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<p><b>OBJECTIVE</b>To study the effect of allitridum on rapidly delayed rectifier potassium current (IKr) in HEK293 cell line.</p><p><b>METHODS</b>HEK293 cells were transiently transfected with HERG channel cDNA plasmid pcDNA3.1 via Lipofectamine. Allitridum was added to the extracellular solution by partial perfusion after giga seal at the final concentration of 30 µmol/L. Whole-cell patch clamp technique was used to record the HERG currents and gating kinetics before and after allitridum exposure at room temperature.</p><p><b>RESULTS</b>The amplitude and density of IHERG were both suppressed by allitridum in a voltage-dependent manner. In the presence of allitridum, the peak current of IHERG was reduced from 73.5∓4.3 pA/pF to 42.1∓3.6 pA/pF at the test potential of +50 mV (P<0.01). Allitridum also concentration-dependently decreased the density of the IHERG. The IC50 of allitridum was 34.74 µmol/L with a Hill coefficient of 1.01. Allitridum at 30 µmol/L caused a significant positive shift of the steady-state activation curve of IHERG and a markedly negative shift of the steady-state inactivation of IHERG, and significantly shortened the slow time constants of IHERG deactivation.</p><p><b>CONCLUSION</b>Allitridum can potently block IHERG in HEK293 cells, which might be the electrophysiological basis for its anti-arrhythmic action.</p>
Subject(s)
Humans , Allyl Compounds , Pharmacology , Anti-Arrhythmia Agents , Delayed Rectifier Potassium Channels , Ether-A-Go-Go Potassium Channels , HEK293 Cells , Patch-Clamp Techniques , Potassium Channel Blockers , Pharmacology , Sulfides , Pharmacology , TransfectionABSTRACT
Objective To study the constituents in Melicope pteleifolia. Methods Plant material was isolated with 80% EtOH. Compounds were separated with chromatographic methods and their structures were elucidated on the basis of spectral analysis (EI-MS, 1H-NMR, and 13C-NMR) and chemical evidence. Results Five compounds were isolated from petrol ether or ethyl acetate soluble fraction. Their structures were identified as 3,5,3'-trihydroxy-4'-methoxy-7-(3-methylbut-2-enyloxy) flavone (pteleifolosin C, 1), 3,7-dimethoxyl kaempferol (kamatakenin, 2), vanillic acid (3), tricosanoic acid tetradecyl ester (4), and p-sitosterol (5), respectively. Conclusion Compound 1 is a new structure named pteleifolosin C. Compounds 2-4 are isolated from this plant for the first time.
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Objective To investigate the chemical constituents of Citrus medica var. sareodactylis from Sichuan province, and to provide evidence for the development and utilization and quality evaluation of the medicinal material.Methods Various chromatographic techniques were used to purify the components of this herb. Compounds were identi-fied by their physical characteristics and spectral feature. Results Seven compounds were isolated from Citrus medica var. sarcodactylis, and they were identified as sibiricol (Ⅵ), 7-methylesculetin (Ⅶ), bergapten (Ⅷ), sigmasteryl acetate(Ⅸ), 5-methoxyfurfural(Ⅹ), limonin(Ⅺ), daucosterol (Ⅻ). Conclusion Compound Ⅵ, Ⅶ and Ⅸ are isolated from plants of Rutaceae for the first time.
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Objective To develop a HPLC method for the determination of Lasiokaurin in the stems and leaves of Rabdosia nervosa.Methods HPLC was performed on a Kromsil C18 reversed-phase column(250mm?4.2mm,5?m).All of the reference substances and samples were separated with the mobile phase of methanol :water(55:45) under isocratic elution for 30min,flow rate was 1.0ml/min,the detection wavelength was 234nm,and the column temperature was 30℃.Results The content of Lasiokaurin was 0.005mg/g in the stems and 0.372mg/g in the leaves,the content in the stems were almost 1/75 times as much as that in the leaves.The average recovery of Lasiokaurin was 96.21%.Conclusion This developed method,which is simple and with good precision,high sensitivity and selectivity,can be used for quality evaluation of Lasiokaurin in Rabdosia nervosa.
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Objective To study the chemical constituents of Evodia lepta.Methods The chemical constituents were isolated by chromatographic methods and their structures were elucidated by physicochemical characteristics and spectral data.Results Two compounds were isolated and their structures were identified as erythro-3-(1',2',3'-trihydroxy) isopentyl-7-hydroxycoumarin(Ⅰ) and?-daucosterol (Ⅱ).Conclusion CompoundⅠis a new one named evodosin A while compoundⅡis isolated from E. lepta for the first time.
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Objective To establish the determination of prim-O-glucosylcimifugin in Biyan Tablets by HPLC.Methods The HPLC determination was carried out on Diamonsil C18 column(4.6 mm? 250 mm,5 ? m).The mobile phase consisted of methanol-acetonirile-H2O(18 :12 :70) with a flow rate of 1.0 mL/min,and the ultraviolet detection wavelength was set at 254 nm.Results Prim-O-glucosylcimifugin showed a good linearity in the range of 0.1888～ 1.534 ? g with the peak area score,the coefficient was 0.9997,and the average recovery was 101.74 %(RSD=2.97 %).Conclusion The method is accurate and reliable,and can be used for the quality control of Biyan Tablets.
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Objective To determine the icariin content in Qianlie Shule Granules (QSG). Methods After proper pre-treatment,HPLC method was performed on a C18 column. The mobile phase consisted of acetonitrile-water (29 ∶71) and the UV d etective wavelength was set at 270 nm. Results The peak of icariin was separated completely. The calibration curve of icariin was linear within 0.16～1.2 mg?mL -1,Y=0.028 7X-0.009 62 (r=0.999 9). Conclusion This method is accurate and su itable for the determination of icariin content.