ABSTRACT
OBJECTIVE：To establish th e method for the determination of related substances in fidaxomicin raw material. METHODS：The detection ability of NP-HPLC-UV ，RP-HPLC-ELSD and RP-HPLC-UV systems for the related substances in fidamycin raw material was investigated and the best chromatographic system was selected . The HPLC detection method for the related substances was established. The detection was performed on Agilent Eclipse XDB C 18 column with mobile phase A consisted of 0.2％ triethylamine buffer solution （pH 3.8）-acetonitrile（55∶45，V/V），mobile phase B consisted of 0.2％ triethylamine buffer solution（pH 3.8）-acetonitrile（20∶80，V/V）at the flow rate of 1.0 mL/min（gradient elution ）；the detection wavelength was set at 230 nm，and column temperature was 35 ℃；the sample size was 10 µL. Calculation of the content of related substances was principal component self-control method without correction factor. RESULTS ：The impurities C and F could not be separated effectively in NP-HPLC-UV system. In RP-HPLC-ELSD system ，only impurities C ，D，E and F could be detected. In RP-HPLC-UV system ，11 impurities could be detected. In the study of methodology ，the linear ranges were 0.5-20.0 μg/mL for fidaxomicin（R2＝0.999 9）；the LOD was 0.05 ng，LOQ was 0.15 ng；RSDs of reproducibility and intermediate precision tests were less than 2.0％（n＝6）；average recovery was 98.4％（RSD＝3.6％，n＝9）. The sum of impurities in 3 batches of raw materials were 0.53％，0.51％，0.51％，respectively. CONCLUSIONS ：The effect of detecting impurities by RP-HPLC-UV are the best. Established method is specific and sensitive ，and can be used for the determination of related substance in fidaxomicin raw material.
ABSTRACT
To study the coumarins of Anemone raddeana Regel, the compounds were separated by silica gel column chromatography and HPLC. Their structures were identified by their physicochemical property and spectral analysis. Two new compounds were isolated and identified as 4, 7-dimethoxyl-5-methyl-6-hydroxy coumarin (1) and 4, 7-dimethoxyl-5-formyl-6-hydroxycoumarin (2). The bioassays indicated that compounds 1 and 2 could significantly inhibit the proliferation of cancer cell, and showed the agonist effect on the transactivity of retinoic acid receptor-alpha (RARalpha). In addition, the two compounds had inhibitory effect against human leukocyte elastase (HLE).
ABSTRACT
Objective:To investigate the effect of ethyl acetate extract from Cortex periplocae (CPEAE) on apoptosis of human esophageal carcinoma cell line TE-13 and to elucidate its mechanism. Methods:Inhibitory effect of CPEAE on TE-13 proliferation was tested by MTT assay. The morphological changes of cell apoptosis were observed by Giemsa staining and transmission electron microscopy. Cell cycle and apoptotic ratio were tested by flow cytometry (FCM). The protein expression of CDK4 was observed by Western blotting.Results:CPEAE inhibited proliferation of TE-13 cells in a concentration-dependent and time-dependent manner, and its IC_(50) value was (2.443±0.005) μg/mL at 48 h (P<0.05). The characteristic morphological changes of apoptosis were observed in TE-13 cells after treatment with CPEAE under transmission microscope. A typical subdiploid peak was detected by flow cytometry. CPEAE decreased the expression of gene CDK4 in TE-13 cells. Conclusion:CPEAE can induce apoptosis of TE-13 cells. The effect is related with down-regulation of CDK4 expression.