Simulation Analysis of Occupancy Rates of Baicalein， Quercetin and Galangin on Target Sites of Xanthine Oxidase / 中国实验方剂学杂志

Objective:To simulate the occupancy rates of baicalein， quercetin and galangin on the target sites of xanthine oxidase <italic>in vivo</italic>. Method:In this experiment， the half inhibitory concentration （IC₅₀） of febuxostat， baicalein， quercetin and galangin against xanthine oxidase were determined by <italic>in vitro</italic> enzymatic reaction. Binding free energy was predicted by molecular docking technology and their association rate constant （k_on） and dissociation rate constant （k_off） were determined by surface plasmon resonance technology. Based on measured binding kinetic parameters （k_on and k_off） and extracted pharmacokinetic data， the target occupancy model <italic>in vivo</italic> was established. Result:The IC₅₀values of febuxostat， baicalein， quercetin and galangin were 0.002 7， 1.63， 0.38， 1.59 µmol·L^-1， respectively. The IC₅₀ of febuxostat was very close to that reported in the literature. The predicted curve of target occupancy rate <italic>in vivo</italic> of febuxostat was consistent with its duration of clinical efficacy. When single intragastric administration of long-circulating liposomes of quercetin with dose of 100 mg·kg^-1 in rats， the time of target occupancy rate >70% <italic>in vivo</italic> lasted for about 3.9 h. When rats were orally administered baicalein and galangin with dose of 200 mg·kg^-1， the time of target occupancy rate >50% <italic>in vivo </italic>lasted for about 10 h and 1.7 h， respectively. Conclusion:The prediction model of xanthine oxidase target occupancy constructed by drug target binding kinetics and <italic>in vivo</italic> pharmacokinetic curves can effectively evaluate the <italic>in vivo</italic> inhibitory activity of compounds against the target.

Effect of Paiteling on HeLa Cell Proliferation and Metastasis Ability and PI3K/Akt Signal Transduction Pathway / 中国实验方剂学杂志

Objective:To explore the effect of Paiteling on the proliferation，metastasis and invasion of HeLa cells and relevant proteins of phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway. Method:① HeLa cells were divided into blank group and Paiteling concentration gradient groups (3.906，2.604，1.953，1.563，1.302，1.116，0.977 g·L-1). After drug intervention for 24 h，the cell morphological changes were observed under microscope. The cell viability was measured by thiazole blue (MTT) colorimetry，and the half inhibitory concentration (IC50) of Paiteling on HeLa cells was calculated. ② HeLa cells were divided into blank group，cisplatin group (0.01 g·L-1)，Paiteling high-dose group (2.974 g·L-1)，Paiteling medium-dose group (1.487 g·L-1) and Paiteling low-dose group (0.991 g·L-1). Cell proliferation and toxicity test (CCK-8) method was used to detect the effect of Paiteling on the proliferation ability of HeLa cells，scratch test was used to detect cell migration，and invasion test (Transwell) was used to detect changes in cell invasion ability. ③ Inhibitor LY294002 group (0.006 g·L-1) was added. Western blot (WB) was used to detect the expressions of Paiteling on PI3K，Akt，recombinant human B-cell lymphoma factor-xl (Bcl-xl)，and B-cell lymphoma/leukemia associated D protein (Bad). Result:① Compared with the blank group，microscopic observation showed that the number of cells in the treatment group was significantly reduced, and the cell morphology was incomplete. MTT experiments showed that Paiteling has a significantly inhibitory effect on HeLa cell proliferation (P<0.01). The IC50 of Paiteling on HeLa cells was calculated as 2.974 g·L-1. ② The CCK-8 experiment showed that compared with the blank group，all the drug-treated groups had an inhibitory effect on HeLa cell proliferation at 24，36，48 h (P<0.01), compared with the cisplatin group，middle and low-dose Paiteling groups showed a reduced inhibitory effect on HeLa cell proliferation at each time point (P<0.01). The scratch test showed that，compared with the blank group，each drug-added group could inhibit the migration ability of HeLa cells (P<0.01)，and the cell migration rate of the high-dose Paiteling group was lower than that of the cisplatin group (P<0.05). Transwell experiments showed that compared with the blank group，the number of membranes permeated by HeLa cells in each drug-treated group was decreased (P<0.01)，and the number of membranes permeated in the middle and low-dose Paiteling groups was increased compared with the cisplatin group (P<0.01). ③ Western blot showed that compared with the blank group，the expression levels of PI3K，Bcl-xl，and Akt in the high，medium，and low-dose Paiteling groups and the LY294002 group decreased (P<0.05，P<0.01)，while the expression of Bad increased (P<0.01). Compared with the high-dose Paiteling group，the PI3K，Akt，and Bcl-xl protein expressions were increased in the low-dose Paiteling group (P<0.01)，whereas Bad expression was decreased (P<0.01). Conclusion:Paiteling can inhibit HeLa cell proliferation，metastasis and invasion ability in a dose-dependent and time-dependent manner，which may be related to its effect on the expressions of PI3K/Akt signaling pathway-related proteins.