 in the DE group (p = 0.009). Change of eos/hpf from pre- to post-treatment was -49.86 ± 45.02 vs. -34.29 ± 23.44 in the BUD group vs. -0.3 ± 23.95 in the DE group (p = 0.011). There were no significant differences between DE+PRED and DE+BUD groups (p = 0.470, p = 0.363, respectively). CONCLUSION: BUD is effective in the treatment of EGE and has similar effectiveness with PRED.

Salvianolic acid inhibits the effects of high glucose on vascular endothelial dysfunction by modulating the Sirt1-eNOS pathway.

Salvianolic acid (SA) is known for improving blood circulation, scavenging hydroxyl radicals, and preventing platelet aggregation. The research explored whether SA can protect against cardiovascular disease induced by high glucose conditions. Our results indicate that SA significantly increases cells viability and nitric oxide levels while decreasing reactive oxygen species generation. SA upregulated the expression levels of Bcl-2 and decreased the levels of Bax, cleaved caspase-3, and cleaved caspase-9. Furthermore, the expression levels of Sirtuin 1 (Sirt1) and p-endothelial nitric oxide synthase (eNOS) were markedly increased in response to SA treatment. Moreover, exposure of human umbilical vein endothelial cells to Ex527 resulted in reducing expression of p-eNOS. However, the beneficial effects of SA were abolished partially when Ex527 was added. These findings suggest that SA can be used as a potential therapeutic to protect against high glucose-induced endothelial injury by modulating Sirt1-eNOS pathway.

Dioscorea bulbifera L. delays the excretion of doxorubicin and aggravates doxorubicin-induced cardiotoxicity and nephrotoxicity by inhibiting the expression of P-glycoprotein in mice liver and kidney.

We aimed to investigate the drug-drug interaction (DDI) between doxorubicin (DOX) and Dioscorea bulbifera L. (DB) solution in mice, and to explore the effect of P-glycoprotein (P-gp) on this type of DDI. The toxicity of DOX in the liver, kidneys, and heart was assessed with alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine (Cr), urea nitrogen (BUN), creatine kinase MB (CK-MB), creatine kinase (CK) and histopathology. High-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was used to determine the concentrations of DOX in the serum, liver, kidneys and heart. Immunohistochemistry and western blots were used to determine the expression levels of P-gp in these tissues. Our results demonstrated that, after co-administration of DOX and DB, survival was significantly decreased compared with either administration of DOX or DB alone, or water. Co-administration of DOX and DB induced elevated levels of toxicity in the heart and kidneys, but not the liver, compared with DOX alone. We conclude that concurrent treatment with DOX and DB results in increased levels of toxicity due to the accumulation of DOX in the body. Delayed excretion of DOX is associated with inhibition of P-gp in liver and kidneys.

Pharmacokinetics and tissue distribution of oroxin B in rats using a validated LC-MS/MS assay.

A highly sensitive LC-MS/MS method was developed to measure oroxin B in rat plasma and tissue homogenates. The analyte and IS were isolated from biological matrices by a simple protein precipitation followed by centrifugation. Detection was conducted by electrospray negative-ionization mass spectrometry in selected-reaction monitoring mode. The assay was linear in the concentration range 4.52-904 ng/mL with intra- and inter-day precision of <14.41%. It was successfully applied to the pharmacokinetics and tissue distribution studies of oroxin B after an intravenous dose of 1.0 mg/kg in rats. The results would be useful for further development of oroxin B.

Autophagy inhibition-enhanced assembly of the NLRP3 inflammasome is associated with cisplatin-induced acute injury to the liver and kidneys in rats.

The nucleotide-binding oligomerization domain-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome has a key role in the inflammatory response. We found that cisplatin (7.5, 15 mg/kg, IV) could induce acute injury to the liver and kidneys of rats. Western blot and immunohistochemical analyses showed that expression of NLRP3, caspase-1 and interleukin-1ß was upregulated significantly in a dose-dependent manner after cisplatin exposure. Autophagy could inhibit NLRP3 expression and assembly of the NLRP3 inflammasome. Expression of light chain 3 II/I and p62 suggested that autophagy was inhibited during injury to the liver and kidneys. These data suggested that cisplatin might activate NLRP3 by inhibiting autophagy in the liver and kidneys of rats.

Dysregulation of BSEP and MRP2 May Play an Important Role in Isoniazid-Induced Liver Injury via the SIRT1/FXR Pathway in Rats and HepG2 Cells.

To explore the role of the abnormal expression of the bile salt export pump (BSEP) and multidrug resistance protein 2 (MRP2) in isoniazid (INH)-induced liver injury, we assessed the liver injury induced by INH in rats and HepG2 cells in vitro. The regulatory pathways via Sirtuin 1 (SIRT1) and farnesoid X receptor (FXR) were also determined. Rat liver injury was assessed by histopathological and biochemical analysis and HepG2 cytotoxicity was assessed by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test. The levels of protein were determined by Western blot. The results indicated that INH could induce hepatotoxicity in vivo and in vitro in a dose dependent manner. The liver index and serum biochemical analysis, especially the levels of total bile acids (TBA), total bilirubin (TBIL), and direct bilirubin (DBIL), were significantly increased in rats. The INH hepatotoxicity was severe in the high dose group, and occurred alongside the down-regulation of BSEP and MRP2 in vivo and in vitro, leading to the accumulation of toxic substrates in the hepatocytes. The SIRT1/FXR pathway was identified as being important for the down-regulation of transporters. In summary, our study indicated that the down-regulation of BSEP and MRP2 represents one mechanism of INH-induced liver injury and the down-regulation of SIRT1/FXR may be a key regulator. This will inform the development of novel therapies and enable the prevention of INH-induced liver injury.

Quantitative determination of mogroside V in rat plasma by LC-MS/MS and its application to a pharmacokinetic study.

Mogroside V is the most abundant (approximately 0.50%) cucurbitane-type triterpene glycoside in Siraitia grosvenorii and exhibits significant antitussive, expectorant, anti-carcinogenic, and anti-inflammatory effects. A sensitive, robust and selective liquid chromatography tandem with mass spectrometry (LC-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of mogroside V in rat plasma. Samples were prepared through an one-step deproteinization procedure with 250 µL of methanol to a 75-µL plasma sample. Plasma samples were effectively separated on a Shiseido Capcell Pak UG120 C18 column (2.0 × 50mm, 3.0µm) using a mobile phase consisting of methanol: water (60:40, v/v) with an isocratic elution program. The running time for each sample was 7.0 min and the elution times of mogroside V and IS were 2.0 and 4.8 min, respectively. The detection relied on a triple-quadrupole tandem with mass spectrometer equipped with negative-ion electrospray ionization interface by selected-reaction monitoring (SRM) of the transitions at m/z 1285.6 → 1123.7 for mogroside V and m/z 1089.6 → 649.6 for IS. The calibration curve was linear over the range of 96.0-96000ng/mL with a limit of quantitation (LOQ) of 96.0ng/mL. Intra-day and inter-day precisions were both <10.1%. Mean recovery and matrix effect of mogroside V in plasma were in the range of 91.3-95.7% and 98.2-105.0%, respectively. This method was successfully applied in the pharmacokinetic study of mogroside V after intravenous or intraperitoneal administration of 1.12mg/kg mogroside V in rats.

Prescription Optimization and Oral Bioavailability Study of Salvianolic Acid Extracts W/O/W Multiple Emulsion.

The purpose of this study is to develop a new method of preparing salvianolic acid extracts (SAE) water-in-oil-in-water (W/O/W) multiple emulsion (ME). SAE injection is used in the treatment of brain infarct and promotion of blood circulation in China. However, the injection is not convenient, and the oral preparation has poor bioavailability. Hence, a new preparation that is convenient and stable with good biological availability is required. SAE ME was prepared by two-step emulsification method. Combined with single-factor investigation and orthogonal test, the embedding rate and centrifugal retention rate were taken as the comprehensive indexes to optimize the formulation of SAE ME. The ME size was tested by laser particle size analyzer. The pharmacokinetic studies were conducted in Sprague-Dawley rats with HPLC-MS/MS method. The blood coagulation and hemorheology tests were conducted to assess the effect of preparation in rats. The best preparation technique for SAE ME is by the use of trospium chloride; SAE represent 12% of water in the phase, lipophilic emulsifier hydrophilic lipophilic balance value=4.3, lipophilic emulsifier is 20% of the oil phase. The median diameter of particle is (0.608±0.05) µm and the Cmax of ME is 3-fold higher compared to Cmax of free drug. The oral biavailability of ME is 26.71-fold higher than that of free drug with good effect on blood circulation. SAE ME is stable hence, improves the biological availability and slows down drug release.

Development of an LC-MS/MS method for quantification of two pairs of isomeric flavonoid glycosides and other ones in rat plasma: Application to pharmacokinetic studies.

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous determination of six flavonoid glycosides - isoorientin (1), orientin (2), 2″-O-ß-d-xylopyranosyl isoorientin (3), 2″-O-ß-d-xylopyranosyl isovitexin (4), 6-C-l-α-arabipyranosyl vitexin (5) and vitexin (6) - in rat plasma using isoquercitrin as the internal standard (IS). Plasma samples were prepared by a one-step protein precipitation with acetonitrile. Chromatographic analysis was carried out on a 25 cm C18 column with a gradient mobile phase consisting of acetonitrile and 0.1% aqueous formic acid. Six analytes and IS were detected through electrospray ionization in negative-ion selection reaction monitoring mode. The mass transitions were as follows: m/z 447.2 → 327.0 for 1, m/z 447.2 → 327.0 for 2, m/z 579.3 → 458.9 for 3, m/z 563.0 → 293.1 for 4, m/z 563.0 → 353.0 for 5, m/z 431.1 → 311.1 for 6, and m/z 463.1 → 300.2 for IS. Calibration curves exhibited good linearity (r2 > 0.9908) over a wide concentration range for all compounds. Intra- and inter-day precision (RSD, %) at four different levels were both <14.2% and the accuracy (RE, %) ranged from -11.9 to 12.0%. The extraction recoveries of the six components ranged from 88.2 to 103.6%. The validated assay was successfully applied to the pharmacokinetic studies of the six components in male rat plasma after intravenous administration of total flavonoids of Scorzonera austriaca Wild.

An LC-MS/MS method for determination of calceorioside B with cardiomyocyte protective activity in rat plasma and application to a pharmacokinetic study.

A simple, sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of calceorioside B (CLB) in rat plasma. Detection was performed on a Thermo Scientific Hypersil Gold chromatography column using isocratic elution with a mobile phase of methanol-5 m m ammonium acetate-formic acid (70:30:0.1, v/v/v). Mass spectrometry was performed in selection reaction monitoring mode using a positive electrospray ionization interface. Good linearity was found for CLB in plasma in the linear range of 1.00-500 ng/mL (r > 0.9960). The validated method was successfully applied to the pharmacokinetic study of CLB in rats.

Development and validation of an LC-MS/MS method for the determination of bullatine A in rat plasma: application to a pharmacokinetic study.

Bullatine A is a diterpenoid alkaloid of Xue-Shang-Yi-Zhi-Hao (Aconitum brachypodum), which is widely used in traditional Chinese medicine for the treatment of rheumatism and pain. The plasma levels of bullatine A were measured by a rapid and sensitive LC-MS/MS method. Samples were prepared using acetonitrile precipitation and the separation of bullatine A was achieved on a Capcell Pak MG-C18 column by isocratic elution using acetonitrile (phase A) and 0.1% formic acid (phase B, pH 4.0; A:B, 30:70, v/v) as the mobile phase at a flow rate of 0.5 mL/min. Detection was performed on a triple-quadrupole tandem mass spectrometer by multiple-reaction monitoring of the transitions at m/z 344.2 → 105.2 for bullatine A and m/z 256.2 → 167.1 for the internal standard. The linearity was found to be within the concentration range of 1.32-440 ng/mL with a lower limit of quantification of 1.32 ng/mL. Only 1.3 min was needed for an each analytical run. This method was successfully applied in the determination of the active component bullatine A in rat plasma after intramuscular administration of A. brachypodum injection.

Development and validation of a LC-MS/MS method for determination of pinoresinol diglucoside in rat plasma: Application to pharmacokinetic study.

Pinoresinol diglucoside (PD), a typical marker compound in Ecommia ulmoides Oliv., is an important and natural antihypertensive drug. A selective, sensitive, and rapid liquid chromatography tandem mass spectrometric (LC-MS/MS) analytical method was developed for the determination of PD in rats. After simple protein precipitation with acetonitrile, chromatographic separation of PD was conducted using a reversed-phase ZORBAX SB C18 analytical column (4.6mm × 150 mm, 5 µm particles) with a mobile phase of 10mM ammonium acetate-methanol-acetic acid (50:50:0.15, v/v/v) and quantified by selected reaction monitoring mode under positive electrospray ionization condition. The chromatographic run time was 3.4 min for each sample, in which the retention times of PD and the internal standard were 2.87 and 2.65 min, respectively. The calibration curves were linear over the range of 1.00~3000 ng/mL and the lower limit of quantification was 1.00 ng/mL in rat plasma. The precision expressed by relative standard deviations were <8.9% for intra-batch precision and <2.0% for inter-batch precision, and the intra- and inter-batch accuracy by relative error was within the range of -3.9% ~7.3%, which met acceptable criteria. The LC-MS/MS method was successfully applied to investigate the pharmacokinetics and oral bioavailability of PD in rats, with the bioavailability being only 2.5%.

Simultaneous determination of sesquiterpene lactones isoalantolactone and alantolactone isomers in rat plasma by liquid chromatography with tandem mass spectrometry: application to a pharmacokinetic study.

A selective, sensitive, and accurate LC-MS/MS method for the simultaneous determination of isoalantolactone and alantolactone in rat plasma has been developed using psoralen as the internal standard. LC-MS/MS analysis was carried out on a Triple Quadrupole mass spectrometer using positive ion ESI and the selected reaction monitoring mode. The assays were linear in the range of 7.5-750 ng/mL for isoalantolactone and 5.5-550 ng/mL for alantolactone. The average recoveries in plasma samples both were better than 85%. The intra- and inter-day precision and accuracy values were found to be within the assay variability criteria limits according to the US FDA guidelines. The method was successfully applied to pharmacokinetic studies of the two structural isomers after an intravenous injection of Inula helenium formulation to rats.

LC-ESI-MS/MS analysis and pharmacokinetics of jolkinolide B, a potential antitumor active component isolated from Euphorbia fischeriana, in rat plasma.

A simple, specific and reproducible liquid chromatography-electrospray ionization mass spectrometry was developed and validated for the determination of jolkinolide B, a potential antitumor active component isolated from Euphorbia fischeriana, in rat plasma. Chromatographic separation was achieved on a Venusil MP-C18 column using an isocratic elution. Jolkinolide B and osthole (internal standard) were monitored by positive electrospray ionization in the selected reaction monitoring mode. Good linearity (r(2) > 0.996) was achieved by a weighted (1/x(2) ) linear least-squares regression over a concentration range of 6.50-2600 ng/mL. The accuracy and precision of the assay were satisfactory and the method proved to be applicable to pharmacokinetics following a single intravenous bolus injection of jolkinolide B to rats.

Development of an LC-MS/MS method for quantification of kadsurenone in rat plasma and its application to a pharmacokinetic study.

A sensitive and rapid LC-MS/MS method was developed and validated for the determination of kadsurenone in rat plasma using lysionotin as the internal standard (IS). The analytes were extracted from rat plasma with acetonitrile and separated on a SB-C18 column (50 × 2.1 mm, i.d.; 1.8 µm) at 30 °C. Elution was achieved with a mobile phase consisting of methanol-water-formic acid (65:35:0.1, v/v/v) at a flow rate of 0.30 mL/min. Detection and quantification for analytes were performed by mass spectrometry in the multiple reaction monitoring mode with positive electrospray ionization m/z at 357.1 → 178.1 for kadsurenone, and m/z 345.1 → 315.1 for IS. Calibration curves were linear over a concentration range of 4.88-1464 ng/mL with a lower limit of quantification of 4.88 ng/mL. The intra- and inter-day accuracies and precisions were <8.9%. The LC-MS/MS assay was successfully applied for oral pharmacokinetic evaluation of kadsurenone using the rat as an animal model.