Searching for the main anti-bacterial components in artificial Calculus bovis using UPLC and microcalorimetry coupled with multi-linear regression analysis

The fingerprints of artificial Calculus bovis extracts from different solvents were established by ultra-performance liquid chromatography (UPLC) and the anti-bacterial activities of artificial C. bovis extracts on Staphylococcus aureus (S. aureus) growth were studied by microcalorimetry. The UPLC fingerprints were evaluated using hierarchical clustering analysis. Some quantitative parameters obtained from the thermogenic curves of S. aureus growth affected by artificial C. bovis extracts were analyzed using principal component analysis. The spectrum-effect relationships between UPLC fingerprints and anti-bacterial activities were investigated using multi-linear regression analysis. The results showed that peak 1 (taurocholate sodium), peak 3 (unknown compound), peak 4 (cholic acid), and peak 6 (chenodeoxycholic acid) are more significant than the other peaks with the standard parameter estimate 0.453, -0.166, 0.749, 0.025, respectively. So, compounds cholic acid, taurocholate sodium, and chenodeoxycholic acid might be the major anti-bacterial components in artificial C. bovis. Altogether, this work provides a general model of the combination of UPLC chromatography and anti-bacterial effect to study the spectrum-effect relationships of artificial C. bovis extracts, which can be used to discover the main anti-bacterial components in artificial C. bovis or other Chinese herbal medicines with anti-bacterial effects.     

Hepatoprotective Constituents of Total Dibenzocyclooctadiene Lignans from Schisandra chinensis Based on the Spectrum-Effect Relationship

To scientifically clarify the hepatoprotective constituents of Fructus Schizandrae chinensis, eleven batches samples of total dibenzocyclooctadiene lignans (TDL) from Schisandra chinensis were prepared by using the optimum extraction technique. Characteristic high-performance liquid chromatography (HPLC) chromatograms were obtained through HPLC analysis technology, and the hepatoprotective effects of the eleven batches of TDL were evaluated by MTT assay. Based on the chemical and biological activity results, the spectrum-effect relationship between the characteristic HPLC fingerprints and the hepatoprotective effect of TDL was established using Minitab 16.0 data analysis software. On the basis of the spectrum-effect relationship, thirteen compounds (1–13) were obtained from the TDL by chemical natural product chemical separation and purification technology, and their structures were identified on the basis of the spectral data and the literature. Based on these compounds, thirteen common peaks among the thirty-three chromatographic peaks in the above HPLC fingerprints were identified. Our findings showed that some components, including, schisandrin B (2), schisandrin A (3), and schisandrol B (7) had significant roles in promoting hepatoprotective activity. Preliminary verification of the spectrum-effect relationship of TDL from S. chinensis was carried out, and the results confirmed that the activity of a composite of these three key components in optimal ratios was better than that of any individual compound, which potentially confirmed the reliability of the spectrum-effect relationship and the synergistic effects of traditional Chinese medicine.     

Screening and identification of hepatotoxic component in Evodia rutaecarpa based on spectrum–effect relationship and UPLC‐Q‐TOFMS

Evodia rutaecarpa (E. rutaecarpa) has been used to treat aches, vomiting and dysentery in traditional Chinese medicine. However, as a mildly toxic herb its toxic components have not been elucidated. An attempt was made to illuminate the hepatotoxic constituents of E. rutaecarpa. The 50% ethanol extracts of E. rutaecarpa from 19 different sources were used to establish UPLC fingerprints and administered to mice at a dose of 35 g/kg (crude medicine weight/mouse weight) once daily for 14 days. Serum levels of alanine transaminase, aspartate aminotransferase and liver coefficient were used as indices of liver injury. Additionally, the characteristic peaks of 19 fingerprints were identified. Spectrum–effect relationships between fingerprints and hepatotoxic indicators were analyzed using bivariate correlation analysis (BCA). The UPLC fingerprints were established and a total of 28 main compounds were identified. Because of the inherent variations in chemical compositions, the liver injury levels were different among the E. rutaecarpa samples from 19 sites of production. BCA results indicated that compounds dihydrorutaecarpine, 6‐acetoxy‐5‐epilimonin, goshuyuamide I, 1‐methyl‐2‐[(Z)‐5‐undecenyl]‐4(1H)‐quinolone, 1‐methyl‐2‐[(4Z,7Z)‐4,7‐tridecadienyl]‐4(1H)‐quinolone, evocarpine and 1‐methyl‐2‐[(6Z,9Z)‐6,9‐pentadecadienyl]‐4(1H)‐quinolone were tentatively determined as the primary hepatotoxic components. The present study provides a valuable method for the discovery of hepatotoxic constituents by combination of fingerprints and hepatotoxicity index.     

Synthesis and anti-microbial activity of some new fluorinated 1H-pyrazoles

Several new trifluoromethyl-1H-pyrazoles were prepared by reaction of hydrazine monohydrate with 1,3-diketones. Their structures were confirmed by elemental analysis, IR, ¹H NMR and EI-MS spectroscopy. The anti-microbial activities of the newly synthesized compounds were examined by disc diffusion method against Escherichia coli, Staphylococcus aureus, Pyricularia oryzae and Rhizoctnia solani. All the trifluoromethyl-1H-pyrazoles exhibited a certain degree of anti-bacterial and anti-fungal activities.     

Quality evaluation and species differentiation of Rhizoma coptidis by using proton nuclear magnetic resonance spectroscopy

Rhizoma coptidis, a broadly used traditional Chinese medicine, derives from the dried rhizomes of Coptis chinensis Franch, Coptis deltoidea C.Y. Cheng et Hsiao and Coptis teeta Wall. Quantitative determination of protoberberine alkaloids in R. coptidis is critical for controlling its quality. In this study, a rapid, simple and accurate quantitative ¹H NMR (qNMR) method was developed for simultaneous determination of berberine, jatrorrhizine, epiberberine, coptisine, palmatine and columbamine in R. coptidis from the three species. Method validation was performed in terms of selectivity, precision, repeatability, stability, accuracy, robustness and linearity. The average recoveries obtained were in the range of 96.9–102.4% for all the six alkaloids. In addition, the qNMR data were analyzed with analysis of variance (ANOVA), hierarchical clustering analysis (HCA) and principal component analysis (PCA), and the results showed that the contents of the active alkaloids have significant difference among the three species. Compared with the conventional HPLC approach, the proposed qNMR method was demonstrated to be a powerful tool for quantifying the six alkaloids due to its unique advantages of high robustness, rapid analysis time and no need of standard compounds for calibration curves preparation. These findings indicate that this method has potential as a reliable method for quality evaluation of herb medicines, especially for protoberberine alkaloid-containing ones.     

Anti-bacterial effect of four extracts from leaves of Dracontomelon dao on Escherichia coli growth using microcalorimetry coupled with principal component analysis

The anti-Escherichia coli activities of four extracts in leaves of Dracontomelon dao, a traditional folk herb in China were investigated and compared by microcalorimetry. The four extracts are PE fraction, CHCl₃ fraction, EtOAc fraction, and n-BuOH fraction. The heat flow power–time (HFP–time) curves of E. coli growth in the presence of the four extracts were measured using an ampoule method. Then the nine thermal kinetic parameters were obtained from the curves. From the result of principal component analysis, it can be seen that parameters k ₁, k ₂, P ₁, and Q _p2 might be the main parameters in evaluating the anti-E. coli effects. In the presence of CHCl₃ fraction, EtOAc fraction, and n-BuOH fraction, k ₂, Q _p2 of E. coli decreased with increasing concentrations of the extracts. The EtOAc fraction was observed to have the strongest anti-bacterial activity with half-inhibitory concentration IC50 of 98.5 μg mL^?1. So, it can be concluded that EtOAc fraction can be further developed as anti-bacterial bioactive fraction of leaves of Dracontomelon dao.     

Systematic screening and characterization of absorbed constituents and in vivo metabolites in rats after oral administration of Rhizoma coptidis using UPLC-Q-TOF/MS

Rhizoma coptidis has been used for a long time in China owing to its anti-bacterial, anti-diabetes, anti-hyperlipidemia and anti-obesity activities. However, the in vivo biotransformation of Rhizoma coptidis is still unclear to date. In this study, a three-step strategy using UPLC-Q-TOF/MS was applied to clarify the in vivo absorbed constituents and metabolites in rats after oral administration of Rhizoma coptidis. First, alkaloids in Rhizoma coptidis extract were identified. Second, six abundant alkaloids (berberine, palmatine, coptisine, epiberberine, jatrorrhizine, and columbamine) were selected as representative prototypes and the metabolic fates of them in rats were investigated to obtain a database of Rhizoma coptidis-derived metabolites. Finally, the metabolic profiles of Rhizoma coptidis were fully elucidated based on the above-mentioned results. In summary, 29 alkaloids were identified in Rhizoma coptidis, and a database of Rhizoma coptidis-derived metabolites was obtained with 144 characterized metabolites. A total of 89 xenobiotics including 12 absorbed constituents and 77 metabolites were identified in dosed rat biosamples. Major metabolic pathways of Rhizoma coptidis were hydroxylation, reduction, methylation, demethylation, demethylenation, desaturation, glucuronidation and sulfation. This is the first systematic study on the in vivo absorbed constituents and metabolic profiling of Rhizoma coptidis and will be beneficial for its further studies.     

Analysis of alkaloids in Coptis chinensis Franch by accelerated solvent extraction combined with ultra performance liquid chromatographic analysis with photodiode array and tandem mass spectrometry detections

A new method based on accelerated solvent extraction (ASE) followed by ultra performance liquid chromatography (UPLC) analysis has been developed for the identification and quantification of major alkaloids in extracts of Coptis chinensis Franch. The UPLC system consisted of a dual detection system of photodiode array detector (PDA) and positive ion electrospray ionization-tandem mass spectrometry (ESI-MS/MS) in sequential configuration. The operational parameters of ASE including extraction solvent, extraction temperature, static extraction time and extraction cycles were optimized. UPLC analysis was performed on an ACQUITY UPLC BEH C₁₈ column eluted by a mobile phase of acetonitrile spiked with a buffer solution consisting of 0.50% acetic acid and 20 mmol L⁻¹ ammonium acetate. A tandem quadrupole spectrometer operating in either full scan mode or in MS/MS mode for multiple reaction monitoring (MRM) was used for the identification and quantitative analysis of eight major alkaloids in C. chinensis Franch extracts. The samples were also analyzed on a high-performance liquid chromatography-electrospray ionization-time-of-flight mass spectrometry (HPLC-ESI-TOF-MS) system to confirm the identification results. Three of the eight major alkaloids, berberine, palmatine and jatrorrhizine were quantified by UPLC-PDA and UPLC-MS/MS. The results indicated that both UPLC-PDA and UPLC-MS/MS methods were simple, sensitive and reliable for the determination of alkaloids in C. chinensis Franch. Seven Huanglian samples from different locations were analyzed using the established methods. UPLC fingerprints based on the distribution of the eight major alkaloids can serve as a rapid and reliable method for the authentication and quality evaluation of traditional Chinese medicine (TCM) herbs.     

Functional Characterization of Porcine NK-Lysin: A Novel Immunomodulator That Regulates Intestinal Inflammatory Response

Porcine NK-Lysine (PNKL) is a new antimicrobial peptide (AMP) identified in the small intestine. In this study, PNKL protein was obtained through heterologous expression in Escherichia coli and was estimated by SDS-PAGE at 33 kDa. The antibacterial activities of PNKL were determined using various bacterial strains and showed broad-spectrum antimicrobial activity against Gram-negative and Gram-positive bacteria. Furthermore, E. coli K88-challenged IPEC-J2 cells were used to determine PNKL influences on inflammatory responses. Hemolytic assays showed that PNKL had no detrimental impact on cell viability. Interestingly, PNKL elevated the viability of IPEC-J2 cells exposure to E. coli K88. PNKL significantly decreased the cell apoptosis rate, and improved the distribution and abundance of tight junction protein ZO-1 in IPEC-J2 cells upon E. coli K88-challenge. Importantly, PNKL not only down regulated the expressions of inflammatory cytokines such as the IL-6 and TNF-α, but also down regulated the expressions of NF-κB, Caspase3, and Caspase9 in the E. coli K88-challenged cells. These results suggest a novel function of natural killer (NK)-lysin, and the anti-bacterial and anti-inflammatory properties of PNKL may allow it a potential substitute for conventionally used antibiotics or drugs.     

Spectrum-effect relationship between fingerprints and hemopoietic effects of small molecular fraction of Polygoni Multiflori radix praeparata

Polygoni multiflori Radix Praeparata (PMRP) is a traditional medicine used for nourishing essence and blood in China. However, it is unclear which PMRP compounds are responsible for its hematopoietic effect. In this study, spectrum-effect relationship was used to discovery potential hematopoietic compounds. The fingerprints of 20 PMRP batches were established by HPLC and the hematopoietic effect was determined using red blood cell, hemoglobin, hematocrit, and platelet indexes in aplastic anemia model mice. The spectrum-effect relationship between common peaks and hematopoietic efficacy values was established using gray relational analysis and partial least squares analysis. Spectrum-effect relationship results showed that peaks 21 (emodin-8-O-(6´-O-acetyl)-β-D-glucoside), 15 (2, 3, 5, 4′-tetrahydroxystilbene-2-O-di-glucoside), 16 (cis-2,3,5,4′-tetrahydroxy-stilbene-2-O-β-D-glucoside), 11 (unknown), 20(unknown, 12 (epicatechin), 29 (carboxyl emodin), and 31 (emodin) in the fingerprints were closely related to the hematopoietic effect. This work successfully established the spectrum-effect relationship between PMRP hematopoietic effect and its fingerprints, which can be used to explain the material basis for the PMRP hematopoietic effect.     

Bioactivity fingerprint analysis of cyclooxygenase-2 ligands from radix Aconiti by ultrafiltration–UPLC–MSn

A novel fingerprinting method, bioactivity fingerprint analysis, based on an ultrafiltration–ultraperformance liquid chromatography–multistage tandem mass spectrometry (UPLC–MS ⁿ ) method is proposed for the quality control of herbal medicines from the bioactivity viewpoint concerning the efficacy of herbal medicines. The bioactivity fingerprints reflecting the anti-inflammatory activities of radix Aconiti and radix Aconiti preparata were established. With use of ultrafiltration UPLC–MS ⁿ , 11 cyclooxygenase-2 ligands from radix Aconiti preparata and 14 cyclooxygenase-2 ligands from radix Aconiti were found after incubation with cyclooxygenase-2. Twelve of the cyclooxygenase-2 ligands were identified by the ultraperformance UPLC–MS ⁿ method. The enrichment factor of each peak in the bioactivity fingerprint was calculated and was demonstrated to be characteristic, which makes bioactivity fingerprint analysis for the quality control of herbal medicines possible from the viewpoint of their bioactivities.

Combining biofunctional magnetic nanoparticles and ATP bioluminescence for rapid detection of Escherichia coli

A rapid, specific and sensitive method for assay of Escherichia coli (E. coli) using biofunctional magnetic nanoparticles (BMNPs) in combination with adenosine triphosphate (ATP) bioluminescence was proposed. The BMNPs were fabricated by immobilizing a specific anti-E. coli antibody on the surface of amine-functionalized magnetic nanoparticles (about 20 nm in diameter), and then was applied to capture the target bacteria E. coli from samples. The BMNPs exhibited high capture efficiency to E. coli. Transmission electron microscope (TEM) images showed that the BMNPs were bound to the surface of entire E. coli cells. The target bacteria became magnetic so that could be isolated easily from the sample solution by employing an external magnetic field. The concentration of E. coli captured by the BMNPs was then detected by an ATP bioluminescence method. The optimization of ATP measurement was carried out to improve the detection sensitivity. The proposed method was applied to detect the E. coli inoculated into pasteurized milk with low detection limit (20 cfu/mL) and short detection time (about 1 h).     

Fluorescence detection of total count of Escherichia coli and Staphylococcus aureus on water-soluble CdSe quantum dots coupled with bacteria

The aim of this paper was to demonstrate a fluorescence measurement method for rapid detection of two bacterial count by using water-soluble quantum dots (QDs) as a fluorescence marker, and spectrofluorometer acted as detection apparatus, while Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were as detection target bacteria. Highly luminescent water-soluble CdSe QDs were first prepared by using thioglycolic acid (TGA) as a ligand, and were then covalently coupled with target bacteria. The bacterial cell images were obtained using fluorescence microscopy. Our results showed that CdSe QDs prepared in water phase were highly luminescent, stable, and successfully conjugated with E. coli and S. aureus. The fluorescence method could detect 10²-10⁷ CFU/mL total count of E. coli and S. aureus in 1-2 h and the low detection limit is 10² CFU/mL. A linear relationship of the fluorescence peak intensity and log total count of E. coli and S. aureus have been established using the equation Y = 118.68X − 141.75 (r = 0.9907).     

Rapid detection of Escherichia coli contamination in packaged fresh spinach using hyperspectral imaging

A rapid method based on hyperspectral imaging for detection of Escherichia coli contamination in fresh vegetable was developed. E. coli K12 was inoculated into spinach with different initial concentrations. Samples were analyzed using a colony count and a hyperspectroscopic technique. A hyperspectral camera of 400-1000 nm, with a spectral resolution of 5 nm was employed to acquire hyperspectral images of packaged spinach. Reflectance spectra were obtained from various positions on the sample surface and pretreated using Sawitzky-Golay. Chemometrics including principal component analysis (PCA) and artificial neural network (ANN) were then used to analyze the pre-processed data. The PCA was implemented to remove redundant information of the hyperspectral data. The ANN was trained using Bayesian regularization and was capable of correlating hyperspectral data with number of E. coli. Once trained, the ANN was also used to construct a prediction map of all pixel spectra of an image to display the number of E. coli in the sample. The prediction map allowed a rapid and easy interpretation of the hyperspectral data. The results suggested that incorporation of hyperspectral imaging with chemometrics provided a rapid and innovative approach for the detection of E. coli contamination in packaged fresh spinach.     

Towards a receptor-free immobilization and SERS detection of urinary tract infections causative pathogens

Based on molecular-specific surface-enhanced Raman scattering (SERS) spectroscopy we were able to discriminate between rough and smooth strains of Escherichia coli and Proteus mirabilis bacteria. For this purpose, bacteria have been immobilized through electrostatic forces by inducing a positive charge on the glass slide. This way, SERS spectra on bacterial biomass and also on single bacteria could be recorded in less than 2 h, by using concentrated silver nanoparticles as SERS-active substrate. Single-bacterium SERS spectral fingerprints showed to be sensitive to the presence of the O-antigen at strain level and to the microorganisms growth phase. By using principal component analysis (PCA) on the SERS spectra recorded from E. coli and P. mirabilis, these two uropathogens could be fairly discriminated.     

In vitro metabolic study of Rhizoma coptidis extract using liver microsomes immobilized on magnetic nanoparticles

Although metabolic study of individual active compounds isolated from herbal plants has been intensive, it cannot truly reflect the fate of herbs because the herbal extracts in use have many constituents. To address this problem, whole extracts of herbs should be investigated. Microsomes have been heavily used in the in vitro metabolic study of drugs, and various materials have been used to immobilize microsomes to develop highly effective and reusable bioreactors in this field. In this work, rat liver microsomes were immobilized on magnetic nanoparticles (LMMNPs) to develop a highly active and recoverable nanoparticle bioreactor. Using this bioreactor, we investigated the in vitro metabolism of Rhizoma coptidis extract. Incubation of berberine, a major active ingredient of R. coptidis, with LMMNPs for 20 min produced two metabolites, i.e., demethyleneberberine and thalifendine, at high levels. From a comparison of the time courses of thalifendine formation obtained by ultraperformance liquid chromatography–mass spectrometry analysis, it was found that LMMNPs had a higher biological activity than free liver microsomes in metabolizing berberine. Further, the activity of LMMNPs remained almost unchanged after six consecutive uses in the incubation tests. Metabolism of R. coptidis extracts by LMMNPs was studied. The same two metabolites of berberine, i.e., demethyleneberberine and thalifendine, were detected. After a thorough study seeking support for this observation, it was found that demethyleneberberine was the common metabolite of five protoberberine-type alkaloids present in R. coptidis extract, including palmatine, jatrorrhizine, columbanine, epiberberine, and berberine.

Molecular beacons: a real-time polymerase chain reaction assay for detecting Escherichia coli from fresh produce and water

Molecular beacons (MBs) are oligonucleotide probes that fluoresce upon hybridization. The development of a real-time polymerase chain reaction (PCR) assay to detect the presence of Escherichia coli using these fluorogenic reporter molecules is reported. MBs were designed to recognize a 19-bp region of the uid A gene, coding for an enzyme β-glucuronidase. The specificity of the MB-based PCR assay was evaluated for various E. coli strains as well as bacteria species that are present in nature. The capability of the assay to detect E. coli in drinking water and produce was demonstrated. Positive detection of E. coli was demonstrated when >10¹ CFU mL⁻¹ (colony forming unit) was present in the water samples and fresh produce after 18 h of enrichment. These assays could be carried out entirely in sealed PCR tubes, enabling rapid and semiautomated detection of E. coli in food and environmental samples.     

Fingerprint–efficacy study of Radix Aconiti Lateralis Preparata (Fuzi) in quality control of Chinese herbal medicine

For quality control of Chinese herbal medicine (CHM), an attempt on fingerprint–efficacy study of Radix Aconiti Lateralis Preparata (Fuzi) was developed in this paper. The fingerprints of Fuzi from various sources were determined by UPLC and hierarchical clustering analysis. Some quantitative thermo-kinetic parameters such as the heat-flow maximum power (P _max) and its time corresponding to t _max, which obtained from the thermogenic curves of mitochondria metabolic activity affected by Fuzi were analyzed using principal component analysis. The fingerprint–efficacy relationship of chemical fingerprint and promoting effect of Fuzi were established using canonical correlation analysis. Our results showed that the sources and places of production of Fuzi had some significant influence on the chemical fingerprints and promoting metabolic effects of this CHM. Fingerprint–efficacy study provided a powerful way and some references for the quality control of Fuzi and other CHMs.     

左金丸及类方HPLC指纹图谱与生物热活性的“谱-效”关系研究

HPLC法建立左金丸及类方水提液的特征指纹图谱, 计算各特征峰的相对峰面积, 并采用中药色谱指纹图谱相似度评价系统A版(2004 A)计算类方间的相似度; 微量热法测定大肠杆菌在左金丸及类方水提液作用下的热谱曲线, 得到相应的热动力学参数, 如生长速率常数k, 最大产热功率Pm, 最高峰的出峰时间tm和总产热量Qt等, 并对这些热动力学参数进行主成份分析. 典型相关分析法对左金丸及类方HPLC 指纹图谱中特征峰的相对峰面积与其类方作用下大肠杆菌生长代谢的主要热动力学参数相关联, 研究“谱-效”相关性. 结果表明, HPLC 指纹图谱与生物热活性存在很好的相关性, 类方中吴茱萸次碱、盐酸巴马汀、盐酸小檗碱的含量差异是导致其生物热活性不同的主要原因.