Xiao-Juan Wang

Determination of free and glucuronidated kaempferol in rat plasma by LC-MS/MS: application to pharmacokinetic study.

Flavanoid kaempferol is mainly present as glucuronides and sulfates in rat plasma, and small amounts of the intact aglycone are also detected. In the this study, a rapid, specific and sensitive liquid chromatography-electrospray ionization-tandem mass spectrometry method (HPLC-MS/MS) was developed and validated for determination of kaempferol and its major metabolite glucuronidated kaempferol in rat plasma. A liquid-liquid extraction with acetic ether was involved for the extraction of kaempferol and internal standard. Analytes were separated on a C18 column (150 mm x 2.1 mm, 4.5 microm, Waters Corp.) with isocratic elution at a flow-rate of 0.3 ml min(-1). The mobile phase was consisted of 0.5% formic acid and acetonitrile (50:50, v/v). The Quattro Premier HPLC-MS/MS was operated under the multiple reaction-monitoring mode (MRM) using the electrospray ionization technique. The method was validated according to the FDA guidelines for validation of bioanalytical method. The validated method was successfully applied to the study of the pharmacokinetics in rats after oral administration of kaempferol with different doses.

Enhanced efficacy of curcumin with phosphatidylserine-decorated nanoparticles in the treatment of hepatic fibrosis

Abstract Hepatic macrophages have been considered as a therapeutic target for liver fibrosis treatment, and phosphatidylserine (PS)-containing nanoparticles are commonly used to mimic apoptotic cells that can specifically regulate macrophage functions, resulting in anti-inflammatory effects. This study was designed to test the efficacy of PS-modified nanostructured lipid carriers (mNLCs) containing curcumin (Cur) (Cur-mNLCs) in the treatment of liver fibrosis in a rat model. Carbon tetrachloride-induced liver fibrosis in rats was used as an experimental model, and the severity of the disease was examined by both biochemical and histological methods. Here, we showed that mNLCs were spherical nanoparticles with decreased negative zeta potentials due to PS decoration, and significantly increased both mean residence time and area under the curve of Cur. In the rats with liver fibrosis, PS-modification of NLCs enhanced the nanoparticles targeting to the diseased liver, which was evidenced by their highest accumulation in the liver. As compared to all the controls, Cur-mNLCs were significantly more effective at reducing the liver damage and fibrosis, which were indicated by in Cur-mNLCs-treated rats the least increase in liver enzymes and pro-inflammatory cytokines in the circulation, along with the least increase in collagen fibers and alpha smooth muscle actin and the most increased hepatocyte growth factors (HGF) and matrix metalloprotease (MMP) two in the livers. In conclusion, PS-modified NLCs nanoparticles prolonged the retention time of Cur, and enhanced its bioavailability and delivery efficiency to the livers, resulting in reduced liver fibrosis and up-regulating hepatic expression of HGF and MMP-2.

Quality evaluation of Semen Cassiae (Cassia obtusifolia L.) by using ultra‐high performance liquid chromatography coupled with mass spectrometry

A sensitive and reliable ultra-high performance liquid chromatography-electrospray ionization-tandem mass spectrometry has been developed and partially validated to evaluate the quality of Semen Cassiae (Cassia obtusifolia L.) through simultaneous determination of 11 anthraquinones and two naphtha-γ-pyrone compounds. The analysis was achieved on a Poroshell 120 EC-C(18) column (100 mm × 2.1 mm, 2.7 μm; Agilent, Palo Alto, CA, USA) with gradient elution using a mobile phase that consisted of acetonitrile-water (30 mM ammonium acetate) at a flow rate of 0.4 mL/min. For quantitative analysis, all calibration curves showed perfect linear regression (r(2) > 0.99) within the testing range. This method was also validated with respect to precision and accuracy, and was successfully applied to quantify the 13 components in nine batches of Semen Cassiae samples from different areas. The performance of developed method was compared with that of conventional high-performance liquid chromatography method. The significant advantages of the former include high-speed chromatographic separation, four times faster than high-performance liquid chromatography with conventional columns, and great enhancement in sensitivity. This developed method provided a new basis for overall assessment on quality of Semen Cassiae.

Application of ultrahigh-performance liquid chromatography coupled with mass spectrometry for analysis of lignans and quality control of Fructus Schisandrae chinensis

Lignans in the drug Fructus Schisandrae chinensis (FSC) exhibit potent biological activities such as antihepatotoxic, antiasthmatic, and antigastric ulcer. An ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry method has been developed to evaluate the quality of FSC through simultaneous qualitative and quantitative analysis of 15 lignans, including schizandrin A, B, and C; schizandrol A and B; gomisin B, C, D, E, G, H, J, and N; tigloylgomisin H; and angeloylgomisin H. The compounds were separated on a Zorbax Eclipse Plus C(18) (2.1 × 100 mm, 1.8 μm) column with a gradient elution of acetonitrile and 0.1% formic acid. Lignans were identified through their retention times, accurate mass data, and characteristic ions by comparison with a reference substance. All calibration curves showed perfect linear regression (r(2) > 0.99) within the test range. The limits of detection and quantitation fell in the ranges of 0.1-4 ng/mL for all the analytes with an injection of 10 μL. Good results were obtained with respect to repeatability (relative standard deviation <4.6%) and recovery (85.58-105.82%). Meanwhile, the entire sample analysis time was less than 10 min. This developed method provided a new basis for the overall assessment of the quality of FSC.

Simultaneous determination of tectorigenin, irigenin and irisflorentin in rat plasma and urine by UHPLC–MS/MS: Application to pharmacokinetics

A sensitive and reliable ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) has been developed and validated for the simultaneous determination of three active components, i.e., tectorigenin, irigenin and irisflorentin, in rat plasma and urine after oral administration of Rhizoma Belamcandae extract. Chromatographic separation was achieved on a Zorbax SB-C(18) column (50 mm × 2.1 mm, 1.8 μm; Agilent, USA) with gradient elution using a mobile phase that consisted of acetonitrile - 0.1% formic acid in water at a flow rate of 0.4 mL/min. Detection was performed by a triple-quadrupole tandem mass spectrometer in multiple reaction monitoring (MRM) mode via polarity switching between the negative (for tectorigenin and irigenin) and positive (for irisflorentin) ionization modes. The calibration curve was linear over a range of 50-50,000 ng/mL for tectorigenin, 10-5000 ng/mL for irigenin and 0.1-200 ng/mL for irisflorentin, respectively. The intra- and inter-day precisions (RSD %) were within 11.3% for all analytes, whereas the deviation of assay accuracies ranged from -8.7 to +11.1%. All analytes were proven to be stable during all sample storage and analysis procedures. This method was successfully applied to a pharmacokinetic study of the three isoflavones after oral administration of Rhizoma Belamcandae extract to rats.

Enhancement of Anti-Inflammatory Activity of Curcumin Using Phosphatidylserine-Containing Nanoparticles in Cultured Macrophages

Macrophages are one kind of innate immune cells, and produce a variety of inflammatory cytokines in response to various stimuli, such as oxidized low density lipoprotein found in the pathogenesis of atherosclerosis. In this study, the effect of phosphatidylserine on anti-inflammatory activity of curcumin-loaded nanostructured lipid carriers was investigated using macrophage cultures. Different amounts of phosphatidylserine were used in the preparation of curcumin nanoparticles, their physicochemical properties and biocompatibilities were then compared. Cellular uptake of the nanoparticles was investigated using a confocal laser scanning microscope and flow cytometry analysis in order to determine the optimal phosphatidylserine concentration. In vitro anti-inflammatory activities were evaluated in macrophages to test whether curcumin and phosphatidylserine have interactive effects on macrophage lipid uptake behavior and anti-inflammatory responses. Here, we showed that macrophage uptake of phosphatidylserine-containing nanostructured lipid carriers increased with increasing amount of phosphatidylserine in the range of 0%–8%, and decreased when the phosphatidylserine molar ratio reached over 12%. curcumin-loaded nanostructured lipid carriers significantly inhibited lipid accumulation and pro-inflammatory factor production in cultured macrophages, and evidently promoted release of anti-inflammatory cytokines, when compared with curcumin or phosphatidylserine alone. These results suggest that the delivery system using PS-based nanoparticles has great potential for efficient delivery of drugs such as curcumin, specifically targeting macrophages and modulation of their anti-inflammatory functions.

Stimulation of autophagic activity in human glioma cells by anti-proliferative ardipusilloside I isolated from Ardisia pusilla

AIMS Ardipusilloside I (ADS-I), a triterpenoid saponin isolated from Ardisia pusilla A.DC (Myrsinaceae), has been recently tested for cancer treatment including brain cancer. However, the mechanism of its action remains elusive. The present study was to investigate the role of autophagy activation in the anti-tumor activities of ADS-I in human glioma cells. MAIN METHODS The tetrazolium dye (MTT) colorimetric assay was used for the measurement of cell proliferation in cultured glioma cells, transmission electron microscopy (TEM) for the examination of autophagic activity, flow cytometric analysis for the determination of cell cycle and apoptotic cells, and immunocytochemistry and Western blot for protein expression of microtubule-associated protein light-chain 3 (LC3) and Beclin 1. KEY FINDINGS ADS-I significantly inhibited the proliferation of both U373 and T98G glioma cells in cultures in a dose-dependent manner. The cytotoxic activity of ADS-I against glioma cell growth was associated not only with the induction of cell cycle arrest at G2/M phase and cell apoptosis in flow cytometric analysis, but also with the activation of autophagy, indicated by the formation of autophagosomes and up-regulated expression of both autophagic protein Beclin 1 and LC3 in glioma cells. Additionally, the treatment with chloroquine, an autophagy inhibitor, reduced ADS-1-mediated cell death. SIGNIFICANCE These data suggest that the anti-proliferative activity of ADS-I in human glioma cells is associated with the activation of autophagy in addition to cell cycle arrest and apoptosis, and the antagonistic effect of chloroquine suggests an important role of autophagy in ADS-I-mediated cell death against tumor growth.

Inhibition of tumor-induced angiogenesis and its mechanism by ardipusilloside I purified from Ardisia pusilla

The aim of this study was to evaluate the effects of ardipusilloside I isolated from Ardisia pusilla on tumor angiogenesis and its mechanism of action. The anti-angiogenic effect in vivo was evaluated on xenograft in the athymic mice model and the chicken chorioallantoic membrane (CAM) neovascularization model, the inhibition of growth in vitro was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, and the mechanism was demonstrated through detecting microvessel density (MVD), vascular endothelial growth factor (VEGF), VEGF receptor 2 (VEGFR2) and P-VEGFR2 protein expressions, as well as mRNA expressions of VEGF and VEGFR2. The results showed that ardipusilloside I had a good inhibitory effect on A549 xenografted tumor growth, angiogenesis of CAM, and A549 cell growth. Compared to the negative control, MVD protein and mRNA expressions of VEGF and VEGFR were significantly inhibited by ardipusilloside I in a dose-dependent manner. These findings suggested that ardipusilloside I might be a promising candidate as angiogenesis inhibitors.

Simultaneous determination of aurantio-obtusin, chrysoobtusin, obtusin and 1-desmethylobtusin in rat plasma by UHPLC-MS/MS

A sensitive and reliable ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the simultaneous determination of four active components of Semen Cassiae extract (aurantio-obtusin, chrysoobtusin, obtusin and 1-desmethylobtusin) in rat plasma after oral administration. Chromatographic separation was achieved on an Agilent Poroshell 120 C18 column with gradient elution using a mobile phase that consisted of acetonitrile-ammonium acetate in water (30 mm) at a flow rate of 0.4 mL/min. Detection was performed by a triple-quadrupole tandem mass spectrometer in multiple reaction monitoring mode. The calibration curve was linear over a range of 3.24-1296 ng/mL for aurantio-obtusin, 0.77-618 ng/mL for chrysoobtusin, 34.55-1818 ng/mL for obtusin and 1.86-1485 ng/mL for 1-desmethylobtusin. Inter- and intra-day assay variation was <15%. All analytes were shown to be stable during all sample storage and analysis procedures.

Metabolism and Pharmacokinetic Study of Ardipusilloside I in Rats

Ardipusilloside I, extracted from ARDISIA PUSILLA A.DC, effectively inhibits the progression of several cancers in animal models and is a potential anti-cancer drug candidate. However, the metabolism and pharmacokinetic characteristics of ardipusilloside I remain unknown. In this study, we developed a highly sensitive liquid chromatography-tandem MS method to determine the ardipusilloside I concentration in rat plasma using ginsenoside Re (whose structure is similar to ardipusilloside I) as the internal standard. After oral administration of ardipusilloside I, its four possible metabolites (M1, M2, M3, and M4, whose structures were determined by MS) were detected in the content from rat small intestine. In rat plasma, however, only M3 and M4 were detected after oral administration of ardipusilloside I. None of the metabolites were detected in plasma samples after intravenous administration of ardipusilloside I to rats. These results indicated that the metabolites, but not the drug itself, were absorbed into plasma after oral administration of ardipusilloside I to rats and that M3 and M4 may be responsible for the antitumor activity of orally administered ardipusilloside I in rat models of cancer.