Evaluation the binding of chlorogenic acid with bovine serum albumin: Spectroscopic methods, electrochemical and molecular docking.

Chlorogenic acid(CGA) is the common active phenolic acid in Chinese medicinal materials such as honeysuckle and eucommia. It is a class of small molecules with multiple activities such as antioxidant, inhibiting cancer cells, lowering blood sugar and lowering blood pressure. In this paper, UV-vis spectroscopy, fluorescence spectroscopy, circular dichroism, molecular dynamics simulation and cyclic voltammetry (CV) electrochemical analysis were used to investigate the mechanism about interaction between CGA and BSA. Based on fluorescence quenching analysis, CGA quenched the inherent fluorescence of BSA remarkably through a static mechanism. The obtained value of binding constant (Kb = 5.75 × 105 L·mol-1) revealed a high binding affinity between CGA and BSA. The simulated molecular docking showed that hydrophobic force were also involved in the interaction between BSA and CGA. This paper also investigate the effect of temperature and metal ions on the binding of CGA and BSA. When the temperature increased, the binding of BSA and CGA was destroyed. Metal ions affect both the structure of BSA and the combination of BSA and CGA. By studying the mechanism of CGA interaction with BSA, we elucidated the storage and transport mechanism of CGA in vivo under simulated human environment and temperature conditions.

The Herb-Drug Pharmacokinetic Interaction of Fluoxetine and Its Metabolite Norfluoxetine with a Traditional Chinese Medicine in Rats by LC-MS/MS.

BACKGROUND: Fluoxetine (FLU) is the first-line and widely used medication for depression. The combination of Chaihu Shugan san (CSGS) and FLU is commonly used to enhance antidepressant effects and reduce side effects. OBJECTIVE: The primary objective of this study was to investigate the potential pharmacokinetic effect of CSGS on FLU. MATERIALS AND METHODS: Thirty-two healthy adult male Sprague-Dawley (SD) rats were randomly divided into four groups, the fluoxetine group and multiple dose groups A, B, and C. The rats in the different groups were orally administered with a combination of FLU and different doses of CSGS for 14 d. On the fifteenth day, serial blood samples were taken from the caudal vein before the administration and at 0.25, 0.5, 0.75, 1, 2, 4, 6, 8, 10, 12, 24, 36, and 48 h after the administration. A liquid-liquid extraction method was applied to extract the analytes from serum. Then, the concentrations of FLU and its metabolite, norfluoxetine (NOF), were determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The pharmacokinetic parameters were calculated by DAS 3.2.8 program and compared by statistic analysis. RESULTS: Compared with the FLU group, the FLU and NOF area under the plasma concentration-time curve (AUC) (0-∞) in multiple dose group C was significantly increased, while the NOF AUCs (0-∞) in multiple dose group A and multiple dose group B were decreased. Compared with the FLU group, the NOF clearance (CL) in multiple dose group C was decreased, while the CL in multiple dose groups A and B was increased. DISCUSSION AND CONCLUSION: There were some differences in pharmacokinetic parameters between the FLU group and multiple dose groups, and CSGS can affect the pharmacokinetics of fluoxetine.

Efficacy of Weikang Pian in Patients with Functional Dyspepsia: A Double-Blind, Randomized, Placebo-Controlled Clinical Trial.

BACKGROUND: FD (functional dyspepsia) is a common functional gastrointestinal disorder, which lacks effective and safe treatment. Chinese herbal medicine (CHM) has been applied in FD treatment for thousands of years with satisfactory clinical outcomes. Zhishi is a classical traditional Chinese medicine used to treat FD. Weikang pian (WKP) is made of flavonoids extracted from zhishi which could effectively alleviate the symptoms of FD. This research aimed to assess the efficacy and safety of WKP in FD treatment. METHODS: This was a randomized, double-blinded and placebo-controlled clinical trial. The patients were diagnosed as FD according to RomeIII criteria. Then, FD patients were selected and assigned randomly to either WKP or placebo group. The subjects randomly received WKP or placebo for 4 weeks with 4 tablets each time, 3 times daily. The single dyspepsia symptom (SDS) scale and the gastric emptying function were measured before and after the treatment. Moreover, the safety of the trial and patient compliance were evaluated. RESULTS: A total of 60 FD patients were eventually enrolled in the trial, among them 45 patients in the WKP group and 15 patients in the placebo group. The primary outcome was the SDS scale, including assessments of postprandial distension, early satiety, epigastric burning, and pain. The secondary outcome was the gastric emptying function. Compared with the placebo group, the symptoms of FD in the WKP group were relieved after 4 weeks of treatment (P < 0.05). Some minor changes appeared in the four groups, but there were no significant differences in gastric emptying parameters of GER (2-hour gastric emptying rate) and GET/2 (gastric semiempty time) (P > 0.05). Severe adverse events were absent. The compliance to treatment was 94%-96%, and there was no significant difference between the groups. CONCLUSION: WKP can relieve FD symptoms to some extent. This trial is registered with Chinese Clinical Trial Registry (ChiCTR): CTR 20132482.

Biosensing technologies for Mycobacterium tuberculosis detection: status and new developments.

Biosensing technologies promise to improve Mycobacterium tuberculosis (M. tuberculosis) detection and management in clinical diagnosis, food analysis, bioprocess, and environmental monitoring. A variety of portable, rapid, and sensitive biosensors with immediate "on-the-spot" interpretation have been developed for M. tuberculosis detection based on different biological elements recognition systems and basic signal transducer principles. Here, we present a synopsis of current developments of biosensing technologies for M. tuberculosis detection, which are classified on the basis of basic signal transducer principles, including piezoelectric quartz crystal biosensors, electrochemical biosensors, and magnetoelastic biosensors. Special attention is paid to the methods for improving the framework and analytical parameters of the biosensors, including sensitivity and analysis time as well as automation of analysis procedures. Challenges and perspectives of biosensing technologies development for M. tuberculosis detection are also discussed in the final part of this paper.

Using fluorescent nanoparticles and SYBR Green I based two-color flow cytometry to determine Mycobacterium tuberculosis avoiding false positives.

A method using an improved two-color flow cytometric analysis by a combination of bioconjugated fluorescent silica nanoparticles and SYBR Green I (FSiNP@SG-FCM) has been developed for detection of pathogenic Mycobacterium tuberculosis. Antibody-conjugated nanoparticles were prepared by oriented immobilization of the anti-M. tuberculosis antibody onto Tris(2,2-bipyridyl)dichlororuthenium(II) hexahydrate-doped fluorescent silica nanoparticles (RuBpy-doped FSiNPs) through Protein A. M. tuberculosis was specially labeled with antibody-conjugated RuBpy-doped FSiNPs, then stained with a nucleic acid dye SYBR Green I to exclude background detrital particles, followed by multiparameter determination with flow cytometry. With this method, false positives caused by aggregates of nanoparticle-bioconjugates and nonspecific binding of nanoparticle-bioconjugates to background debris could be significantly decreased. This assay allowed for detection of as low as 3.5 x 10(3) and 3.0 x 10(4)cellsml(-1)M. tuberculosis in buffer and spiked urine respectively, with higher sensitivities than the FITC-based conventional flow cytometry. The total assay time including sample pretreatment was within 2h. This proposed FSiNP@SG-FCM method will be promising for rapid detection of M. tuberculosis or other pathogenic bacteria in clinical samples.

Preparation of luminescent Cy5 doped core-shell SFNPs and its application as a near-infrared fluorescent marker.

Cy5 dye is widely used as a biomarker in the research fields of life science because of its excitation at wavelengths above 600nm where autofluorescence of bio-matter is much reduced. However, Cy5 dye could not be encapsulate into silica directly to form stable nanoparticles by using of the traditional methods. In this paper, an improved method had been developed to prepare Cy5 dye doped core-shell silica fluorescent nanoparticles (SFNPs), employing biomolecules conjugated Cy5 as the core material and silica coating produced from the hydrolysis TEOS (tetraethyl orthosilicate) in the water-in-oil microemulsion. To obtain stable Cy5 dye doped SFNPs with core-shell structure, five kinds of biomolecules with different iso-electric point (pI) have been selected to conjugate Cy5 for preparation of core-shell SFNPs. Results demonstrated that very bright and photostable Cy5 doped core-shell SFNPs could be both prepared by use of positive polysine conjugated Cy5 or IgG conjugated Cy5 as the core material, respectively. IgG conjugated Cy5 doped core-shell SFNPs was selected as a demonstration to be characterized and applied as a near-infrared fluorescent marker in cell recognition. The results showed that Cy5 doped core-shell SFNPs prepared by conjugating with a positive biomolecules IgG as the core material were luminescent and stable. About 110 Cy5 dye molecules could be doped in one nanoparticle with size of 42+/-5nm. The breast cancer cells had been selectively recognized by use of the near-infrared fluorescent marker based on the Cy5-IgG doped core-shell SFNPs. And the results demonstrated that this Cy5 doped core-shell SFNPs fluorescence marker was superior to the pure Cy5 dye marker for cell recognition in photostability and detection sensitivity.

Fluorescent nanoparticle-based indirect immunofluorescence microscopy for detection of Mycobacterium tuberculosis.

A method of fluorescent nanoparticle-based indirect immunofluorescence microscopy (FNP-IIFM) was developed for the rapid detection of Mycobacterium tuberculosis. An anti-Mycobacterium tuberculosis antibody was used as primary antibody to recognize Mycobacterium tuberculosis, and then an antibody binding protein (Protein A) labeled with Tris(2,2-bipyridyl)dichlororuthenium(II) hexahydrate (RuBpy)-doped silica nanoparticles was used to generate fluorescent signal for microscopic examination. Prior to the detection, Protein A was immobilized on RuBpy-doped silica nanoparticles with a coverage of approximately 5.1 x 10(2) molecules/nanoparticle. With this method, Mycobacterium tuberculosis in bacterial mixture as well as in spiked sputum was detected. The use of the fluorescent nanoparticles reveals amplified signal intensity and higher photostability than the direct use of conventional fluorescent dye as label. Our preliminary studies have demonstrated the potential application of the FNP-IIFM method for rapid detection of Mycobacterium tuberculosis in clinical samples.