黄芩药材中铅的测定及其水煎过程中铅的浸出率研究

测定了黄芩药材中有害元素铅的含量，并研究了黄芩水煎过程中铅的浸出率。     

Simultaneous Determination of Seven Active Compounds in Radix Salviae Miltiorrhizae by Temperature-Controlled Ultrasound-Assisted Extraction and HPLC

A simple and effective high-performance liquid chromatographic (HPLC) method has been developed for simultaneous quantification of three phenolic acids (3,4-dihydroxyphenyllactic acid (Chinese name danshensu), protocatechuic aldehyde, and salvianolic acid B) and four diterpenes (dihydrotanshinone I, cryptotanshinone, tanshinone I, and tanshinone II_A) in radix salviae miltiorrhizae. Chromatography was performed on a 250 mm × 4.6 mm i.d., 5-μm particle size, C₁₈ column. The mobile phase was a linear gradient prepared from 0.1% (v/v) aqueous formic acid and acetonitrile at a flow-rate of 1.0 mL min⁻¹. All the target components were well separated with high resolution and without interference. Good linearity (R ² > 0.999) was observed over the concentration ranges investigated, and intra-day and inter-day precision were high. Temperature-controlled ultrasound-assisted extraction was used to prevent hydrolysis of thermally unstable components during the sample-extraction procedure, and the extraction conditions were carefully optimized. Recovery of the seven components was from 98.45 to 100.63% and relative standard deviations were always <1.5%. The validated method was successfully used for simultaneous quantification of the three phenolic acids and the four diterpenes in radix salviae miltiorrhizae of different geographic origins.     

A rapid method for simultaneous determination of 14 phenolic compounds in Radix Puerariae using microwave-assisted extraction and ultra high performance liquid chromatography coupled with diode array detection and time-of-flight mass spectrometry

A microwave-assisted extraction (MAE) and ultra high performance liquid chromatography coupled with diode array detection and time-of-flight mass spectrometry (UHPLC-DAD-TOF-MS) method was developed for simultaneous determination of 14 phenolic compounds in the root of Pueraria lobata (Wild.) Ohwi and Pueraria thomsonii Benth. Operational conditions of MAE were optimized by central composite design (CCD). The optimized result was 65% ethanol as extraction solvent, 17 mL of extraction volume, 100 °C of extraction temperature and 2 min of hold time. A Zorbax SB C₁₈ (50 mm × 4.6 mm I.D., 1.8 μm) and gradient elution were used during the analysis. The chromatographic peaks of 14 investigated compounds in samples were successfully identified by comparing their retention time, UV spectra and TOF mass data with the reference substances. All calibration curves showed good linearity (r > 0.9997) within the test ranges. The intra-day and inter-day variations were less than 1.77% and 2.88%, respectively. The developed method was successfully applied to determine the investigated compounds in 10 samples of Radix Puerariae Lobatae and Radix Puerariae Thomsonii, respectively. The result indicated that MAE and UHPLC-DAD-TOF-MS system might provide a rapid method for the quality control of Radix Puerariae.     

Preparative enrichment and separation of astragalosides from Radix Astragali extracts using macroporous resins

The enrichment and separation of astragalosides I–IV (AGs I–IV) were studied on eight macroporous resins in the present study. SA‐3 resin offered the best adsorption and desorption capacities for AGs I–IV than other resins. The models of adsorption kinetics were investigated in order to elucidate the mechanism of adsorption. The pseudo‐second‐order model was the better choice than the pseudo‐first‐order model to describe the adsorption behavior of AGs I–IV onto SA‐3 resin. The equilibrium experimental data were well fitted to Langmuir and Freundlich isotherms. SA‐3 resin adsorption chromatography tests were carried out to optimize the separation process of AGs I–IV from Radix Astragali extracts. With the optimum parameters for adsorption and desorption, the contents of AGs I–IV were 8.78‐, 11.60‐, 10.52‐ and 11.28‐fold increased with the recovery yields being 65.88, 90.92, 84.25 and 94.17%, respectively. The preparative enrichment and separation of AGs I–IV from Radix Astragali extracts can be easily and effectively achieved by SA‐3 resin adsorption chromatography. The developed methodology can also be referenced for the separation of other active constituents from herbal materials and manufacture of Radix Astragali products.     

Simultaneous determination of ten flavonoids of crude and wine‐processed Radix Scutellariae aqueous extracts in rat plasma by UPLC‐ESI‐MS/MS and its application to a comparative pharmacokinetic study

Radix Scutellariae (RS) is a herbal medicine with various pharmacological activities to treat inflammation, respiratory and gastrointestinal infections, etc. In this study, a rapid, sensitive and selective UPLC‐ESI‐MS/MS method was developed for simultaneous determination of 10 flavonoids – scutellarin, scutellarein, chrysin, wogonin, baicalein, apigenin, wogonoside, oroxylin A‐7‐O‐glucuronide, oroxylin A and baicalin – from RS aqueous extracts in rat plasma with propyl paraben as internal standard (IS). Chromatographic separation was achieved on a C₁₈ column using gradient elution with the mobile phase consisting of methanol and water (containing 0.1% formic acid) at a flow rate of 0.2 mL/min. The detection was performed in multiple reaction monitoring mode using electrospray ionization in negative mode. The validated method showed good linearity over a wide concentration range (r >0.9935). The intra‐ and interday assay variabilities were <9.5% and <12.4% for all analytes, respectively. The extraction recovery ranged from 71.2 to 89.7% for each analyte and IS. This method was successfully applied to pharmacokinetic comparision after oral administration of crude and wine‐processed RS aqueous extracts. There were significant differences in some pharmacokinetic parameters of most analytes between crude and wine‐processed RS. This suggested that wine‐processing exerted effects absorption of most flavonoids. Copyright © 2014 John Wiley & Sons, Ltd.     

A practical strategy for the characterization of coumarins in Radix Glehniae by liquid chromatography coupled with triple quadrupole-linear ion trap mass spectrometry

The aim of the present study was to develop a practical method for the characterization of coumarins in Radix Glehniae by liquid chromatography–mass spectrometry (LC–MS). First, 10 coumarin standards (including two pairs of isomers) were studied, and mass spectrometry fragmentation patterns and elution time rules for the coumarins were found. Then, an extract of Radix Glehniae was analyzed by the combination of two scan modes, i.e., multiple ion monitoring-information-dependent acquisition-enhanced product ion mode (MIM-IDA-EPI) and precursor scan information-dependent acquisition-enhanced product ion mode (PREC-IDA-EPI) on a hybrid triple quadrupole-linear ion trap mass spectrometer. A total of 41 coumarins were identified on the basis of their mass spectrometry fragmentation patterns. This is the first time that these two scan modes have been combined to characterize chemical constituents in traditional Chinese medicine. This new method allowed the identification of coumarins in Radix Glehniae in trace amounts. The methodology proposed in this study could be valuable for the structural characterization of coumarins from complex natural and synthetic sources.     

Identification and determination of the saikosaponins in Radix bupleuri by accelerated solvent extraction combined with rapid‐resolution LC‐MS

A method based on accelerated solvent extraction combined with rapid‐resolution LC–MS for efficient extraction, rapid separation, online identification and accurate determination of the saikosaponins (SSs) in Radix bupleuri (RB) was developed. The RB samples were extracted by accelerated solvent extraction using 70% aqueous ethanol v/v as solvent, at a temperature of 120°C and pressure of 100 bar, with 10 min of static extraction time and three extraction cycles. Rapid‐resolution LC separation was performed by using a C₁₈ column at gradient elution of water (containing 0.5% formic acid) and acetonitrile, and the major constituents were well separated within 20 min. A TOF‐MS and an IT‐MS were used for online identification of the major constituents, and 27 SSs were identified or tentatively identified. Five major bioactive SSs (SSa, SSc, SSd, 6″‐O‐acetyl‐SSa and 6″‐O‐acetyl‐SSd) with obvious peak areas and good resolution were chosen as benchmark substances, and a triple quadrupole MS operating in multiple‐reaction monitoring mode was used for their quantitative analysis. A total of 16 RB samples from different regions of China were analyzed. The results indicated that the method was rapid, efficient, accurate and suitable for use in the quality control of RB.     

Micellar and aqueous‐organic liquid chromatography using sub‐2 μm packings for fast separation of natural phenolic compounds

The objective of the present work was to investigate the chromatographic behavior of natural phenolic compounds in micellar and aqueous‐organic LC using a short column packed with 1.8 μm particles. Firstly, the effect of ACN and SDS on elution strength and selectivity was examined by isocratic submicellar (0–30% ACN/5% 1‐butanol/1–6 mM SDS) and micellar (0–30% ACN/5% 1‐butanol/40–60 mM SDS) systems. The varied concentrations of two modifiers in the mobile phases revealed different eluting power. Then, the application of organic modifier gradient was discussed in both submicellar and micellar LC using mobile phases of 4 mM SDS/5% 1‐butanol or 50 mM SDS/5% 1‐butanol containing ACN gradient from 0 to 30%, respectively. For micellar system, the separation was found to be better in gradient than isocratic elution. Additionally, the sensitivity of aqueous‐organic LC was examined. The mobile phase was a mixture of ACN and water employing gradient elution at a flow rate of 0.5 mL/min, with analysis time below 9 min. It was found that separation efficiency was significantly better compared with micellar LC. Besides, the aqueous‐organic LC has been applied to separation of various phenolic compounds in Yangwei granule or Radix Astragali samples.     

Sensitive high-performance anion-exchange chromatographic determination of paeoniflorin and albiflorin by pulsed amperometric detection after solid-phase extraction

We developed a method to simultaneously determine paeoniflorin and albiflorin levels using high-performance anion-exchange liquid chromatography with pulsed amperometric detection (HPAEC-PAD). The main principle of our method includes solid-phase extraction step using Amberlite XAD-2 sorbent to remove sugars and to selectively determine glycosides by PAD. Under these conditions, the linear dynamic range was 0.01–100 μg/mL, and the albiflorin and paeoniflorin detection limits (S/N = 3) were 5 and 10 pg, respectively. The intra- and inter-day precisions (RSDs) were <5.07%, and the average recoveries from Paeoniae Radix and Si-ni-san ranged from 97.12 to 101.15%. Our method showed high selectivity, high sensitivity, and good repeatability for analyzing albiflorin and paeoniflorin in oriental medicinal preparation.