Accumulation of nitidine chloride in rat heart and the underlying mechanism / 药学学报

Nitidine chloride (NC) is a compound with prominent anti-tumor activity. To determine potential cardiotoxicity of NC, this study was designed to investigate the distribution of NC in rat heart and the underlying mechanism. The animal studies were approved by Institutional Animal Care and Use Committee of Zhejiang University Medical Center (2015-380-01) and complied with the standards of animal welfare in China. At 0.25, 0.5 and 2 h after a single intravenous injection (iv) of 5 mg·kg-1 NC, the concentrations of NC in rat heart were 47.7, 71.1 and 63.2 μg·g-1 respectively, which were 576, 1 352 and 1 212 folds of that in plasma. This study also revealed that the NC concentration in heart was 458.5 μg·g-1 (7 336 folds of that in plasma) at 2 h after the last dose in rats, after daily iv administration of NC at 5 mg·kg-1·day-1 for successive 20 days. Further studies showed that the accumulations of NC in MDCK-hOCT1 and MDCK-hOCT3 cells were 16.1 and 4.99 folds higher than that of the mock cells, respectively. There is no significant difference between the accumulations of NC in MDCK cells transfected with hOCTN1, hOCTN2 or hPMAT and the mock cells. Additionally, quinidine, L-tetrahydropalmatine and Decynium 22, the inhibitors of OCTs, clearly reduced the accumulations of NC in primary cardiomyocytes and cardiac fibroblasts from neonatal rats. MTT assay showed that the LC50 of NC on cardiomyocytes and cardiac fibroblasts were 10.9 and 10.4 μmol·L-1, respectively. Moreover, treatment of the primary cardiomyocytes and cardiac fibroblasts with NC (1～15 μmol·L-1) for 48 h resulted in significantly increased LDH enzyme leakage. These results indicated that NC can be highly accumulated in the heart, and accumulation is mediated by OCT1 and OCT3, but not by OCTN1, OCTN2 and PMAT. The accumulated NC has potential cytotoxicity as shown in the results from primary cardiomyocytes and cardiac fibroblasts.

Mechanism for ginkgolic acid (15 : 1)-induced MDCK cell necrosis: Mitochondria and lysosomes damages and cell cycle arrest / 中国天然药物

Ginkgolic acids (GAs), primarily found in the leaves, nuts, and testa of ginkgo biloba, have been identified with suspected allergenic, genotoxic and cytotoxic properties. However, little information is available about GAs toxicity in kidneys and the underlying mechanism has not been thoroughly elucidated so far. Instead of GAs extract, the renal cytotoxicity of GA (15 : 1), which was isolated from the testa of Ginkgo biloba, was assessed in vitro by using MDCK cells. The action of GA (15 : 1) on cell viability was evaluated by the MTT and neutral red uptake assays. Compared with the control, the cytotoxicity of GA (15 : 1) on MDCK cells displayed a time- and dose-dependent manner, suggesting the cells mitochondria and lysosomes were damaged. It was confirmed that GA (15 : 1) resulted in the loss of cells mitochondrial trans-membrane potential (ΔΨm). In propidium iodide (PI) staining analysis, GA (15 : 1) induced cell cycle arrest at the G0/G1 and G2/M phases, influencing on the DNA synthesis and cell mitosis. Characteristics of necrotic cell death were observed in MDCK cells at the experimental conditions, as a result of DNA agarose gel electrophoresis and morphological observation of MDCK cells. In conclusion, these findings might provide useful information for a better understanding of the GA (15 : 1) induced renal toxicity.

Establishment and application of cell models with stable expression of hOCTN1/2 / 药学学报

Human carnitine/organic cation transporter 1 and 2(hOCTN1 and hOCTN2) mediate transport of endogenous and exogenous compounds. The present study aimed to establish cell models with stable expression of hOCTN1 or hOCTN2 to study interactions with compounds and transporters. MDCK cells were transfected with pcDNA3.1(+) plasmid vector containing hOCTN1 or hOCTN2(pcDNA3.1(+)-hOCTN1/2), several stable transfected clones were obtained after G418 screening. hOCTN1 and hOCTN2 clones were screened with ergothioneine and mildronate respectively as substrates to identify the best candidates. We explored interactions of endogenous substances, alkaloids, flavonoids and ACEIs with hOCTN1/2. As a result, the cellular accumulation of ergothioneine in MDCK-hOCTN1 or mildronate in MDCK-hOCTN2 was 122 and 108 folds of the control cells, respectively. The kinetic parameters, Km and Vmax of ergothioneine, mediated by MDCK-hOCTN1, were 8.19±0.61 μmol·L-1 and 1427±49 pmol·mg-1(protein)·min-1; while Km and Vmax of mildronate by MDCKhOCTN2 were 52.3±4.3 μmol·L-1 and 2454±64 pmol·mg-1(protein)·min-1. Dopamine, glutamine, piperine, berberine, nuciferine, lisinopril and fosinopril could inhibit ergothioneine or mildronate uptake by MDCKhOCTN1/2. In conclusion, cell models with good stable hOCTN1 and hOCTN2 functions have been established successfully, which can be applied to the study of interactions between compounds and transporters of hOCTN1 and hOCTN2.

Expression and regulation of drug transporters in placenta / 药学学报

Placenta, an important organ, mediates the exchange of nutrients and metabolites between mother and fetus. The transporters, including ATP-binding cassette (ABC) transporters and solute carrier (SLC), expressed in the syncytiotrophoblast play a vital role in substance exchange. Some transporters, such as organic cation transporters (OCTs) and organic anion transporters (OATs), mediate the uptake of endogenous substances and drugs. Some transporters, such as P-glycoprotein (P-gp), breast cancer resistance protein (BCRP) and multidrug resistance-associated proteins (MRPs), can excrete their substrates from the syncytiotrophoblast to the maternal circulation. However, the expression and activity of these transporters are not uniform throughout the gestation period, since they can be affected by physiological and pathological changes during pregnancy or drugs. Thus, an understanding of the role of placental transporters and the variation in their expression and activity in response to physiological and pathological changes is essential for efficient and safe therapy during pregnancy, and it also has important value in the development of drug treatment in pregnancy.

Screening and verifying potential NTCP inhibitors from herbal medicinal ingredients using the LLC-PK1 cell model stably expressing human NTCP / 中国天然药物

NTCP is specifically expressed on the basolateral membrane of hepatocytes, participating in the enterohepatic circulation of bile salts, especially conjugated bile salts, to maintain bile salts homeostasis. In addition, recent studies have found that NTCP is a functional receptor of HBV and HDV. Therefore, it is important to study the interaction between drugs and NTCP and identify the inhibitors/substrates of NTCP. In the present study, a LLC-PK1 cell model stably expressing human NTCP was established, which was simple and suitable for high throughput screening, and utilized to screen and verify the potential inhibitors of NTCP from 102 herbal medicinal ingredients. The results showed that ginkgolic acid (GA) (13 : 0), GA (15 : 1), GA (17 : 1), erythrosine B, silibinin, and emodin have inhibitory effects on NTCP uptake of TCNa in a concentration-dependent manner. Among them, GA (13 : 0) and GA (15 : 1) exhibited the stronger inhibitory effects, with IC50 values being less than 8.3 and 13.5 μmol·L(-1), respectively, than the classical inhibitor, cyclosporin A (CsA) (IC50 = 20.33 μmol·L(-1)). Further research demonstrated that GA (13 : 0), GA (15 : 1), GA (17 : 1), silibinin, and emodin were not substrates of NTCP. These findings might contribute to a better understanding of the disposition of the herbal ingredients in vivo, especially in biliary excretion.

Establishment of MDCK cell models expressing human MATE1 or co-expressing with human OCT1 or OCT2 / 药学学报

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.

In vitro interaction of deferiprone with cellular membrane transporters of hOCTs and hOAT1 / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To develop a LC-MS/MS method for determination of deferiprone in cell lysate and to study the potential interaction between deferiprone and hOCTs or hOAT1 transporters in vitro.</p><p><b>METHODS</b>The determination was performed on an Agilent Eclipse Plus C18 column(3.5 μm, 2.1 mm×50 mm).The gradient mobile phase was composed of solvent A:0.1% formic acid in water, and B:0.1% formic acid in acetonitrile. The mass spectrometer with an electrospray interface was operated in positive ion mode with multiple reaction monitoring (MRM) scan mode monitored the ion pair of deferiprone at m/z 140→96, or phenacetin at m/z 180→110. The effects of deferiprone on the accumulation of typical substrates of hOCTs and hOAT1 were evaluated by MDCK-hOCTs and MDCK-hOAT1 cells respectively. The accumulation of deferiprone was also investigated in MDCK-hOCTs cells and mock cells with or without typical inhibitors.</p><p><b>RESULTS</b>The standard curve was linear over the range of 5-300 nmol/L. The assay recovery of deferiprone was above 94%, and the intra-day precision (RSD) was less than 2.0%. The accumulation of MPP(+) in MDCK-hOCTs cells with 300 μmol/L deferiprone were 73.5%, 87.1% and 70.4%, respectively. The uptake of deferiprone in MDCK-hOCTs and mock cells did not show significant difference. Deferiprone of 100 μmol/L did not significantly affect the accumulation of 6-CF in MDCK-hOAT1 cell.</p><p><b>CONCLUSION</b>The method is sensitivity and suitable for the determination of deferiprone in cell lysate. Deferiprone can significantly inhibit hOCT1 and hOCT3, but has no effects on hOCT2 and hOAT1. hOCTs may not play a major role in the transport of deferiprone.</p>

The role of ADME evaluation in translation research of innovative drug / 药学学报

New Chemical Entities (NCEs) development is a systematic long-term project that involves multiple disciplines. The translation research will help to build an advanced R&D system from the basic laboratory research, preclinical studies and clinical evaluation to clinical application of drug, for the purpose of shortening the R&D cycle and accelerate the launch of new drugs. In new drug R&D and its clinical application, drug disposition (absorption, distribution, metabolism, excretion, ADME) properties are important criteria for assessing drug-likeness of candidates. ADME evaluation of NCEs plays an important role in the translation research throughout innovative drug R&D process. Therefore, ADME evaluation at the early stage of drug design and development will be helpful to improve the success rate and reduce costs, and further access to safe, effective drugs.

Determination of quercetin metabolism in UGT1A3 cDNA-expressing cells by RP-HPLC / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To develop a RP-HPLC method for the determination of quercetin in UGT1A3 cDNA-transfected cells.</p><p><b>METHODS</b>The 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.</p><p><b>RESULT</b>The 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.</p><p><b>CONCLUSION</b>The method established is accurate and simple and suitable for the determination of quercetin in UGT1A3 cDNA-expressed cells.</p>

Chiral separation of fluvastatin enantiomers with in vitro cellular method / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To establish a chiral separation method for determination of fluvastatin enantiomer with in vitro cellular model.</p><p><b>METHODS</b>The 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.</p><p><b>RESULT</b>The 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 %.</p><p><b>CONCLUSION</b>The normal-phase HPLC chiral separation method was accurate and suitable for study on the stereoselectivity of fluvastatin with in vitro cellular model.</p>

Inhibitory and inductive effects of (-)- and (+)-tetrahydropalmatine on CYP450 in mice / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the inhibitive and inductive effect of (-)-tetrahydropalmatine (THP) and (+)-THP on main CYP450 isoforms in mouse liver microsomes.</p><p><b>METHODS</b>The 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.</p><p><b>RESULT</b>The 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).</p><p><b>CONCLUSION</b>There 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.</p>

Antiarrhythmic effect of ethyl acetate extract from Chrysanthemum Morifolium Ramat on rats / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effect of ethyl acetate extract from Chrysanthemum Morifolium Ramat (CME) on experimental arrhythmia induced by ischemia/reperfusion or aconitine in rats and to explore its underlying mechanisms.</p><p><b>METHODS</b>Arrhythmia model in intact rat was induced by aconitine (30 microg/kg body weight, i.v.). In isolated Langendorff perfused rat hearts, regional ischemia and reperfusion was induced by ligation and release of left anterior descending artery. The ventricular fibrillation threshold (VFT), effective refractory period (ERP), and diastolic excitation threshold (DET) in the isolated heart were measured. The action potentials of papillary muscle in rat right ventricle were recorded by conventional glass microelectrode technique.</p><p><b>RESULTS</b>Compared with control group CME significantly decreased the number and duration of ventricular tachycardia (VT); delayed the occurrence of ventricular premature beats (VPB) and VT induced by aconitine. Arrhythmia score of the CME group was lower than that in aconitine-treated group. CME markedly prolonged the ERP and increased the VFT in the isolated perfused rat hearts during ischemia and reperfusion. CME prolonged action potential duration at 50% and 90% repolarization of the right ventricular papillary muscles and decreased the maximal rate of rise of the action potential upstroke, but did not affect the resting potential, amplitude of action potential.</p><p><b>CONCLUSION</b>CME can reduce myocardial vulnerability and exerts its antiarrhythmic effects induced by aconitine or ischemia/reperfusion, which may be related to its prolongation of action potential duration and effective refractory period that enhance the electrophysiological stability of myocardiaium.</p>

Determination of bis (p-fluorobenzyl) trisulfide and bis (p-fluoro-benzyl) disulfide in lungs of rat by HPLC / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To establish an HPLC method for analysis of bis(p-fluorobenzyl) trisulfide(BFTS) and bis(p-fluorobenzyl)disulfide(BFDS) in the lungs of rat.</p><p><b>METHODS</b>5.0 ml extract solvent (n-hexane: isopropyl alcohol=95:5, v/v) and 20 microl of 11.50 microg/ml dibenzyl disulfide (internal standard) were added to 0.2 g lung sample followed by homogenization. After centrifugation, 4.0 ml of supernatant was separated and vaporized to dryness, and the residue was reconstituted in mobile phase for HPLC analysis. The HPLC analysis was performed on an SB C18 column using acetonitrile and water (65:35, v/v) as mobile phase with a flow rate of 1.0 ml/min with UV detection at 220 nm.</p><p><b>RESULT</b>The calibration curves for BFTS and BFDS in sample were linear over the concentration ranges of 0.04712-14.78 microg/g(r=0.999) and 0.04831-23.96 microg/g(r=0.999), respectively. The limits of quantification were 0.04712 microg/g and 0.04831 microg/g for BFTS and BFDS, respectively. The assay recoveries for BFTS and BFDS ranged from 95.71%-107.2% and 90.00%-110.5%, respectively. The precisions were obtained with RSD of <10%. The developed method was successfully applied to study the content of BFTS and BFDS in the lungs of rats after intravenous injection of 12.5 mg/kg BFTS.</p><p><b>CONCLUSION</b>The method developed is simple, selective, repeatable and accurate, which can be applied to study the tissue distribution of BFTS and BFDS.</p>

Vascular effect of extract from mulberry leaves and underlying mechanism / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the vascular activity of extract from mulberry leaves (EML) on rat thoracic aorta and the underlying mechanism.</p><p><b>METHODS</b>Isolated thoracic rings of Sprague-Dawley rats were mounted on the organ bath and the tension of the vessel was recorded.</p><p><b>RESULT</b>(1) EML produced a concentration-dependent vasorelaxation of aorta preconstricted by high K(+) (60 mmol/L) or 10(-6) mol/L phenylephrine (PE) in endothelium-intact and endothelium-denuded arteries. (2) EML at EC(50) concentration reduced the calcium dose-response curve. (3) After incubation of aorta with verapamil, EML induced vasocontraction of aorta preconstricted by PE, which was abolished by ruthenium red.</p><p><b>CONCLUSION</b>The vascular effect of EML is biphasic, the vasorelaxation is greater than the vasocontraction. The vasorelaxation induced by EML may be mediated by inhibition of voltage-and receptor-dependent calcium channels in vascular smooth muscle cells, while the vasocontraction is via activation of ryanodine receptor in endoplasmic reticulum.</p>

Difference absorption of l-tetrahydropalmatine and dl-tetrahydropalmatine in intestine of rats / 药学学报

To investigate the difference in absorptive of tetrahydropalmatine (THP) and l-tetrahydropalmatine (l-THP) in rat intestine as well as the mechanism of the absorption of THP, in situ single pass perfusion model was used and the concentration of THP in perfusate was determined by HPLC. The absorption rate constant (k(a)) and effective permeability values (P(eff)) of THP had no significant difference (P > 0.05) at concentration of 8, 16 and 32 microg x mL(-1) in perfusion or in four different regions of intestine of rat (duodenum, jejunum, ileum, colon). The absorption of l-THP and THP in jejunum had significant difference (P < 0.05). The k(a) and P(eff) of THP increased obviously when verapamil was co-perfused with THP, while those of l-THP were not influenced by verapamil. The absorption of THP in intestine showed the passive diffusion process, and without a special absorption region. The stereoselective absorption difference may result from stereoselective combination of P-glycoprotein with d-THP.

Comparison of vasodilatation effect between quercetin and rutin in the isolated rat thoracic aorta / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To determine the possible difference in vasodialtation effect of quercetin and rutin.</p><p><b>METHODS</b>The 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.</p><p><b>RESULTS</b>Quercetin (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.</p><p><b>CONCLUSION</b>The 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.</p>

Determination of main flavone glycosides in Flos Chrysanthemi and observation of factors influenced contents / 中国中药杂志

<p><b>OBJECTIVE</b>To 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.</p><p><b>METHOD</b>The 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.</p><p><b>RESULT</b>The 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.</p><p><b>CONCLUSION</b>The contents of two components were influenced by process, plane site, source and sorts, especially by source and sorts.</p>

Cultivation of Students' Comprehensive Abilities in Independence Experiment and Practice / 中华医学教育探索杂志

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.

Synthesis and vasorelaxation action of flavonoids / 药学学报

<p><b>AIM</b>To search for flavonoids which possess stronger vasorelaxation action.</p><p><b>METHODS</b>Four 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.</p><p><b>RESULTS</b>Most 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.</p><p><b>CONCLUSION</b>Compound 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.</p>

Determination of luteolin and luteolin-7-beta-D-glucoside in Chrysanthemum morfolium Ramat. from different collection time by RP-HPLC / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To observe the content variation of luteolin and luteolin-7-beta-D-glucoside in Chrysanthemum morifolium Ramat. (CMR) from different collection time.</p><p><b>METHODS</b>RP-HPLC was used to analyze these two components in CMR collected in 2001 and 2002.</p><p><b>RESULT</b>The 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.</p><p><b>CONCLUSION</b>The content of luteolin-7-beta-D-glucoside reflects the quality of Chrysanthemum morifolium Ramat. more viably than that of luteolin.</p>