Highly selective recognition of Al3+ and I- ions using a bi-functional fluorescent probe.

A tripodal fluorescent probe L1 armed with Rhodamine B and 1-naphthaleneisothiocyanates was prepared in high yield. A study of the recognition properties revealed that probe L1 exhibited high sensitivity and selectivity towards Al3+ through a "FRET" fluorescence response and colorimetric response with low detection limits of the order of 10-8 M. Meanwhile, probe L1 also possessed high recognition ability for I- through fluorescence decay, which given there are comparatively few selective fluorescent probes for I-, is significant. Furthermore, the complexation mechanisms were fully investigated by spectral titrations, 1H NMR spectroscopic titrations and mass spectrometry. The utility of probe L1 as a biosensor in living cells (PC3 cells) towards Al3+ ions has also been demonstrated.

[Studies on interaction of sinafloxacin with bovine serum albumin and effect of the coexistent metal ions on the reaction].

Serum albumin is the most abundant protein in plasma. It can bind with many intrinsic and extrinsic materials. The study of the interaction between serum albumin and drugs is a very important task in life science and chemistry. Quinolone drug is a kind of antibacterial drugs which have been used widely in clinical medicine, but its pharmacology and toxicology still have to be studied further. Sinafloxacin is a new quinolone antibiotics. The interaction between sinafloxacin and bovine serum albumin (BSA) at different temperatures and pH was investigated by fluorescence and UV absorption spectroscopy. The experimental results demonstrate that the fluorescence quenching of BSA by sinafloxacin is a result of the formation of sinafloxacin-BSA complex and the quenching mechanism is mainly static quenching. The interaction association constants of BSA and sinafloxacin were determined from the double reciprocal Lineweaver-Burk plot. The binding distance(r = 3.64 Rnm) and energy transfer efficiency (E = 0.163) between donor (BSA) and acceptor (sinafloxacin) were obtained based on Förster's non-radiative energy transfer theory. There is a strong interaction between sinafloxacin and BSA. From thermodynamic coordination it can be judged that the binding force between sinafloxacin and BSA is mainly electro-static force. The effect of sinafloxacin on the conformation of BSA was analyzed by synchronous fluorescence spectrometry and three-dimensional fluorescence spectrometry. The emission maximum of tyrosine residues does not show a significant shift, while the small blue shift of tryptophan residues indicates that the hydrophobicity of microenvironment was increased. In addition, in the plasma, there are some metal ions, which can participate in many important vital actions and affect the reactions of the drugs with the serum albumins. So the effect of Cu(II), Fe(III), Zn( II) and Mg(II) on the binding constant of sinafloxacin to BSA was also discussed and it was shown that the interaction between BSA and sinafloxacin was decreased. In short, the results offer a reference for the studies on the biological effects and action mechanism of sinafloxacin with albumins in vivo.

[Isolation and structure identification of chemical constituents from Patrinia villosa].

AIM: To study the chemical constituents of Patrinia villosa Juss. METHODS: Solvent extraction, silica gel column and preparative liquid chromatography were used to separate the chemical constituents, and the chemical structures were elucidated by physico-chemical properties and spectra data. RESULTS: Eight compounds were isolated and identified as bolusanthol B (1), (2S)-5, 7, 2', 6'-tetrahydroxy-6,8-di (gamma,gamma-dimethylallyl) flavanone (2), orotinin (3), (2S)-5, 7, 2', 6'-tetrahydroxy-6-lavandulylated flavanone (4), 3'-prenyl-apigenine (5), luteolin (6), quercetin (7) and apigenin (8). CONCLUSION: Compound 2 and 4 are new compounds, compounds 1, 3 and 5 were separated from Patrinia genius for the first time, compounds 6, 7 and 8 were isolated from Patrinia vollosa Juss for the first time.

[Studies on chemical constituents of Patrinia villosa].

OBJECTIVE: To investigate the chemical constituents of Patrinia villosa. METHOD: The chemical constituents were isolated by silica gel column chromatography and semi-preparative high-performance liquid chromatography, and identified by physicochemical properties and spectral analysis (MS, 1H-NMR and 13C-NMR). RESULT: Seven compounds were isolated from ethyl acetate and n-butanol extract and identified as: 5-hydroxyl-7, 3', 4'-trimethoxy flavone (I), 5-hydroxyl-7, 4'-dimethoxy flavone (II), luteolin (III), quercetin (IV), isoorientin (V), isovitexin (VI) and 8-C glucosylprunetin (VII). CONCLUSION: Compounds I , II, III, V, VI and VIII were obtained from the plant of genus Patrinia for the first time, compound IV was separated from P. villosa for the first time.

[Stereoselective pharmacokinetics of tetrahydropalmatine in rats].

AIM: To investigate the stereoselective pharmacokinetic process of tetrahydropalmatine (THP) in rats. METHODS: The concentrations of tetrahydropalmatine enantiomers in rat plasma were determined by coupled achiral and chiral HPLC method. The differences in plasma concentrations and pharmacokinetic parameters between the two enantiomers were compared by paired t-test. RESULTS: The plasma levels of l-THP were always higher than those of d-THP in eight rats. There was significant difference between the main pharmacokinetic parameters of the two enantiomers. CONCLUSION: Tetrahydropalmatine showed significant stereoselective pharmacokinetics in rats after an ig dose of the racemate.

[Two new C21 steroidal glycosides from Marsdenia tenacissima].

AIM: To study the chemical constituents of Marsdenia tenacissima (Roxb.) Wight et Arn. METHODS: To separate compounds with various chromatography technology and to elucidate their structures by chemical and spectral analysis. RESULTS: Two compounds were isolated from Marsdenia tenacissima and their stuctures were determined as tenacissosides J (I) and tenacissosides K (II). CONCLUSION: Compounds I and II are new C21 steroidal glycosides.

[Determination of chemical constituents of essential oil from the fruit of Eucalyptus globulus by GC-MS].

OBJECTIVE: The chemical components of essential oil from fruit of Eucalyptus globulus were analyzed by GC-MS. METHOD: The essential oil were extracted by steam distillation, then separated by capillary gas chromatography. The amount of the component from essential oil were determined by normalization methods. Chromatographic conditions were: capillary column DB-WAX (0.32 mm x 30 m, 0.25 microm) was used, column temperature: initial temperature at 40 degrees C for 3 min,ramping 5 C x min(-1) to 250 degrees C (holding for 10 min) the detector MS. RESULT: 31 component from the fruit of E. globulus were identified, which accounted for over 93.7% of total volatile oil. CONCLUSION: The methods is reliable, stabilize and can be applied to identify the volatile oil from the fruit of E. globulus.

[Studies on NaNO2-induced DNA mutation by convolution spectrometry].

AIM: To study the sodium nitrite induced DNA mutation by convolution spectrometry (CS). METHODS: The spectra of sodium nitrite-induced mutative calf thymus DNA was compared with ego criteria based on Spectra of the primary DNA within the wavelength range from 200 to 340 nm. Distilled water served as blank and normal saline served as negative control. Any difference was quantitatively expressed by differential value (delta) of convolution spectra. Near-infrared spectroscopy was employed as the reference method. RESULTS: The differential value was positively correlated with the increasing time and concentration of sodium nitrite. delta values increased to 1.37%, 2.41% and 5.44% respectively within 2-hour's reaction between calf thymus DNA and 0.5, 0.05 and 0.005 microgram.mL-1 sodium nitrite, while on the contrary, changes could be hardly observed on the corresponding UV absorption spectra. The results were also confirmed by their corresponding near-infrared spectra. CONCLUSION: The delta values can be used to represent the compound's strength of mutagenesis. Every convolution procedure takes less than one minute, so CS provides a fast, simple and inexpensive alternative method to determine chemical or medicinal DNA mutation.

[Solubility behavior of four diastereomeric salts and two amino acids in near-critical CO2].

AIM: To establish a suitable condition for extraction of phenylalanine (Phe), 5-hydroxytryptophan (5-OH-Trp) and four diastereomeric salts, (1R,2S)-ephedrine- (2S,3S)-tartaric acid, (1R,2S)-ephedrine-(2R,3R)-tartaric acid, (1S,2S)-pseudoephedrine-(2S,3S)-tartaric acid, (1S,2S)-pseudoephedrine- (2R,3R)-tartaric acid in supercritical fluid extraction and to assess the solubilities of Phe, 5-OH-Trp and the four diastereomeric salts in CO2. METHODS: Single-pass method and HPCE. RESULTS: The solubilities of Phe, 5-OH-Trp and the four diastereomeric salts in CO2 were determined over temperature and pressure ranges of 25-50 degrees C and 6.32-34.03 MPa respectively. The experimental results showed that the solubilities of Phe, 5-OH-Trp and the four diastereomeric salts do not increase with density of CO2. There existed a maximum in the critical region of CO2. CONCLUSION: The dramatically high solubilities in the pressure of 6.32-7.78 MPa show a critical behavior, which can be explained by critical characteristic through thermodynamics analysis. The results suggest that the separation of Phe, 5-OH-Trp and the four diastereomeric salts is more efficient in critical region of CO2.

[Studies on chemical constituents in fruit of Eucalyptus globulus].

OBJECTIVE: AIM To study the chemical constituents of the fruit of Eucalyptus globulus. METHOD: Various column chromatographies with silica gel were employed for the isolation and purification. The structures of the compounds were elucidated with of spectral analyses and chemical methods. RESULT: Five compounds were isolated and elucidated as follows: betulonic acid (I), betulinic acid (II), ursolic acid (III), corosolic acid (IV), daucosterol (V). CONCLUSION: Compound I, II, III and IV were isolated from this plant for the first time.