Development and validation of a high-performance liquid chromatography coupled with ultraviolet detection method for the determination of isocorydine in rat plasma and its application in pharmacokinetics.

A new HPLC-UV method has been developed, validated and applied for the determination of isocorydine (CAS 475-67-2) in rat plasma after oral or intravenous (i. v.) administration. Caffeine was used as the internal standard (IS). The analyte and IS were extracted from rat plasma by liquid-liquid extraction (LLE) with methyl tert-butyl ether and they were separated on an XTerra C18 column (250×4.6 mm, 5 µm, pH 1-12) with UV detection at 264 nm. The mobile phase consisted of methanol and 0.02 mol/L potassium dihydrogen phosphate-phosphoric acid buffer solution (pH 3.2) (30:70, v/v) at a flow rate of 1 mL/min for 8.5 min. The retention times of isocorydine and caffeine were approximately 6.5 and 5.1 min, respectively. The good linearity of the calibration curves was observed over the concentration range of 0.05-8 µg/mL (n=8, r 2≥0.9995). The lower limit of quantification (LLOQ) was 0.05 µg/mL [signal to noise ratio (S/N)≥10], and the limit of detection (LOD) was demonstrated as 0.01 µg/mL (S/N≥3). The mean extraction recovery ranged from 83.7% to 89.5% at 3 quality control (QC) concentrations. Intra-day and inter-day precision (relative standard deviation, RSD%) were within 4.7% and accuracy (relative error, RE%) ranged from -1.2% to 4.5%. The developed method was successfully applied to determination of the pharmacokinetic properties of isocorydine in rats after oral administration at a dose of 20 mg/kg and i. v. injection at 5 mg/kg.

Determination of the plasma pharmacokinetic and tissue distributions of swertiamarin in rats by liquid chromatography with tandem mass spectrometry.

An LC-MS/MS method was developed for the quantification of swertiamarin (CAS 17388-39-5) in rat plasma and tissues using gentiopicroside as the internal standard (IS). Swertiamarin and an IS were extracted from plasma and tissues by a simple solid-phase extraction (SPE) procedure. Separation was achieved on a Phenomenex kinetex-C18 column (100 mm×2.1 mm, 2.6 µm) with an isocratic mobile phase consisting of methanol and water (22:78, v/v) with 0.1% acetic acid at a flow rate of 0.2 mL/min. The analyte and IS were detected by negative ion electrospray ionisation in multiple-reaction monitoring mode while monitoring the transitions of m/z 433 [M + CH3COO] - →179 and m/z 415 [M + CH3COO] - →179 for swertiamarin and the IS, respectively. The method was validated with respect to selectivity, matrix effect, linearity, accuracy, precision, recovery and stability. The method was successfully applied in a pharmacokinetic study of swertiamarin after intravenous and oral administration to rats. The pharmacokinetics of swertiamarin showed rapid absorption and elimination, and its absolute bioavailability was low at 10.3%. After oral administration to rats, swertiamarin was rapidly and widely distributed in its tissues. High concentrations were found in the liver and kidney, indicating that swertiamarin was possibly absorbed in the liver and eliminated by the kidney.

Chemical constituents of Selinum cryptotaenium.

A new pyranocoumarin, named secryptotaenin A, determined as 3'(S)-angeloyloxy-3',4'-dihydroseselin, was isolated from the roots of Selinum cryptotaenium, along with thirteen known compounds, umbelliferone, osthol, coumurrayin, (+)-heraclenol, longshengensin A, anomalin, ferulic acid, galactitol, stearic acid, melissic acid, lignoceric acid, beta-sitosterol and daucosterol. Their structures were determined on the basis of spectroscopic methods.

Constituents from Limonia crenulata.

A new indole alkaloid, crenulatine (1), along with twenty known compounds, was isolated from the stems of Limonia Crenulata. Their structures were identified by spectral means. Those compounds include four alkaloids, four coumarins, two flavanones, three tetranortriterpenoids, one triterpenoid, three steroids, two lignans and two aromatic compounds.

[Studies on the chemical constituents of Evodia rutaecarpa (Juss.) Benth. var. officinalis (Dode) Huang].

AIM: To study the chemical constituents of the unriped fruits from Evodia rutaecarpa (Juss.) Benth. var. officinalis (Dode) Huang. METHODS: Various chromatographic techniques were used to separate and purify the constituents. Their structures were elucidated on the physico-chemical properties and spectral data. RESULTS: A lot of compounds were isolated of the unriped fruits from Evodia rutaecarpa (Juss.) Benth. var. officinalis (Dode) Huang. This paper reports mainly compounds identified as shihulimonin A, emodin, physcion, chrysophanol and limonin. CONCLUSION: Shihulimonin A is a new compound. Emodin, physcion and chrysophanol were isolated from the Evodia for the first time.

[A study of the relation between interval of the injury and the reaction of neurons, glial cells after experimental brain contusion].

OBJECTIVE: To observe the change of c-fos protein(Fos) and nerve growth factor receptor (NGFR) staining in the brain of rat after experimental brain contusion. METHODS: Immunohistochemistry of c-fos and NGFR were applied to investigate the brain contusion. RESULTS: (1) The expression of Fos protein could be observed at 0.5 h after injury and then increased with the prolonging of time. By 3 h after injury, the positive staining cells could be detected massively not only in and round the wound site but also in other areas of the whole ipsilateral cortex. The stains decreased 6-12 h later and could hardly be detected 1 d after the brain contusion. The control-experiment is negative. (2) NGFR positive staining cells could be found round the wound area 1 d postlesion. At 3 d following injury, a peak of massive positively stained cells appeared both in number and in intensity, showing significant differences compare with that of 1 d after damage (P < 0.01). 5 d later the positive express declined slowly. The express in the control-rat is negative. CONCLUSION: There is a rule that the expression of Fos and NGFR positive staining changes with time going after brain contusion, which will be of great value in estimation of brain injury time. Detection of Fos can be used for time deduction in earlier period after injury, while NGFR in later period. They are also very important for distinguishing between antemortem or postmortem injury.

[Studies on the chemical constitutents of the traditional Chinese medicine "yun qian-hu" (Peucedanum rubricaule Shan et Shch.)].

A new coumarin-glycoside and twelve known coumarins together with seven other known compounds have been isolated from the roots of Peucedanum rubricaule Shan et Shch. (Umbelliferae). The new coumarin-glycoside named rubricauloside, has been elucidated as 5,7-dimethoxy-8-[2'-hydroxy-3'-methyl, 3'-O-beta-d- apiofuranosyl(1----6)-beta-D-glucopyranosyl-butyl]-courmarin by means of spectral and chemical analysis.