Biomedical subjects

Yujie Fu

Publications and source records attributed to Yujie Fu.

7 recordsLinked to original sources

PubMed2006

Preparative separation of vitexin and isovitexin from pigeonpea extracts with macroporous resins.

Vitexin and isovitexin are a pair of isomeric compounds known as the major constituents in pigeonpea leaves and possess various pharmacological activities. In the present study, the preparative separation of vitexin and isovitexin with macroporous resins (Nankai Hecheng S & T, Tianjin, China) was studied. The performance and adsorption characteristics of eight macroporous resins including ADS-5, ADS-7, ADS-8, ADS-11, ADS-17, ADS-21, ADS-31 and ADS-F8 have been evaluated. The research results indicate that ADS-5 resin is most appropriate for the separation of vitexin and isovitexin. Langmuir and Freundlich isotherms were used to describe the interactions between solutes and resin at different temperatures, and the equilibrium experimental data were well fitted to the two isotherms. Column packed with ADS-5 resin was used to perform dynamic adsorption and desorption tests to optimize the separation process. The optimum parameters for adsorption were as follows: the concentration of vitexin and isovitexin in sample solution: 0.22 and 0.40mg/mL, respectively, processing volume: 3 BV, flow rate: 1mL/min, pH 4, temperature: 25 degrees C; for desorption: ethanol-water (40:60, v/v), 5 BV as an eluent, flow rate: 1mL/min. After one run treatment with ADS-5 resin, the contents of vitexin and isovitexin were increased 4.07-fold and 11.52-fold from 0.86%, 1.53% to 3.50% and 17.63%, the recovery yields were 65.03% and 73.99%, respectively. In conclusion, the preparative separation of vitexin and isovitexin can be easily and effectively achieved via adsorption and desorption on ADS-5 resin, and the method can be referenced for the separation of other flavone C-glucosides from herbal materials.

Adsorption↗

PubMed2006

Optimization of luteolin separation from pigeonpea [Cajanus cajan (L.) Millsp.] leaves by macroporous resins.

In the present study, the performance and separation characteristics of eight macroporous resins for the separation of luteolin (LU) from pigeonpea leaves extracts have been evaluated. The adsorption and desorption properties of LU on macroporous resins including AB-8, NKA-9, NKA-2, D3520, D101, H1020, H103 and AL-2 have been compared. AL-2 resin offers the best adsorption and desorption capacity for LU than other resins based on the research results, and its adsorption data at 25 degrees C fit best to the Freundlich isotherm. Dynamic adsorption and desorption experiments have been carried out with the column packed by AL-2 resin to optimize the separation process of LU from pigeonpea leaves extracts. The optimum parameters for adsorption were sample solution LU concentration 65.5 microg/ml, pH 5, processing volume 3 BV, flow rate 1.5BV/h, temperature 25 degrees C; for desorption were elution solvent ethanol-water (50:50, v/v) 2 BV and followed by ethanol-water (60:40, v/v) 2 BV, and flow rate 1BV/h. After treated with AL-2 resin, the LU content in the product was increased 19.8-fold from 0.129% to 2.55%, with a recovery yield of 78.54%. The results showed that AL-2 resin revealed a good ability to separate LU. Therefore, we conclude that results in this study may provide scientific references for the large-scale LU production from pigeonpea or other plants extracts.

Adsorption↗

PubMed2006

Capillary zone electrophoresis method for fingerprint of allantoic fluid in normal and infected SPF embryonated chicken eggs.

A capillary zone electrophoresis method was developed for fingerprint determination of allantoic fluid in specific pathogen free (SPF) embryonated chicken eggs. The effects of some crucial parameters, such as buffer type, pH, wavelength and running voltage on the separation were studied systematically. The components of the allantoic fluid were well separated using a fused-silica uncoated capillary with an effective length of 50 cm and an internal diameter of 50 microm. One hundred millimolars sodium tetraborate buffer containing 20 mM sodium dihydrogen phosphate with a final pH 9.8 was used as a running buffer. Comparative fingerprints of allantoic fluid in normal and infected with infectious bronchitis virus (IBV) SPF embryonated chicken eggs were also evaluated. The results showed that there were significant differences between composition of normal allantoic fluid and allantoic fluid infected with IBV, which led to different migration behavior. This method was shown to be stable and reproducible with a relative standard deviation of less than 5% for both migration time and peak current.

Allantois↗

PubMed2006

Synthesis and antitumor activity of novel 10-substituted camptothecin analogues.

In an attempt to improve the antitumor activity and decrease the cytotoxicity of camptothecin, 18 new 10-substituted camptothecin derivatives were prepared. The cytotoxicity in vitro on cancer cell lines and antitumor activity in vivo, and inhibitory properties of topoisomerase I of these derivatives were evaluated. Most of these derivatives possessed lower cytotoxicities than CPT, and the compounds 13, 21, 22, 23, and 24 showed similar topoisomerase I inhibitory activity to CPT. Analogues 13 exhibited the best antitumor activity in vivo among all derivatives we prepared.

Animals↗

PubMed2006

Simultaneous determination of catechin, rutin, quercetin kaempferol and isorhamnetin in the extract of sea buckthorn (Hippophae rhamnoides L.) leaves by RP-HPLC with DAD.

A rapid and specific reversed-phase high performance liquid chromatography (RP-HPLC) method with diode array detection (DAD) at room temperature was used and validated for the simultaneous determination of five flavonoids (catechin, CA; rutin, RU; quercetin, QU; kaempferol, KA; isorhamnetin, IS) in the extract of sea buckthorn (Hippophae rhamnoides L.) leaves. The sample pretreatment process involved ultrasonic extraction with 85% ethanol under the frequency of 80 kHz, at a temperature of 45 degrees C for 30 min and with the ratio of liquor to material of 15 mL g-1, followed by separation on HIQ SIL C18V column with methanol-acetonitrile-water (40:15:45, v/v/v) containing 1.0% acetic acid as a mobile phase. The extract was detected by DAD at the wavelength of 279 nm for CA, 257 nm for RU, 368 nm for QU, KA and IS. Calibration curves were found to be linear with the ranges of 0.011-0.520 mg ml-1 (CA), 0.007-0.500 mg ml-1 (RU), 0.019-0.280 mg ml-1 (QU), 0.010-0.440 mg ml-1 (KA) and 0.008-0.400 mg ml-1 (IS). The correlation coefficients of linear regression analysis and detection limits were between 0.9963-0.9999 and 0.00079-0.00290 mg ml-1. The contents of CA, RU, QU, KA and IS in sea buckthorn leaves were successfully determined with 3.8, 5.2, 7.3, 10.9 and 11.9 min with satisfactory reproducibility and recovery. Recoveries of the five flavonoids were between 97.27 and 99.98%. The method was applied to the determination of flavonoids in sea buckthorn leaves and was found to be simple, rapid and efficient.

Catechin↗

PubMed2006

Rapid separation of four main taxoids in Taxus species by a combined LLP-SPE-HPLC (PAD) procedure.

A method is described for the simultaneous determination of paclitaxel and three related taxoids, 10-deacetylbaccatin III (10-DAB III), baccatin III, and cephalomannine, in the extracts from the needles of three Chinese yew species, Taxus cuspidata, T. chinensis, and T. media. SPE was applied as the sample preparation technique and RP-HPLC with a photodiode array detector (PAD) was used for the analysis of extract samples. The crude extracts were treated with an improved SPE cartridge packed with a combination of 1-vinyl-pyrrolidin-2-one and divinyl-benzene. The eluent was 75% methanol. The following separation was achieved with a gradient program on an HIQ SIL C18W column in a system of ACN/water within 60 min. The samples were detected by PAD at wavelengths of 232.1 nm for 10-DAB III, 229.8 nm for baccatin III and paclitaxel, and 223.9 nm for cephalomannine. The content of 10-DAB III, baccatin III, cephalomannine, and paclitaxel varied from 0.0277 to 0.0875, 0.0254 to 0.0405, 0.0715 to 0.2486, and 0.0996 to 0.1301 mg/g in fresh needles of the above yew species, respectively. The assay achieved good resolution in the separation between the four compounds, and it can be used for quality control or purity determination for those in bulk and pharmceutical dosage forms.

Alkaloids↗

PubMed2004

[Developments in preparation and experimental method of solid phase microextraction fibers].

Solid phase microextraction (SPME) is a simple and effective adsorption and desorption technique, which concentrates volatile or nonvolatile compounds from liquid samples or headspace of samples. SPME is compatible with analyte separation and detection by gas chromatography, high performance liquid chromatography, and other instrumental methods. It can provide many advantages, such as wide linear scale, low solvent and sample consumption, short analytical times, low detection limits, simple apparatus, and so on. The theory of SPME is introduced, which includes equilibrium theory and non-equilibrium theory. The novel development of fiber preparation methods and relative experimental techniques are discussed. In addition to commercial fiber preparation, different newly developed fabrication techniques, such as sol-gel, electronic deposition, carbon-base adsorption, high-temperature epoxy immobilization, are presented. Effects of extraction modes, selection of fiber coating, optimization of operating conditions, method sensitivity and precision, and systematical automation, are taken into considerations in the analytical process of SPME. A simple perspective of SPME is proposed at last.

Chromatography, Gas↗