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Objective To explore the role of P-glycoprotein(P-gp)on cellular uptake and metabolism in the transmembrane transport of quercitrin.Methods Caco-2 cell monolayer and P-gp inhibitor Cyclosporin A(CysA)were used in the study.Quercitrin, quercetin,isorhamnetin and tamarixetin were determined by LC-MS to study cellular uptake and metabolism of quercitrin on Caco-2 cells.Results Uptake of quercitrin by Caco-2 cells:in different concentration groups of quercitrin coincubating with and without Cy?sA,intracellular accumulation presented the following characteristics:the amount of quercitrin first rose,reached the peak in 60 min and then declined to a steady-state in 120 min.And meanwhile there were significant differences between the two different processing groups incubating with and without CysA(P<0.05);quercetin was detected in all groups(3.0,9.0 and 27.0 mg/L).But in the higher concentration groups incubating with and without CysA,the intracellular quercetin presented a characteristics similar to its original glycosides and showed a significant difference(P<0.05),while the other groups showed no concentration-and time-dependence.At the same time,isorhamnetin and tamarixetin were detected in two higher concentration groups incubating with and without CysA, which showed the trend similar to the original glycosides but no significant difference was obtained between the two processing groups(P>0.05).Isorhamnetin and tamarixetin were not detected in the low and middle concentration groups.Transmembrane transport:on the basal lateral of all groups,the content of the quercitrin in 150 min incubation time showed a trend of continuous rise,and there was no significant difference between the two processing groups.Quercetin,isorhamnetin and tamarixetin were not detected.Conclu?sion Intact quercitrin could be absorbed into the Caco-2 cells and transported across the Caco-2 cell monolayer,and suffered a series of further metabolism in the Caco-2 cells and the basal side of Caco-2 cell monolayer,leading to different characteristics between intra?cellular accumulation and transmembrane transport.P-gp reduces the transmembrane transport of quercitrin by its efflux function,but did not involved in quercitrin metabolism.
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Objective To investigate the effect of procyanidin on permeability of rodamin 123(R123)and fluorescein sodium (FS)via different intestinal mucosa in rat. Methods The cumulative permeability and the apparent permeability cofficient(Papp)of R123 and FS via rat intestinal membranes at the procyanidin concentration of 20 mg/L was evaluated by the method of Ussing Cham?ber. The concentrations of R123 and FS in the receptor samples were determined by fluorospectrophotometry. Results The absorptive directed permeability of R123 across all membranes was increased by co-administration of procyanidins,whereas that of the secretive direct was decreased. Compared with control group,the secretive directed permeability of R123 was significantly decreased in colon (P<0.01). Conclusion Procyanidin could inhibit the secretion of R123 on different intestinal mucosa which might be related to the inhibition of P-gp function.
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Objective To investigate the effect of procyanidin on permeability of rodamin 123(R123)and fluorescein sodium (FS)via different intestinal mucosa in rat. Methods The cumulative permeability and the apparent permeability cofficient(Papp)of R123 and FS via rat intestinal membranes at the procyanidin concentration of 20 mg/L was evaluated by the method of Ussing Chamber. The concentrations of R123 and FS in the receptor samples were determined by fluorospectrophotometry. Results The absorptive directed permeability of R123 across all membranes was increased by co-administration of procyanidins, whereas that of the secretive direct was decreased. Compared with control group, the secretive directed permeability of R123 was significantly decreased in colon (P<0.01). Conclusion Procyanidin could inhibit the secretion of R123 on different intestinal mucosa which might be related to the inhibition of P-gp function.
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Objective The pathogenesis of intractable epilepsy was explored by examining the expression of the P-gp , GST-Pi as well as MDR1 in peripheral blood of the patients with intractable epilepsy. The potential of the above mentioned three genes as the biomarkers for treatment of intractable epilepsy was investigated. Methods Thirty-one sub?jects with refractory epilepsy, 33 subjects under good circumstances by antiepileptic drugs, and 37 healthy subjects were included in the present study. fluorescence quantitative polymerase chain reaction and flow cytometry were used to detect mRNA levels of MDR1 and GST-Pi and P-gp of MDR1 in the peripheral blood of the patients, respectively. Results The expression levels of MDR1 and GST-Pi were significantly higher in the AEDs intractable group(1.36±0.14,0.585±0.257) than in the treatment group(0.82±0.15,0.309±0.217, P<0.05)The expression levels of MDR1 and GST-Pi were signifi?cantly higher in the AEDs treatment group than in the normal group(0.27±0.07,0.134±0.223,P<0.05). The expression levels of P-gp were significantly higher in the AEDs of the intractable group(0.104±0.084)than in the treatment group (0.063 ± 0.030, P<0.05). The GST-Pi gene expression levels were significantly higher in three(0.535 ± 0.256)or two (0.425±0.254)kinds of antiepileptic drugs combination therapy than in single drug treatment(0.267±0.265, P<0.05). Leucocyte P-gp levels were significantly higher in combination therapy of three kinds of antiepileptic drugs(0.141 ± 0.096)than in combination therapy of two kinds of antiepileptic drugs(0.071±0.020)or in monotherapy(0.050±0.020, P<0.05). Conclusion MDR1 and GST-Pi gene expression levels of peripheral blood can be used as the reference in?dex for treatment of intractable epilepsy and the resistant index of combination treatment for intractable epilepsy.
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Flavonoids are constituents of fruits, vegetables, and plant derived beverages, as well as components in herbal dietary supplements. The objective of this investigation was to characterize and determine the effect of the Flavonoids on P-glycoprotein (P-gp) which is an important protein involved in multidrug resistance (MDR). Homology modeling of Pglycoprotein (Human) has been performed based on the crystal structure of the 2HYD (Chain A; Structure of a bacterial multidrug ABC transporter) by using Modeller software. With the aid of the molecular mechanics and molecular dynamics methods, the final model is obtained and is further assessed by procheck and verify 3D graph programs, which showed that the final refined model is reliable. With this model, a flexible docking study of P-glycoprotein with a group of Flavonoids which were selected from the previous publications was performed. The results indicated that GLN- 47, TYR -53, SER -83, ILE- 87, GLY -100, ARG -154 in P- glycoprotein are important determinant residues in binding as they have strong hydrogen bonding with Flavonoids. These hydrogen binding interactions play an important role for stability of the complex. Among the 13 Flavonoids docked, Acetylgenistin showed best docking result with Pglycoprotein. Our results may be helpful for further experimental investigations.
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Objective To investigate the reverse effect and mechanism of the extracted solution of chinese medicine MBC on the drug-resistance of K562/ADM in vitro. Methods MTT assay was used to determine the IC50 of ADM on K562/ADM cell line and the reverse multiples of the drug-resistance before and after MBC treatment. Flow cytometry(FCM) was applied to assess the intracellular concentration of Rh123. Results 8?10 -1 ?g/ml MBC increased cytotoxic effect of ADM on 562/ADM cells, the reverse multiple was 6 28, and MBC could increase the intracellular concentration of Rh123. Conclusion MBC could increase killing effect of ADM on the drug-resistant K562/ADM cell and partly reverse the drug-resistance of K562/ADM cell.
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three years survival group,and those who died within 3 yrs had P-gp positive expression(24 cases,53.3%).Comparing of the two groups showed statistical significance(P3 year survival stage group,and the patients who died within three years group,the P27 expression was positive in 26 cases(56.5%)(P