This article introduces the independent experiment and social investigation activities in the course of medication analy- sis set up for strengthening students' comprehensive abilities.These activities create a good study atmosphere for enhancing stu- dents' ability to do research and their humanistic qualities.

Acetaminophen ; metabolism ; Animals ; Cells, Cultured ; Drug Interactions ; Flavonoids ; metabolism ; Hepatocytes ; metabolism ; Humans

To establish single- and double-transfected transgenic cells stably expressing hMATE1, hMATE1 cDNA was cloned by RT-PCR from human cryopreserved kidney tissue, and subcloned into pcDNA3.1(+) plasmid by virtue of both HindIII and Kpn I restriction enzyme sites. Subsequently, the recombined pcDNA3.1(+)- hMATE1 plasmid was transfected into MDCK, MDCK-hOCT1 or MDCK-hOCT2 cells using Lipofectamine 2000 Reagent. After a 14-day-cultivation with hygromycin B at the concentration of 400 µg · mL(-1), all clones were screened with DAPI and MPP+ as substrates to identify the best candidate. The mRNA content of hMATE1, the cellular accumulation of metformin with or without cimetidine as inhibitor, or transportation of cimetidine was further valuated. The results showed that all of the three cell models over expressed hMATE1 mRNA. The cellular accumulation of metformin in MDCK-hMATE1 was 17.6 folds of the control cell, which was significantly inhibited by 100 µmol · L(-1) cimetidine. The transcellular transport parameter net efflux ratios of cimetidine across MDCK-hOCT1/hMATE1 and MDCK-hOCT2/hMATE1 monolayer were 17.5 and 3.65, respectively. In conclusion, cell models with good hMATE1 function have been established successfully, which can be applied to study the drug transport or drug-drug interaction involving hMATE1 alone or together with hOCT1/2 in vitro.
Animals ; Biological Transport ; Cimetidine ; pharmacology ; DNA, Complementary ; Dogs ; Drug Interactions ; Humans ; Madin Darby Canine Kidney Cells ; Metformin ; pharmacology ; Organic Cation Transport Proteins ; genetics ; metabolism ; Transfection

OBJECTIVETo observe the content variation of luteolin and luteolin-7-beta-D-glucoside in Chrysanthemum morifolium Ramat. (CMR) from different collection time.

METHODSRP-HPLC was used to analyze these two components in CMR collected in 2001 and 2002.

RESULTThe content of luteolin was significantly lower than that of luteolin-7-beta-D-glucoside. Furthermore, the former showed no marked changes during collection, while the latter did not varied markedly in early collection but decreased significantly in later collection.

CONCLUSIONThe content of luteolin-7-beta-D-glucoside reflects the quality of Chrysanthemum morifolium Ramat. more viably than that of luteolin.

Chromatography, High Pressure Liquid ; Chrysanthemum ; chemistry ; Flavonoids ; analysis ; Glucosides ; analysis ; Luteolin

AIMTo search for flavonoids which possess stronger vasorelaxation action.

METHODSFour quercetin glycosides (1a - d) were synthesized from quercetin in three steps i. e. selective protection of quercetin, condensation with corresponding acetyiglycosyl bromide, and then removal of the protecting group; Six flavone compounds (2a - f) were prepared from phloroglucinol according to the conventional methods; The structures of synthetic compounds were confirmed by IR, 1H NMR, 13C NMR and MS. Vasorelaxation action of ten synthetic quercetin derivatives (or analogues) and four natural flavonoids compounds were examined on the isolated rat thoracic aorta rings; Comparative octanol-water partition coefficients (logP) were measured using a reversed-phase HPLC method.

RESULTSMost of the tested flavonoids showed concentration dependent relaxation effects against PE-induced contractions of rat aortic rings. These compounds had stronger action with the augment of logP values.

CONCLUSIONCompound 3-bromo-5 ,7-dihydroxyflavone (2d) was identified to have the most potent vasodilating action. These compounds exert vasodilating effects that are related to the logP values. A structure-activity relationship of flavonoids was suggested.

Animals ; Aorta, Thoracic ; drug effects ; Dose-Response Relationship, Drug ; Flavonoids ; chemical synthesis ; chemistry ; pharmacology ; Male ; Molecular Conformation ; Molecular Structure ; Quercetin ; administration & dosage ; analogs & derivatives ; chemical synthesis ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Structure-Activity Relationship ; Vasodilation ; drug effects ; Vasodilator Agents ; administration & dosage ; chemical synthesis ; pharmacology

OBJECTIVETo determine the possible difference in vasodialtation effect of quercetin and rutin.

METHODSThe isolated rat thoracic aorta was treated with phenylephrine (PE), and the effects of quercetin and rutin on the preconstricted aorta rings with or without endothelium were determined by organ bath technique. Nitric oxide synthase inhibitor L-N(G)-nitroarginine methyl-ester (L-NAME), guanylyl cyclase inhibitor methylene blue, cyclooxygenase inhibitor indomethacin were used to explore the mechanism.

RESULTSQuercetin (10-160 micromol/L) caused vasorelaxation of aorta rings preconstricted with PE in endothelium-intact and denuded aorta rings in a dose-dependent manner. Rutin(10-160 micromol/L) caused dose-dependent vasorelaxation in endothelium-intact rings preconstricted with phenylephrine, but not in denuded aorta rings. The maximal response (Rmax) values calculated from vasorelaxation curves of quercetin and rutin were (77.20+/-6.11)% and (44.28+/-7.48)%, respectively. There was no difference between median effective concentration (EC(50)) values of quercetin and rutin. Pretreatment with L-NAME (0.1 mmol/L) abolished the vasorelaxation by rutin,but did not influence the vasodilating effect of quercetin in endothelium-intact rings. Pretreatment with methylene blue (10 mmol/L) canceled the vasorelaxation both by quercetin and rutin. Pretreatment with indomethacin (10 micromol/L) attenuated the vasodilatation of quercetin, but did not affect the vascular effect of rutin.

CONCLUSIONThe vasodilatation effect of quercetin is more potent than rutin. The vasodilatation effect of quercetin might be mediated by guanylyl cyclase and cyclooxygenase-dependent pathway, while the vasodilatation by rutin might be via nitric oxide-guanylyl cyclase pathway.

Animals ; Aorta, Thoracic ; drug effects ; Dose-Response Relationship, Drug ; Guanylate Cyclase ; metabolism ; In Vitro Techniques ; Male ; Nitric Oxide ; metabolism ; Phenylephrine ; pharmacology ; Prostaglandin-Endoperoxide Synthases ; metabolism ; Quercetin ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Rutin ; pharmacology ; Vasodilator Agents ; pharmacology

OBJECTIVETo investigate the inhibitive and inductive effect of (-)-tetrahydropalmatine (THP) and (+)-THP on main CYP450 isoforms in mouse liver microsomes.

METHODSThe in vitro inhibitory effect was evaluated by incubating (-)-THP or(+)-THP with the probe substrates of main phase I metabolic enzymes in mouse liver microsomes, and the remaining substrates were determined by HPLC or LC-MS/MS method. Mice were administered with (-)-THP or(+)-THP at dosage of 240 mg/kg or 60 mg/kg by gastric lavage for successive 7 days, then the cocktail-LC-MS method was applied to assess the activities of main CYP450 isoforms in mouse liver microsomes.

RESULTThe IC(50) values of both (-)-THP and (+)-THP on isoforms studied were higher than 100 μmol/L except that IC(50) value of (+)-THP on CYP2C was 43.89 μmol/L, indicating weak inhibition of (-)-THP and (+)-THP on CYP1A2, CYP2D22, CYP2E1 and CYP3A11 in vitro. Compared with the vehicle group, the activities of CYP2D22, CYP2E1 and CYP3A11 were not increased significantly in (-)-THP and (+)-THP treatment groups, while the activities of CYP1A2 in 60 mg/kg and 240 mg/kg (-)-THP groups were 68.7% and 73.0% higher, than that of the vehicle group (P < 0.05, P < 0.01, respectively), the activity of CYP2C37 in 240 mg/kg (-)-THP treatment group was 80.4%, higher than that of the vehicle group (P < 0.05).

CONCLUSIONThere is negligible or weak inhibition on main CYP450 in mouse liver microsomes by (-)-THP and (+)-THP in vitro. (+)-THP does not induce main CYP450 in mouse liver microsomes while (-)-THP weakly induces CYP1A2 and CYP2C37.

Animals ; Berberine Alkaloids ; pharmacology ; Cytochrome P-450 Enzyme System ; drug effects ; metabolism ; Male ; Mice ; Mice, Inbred ICR ; Microsomes, Liver ; drug effects ; enzymology

OBJECTIVETo establish a chiral separation method for determination of fluvastatin enantiomer with in vitro cellular model.

METHODSThe determination was performed on Chiralpak AD column (4.6 mm × 250 mm); and the phase consisted of hexane-isopropanol-trifluoroacetic acid (90:10:0.1) at a flow rate of 0.5 ml/min with UV detection of 239 nm.

RESULTThe standard curve was linear over the concentration range of 20 μmol/L-300 μmol/L (r² = 0.9993, r² = 0.9997). The recovery for this assay was (99.4 ± 0.8)%, precision for inter-assay and intra-assay was <10 %.

CONCLUSIONThe normal-phase HPLC chiral separation method was accurate and suitable for study on the stereoselectivity of fluvastatin with in vitro cellular model.

Cells, Cultured ; Chromatography, High Pressure Liquid ; methods ; Fatty Acids, Monounsaturated ; isolation & purification ; Indoles ; isolation & purification ; Stereoisomerism

OBJECTIVETo develop a RP-HPLC method for the determination of quercetin in UGT1A3 cDNA-transfected cells.

METHODSThe lysate of cells transfected with human recombinant uridine 5-diphosphate glucuronosyltransferases UGT1A3 cDNA was co-incubated with quercetin, the reaction was terminated with acetonitrile, and luteolin was used as internal standard. The determination was performed on a C(1) reversed phase column with a mobile phase of methanol-0.1% formic acid (V/V) at a flow rate of 1.0 ml/min. The gradient elution was as follows: 0 - 25 min (30:70-80:20, methanol:0.1% formic acid), > 25-25.5 min (80:20), >25.5-27 min (80:20-30:70), > 27-30 min (30:70). A UV-VIS detector was operated at 368 nm.

RESULTThe standard curve was linear over the concentration range of 5-200 μmol/L (r = 0.9999). The limit of detection was 1.25 μmol/L(S/N ≥ 3), and the limit of quantification was 5 μmol/L (S/N >10, RSD = 6.99%). The method afforded recoveries of 99.1%-103.5%, and precisions for inter- and intra-assay were < 2.5% and < 8%, respectively. In addition, kinetic analysis indicated that the K(m), V(max) and CL(int) (V(max)/K(m)) values for quercetin glucuronide were (62.95 ± 13.16) μ mol/L, (284.50 ± 24.35)nmol*min⁻¹*g⁻¹ and 4.52 ml*min⁻¹*g⁻¹, respectively.

CONCLUSIONThe method established is accurate and simple and suitable for the determination of quercetin in UGT1A3 cDNA-expressed cells.

Cells, Cultured ; Chromatography, High Pressure Liquid ; methods ; Glucuronosyltransferase ; genetics ; Humans ; Quercetin ; analysis ; pharmacokinetics ; Transfection

OBJECTIVETo determine and compare the content of luteolin-7-O-beta-D-glucoside and apigenin-7-O-beta-D-glucoside in Flos Chrysanthemi from different collection time, sources, grades and processes.

METHODThe contents were determined by RP-HPLC. Zorbax SB C18 column (4.6 mm x 250 mm, 5 microm) was used as analysis column, the mobile phase was acetonitrile-pH 2.0 phosphate buffer solution with gradient elution, the detector was set at 338 nm.

RESULTThe contents of two components changed at some degree in Flos Chrysanthemi from different collection time, different plant sites or with different grades, while the contents varied obviously among Flos Chrysanthemi from different source and different sorts. No obvious difference was found in Flos Chrysanthemi from different year.

CONCLUSIONThe contents of two components were influenced by process, plane site, source and sorts, especially by source and sorts.

Apigenin ; analysis ; China ; Chrysanthemum ; chemistry ; Drug Compounding ; Ecosystem ; Flowers ; chemistry ; Glucosides ; analysis ; Luteolin ; analysis ; Plants, Medicinal ; chemistry ; Seasons