Screening and identification of the active components from Puerariae Radix by HUVEC/CMC-LC-MS2.

Puerariae Radix (PR) serves as food and medicinal plant for thousands of years with explicit efficacy for heart diseases, while biological target specifically binding-oriented screening of the active components in PR remains a preliminary stage. Cell membrane chromatography (CMC) is newly developed approach where interactions between active components and certain biological targets can be effectively studied, Human umbilical vein endothelial cell (HUVEC) membrane, with its abundant receptors such as ß and AT1, is most eligible for constructing CMC. In this study, an HUVEC/CMC-LC-MS2 system was developed for screening active components in PR, 11 compounds were screened out and four of them were identified. Besides puerarin, the rest identified are daidzin, pueroside D and 3'-hydroxypuerarin. The study provides more reference for CMC applications and PR exploitation.

Phytochemical composition and antibacterial activity of the essential oils from different parts of sea buckthorn (Hippophae rhamnoides L.).

Essential oils from the seed, pulp, and leaf of sea buckthorn were obtained with hydrodistillation, and their phytochemical composition was analyzed through gas chromatography-mass spectrometry. Furthermore, the antibacterial activity of the oils was tested on five food-borne bacteria by spectrometry and evaluated in terms of minimum inhibitory concentration. The results indicate that the composition of all essential oils is dominated by free fatty acids, esters, and alkanes. Minimum inhibitory concentration values on each bacterium were obtained for oils from different parts. The oils from different parts exhibited nearly equal inhibitory effect on Staphylococcus aureus. The pulp oil was found to be the most effective for the rest of bacteria tested except Escherichia coli, on which seed oil shows twice the inhibitory effect to that of leaf or pulp oil. Three natural inhibitory examples were found comparable with or even better than the positive control: pulp oil on Bacillus subtilis, and pulp oil and leaf oil on Bacillus coagulans.

Study on the adsorption property of lysozyme on weak cation exchanger based on monodisperse poly(glycidymethacrylate-co-ethylenedimethacrylate) beads.

A type of weak cation exchanger was prepared based on poly(glycidylmethacrylate-co-ethylenedimethacrylate). The effects of pH and ionic strength on the adsorption behavior were studied, and the results suggested that the adsorption of lysozyme onto a weak cation exchanger is electrostatic interaction, and that the adsorption behavior is in accordance with the Langmuir adsorption model with a correlation coefficient greater than 0.99. It was also found that increasing ionic strength led to a decrease of the adsorption of lysozyme from 49.50 to 28.09 mg/g. Preliminary chromatographic experiments were conducted to test the separation properties of the weak cation exchanger, and the results demonstrated that the retention time of different proteins could be predicted in order of their isoelectric point.

Cardiac muscle sarcolemma chromatographic stationary phase and its potential application in drug screening.

A new bioactive packing material for liquid chromatography, sarcolemma chromatography stationary phase (SCSP), is presented. Its surface characteristics are investigated, and it is found that the acceptors embedded in sarcolemma remained bioactive for more than a week. The retention behavior of antagonists and activators related to cardiac muscle sarcolemma on the SCSP chromatographic column shows the screening function of the SCSP column, and the retention behavior of the active components in the aether extract from the Chinese herb Ligusticum chuanxiong Hort. on the SCSP column reveals, to a certain extent, the separation function of the SCSP column. These suggest that SCSP is a potentially useful material in drug screening.

[Study on the interactions between Ligusticum chuanxiong extract and cardiac muscle membrane receptors by CMSP chromatography].

OBJECTIVE: To study the interactions between Ligusticum chuanxiong Hort extract and cardiac muscle membrane receptors. METHOD: The cell membrane of rabbit cardiac muscle was fixed on silicon to make cell membrane stationary phase (CMSP), and then the interactions were studied by comparing the retention characteristics of the extracts from different solvents with those of the antagonists or activators corresponding to known receptors in cardiac muscle membrane, and by competition effect on the retention characteristics of extracts when adding the antagonists or activators into the mobile phase. RESULT: Water extract and ethanol extract both had retentions on CMSP; the retention characteristics of water extract could be affected when water extract was in competition with the antagonists for alpha receptor, and could not be affected when with the activator beta1 receptor. CONCLUSION: It is possible that some components in water extract may combine with alpha receptor and no component with beta1 receptor, and that some components in ethanol extract may combine with cardiac muscle cell membrane. The process between active components and receptors in vivo can be imitated through the interactions between drugs and CMSP. The method provides references for the resolution of two applications: to screen the active components from Chinese medicine, and to figure out the type of receptors involved.

[Study on the interactions between four components in Ligusticum chuanxiong rhizome and acceptors on cardiac muscle membrane].

OBJECTIVE: To study the interactions between four components in Ligusticum chuanxiong rhizome and heart cell membrane acceptors. METHOD: Through observing the retention characteristics of the four components (tetramethylpyrazine, vanillic, chrysophol, ferulic acid) on cell membrane stationary phase (CMSP) chromatographic column, whether the components combine with cell membrane acceptors was studied, and through further comparing the retention characteristics with those of known activators or antagonists corresponding to cell membrane acceptors, the kind of acceptor with which one component combines was studied. RESULT: Tetramethylpyrazine, vanillic and chrysophol had retention on CMSP chromatographic column while ferulic acid hadn't. The retention characteristics of tetramethylpyrazine were similar to activator and antagonist corresponding to a acceptor, vanillic with beta1 acceptor activator. CONCLUSION: Tetramethylpyrazine, vanillic and chrysophol can all combine with cardiac muscle membrane acceptors, while ferulic acid can not; tetramethylpyrazine probably acts on a acceptor and vanillic acts on beta1 acceptor.

Flow injection catalytic spectrophotometric simultaneous determination of nitrite and nitrate.

A new flow injection catalytic spectrophotometric method is proposed for the simultaneous determination of nitrite and nitrate based on the catalytic effect of nitrite on the redox reaction between crystal violet and potassium bromate in phosphoric acid medium and nitrate being on-line reduced to nitrite with a cadmium-coated zinc reduction column. The redox reaction is monitored spectrophotometrically by measuring the decrease in the absorbance of crystal violet at the maximum absorption wavelength of 610nm. A technique of inserting a reduction column into sampling loop is adopted and the flow injection system produces a signal with a shoulder. The height of shoulder in the ascending part of the peak corresponds to the nitrite concentration and the maximum of the peak corresponds to nitrate plus nitrite. The detection limits are 0.3ngml(-1) for nitrite and 1.0ngml(-1) for the nitrate. Up to 32 samples can be analyzed per hour with a relative standard deviation of less than 2%. The method has been successfully applied for the simultaneous determination of nitrite and nitrate in natural waters.