[Preparation and quality evaluation of total flavonoids microemulsion of "Pueraria lobata-Hovenia dulcis"].

The effective components of flavonoids in the "Pueraria lobata-Hovenia dulcis" drug pair have low bioavailability in vivo due to their unstable characteristics. This study used microemulsions with amphoteric carrier properties to solve this problem. The study drew pseudo-ternary phase diagrams through titration compatibility experiments of the oil phase with emulsifiers and co-emulsifiers and screened the prescription composition of blank microemulsions. The study used average particle size and PDI as evaluation indicators, and the central composite design-response surface method(CCD-RSM) was used to optimize the prescription; high-dosage drug-loaded microemulsions were obtained, and their physicochemical properties, appearance, and stability were evaluated. The results showed that when ethyl butyrate was used as the oil phase, polysorbate 80(tween 80) as the surfactant, and anhydrous ethanol as the cosurfactant, the maximum microemulsion area was obtained. When the difference in results was small, K_(m )of 1∶4 was chosen to ensure the safety of the prescription. The prescription composition optimized by the CCD-RSM was ethyl butyrate(16.28%), tween 80(9.59%), and anhydrous ethanol(38.34%). When the dosage reached 3% of the system mass, the total flavonoid microemulsion prepared had a clear and transparent appearance, with average particle size, PDI, and potential of(74.25±1.58)nm, 0.277±0.043, and(-0.08±0.07) mV, respectively. The microemulsion was spherical and evenly distributed under transmission electron microscopy. The centrifugal stability and temperature stability were good, and there was no layering or demulsification phenomenon, which significantly improved the in vitro dissolution of total flavonoids.

Assessment of Drying Kinetics, Textural and Aroma Attributes of Mentha haplocalyx Leaves during the Hot Air Thin-Layer Drying Process.

Since Mentha haplocalyx leaves are rich in bioactive constitutes, particularly volatile compounds, there are higher demands for high-quality dried medicinal and aromatic peppermint products. This study aimed to assess the drying kinetics of hot air thin layer drying Mentha haplocalyx leaves and exploring the effects of hot air-drying temperatures on the textural properties and sensory quality. According to our results, the Midilli model is the best model representing the hot air-drying process. The effective moisture diffusivity (Deff) and activation energy (Ea) of the hot air-drying process were determined as 7.51 × 10-9-3.03 × 10-8 m2/s and 57.98 KJ/moL, respectively. The changes of textural and aromatic profiles of dried Mentha haplocalyx leaves were subsequently evaluated by the SEM, GC-MS and E-nose technology. Changes in leaf cellular membrane structures were observed in this study, indicating that the loss of moisture content induced the shrinkage of leaf cells during the hot air-drying process. Moreover, the altered profile of volatile compounds was identified at the different drying temperatures. As a result of the GC-MS analysis, increasing the content of D-carvone from 61.89%, 69.25% and 78.2% resulted in drying temperatures of 35 °C, 45 °C and 55 °C, respectively; while a decreasing trend of other volatile compounds, including D-Limonene, cineole and l-caryophyllene was detected as drying temperature elevated. Finally, the aromatic profile was evaluated by E-nose, and results of the flavor radar fingerprint and PCA showed that aromatic profiles were significantly altered by the drying process. The overall results elucidated that the hot air thin layer drying at 35 °C efficiently improved the final quality of dried Mentha haplocalyx leaves by maintaining flavor properties.

[Kinetics and variation of volatile components of Atractylodis Macrocephalae Rhizoma during hot-air drying].

The present study explored the kinetics and variation of volatile components of Atractylodis Macrocephalae Rhizoma during the hot-air drying process to obtain the optimal process parameters under multiple goals such as drying efficiency and drying quality. The dry basis moisture content and drying rate curves along with the change of drying time of Atractylodis Macrocephalae Rhizoma were investigated at five levels of drying air temperatures(30, 40, 50, 60, and 70 ℃). The relationship between moisture ratio and time in the drying process of Atractylodis Macrocephalae Rhizoma was fitted and verified by Midilli model, Page model, Overhults model, Modified Page model, Logaritmic model, Two terms Exponential model, and Newton model. Meanwhile, the effective diffusion coefficient of moisture(D_(eff)) and activation energy(E_a) in Atractylodis Macrocephalae Rhizoma were calculated under different drying air temperatures. GC-MS was used to determine the volatile components and content changes of the fresh Atractylodis Macrocephalae Rhizoma and dried products at different temperatures. The dry basis moisture content and drying rate of Atractylodis Macrocephalae Rhizoma were closely related to the temperature of the drying medium, and the moisture of the Atractylodis Macrocephalae Rhizoma decreased with the prolonged drying time. As revealed by the drying rate curve, the drying rate increased with the increase in hot air temperature, and the migration of moisture was accelerated. The comparison of the correlation coefficient(R~2), chi-square(χ~2), and root mean standard error(RMSE) of each model indicated that the parameter average of the Midilli model had the highest degree of fit, with R~2=0.999 2, χ~2=8.78×10~(-5), and RMSE=8.20×10~(-3). Besides, the D_(eff) at 30-70 ℃ was in the range of 1.04×10~(-9)-6.28×10~(-9) m~2·s~(-1), and E_a was 37.47 kJ·mol~(-1). The volatile components of fresh Atractylodis Macrocephalae Rhizoma and dried products at different temperatures were determined by GC-MS, and 18, 18, 18, 17, 17, and 18 compounds were identified respectively, which accounted for more than 84.76% of the volatile components. In conclusion, the hot-air drying of Atractylodis Macrocephalae Rhizoma can be model-fitted and verified and the variation law of the moisture and volatile components of Atractylodis Macrocephalae Rhizoma with temperature is obtained. This study is expected to provide new ideas for exploring the drying characteristics and quality of aromatic Chinese medicine.

[Research advances in drug resistance mechanisms of bacterial biofilm and natural drug intervention].

Drug resistance resulting from bacterial biofilms can invalidate antibacterial agents. Therefore,eradicating bacterial biofilms to reverse drug resistance is a hotspot in the pharmaceutical research. In recent years,numerous studies have revealed the complicated mechanism of bacterial biofilm formation and strong drug resistance with multiple influential factors involved. This paper gives a comprehensive review on the process of biofilm formation and intervention by natural drugs,which can provide some reference and evidence for the following studies.

[Effect of fluidized bed technology on micromeritics properties of Leonurus Herba extract].

Based on different binders, the Leonurus Herba extract powders were fluidized and modified. The physical properties such as hygroscopicity, flowability, filling property and compression property were studied by various micromeritics methods before and after modification. The results showed that the physical properties of Leonurus Herba extract were close to those of microcrystalline cellulose, and its comprehensive flow index was between 61-75. Fluidization process can improve hygroscopicity, so the moisture absorption indexes of the samples were significantly lower than those of the original Leonurus Herba extract samples. With the plastic constant, compression ratio and yield stress, Heckel equation and Kawakita equation as the the investigation indicators, results showed that fluidization process based on binder water was superior to other methods in increasing the compressibility of the extracts. In low and medium pressure, the fluidized and modified extract can form the tablets with a certain strength. Fluidized transformation had a greater influence on the properties of original Leonurus Herba extracts, which was instructive to guide significance for the surface modification of pharmaceutical powders and provide the basis for the development of extract tablet.

[Effect and regulation of drying on quality of traditional Chinese medicine pills].

The dry quality of traditional Chinese medicine pills is the hot spot of pills research, because their quality has a crucial effect on the efficacy and development of dosage forms. Through literature research and statistical analysis, we would review the current problems on the drying of traditional Chinese medicine pills in this paper, and surrounding the evaluation system for traditional Chinese medicine pills, analyze the characteristics of common drying equipment and processes as well as their effect on quality of pills, discuss the problems in drying equipment and process as well as quality, and put forward the corresponding strategies, hoping to provide new ideas and new methods for the quality improvement of traditional Chinese medicine pills and quality standards.

Preparation and structural determination of four metabolites of senkyunolide I in rats using ultra performance liquid chromatography/quadrupole-time-of-flight tandem mass and nuclear magnetic resonance spectra.

BACKGROUND: Senkyunolide I (SEI) is one of the most important bioactive phthalides of Ligusticum chuanxiong Hort. (Umbelliferae), a Traditional Chinese Medicine. Our previous studies suggested that it might be developed as a potential treatment for migraine. METHODS: In this paper, we aimed to isolate and characterize the main metabolites of SEI after gavage feeding in rats. Their structures were identified precisely on the basis of nuclear magnetic resonance (NMR) spectroscopy and UPLC/Q-TOF-MS spectrometry. We also established the main metabolic pathways of SEI in rats. RESULTS: Four metabolites (M1-M4) were isolated, for the first time, from bile samples of rats by preparative high-performance liquid chromatography. Their structures were determined as SEI-6S-O-ß-D-glucuronide (M1), SEI-7S-O-ß-D-glucuronide (M2), SEI-7S-S-glutathione (M3) and SEI-7R-S-glutathione (M4) on the basis of the molecular mass of the analytes, using ultra performance liquid chromatography/quadrupole-time-of-flight mass spectrometry and 1D and 2D NMR. CONCLUSIONS: The results demonstrated that glucuronide and glutathione conjugation were the major pathways of SEI metabolism in vivo, and the configuration at the 7th-position could be inverted during glutathione conjugation.

[Preparation of ferulic acid, senkyunolide I and senkyunolide H from Ligusticum chuanxiong by preparative HPLC].

Preparative HPLC was used to prepare ferulic acid, senkyunolide I and senkyunolide H from Ligusticum chuanxiong. The separation was conducted on a Shim-Pack Prep-ODS (20.0 mm x 250 mm, 5 microm) column with the mobile phase of methanol-0.2% glacial acetic acid (50:50)at the flow rate of 5 mL x min(-1). The detection wavelength was 278 nm, and the purity of each compound was detected by HPLC analysis. Spectral data analyses including UV, ESI-MS and NMR were used to identify their structures. This method is simple, fast, which is suitable for preparation of standard reference of ferulic acid, senkyunolide I and senkyunolide H from L. chuanxiong and can meet the requirement of new drug research and development.

Identification of senkyunolide I metabolites in rats using ultra performance liquid chromatography/quadrupole-time-of-flight tandem mass spectrometry.

Ligusticum chuanxiong Hort. (Umbelliferae) has been widely prescribed to treat cardiovascular disease in China for centuries. Senkyunolide I is one of the major bioactive components in L. chuanxiong, which shows pharmacological activities against migraines and oxidative damage. In this paper, ultra performance liquid chromatography/quadrupole-time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS) was applied for the rapid analysis of senkyunolide I metabolites in rats after its intravenous administration. The non-metabolized parent compound and eighteen metabolites from drug-treated samples in rat plasma, urine and bile were identified. Our analysis indicated that methylation, hydration, epoxidation, glucuronidation and glutathione conjugation were the major pathways of senkyunolide I metabolism in vivo. This study provides important information regarding the metabolism of senkyunolide I, which will be helpful for understanding its mechanism of action. Furthermore, this work demonstrates the potential of using UPLC/Q-TOF-MS for the rapid and reliable characterization of the metabolites of natural products.

[Characterization of flowability of pharmaceutical powders based on multivariate analysis method].

The main methods of characterizing the flowability of pharmaceutical powders include repose angle method, HR method, Carr's index method, Jenike flow function method, fractal dimension method, and mass flow rate method, etc. Regarding powders with different flowabilities as the research subject, comprehensive features of pharmaceutical materials were investigated and characterized. The multivariate analysis method was employed to evaluate and analyze flowability values of the tested pharmaceutical materials. Comparing with the method of the mass flow rate, it was feasible to use multivariate analysis method to evaluate the flowability of powders. Simultaneously, the flowability of pharmaceutical materials could be ranked and definitely quantified, and critical values be determined according to the actual production, which has promoted the previous methods dependent only on the single parameter, i.e. repose angle and compression degree methods. A relatively objective standard method of evaluating flowability of powders is formed.