ABSTRACT
@#Liver cholesterol metabolism disorder plays an important role in the development of non-alcoholic fatty liver disease (NAFLD).In order to reveal the molecular mechanism of cholesterol homeostasis imbalance induced by saturated fatty acids, HepG2 cells were stimulated with palmitic acid (PA).Lipids accumulation was analyzed by Oil Red O staining, intracellular triglyceride and cholesterol quantification.The level of genes and proteins related to cholesterol homeostasis was measured by RT-qPCR and western blotting.Additionally, intracellular bile acids and mitochondrial oxysterols were detected by LC-MS/MS.The results demonstrated that intracellular lipids such as TG and TC were significantly increased in the model with PA stimulation.Although no significant difference was detected in genes related to cholesterol synthesis and uptake, the protein expression of ABCG5 and LXRα were significantly down-regulated, indicating a decrease in cholesterol efflux.Meanwhile, the gene expression of STARD1 and CYP7B1, which are responsible for bile acid alternative synthesis, were markedly enhanced, along with a significant increase of cholesterol and 27-OHC in mitochondria and CDCA in cells.These results suggested that PA overload may disrupt cholesterol homeostasis by inhibiting cholesterol efflux and promoting bile acids synthesis.
ABSTRACT
@#In order to reveal the intestinal absorption mechanism of saikosaponin d (SSd) in vitro and in vivo, the current research investigated the effects of different experimental conditions (time, concentration, temperature, pH, intestinal segments), transporter inhibitors, paracellular pathway enhancer, metabolic enzyme inhibitors on the intestinal absorption of SSd, in Caco-2 monolayers and a single pass perfusion model in rats.The results showed that the apparent permeability coefficient (Papp) and effective permeability coefficient (Peff) of SSd were 4.75 × 10-7 - 6.38 × 10-7 cm/s and 0.19 × 10-4- 0.27 × 10-4 cm/s, respectively, indicating that it was a low permeability compound, and that the transmembrane transport of SSd was concentration-dependent (0.5-5 μmol/L) and time-dependent (0-180 min).Ileum was the main absorption site for SSd. Experimental results based on Caco-2 monolayers showed that the P-gp inhibitor and paracellular permeability enhancer significantly increased the absorption of SSd (P < 0.05), which was consistent with the results obtained in rats. Inhibitors of OATPs and OCTs showed different results in vitro and in vivo, which may be related to the lower expression of them in jejunum.In summary, the intestinal absorption of SSd occurs through a carrier-mediated and energy-dependent transport, as well as passive diffusion, and P-glycoprotein plays an important role in the active transport of SSd.
ABSTRACT
@#By silica gel column chromatography, solvent extraction and preparative high performance liquid chromatography (HPLC), four new related substance were isolated and purified from the mass production and preparation process of alogliptin benzoate. Then it was analyzed and confirmed by various spectrum identification methods such as nuclear magnetic resonance (NMR) spectroscopy, high-resolution mass spectrometry (HR-MS) and Fourier-transform infrared spectroscopy (FTIR) according to its physical and chemical properties. The chemical structures of the four related substances produced in each step of the synthesis process of alogliptin benzoate were determined, and they were named as impurities L, M, T, and V. These four related substances were new impurities which were found for the first time. The isolation and identification of these impurities are of great importance to the quality control of alogliptin benzoate, and the optimization of manufacturing process.
ABSTRACT
AIM: To study the HPLC fingerprints and establish a sensitive and specific method for the quality control of Andrographis paniculata(Burm.f.) Nees. METHODS: All 23 samples of Andrographis paniculata(Burm.f.) Nees collected from 10 different places were determined by RP-HPLC.Shimadzu-ODS column was used with maxtures of 0.1% formic acid-acetonitrile and 0.2% formic acid-water as mobile phase in gradient mode.The flow rate was set at 1.0 mL/min.The column temperature was set at 25℃ and detecting wavelength at 254 nm.Hierarchical clustering,nonlinear mapping and similarity criteria were applied to evaluate the fingerprints. RESULTS: The simple and specific method with good repeatability was established.There were different contents of each component contained in habitat samples produced in individual area. CONCLUSION: The proceeding is suitable to differentiate Andrographis paniculata(Burm.f.) Nees from different places conveniently and can be used for the quality control of this herb.