ABSTRACT
Objective: To determine the apparent oil/water(O/W)partition coefficient of hydroxytyrosol butyrate(HT-Bu), and investigate the solubility, dissolution tendency and stability of HT-Bu in different buffers, so as to provide theoretical basis for the preparation research of HT-Bu. Methods: The appearance and solubility of HT-Bu were investigated, and a high performance liquid chromatography(HPLC)method was established for the quantitative determination of HT-Bu. The solubility and O/W partition coefficient of HT-Bu in different pH buffer solutions were determined by the shakeing flask method. Results: HT-Bu was slightly yellow-colored, viscous, odorless and tasteless oily liquid. The quantitative HPLC method for the HT-Bu determination showed a good linearity within the concentration range of 5-50 μg/ml(r=0.9998). The apparent O/W partition coefficient of HT-Bu was 1.0. In the acetonitrilewater(60:40, V/V) solution, HT-Bu was stable within 12 hours at room temperature. In the different pH buffer solutions(pH 2.0-9.0), the solubility of HT-Bu increased at first and then decreased with the increase of the solution pH. HT-Bu was unstable at pH 5.5, with a large amount decomposed after kept in the solution for 6 h. HT-Bu was stable at pH 8, 0 giving a little amount decomposed after 12 h in the solution, and stable at pH 7.4 showing no significant decomposition after 12 h keeping in the solution. Conclusion: HT-Bu showed a good water solubility, which is unstable in acidic and alkaline solutions.
ABSTRACT
Objective To explore the role and mechanism of 17-allylamino-17-demethoxygeldanamycin (17-AAG) in neurons apoptosis induced by oxygen-glucose deprivation and recovery (OGD/R).Methods Primary rat neurons were cultivated in vitro,and OGD/R model was reproduced.Neurons were exposed to OGD for 0.5h,1h and 2h,and then reperfusion for 24h,the effect of OGD/R on neurons apoptosis was detected by TUNEL assay.On OGD/R,neurons were treated with different concentrations of 17-AAG (0.5,1.0 and 2.0μmol/L),and the effect of 17-AAG on OGD/R treated neurons apoptosis was detected by TUNEL assay.Western blotting was performed to detect the expression of heat shock protein 70 (HSP70).HSP70 interference lentivirus was then constructed.The effect of HSP70 interference on the neurons apoptosis treated with OGD/R and 17-AAG was detected by TUNEL assay.Results OGD/R significantly induced neurons apoptosis,and the rate of neurons apoptosis increased with the increase of OGD time.17-AAG obviously inhibited the neurons apoptosis induced by OGD/R,and the higher the 17-AAG concentration,the more obvious the inhibition.OGD/R significantly suppressed the expression of HSP70 protein in neurons,and 17-AAG obviously reversed the inhibition of HSP70 protein expression induced by OGD/R.However,HSP70 lentivirus interference markedly reversed the protective effect of 17-AAG on OGD/R treated neurons.Conclusion 17-AAG may inhibit the apoptosis of OGD/R treated neurons by up-regulating HSP70.