LC-MS determination and pharmacokinetic study of salidroside in rat plasma after oral administration of suspensions of traditional Chinese medicine Erzhi Wan and Fructus Ligustri lucidi

A simple, rapid and sensitive liquid chromatography-mass spectrometry (LC-MS) method was developed for the determination of salidroside in rat plasma and study of its pharmacokinetics after oral administration of suspension of Erzhi Wan and Fructus Ligustri lucidi into Wistar rats. Plasma sample of 200 μL was extracted with acetic ether-isopropanol (2:1) and the extraction was performed on a Kromasil C₁₈ column (150 mm × 4. 6 mm, 5 μm) with the mobile phase of methanol-water (41:59, v/v) within a run time of 6.0 min. The analyte was monitored with positive electrospray ionization (ESI) by selected ion monitoring (SIM) mode. The target ions were m/z 323.05 for salidroside and m/z 411.05 for internal Standard (IS) geniposide. A good linear relationship was obtained over the range of 5.0–500.0 ng/mL and the lower limit of quantification was 5.0 ng/mL. The validated method was successfully applied to the pharmacokinetic study of salidroside in rat plasma after oral administration of suspension of Erzhi Wan and Fructus Ligustri lucidi.

[RP-HPLC simultaneous determination of five triterpenoid acids in different parts of Poria cocos by UV wavelengths switch]

To establish a method for simultaneous determination of dehydrotumulosic acid, polyporenic acid C, 3-epi-dehydrotumulosic acid, dehydropachymic acid and pachymic acid in Poria, a RP-HPLC method detected by UV wavelengths switch had been developed, including 210 nm (48-55 min) for pachymic acid and 241 nm (0-48 min) for dehydrotumulosic acid, polyporenic acid C, 3-epi-dehydrotumulosic acid, dehydropachymic acid, separately. The system consisting of a Kromasil C18 column (250 mm x 4.6 mm, 5 microm) and a mixture of acetonitrile and 0.05% phosphate acid as the mobile phase was adopted; The flow rate was 1.0 mL x min(-1). The linear response range was 30.5-610.0 microg x mL(-1) (r = 0.999 6) for dehydrotumulosic acid, 12.66-253.2 microg x mL(-1) (r = 0.999 5) for polyporenic acid C, 2.99-59.7 microg x mL(-1) (r = 0.999 7) for 3-epi-dehydrotumulosic acid, 6.13-122.5 microg x mL(-1) (r = 0.999 5) for dehydropachymic acid and 11.3-226.0 microg x mL(-1) (r = 0.9995) for pachymic acid. The average recoveries of these compounds were 98.5% (RSD = 1.9%), 99.4% (RSD = 1.7%), 97.9% (RSD = 1.2%), 96.7% (RSD = 2.5%) and 97.9% (RSD = 2.3%), respectively. The method is simple, accurate and reproducible for quality control of Poria.

[Analysis of monosaccharide compositions in Heterosmilax japonica polysaccharide by precolumn derivation HPLC]

OBJECTIVE

To establish precolumn derivation HPLC method to determine the monosaccharides in Heterosmilax japonica polysaccharide.

METHODS

Heterosmilax japonica sample was hydrolyzed with trifluoroacetic (TFA)and derivated by 1-phenyl-3-methyl-5-pyrazolone (PMP). The monosaccharide composition of Heterosmilax japonica polysaccharide was carried out by reversed-phase technique on a Kromasil C18 column with a mobile phase composed of 100 mmol/L ammonium acetate buffer (pH5.5) and acetonitrile in the ratio of 77: 23. The detection was carried out at 245 nm.

RESULTS

The Heterosmilax japonica polysaccharide composed of mannose, rhamnose, glucose, galactose and xylose with amolar ratio of 66: 1:7590: 452: 528.

CONCLUSION

The HPLC method with precolumn derivatization is appropriate for the analysis of monosaccharide composition of Heterosmilax japonica polysaccharide and the method is simple, quick and accurate.

[Simultaneous determination of anthraquinones in Liuwei'anxiao capsules by HPLC]

OBJECTIVE

To establish an RP-HPLC method for measuring the contents of aloe-emodin, rhein, emodin, chrysophanol and physion in Liuwei'anxiao Capsules (traditional Chinese medicine).

METHODS

The analysis was carried out with a Diamonsil-C18 column (200 mm x 4.6 mm, 5 microm) and a mobile phase of methanol-0.05% phosphoric acid solution with gradient elution. The flow rate was 1.0 mL/min and the column temperature was 35 degrees C. The detection wavelength was 254 nm.

RESULTS

The calibration curve was linear within the range of 1.622 - 16.22 microg/mL (r1 = 0.9998), 0.6960 - 6.960 microg/mL (r2 = 0.9998), 2.448 - 24.48 microg/mL (r3 = 0.9995), 2.752 - 27.52 microg/mL (r4 = 0.9997), 2.702 -27.02 microg/mL (r = 0.9997) for aloe-emodin, rhein, emodin, chrysophanol and physion, respectively.

CONCLUSION

This method is convenient, accurate and reproducible for the quality control of Liuwei'anxiao Capsules.

[Effects of ligustrazine on extracellular acetylcholine levels in rat brain dialysate]

Using brain microdialysis and LC-MS/MS to detect acetylcholine in rat brain to investigate the effects of ligustrazine. A liquid chromatography-tandem mass spectrometry method has been developed and validated for the determination of acetylcholine in rat brain dialysate sampling by microdialysis. The results indicated that ligustrazine administration by subcutaneous injection significantly increased Ach release in rat medial prefrontal cortex and nucleus accumbens in a dose-related manner. The drug' s effect on Ach release in rat brain could be directly detected by microdialysis combined with HPLC-MS/MS and this method is selective and sensitive.

Proteomic analysis of differential protein expression in rat platelets treated with notoginsengnosides

Sanqi, the root of Panax notoginseng, is a popularly used traditional Chinese medicine with cardiovascular effects. Notoginsengnosides (NG) isolated from Sanqi could inhibit ADP-induced platelet aggregation of rat washed platelets. To identify the possible target proteins of NG in platelets, two-dimensional gel electrophoresis (2-DE)-based comparative proteomics was performed and proteins altered in expressional level after NG treatment were identified by MALDI-TOF MS/MS. Treatment of 200 microg/ml NG caused regulation of the levels of 12 proteins, which play important roles in platelet activation, oxidative stress and cytoskeleton. In the NG-treated platelets, there were increase in the levels of growth factor receptor-bound protein 2 (Grb2), thrombospondin 1, tubulin alpha 6 and decrease in the levels of thioredoxin, Cu-Zn superoxide dismutase, DJ-1 protein, peroxiredoxin 3, thioredoxin-like protein 2, ribonuclease inhibitor, potassium channel subfamily V member 2, myosin regulatory light chain 9 and laminin receptor 1. The change in the levels of these proteins caused by NG treatment might contribute to the inhibitive effect of NG on platelet aggregation. Furthermore, analysis of the reactive oxygen species (ROS) level indicated that NG could decrease the ROS level in platelets. The regulation of ROS level might play important role in the effect of NG on platelets.

Interaction of salvianolic acids and notoginsengnosides in inhibition of ADP-induced platelet aggregation

Salvia miltiorrhiza and Panax notoginseng were both considered to be beneficial to cardiovascular diseases in traditional Chinese medicine and often used in combination. To examine the possible interaction between them, the effects of the active fractions of these two herbs, salvianolic acids (SA) and notoginsengnosides (NG), on platelet aggregation were checked respectively or in combination in vitro and in vivo. Both the platelet aggregation of platelet rich plasma (PRP) and washed platelet after ADP induction were checked. In vitro study showed that both SA and NG had an inhibitory effect on platelet aggregation. However, there is no synergistic effect of the combination of SA and NG in vitro. In vivo study showed that i.g. 550 mg/kg/day SA or NG for 5 days could significantly inhibit ADP-induced platelet aggregation of PRP. Moreover, combination of SA and NG at a ratio of 5:1 had a synergistic effect on platelet aggregation of PRP. The mechanism for the synergism of SA and NG in vivo was not clear. High performance liquid chromatography analysis of the plasma of rats received SA, NG or combination of SA and NG showed that co-administration of NG caused change in the plasma distribution profile of SA. The influence of combination on the absorption and/or metabolism of SA may be one of the reasons for the synergism of SA and NG in vivo.

[Simultaneous determination of matrine, oxysophocarpin and oxymatrine in rat plasma by HPLC-MS and its application in the pharmacokinetic study]

To establish an HPLC-MS method for simultaneous determination of matrine, oxymatrine and oxysophocarpine in rat plasma after oral administration of herbal preparation, namely Sanwu Huangqin decoction, and the pharmacokinetic porameters were calculated as well. Matrine, oxymatrine, oxysophocarpine, and internal standard pseudoephedrine were extracted from plasma with liquid-liquid extraction, then separated on a Kromasil C18 column by using acetonitrile-0.1% aqueous formic acid (10 : 90) as mobile phase. Electrospray ionization (ESI) source was applied and operated in positive ion mode. The linear calibration curve was obtained in the concentration range of 10 -5 000 ng x mL(-1) for matrine, 2 - 1 000 ng x mL(-1) for oxymatrine, and 2 - 1 000 ng x mL(-1) for oxysophocarpine. The extraction recovery was 89.1% - 93.5%, 83.9% - 91.3%, and 85.4% - 88.0% accordingly. The inter- and intra- day precision (RSD) was below 15.0% calculated from quality control (QC) samples. Matrine, oxymatrine and oxysophocarpine concentration time profile conformed to a two-compartment pharmacokinetic model. The method was shown to be effective, convenient, and suitable for simultaneous pharmacokinetic study of matrine, oxymatrine, and oxysophocarpine in rat.

[Analysis of the main components of coptis-evodia herb couple by HPLC-DAD-MS]

A comprehensive HPLC-DAD-MS method was developed to study the chemical components of semi-bionic extract of Coptis-Evodia herb couple. The extract was isolated on a Hypersil BDS C18 column (4.6 mm x 200 mm, 5 microm) using acetonitrile-ammonium formic buffer as mobile phase by gradient elution. Detection was performed on DAD and MS equipped with an electrospray ionization (ESI) source by full scan and product full scan on positive mode. The chromatogram of Coptis-Evodia showed seventeen main peaks, eight of which were from Evodia while the others were from Coptis. By comparison of the retention time, the on-line UV spectra and MS spectra, four peaks were identified as jatrorrhizine, hydroxevodiamine, palmatine and berberine, and three peaks were deduced as epiberberine, columbamine and coptisine. In addition, berberine and palmatine were quantitatively determined. No new component was created in the semi-bionic extract of the herb couple, yet the solubilities of berberine and palmatine decreased.

[Determination of macrozamin in Rhizoma Heterosmilacis Japonicae by RP-HPLC]

OBJECTIVE

To develop a RP-HPLC method for the determination of the content of macrozamin in Rhizoma Heterosmilacis Japonicae.

METHOD

A Century C18 AQ column (4.6 mm x 250 mm, 5 microm) was used with the mobile phase consisted of water (4:96). The flow rate was 1.0 mL x min(-1). The detection wavelength was set at 215 nm, and the column temperature was 35 degrees C.

RESULT

The calibration curve was linear (r = 0.999 8) in the range of 19.12 - 382.4 microg x mL(-1) for macrozamin, the average recovery of the method was 99.5%, with RSD 2.1% (n = 9).

CONCLUSION

This method can be used for the quality study of Rhizoma Heterosmilacis Japonicae.

Determination of arbidol in rat plasma by HPLC-UV using cloud-point extraction

A method based on cloud-point extraction (CPE) was developed to determine arbidol in rat plasma by high performance liquid chromatography separation and ultraviolet detection (HPLC-UV). The non-ionic surfactant Triton X-114 was chosen as the extract solvent. Variable parameters affecting the CPE efficiency were evaluated and optimized. A Zorbax SB-C(18) column (4.6 mm i.d. x 150 mm, 5 microm particle size) was used for isocratic elution separation at 40 degrees C with detection wavelength at 316 nm. Under the optimum conditions, the method was shown to be reproducible and reliable with intraday precision below 6.6%, interday precision below 8.8%, accuracy within +/-5.0% and mean extraction recovery more than 89.7%, which were all calculated using a range of spiked samples at three concentrations of 0.2, 2 and 16 microg/ml for arbidol in plasma. The linear range was from 0.08 to 20 microg/ml. After strict validation, the method was successfully applied to the pharmacokinetic study of arbidol in rats after oral and intravenous administration, respectively.

Determination of mildronate in human plasma and urine by liquid chromatography–tandem mass spectrometry

A sensitive and selective analytical method based on liquid chromatography-triple-quadrupole mass spectrometer has been developed to determine mildronate in human plasma and urine. The aim of this work was to find a valid method to study the pharmacokinetic profiles of mildronate in humans. Mildronate is a heart protection medicine, a carnitine's structural analogue, so levocarnitine was used as an internal standard for quantification. Under the electrospray ionization source positive ion mode, calibration curves with good linearities (r=0.9998 for plasma sample and r=0.9999 for urine sample) were obtained in the range of 1.0-20,000 ng ml(-1) for mildronate. The detection limit was 1 ng ml(-1). Recoveries were around 90% for the extraction from human plasma, and good precision and accuracy were achieved. This method is feasible for the evaluation of pharmacokinetic profiles of mildronate in humans, and to the best of our knowledge, this is the first report on LC-MS-MS analysis of mildronate in plasma and urine.

Survey of heavy metal pollution and assessment of agricultural soil in Yangzhong district, Jiangsu Province, China

We investigated concentrations of Hg, Cd, Pb, Zn, Cu, As, Ni, and Cr in samples of soil, cereal, and vegetables from Yangzhong district, China. Compared to subsoils, the sampled topsoils are enriched in Hg, Cd, Cu, Pb, Zn, and As. High levels of Cd and Hg are observed in most agricultural soils. Concentrations of Cr and Ni show little spatial variation, and high Cu, Pb, and Zn contents correspond well to areas of urban development. High As contents are primarily recorded at the two ends of the sampled alluvion. The contents of Cd, Hg, and total organic carbon (TOC) increase gradually to maximum values in the upper parts of soil profiles, while Cr and Ni occur in low concentrations within sampled profiles. As, Pb, Cu, and Zn show patterns of slight enrichment within the surface layer. Compared to data obtained in 1990, Cd and Hg show increased concentrations in 2005; this is attributed to the long-term use of agrochemicals. Cr and Ni contents remained steady over this interval because they are derived from the weathering of parent material and subsequent pedogenesis. The measured As, Cu, Pb, and Zn contents show slight increases over time due to atmospheric deposition of material sourced from urban anthropogenic activity. Low concentrations of heavy metals are recorded in vegetables and cereals because the subalkaline environment of the soil limits their mobility. Although the heavy metal concentrations measured in this study do not pose a serious health risk, they do affect the quality of agricultural products.

Characterization of flavonoids in the extract of Sophora flavescens Ait. by high-performance liquid chromatography coupled with diode-array detector and electrospray ionization mass spectrometry

A method coupling high-performance liquid chromatography (HPLC) with diode-array detector (DAD) and electrospray ionization mass spectrometry (ESI) was established for the separation and characterization of flavonoids in Sophora flavescens Ait. Based on the chromatographic separation of most flavonoids present in S. flavescens Ait., a total of 24 flavonoids were identified. Fourteen compounds were unambiguously identified comparing experimental data for retention time (t(R)), UV and MS spectra with those of the authentic compounds: 3',7-dihydroxy-4'-methoxy-isoflavone (13), trifolirhizin (14), kurarinol (18), formononetin (19), 7,4'-dihydroxy-5-methoxy-8-(gamma,gamma-dimethylallyl)-flavanone (22), maackiain (21), isoxanthohumol (23), kuraridine (26), kuraridinol (27), sophoraflavanone G (30), xanthohumol (31), isokurarinone (33), kurarinone (35) and kushenol D (38), and additional 10 compounds were tentatively identified as kushenol O (10), trifolirhizin-6''-malonate (15), sophoraisoflavanone A (20), norkurarinol/kosamol Q (24), kushenol I/N (25), kushenol C (28), 2'-methoxykurarinone (29), kosamol R (32), kushecarpin A (34) and kushenol A (37) by comparing experimental data for UV and MS spectra with those of literature. Furthermore, fragmentation pathways in positive ions mode of 24 flavonoid compounds of types of flavanone, flavanonol, flavonol, chalcone, isoflavone, isoflavanone and ptercocarpane were summarized. Some common features, such as CH(3)., H(2)O, CO, CO(2), C(3)O(2) and C(2)H(2)O losses, together with Retro-Diels-Alder fragmentations were observed in the prenylated flavonoids in S. flavescens Ait. The loss of the lanandulyl chain was their characteristic fragmentation, which might help deducing the structure of unknown flavonoid compounds. The present study provided an approach to rapidly characterize bioactive constituents in S. flavescens Ait.