Sceptridium ternatum extract exerts antiasthmatic effects by regulating Th1/Th2 balance and the expression levels of leukotriene receptors in a mouse asthma model.

AIM OF THE STUDY: Sceptridium ternatum Lyon (ST), a common Chinese herb, has been used in treatment of allergic asthma and whooping cough. In the present study, we investigated the Th1/Th2 ratio of peripheral blood and mRNA levels of leukotriene receptors after the treatment of ST in allergic asthma mouse model. MATERIALS AND METHODS: Mouse asthma model was developed by ovalbumin (OVA) sensitization followed by the inhalation of aerosol allergen. Montelukast (10mg/kg), as a positive control drug, and ST were administrated six days before the OVA sensitization for ten days. Airway responsiveness was evaluated by the Medlab 12.0 biological signal processing system. The ratio of Th1/Th2 cells was determined by flow cytometry. The expression level of Cyslt1 was measured by PCR. Pathological changes of lung tissues were examined by H&E staining. RESULTS: ST significantly reduced the airway responsiveness, elevated the ratio of Th1/Th2, and decreased Cyslt1 mRNA level in a dose-dependent manner. High-dose ST distinctly prevented the pathological changes of lung tissues. CONCLUSION: High-dose ST had the same efficacy as Montelukast in a mouse asthma model, and ST could be a potential anti-asthmatic agent.

Insights into the binding of paclitaxel to human serum albumin: multispectroscopic studies.

The interaction of paclitaxel with human serum albumin (HSA) was studied using fluorescence, resonance light scattering, ultraviolet-visible, circular dichroism and Fourier transform infrared spectroscopy at pH 7.4. Fluorescence data revealed that the fluorescence quenching of HSA by paclitaxel was a static quenching procedure. Time-resolved fluorescence data also confirmed the quenching mode, which present a constant decay time of about 5 ns. The binding sites were approximately 1 and the binding constant suggested a weak association (324/M at 298 K), which is helpful for the release of the drug to targeted organs. The thermodynamic parameters, ΔG(○), ΔH° and ΔS° were calculated as - 1.06 × 10(4) J/mol, 361 J/mol per K and 9.7 × 10(4) J/mol respectively at 298 K, suggesting that binding was spontaneous and was driven mainly by hydrophobic interactions. The binding distance between HSA and paclitaxel was determined to be 2.23 nm based on the Förster theory. Analysis of circular dichroism, ultraviolet-visible, three-dimensional fluorescence, Fourier transform infrared and resonance light scattering spectra demonstrated that HSA conformation was slightly altered in the presence of paclitaxel and dimension of the individual HSA molecules were larger after interacting with paclitaxel. These results were confirmed by a molecular docking study.