齐墩果酸的微生物转化

齐墩果酸（OA）是一个分布广泛、含量丰富的天然三萜化合物，常以皂苷元的形式广泛存在于植物中,具有多种重要生物活性。但是OA许多活性较弱，且生物利用度低，限制了其在临床上的应用。一是OA水溶性差;二是抗癌活性仍与临床应用的抗癌药物相差比较大。 真菌在微生物转化中具有种类多、培养条件比较简单等特点，为了寻找到具有转化OA能力的菌株，采取一步发酵的方法，在18株实验室保藏真菌菌株中筛选到5株目的菌株,TLC分析显示有转化效果。 随后采用二步发酵的方法作为复筛，验证5株菌株转化能力，波谱分析结果表明5株菌株对OA确实有转化作用。 选择5株菌种中代号1F-2 2菌株作为放大实验菌株，分离转化产物，得到OA衍生物108（相对分子量414m/z）和1010（相对分子量340 m/z），分离出的产物用于活性检测。寻找到产物108的RP-HPLC分离条件，质谱得出二者相对分子质量。 为验证OA转化产物抗肿瘤活性，首次研究了OA对卵巢癌细胞株IGROV1和人乳腺癌细胞株MDA-MB-231作用，通过细胞增殖抑制实验、用MTT法检测细胞活性，结果表明齐墩果酸可降低卵巢癌细胞株IGROV1和乳腺癌细胞MDA-MB-231细胞增殖能力并呈剂量依赖性，对肿瘤细胞株的半数有效抑制浓度化IC50 分别为36.58μg/mL和38.8μg/mL (P<0．01)。OA能抑制肿瘤细胞活性，并且OA对卵巢癌细胞株IGROV1抑制活性高于乳腺癌细胞MDA-MB-231。 在此基础上，转化产物108和1010对卵巢癌细胞株IGROV1和人乳腺癌细胞株MDA-MB-231的抑制作用也进行研究，MTT实验结果表明，转化产物对两株癌细胞也有抑制活性（P<0．01）。 总之，本文工作为进一步开展齐墩果酸类化合物结构改造和抗肿瘤活性的研究奠定了基础。 Oleanolic acid (OA) is a triterpenoid widely distributed in the nature which possesses various important bioactivities. OA also serves as aglycon of many natural saponins. However, the relatively weak activities and poor bioavailability hinder its clinical use. Firstly, poor water-solubility results in worse bioavailability. Secondly, compared with clinical antitumor drug, the antitumor effect of OA has a great difference, it is worse. Many fungi have ability to transform nature products into a variety of derivatives, and transformation conditions of fungi are simple. Attempt to obtain fungi strains able to biotransform OA, we carried out the following experiments: To investigate the biotransformation 0f OA by strains supplied firstly, we used one-step fermentation method to screen the aimed strains from 18 fungus strains stored in our laboratory. On the basis of the initial screening experiments, we found 5 aimed strains. The TLC results showed that the 5 fungi strains could transform OA into other components derivatives. Then we used two-step fermentation method as secondly screening. We repeated the five strains to do the experiments, analytical data of the results proved the transformation indeed. In the followed experiments work, we chose 1F-2 2 strain as large-scale transformation fungus from the aimed fungi. We got two biotransformation products of OA by 1F-2 2, and named those derivatives 108 and 1010. We found RP-HPLC separation conditions of product 108. The two products were characterized by ESI-MS. To verify the anti-tumor activity of biotransformation products of OA, we studied the inhibition effect of oleanolic acid on the ovarian carcinomas IGROV1 and breast cancer cell line MDA-MB-231 firstly. With an assay based on a tetrazolium dye (MTT), the effects of various concentrations of oleanolic acid on ovarian carcinomas IGROV1 and breast cancer cell line MDA-MB-231 were studied. MTT method was used to measure the tumor cells viability. Compared with the control group, oleanolic acid can significantly inhibit the viability of the ovarian carcinoma cells IGROV1 and MDA-MB-231 breast cancer cell line (P<0．01), IC50 values were 36.58μg/mL or 38.8μg/mL. Oleanolic acid can inhibit the malignant tumor cells viability, and inhibitory activity of OA to ovarian carcinomas IGROV1 was higher than to breast cancer cell line MDA-MB-231. On this basis, we studied the anti-tumor activity of the two derivatives of OA [called 108 (414 m/z) and 1010(340 m/z)]. It came to the conclusion that the two derivatives also showed potent inhibitory effect on the growth of these tumor cells（P<0．01）. Therefore, the results of studies will benefit the further investigating on the relationships of structures and antitumor activities of OA.

Separation of drug enantiomers by capillary electrophoresis in the presence of neutral cyclodextrins

This is a selected review, highlighting our results obtained in an extended screening program ("The German-Chinese Drug Screening Program"), with a focus on a set of original data obtained with heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin(TM-beta-CD) as the chiral solvating agent (CSA). The enantioseparation of 86 drugs by capillary zone electrophoresis in the presence of this CSA was successful for 47 drugs. The migration separation factors (alpha(m)) and the migration retardation factors (R-m) were compared with those found for native beta-cyclodextrin (beta-CD). The patterns thus obtained were also compared with those observed for hexakis(2,3,6-tri-O-methyl)-alpha-CD (TM-alpha-CD) and octakis(2,3,6-tri-O-methyl)-gamma-CD (TM-gamma-CD), respectively. From the statistical data, it can be concluded that there is a remarkable influence of the analyte structure on the electrophoretic data. A substructure 4H was found in the analyte structure that has a significant influence on the analytes' behaviour. Thus, analytes bearing the substructure 4H do not only have a strong affinity to the CDs but also a high rate of success of chiral separation in all systems reviewed. In light of this, the different ring sizes of native cyclodextrins (alpha-, beta- and gamma-CD) readily explain their behaviour towards a limited test set of chiral drugs. Sterical considerations point to the significance of side-on-binding versus inclusion in the cavity of the host. In addition to the findings from the screening program, numerous references to the Literature are given. (C) 2000 Elsevier Science B.V. All rights reserved.

Bioactive, Luminescent and Mesoporous Europium-doped Hydroxyapatite as a Drug Carrier

Bioactive, luminescent and mesoporous europium-doped hydroxyapatite (Eu:HAp) was successfully prepared through a simple one-step route using cationic surfactant as template. The obtained multifunctional hydroxyapatite was performed as a drug delivery carrier to investigate the drug storage/release properties using ibuprofen (IBU) as a model drug

Fabrication, characterization of spherical CaWO4:Ln@MCM-41(Ln=Eu3+, Dy3+, Sm3+, Er3+) composites and their applications as drug release systems

Spherical MCM-41 particles with a diameter of about 150 nm have been successfully coated with CaWO4:Ln (Ln = Eu3+, Dy3+, Sm3+, Er3+) phosphor layers through a simple Pechini sol-gel process. The obtained CaWO4:Ln@MCM-41 composites, which kept the mesoporous structure of MCM-41 and the luminescent properties of phosphors, were investigated as a drug delivery system using aspirin (ASPL) as a model drug.

On the chemical synthesis and drug delivery response of folate receptor-activated, polyethylene glycol-functionalized magnetite nanoparticles

We describe here the chemical synthesis and in vitro drug delivery response of polyethylene glycol (PEG)-functionalized magnetite (Fe3O4) nanoparticles, which were activated with a stable ligand, folic acid, and conjugated with an anticancer drug, doxorubicin. The functionalization and conjugation steps in the chemical synthesis were confirmed using Fourier transform infrared spectroscopy. The drug-release behavior of PEG-functionalized and folic acid-doxorubicin-conjugated magnetic nanoparticles was characterized by two stages involving an initial rapid release, followed by a controlled release. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Preparation and Characterization of Interpenetration Polymer Network Films Based on Poly(vinyl alcohol) and Poly(acrylic acid) for Drug Delivery

A series of full interpenetrating polymer network (full-IPN) films of poly(acrylic acid) (PAA)/poly (vinyl alcohol) (PVA) were prepared by radical solution polymerization and sequential IPN technology. Attenuated total reflectance-Fourier transform infrared spectroscopy, swelling properties, mechanical properties, morphology, and glass transition temperature of the films were investigated. FTIR spectra analysis showed that new interaction hydrogen bonds between PVA and PAA were formed. Swelling property of the films in distilled water and different pH buffer solution was studied. Swelling ratio increased with increasing PAA content of IPN films in all media, and swelling ratio decreased with increasing PVA crosslink degree. Tensile strength and elongation at break related not only to the constitution of IPNs but also to the swelling ratio of IPNs.

Luminescence functionalization of mesoporous silica with different morphologies and applications as drug delivery systems

Ordered mesoporous silica (MCM-41) particles with different morphologies were synthesized through a simple hydrothermal process. Then these silica particles were functionalized with luminescent YVO4:EU3+ layers via the Pechini sol-gel process. The obtained YVO4:Eu3+ and MCM-41 composites, which maintained the mesoporous structure of MCM-41 and the red luminescence property of YVO4:Eu3+ were investigated as drug delivery systems using ibuprofen (IBU) as model drug. The physicochemical properties of the samples were characterized by X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N-2 adsorption, and photoluminescence (PL) spectra, respectively.

Mesoporous silica coated CeF3 : Tb3+ particles for drug release

CeF3:Tb3+ nanoparticles were successfully prepared by a polyol process using diethylene glycol ( DEG) as solvent. After being coated with dense silica, these CeF3:Tb3+ nanoparticles can be coated with mesoporous silica using nonionic triblock copolymer EO20PO70EO20 ( P 123) as structure-directing agent. The composite can load ibuprofen and release the drug in the PBS. The composite was characterized by X-ray diffraction ( XRD), transmission electron microscopy ( TEM), nitrogen absorption/desorption isotherms, fluorescence spectra, and UV/Vis absorption spectra, respectively.

Construction of hollow DNA/PLL microcapsule as a dual carrier for controlled delivery of DNA and drug

DNA/poly-L-lysine (PLL) capsules were constructed through a layer-by-layer (LbL) self-assembly of DNA and PLL on CaCO3 microparticles, and then used as dual carriers for DNA and drug after dissolution of carbonate cores. The permeability of DNA/PLL microcapsules was investigated with fluorescence probes with different molecular weights by confocal microscopy. The result revealed that the fluorescence probes were able to penetrate the capsule walls even its molecular weight up to 150 kDa. The resultant capsules were used to load drug model molecules-fluorescein isothiocyanate (FITC)-dextran (4 kDa) via spontaneous deposition mechanism.

Studies on alkaloids binding to GC-rich human survivin promoter DNA using positive and negative ion electrospray ionization mass spectrometry

Electrospray ionization mass spectrometry (ESI-MS) was used to investigate the binding of 13 alkaloids to two GC-rich DNA duplexes which are critical sequences in human survivin promoter. Negative ion ESI-MS was first applied to screen the binding of the alkaloids to the duplexes. Six alkaloids (including berberine, jatrorrhizine, palmatine, reserpine, berbamine, and tetrandrine) show complexation with the target DNA sequences. Relative binding affinities were estimated from the negative ion ESI data, and the alkaloids show a binding preference to the duplex with higher GC content. Positive ion ESI mass spectra of the complexes were also recorded and compared with those obtained in negative ion mode.

Hydration of drug-DNA complexes: Greater water uptake for adriamycin compared to daunomycin

Water is an integral part of DNA, and the conserved water molecules at the binding sites can modulate drug binding to DNA or protein. We report here that anthracycline antitumor antibiotics, adriamycin (AM) and daunomycin (DM), binding to DNA is accompanied by different hydration changes, with AM binding resulting in the uptake of about twice as many water molecules as DM. These results indicate that water is playing an important role in drug binding to DNA.

Hollow DNA/PLL microcapsules with tunable degradation property as efficient dual drug delivery vehicles by alpha-chymotrypsin degradation

Hollow deoxyribonucleic acid (DNA)/poly-L-lysine (PLL) capsules were successfully fabricated through a layer-by-layer (LbL) self-assembly of DNA and PLL on porous CaCO3 microparticles, followed by removal of templates with ethylenediamine tetraacetic acid disodium salt (EDTA). The enzymatic degradation of the capsules in the presence of alpha-chymotrypsin was explored. The higher the enzyme concentration, the higher is the degradation rate of hollow capsules. in addition, glutaric dialdehyde (GA) cross-linking was found to be another way to manipulate degradation rate of hollow capsules.

Cytotoxicity of liver targeted drug-loaded alginate nanoparticles

In this study, novel liver targeted doxorubicin (DOX) loaded alginate (ALG) nanoparticles were prepared by CaCl2 crosslinking method. Glycyrrhetinic acid (GA, a liver targeted molecule) modified alginate (GA-ALG) was synthesized in a heterogeneous system, and the structure of GA-ALG and the substitution degree of GA were analyzed by H-1 NMR, FT-IR and elemental analysis. The drug release profile under the simulated physiological condition and cytotoxicity experiments of drug-loaded GA-ALG nanoparticles were carried out in vitro. Transmission electron micrographs (TEM) and dynamic light scattering (DLS) analysis showed that drug-loaded GA-ALG nanoparticles have spherical shape structure with the mean hydrodynamic diameter around 214 +/- 11 nm.

Fabrication and characterization of microstructured and pH sensitive interpenetrating networks hydrogel films and application in drug delivery field

Novel microstructured and pH sensitive poly(acryliac acid-co-2-hydroxyethyl methacrylate)/poly(vinyl alcohol) (P(AA-co-HEMA)/PVA) interpenetrating network (IPN) hydrogel films were prepared by radical precipitation copolymerization and sequential IPN technology. The first P(AA-co-HEMA) network was synthesized in the present of IPN aqueous solution by radical initiating, then followed by condensation reaction (Glutaraldehyde as crosslinking agent) within the resultant latex, it formed multiple IPN microstructured hydrogel film. The film samples were characterized by IR, SEM and DSC. Swelling and deswelling behaviors and mechanical property showed the novel multiple IPN nanostuctured film had rapid response and good mechanical property. The IPN films were studied as controlled drug delivery material in different pH buffer solution using cationic compound, crystal violet as a model drug.

A magnetic, luminescent and mesoporous core-shell structured composite material as drug carrier

In this paper, hydrothermal synthesized Fe3O4 microspheres have been encapsulated with nonporous silica and a further layer of ordered mesoporous silica through a simple sol-gel process. The surface of the outer silica shell was further functionalized by the deposition of YVO4:Eu3+ phosphors, realizing a sandwich structured material with mesoporous, magnetic and luminescent properties. The multifunctional system was used as drug carrier to investigate the storage and release properties using ibuprofen (IBU) as model drug by the surface modification. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FT-IR), N-2 adsorption/desorption, photoluminescence (PL) spectra, and superconducting quantum interference device (SQUID) were used to characterized the samples.