Actinolactomycin,a New 2-Oxonanonoidal Antitumor Antibiotic Produced by Streptomyces flavoretus 18522,and its Inhibitory Effect on the Proliferation of Human Cancer Cells

Actinolactomycin 1, a new 2-oxonanonoidal antitumor antibiotic, was isolated from the fermentation broth of Streptomyces flavoretus 18522 through a bioassay-guided separation procedure. The structure of 1 was determined as 4,7-dihydroxy-3,9-dimethyl-2-oxonanone by the spectroscopic methods. Compound 1 inhibited the proliferation of A2780, K562, HCT-15, A549 and HeLa cells with the IC50 values of 1.4 ± 0.4 μmol/L, 8.4 ± 4.7 μmol/L, 9.4 ± 2.2 μmol/L, 15.4 ± 5.6 μmol/L and 13.7 ± 2.0 μmol/L, respectively. Flow cytometric analysis indicated that 1 could inhibit the cell cycle of tsFT210, A2780 and K562 cells mainly at the G0/G1 phase and could also induce apoptosis in K562 cells.

Determination of Clarithromycin in Human Plasma by Liquid Chromatography-Tandem Mass Spectrometry： Validation and Application in Clinical Pharmacokinetic Study

Aim To develop a liquid chromatographic-tandem mass spectrometric (LC-MS-MS) method to determine clarithromycin in human plasma. Methods The analyte and internal standard roxithromycin were extracted from plasma samples by n-nexane-dichloromethane-isopropanel (300:150:15, V/V/V) and chromatographed on a C18 column. The mobile phase consisted of methanol-water-formic acid (80:20:1, V/V/V). Detection was performed on a triple quadrupole tandem mass spectrometer via electrospray ionization source (ESI) in the positive mode. Results The method had a lower limit of quantification of 10.0 ng·mL^-1 when 0.2 mL plasma was used. The linear calibration curves were obtained in the concentration range of 10.0-5000 ng·mL^-1. The intra-and inter-rum precisions were lower than 3.3% in terms of relative standard deviation (RSD), and the accuracy ranged±0.7% in terms of relative error (RE). Tmax, Cmax, T1/2 and AUC0-24h values were found to be (3.1±2.7)h, (8 750±4 734)ng·mL^-1, (5.3±2.2)h, and (5932±2 449)ng·mL^-1, respectively, after a single oral dose of 250 mg clarithromycin tablet to 18 volunteers. Conclusion This validated method was successful in the evaluation of pharmacokinetic profiles of clarithromycin tablets administered to 18 healthy male volubteers.

Identification of Taxus cuspidata Sieb. et Zucc. endophytic fungi-new species, species known and their metabolite

A total of 94 isolates of endophytic fungi were isolated from the bark of 200-yr.-old Taxus cuspidata Sieb. et Zucc.in the primeval forest of the Changbai Mountain Natural Reserve, and 19 species of endophytic fungi were identified, including 10 new recorded-genus-species, 2 new species (Phomopsis Iongiscoleosporu Y. Xiang et Lu An Guo Wu Wen Fang, Coniothyrium macrospoum Y. Xiang J.X. et Lu An Guo Wu Wen Fang), 1 new varied species (Alternaria alternata (Fr.) Keissler var. taxi Y.Xiang et Lu An Guo) and 6 known species of China (Eurotium amstelodomi Mgngin, Eurotium repens de Bary, Botrytis sp.,Penicillium citrinum Thom, Epicoccum nigrium LinK, Fusarium sp.). Through thin layer chromatography (TLC), liquid fermentation metabolite of the strains was determined, and four strains (Alternaria alternata (Fr.) Keissler var. taxi Y. Xiang et Lu An Guo Wu Wen Fang, Botrytis sp., Eurotium amsteloodomi Mgngin, Eurotium repens de Bary) were screened out, whose metabolites reacted positively with the vanillic aldehyde that was one special taxoid developer. Among the four strains, Alternaria alternata (Fr.) Keissler var. taxi Y. Xiang et Lu An Guo, produced one compound largely, which positively reacted with one alkaloids developer-Bismuth potassium iodide. The compound is identified as taxoids type through spectrum analysis. This demonstrates that Alternaria alternata (Fr.) Keissler var. taxiY. Xiang et Lu An Guo can highly produce taxoids largely.

Time-and pH-dependent colon-specific drug delivery for orally administered diclofenac sodium and 5-aminosalicylic acid

AIM: To investigate Time- and pH-dependent colon-specific drug delivery systems (CDDS) for orally administered diclofenac sodium (DS) and 5-aminosalicylic acid (5-ASA), respectively. METHODS: DS tablets and 5-ASA pellets were coated by ethylcellulose (EC) and methacrylic acid copolymers (Eudragit L100 and $100), respectively. The in vitro release behavior of the DS coated tablets and 5-ASA coated pellets were examined, and then in vivo absorption kinetics of DS coated tablets in dogs were further studied. RESULTS: Release profile of time-dependent DS coated tablets was not influenced by pH of the dissolution medium, but the lag time of DS release was primarily controlled by the thickness of the coating layer. The thicker the coating layer, the longer the lag time of DS release is. On the contrary, in view of the pH-dependent 5-ASA coated pellets, 5-ASA release was significantly governed by pH. Moreover, the 5-ASA release features from the coated pellets depended upon both the combination ratio of the Eudragit~ L100 and S100 pH-sensitive copolymers in the coating formulation and the thickness of the coating layer. The absorption kinetic studies of the DS coated tablets in dogs demonstrated that in vivo lag time of absorption was in a good agreement with in vitro lag time of release. CONCLUSION: Two types of CDDS, prepared herein by means of the regular coating technique, are able to achieve site-specific drug delivery targeting at colon following oral administration, and provide a promising strategy to control drug release targeting the desired lower gastrointestinal region.

High-Performance Liquid Chromatographic Method for Determination of Germacrone in Rat Plasma

Aim A reliable high-performance liquid chromatographic (HPLC) method was developed for determination of gennacrone in rat. plasma. Methods The plasma samples were treated with acetonitrile and analyzed by HPLC with UV detection at 244 nm. Results The limit of detection was 100 ng·mL^-1 for germacrone in plasma and the linear range was0.1004-15.06μg· mL^-1 in plasma. The RSD of intra-day and inter-day assay was 1.87%-4.29% and 1.29%-5.15%, respectively. The recoveries of germacrone were over 95%. The endogenous substances in plasma did not show any interference in the analysis. Conclusion The method is accurate and convenient, and suitable for pharmacokinetic studies of gennacrone in rats.

A New Steroidal Saponin from Dioscorea deltoidea Wall var. orbiculata

Bioactivity-guided fractionation led to the isolation of a new steroidal saponin, orbiculatoside B, together with a pair of furostanol saponins, protobioside and methyl protobioside, from the fresh rhizomes of Dioscorea deltoidea Wall var. orbiculata. The new compound was identified to be isonarthogenin 3 O - a - L - rhamnopyranosyl (12) - [ a - L - rhamnopyranosyl - ( 1 4 ) ] - b - D - glucopyranoside by various NMR techniques in combination with chemical methods. The three saponins showed strong activity against Pyricularia oryzae, and were cytotoxic to cancer cell line K562, HCT-15, A549, and A2780a in vitro.

Characterization of a novel toxin-antitoxin module,VapBC,encoded by Leptospira interrogans chromosome

Comparative genomic analysis of the coding sequences (CDSs) of Leptospira interrogans revealed a pair of closely linked genes homologous to the vapBC loci of many other bacteria with respect to both deduced amino acid sequences and operon organizations. Expression of single vapC gene in Escherichia coli resulted in inhibition of bacterial growth,whereas co-expression of vapBC restored the growth effectively. This phenotype is typical for three other characterized toxin-antitoxin systems of bacteria, i.e., mazEF[1], relBE[2] and chpIK[3]. The VapC proteins of bacteria and a thermophilic archeae, Solfolobus tokodaii, form a structurally distinguished group of toxin different from the other known toxins of bacteria. Phylogenetic analysis of both toxins and antitoxins of all categories indicated that although toxins were evolved from divergent sources and may or may not follow their speciation paths (as indicated by their 16s RNA sequences), co-evolution with their antitoxins was obvious.

Metabolites of A Novel Antibiotic Bitespiramycin in Rat Urine and Bile

A sensitive analytical method to identify active metabolites of bitespiramycin in rat urine and bile was developed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC/ESI-MSn). Bitespiramycin and its major active metabolites in rat urine and bile were isolated and identified as Ml serial (spiramycin Ⅰ, Ⅱ, Ⅲ), M2 serial (platenomycin Al, josamycin and leucomycin Al) and M3 serial (deisovalerylplatenomycin Al, deisovaleryl-josamycin, deisovalerylleucomycin Al).

A New Biflavonoid from Stellera chamaejasme L.

A new biflavonoid, stelleranol, was isolated from the roots of Stellera chamaejasme L.. Its structure was determined by the analysis of MS and NMR data, especially 2D NMR spectra.

In Vitro Skin Permeation of Osthol from Hydro-Alcohofic Gel Formulations

Aim To evaluate the in vitro percutaneous absorption behavior of osthol from a series of hydro-alcoholic gel formulations containing three penetration enhancers through excised human skin (stratum cormeum and epidermis,SCE). Methods Excised human skin was mounted in Franz-type diffusion cells. The samples withdrawn from the receptor cell were analyzed for osthol content by high-performance liquid chromatography (HPLC). Results The enhancers azone, menthol and chenopodium increased the osthol percutaneous steady-state fluxes 3.12, 2.00 and 1.25 times those of the enhancer-free formulations (controls), separately. Conclusions The main enhancement mechanism of the skin penetration enhancers azone, menthol and chenopodium is to destroy the barrier fimction of stratum corneum, reducing the resistance of drug transport through the skin and increasing the diffusion coefficients of osthol.

One New A-type Proanthocyanidin Trimer from Lindera aggregata(Sims) Kosterm.

One new A - type proanthocyanidin trimer, lindetannin trimer, was isolated from the stems of Lindera aggregata (Sims) Kosterm.. Its structure was elucidated by spectral and chemical methods.

Effect of Complexation with Hydroxylpropyl-β-Cyclodextrin on Solubility, Dissolution Rate and Chemical Stability of Prostaglandin E1

Aim To study the effect of complexation with hydroxylpmpyl-β-cycledextrin (HP-β-CD) on the solubility, dissolution rate and chemical stability of pmstaglandin E1 (PGE1), thereby providing a basis for preparing a stable solid or aqueous preparation of PGF1 formulated with HP-β-CD. Methods The effect of HP-β-CD on the solubility of PGF1 was studied by phase solubility method. The formation of inclusion complexes of PGE1 with HP-β-CD in the aqueous solution was confirmed by UV spectra, circular dichroism spectroscopy, and that in the solid state by IR spectra and X-ray diffractometry. An solid inclusion complex of PGF1 with HP-β-CD was prepared by lyophilization. The dissolution rate and stability of the inclusion complex were determined and compared with those of PGE1 alone. Meanwhile, the stability of PGF1 aqueous solutions in the presence of HP-β-CD was studied under different pH conditions. Results The solubility of PGF1 increased linearly with increasing HP-β-CD concentration in various pH buffered solutions, showing typical AL-type phase solubility diagrams. The stability and dissolution rate of the solid inclusion complex of PGE1 were significantly increased, compared with those of pure PGE1 . The stability of PGEI in HP-β-CD solutions was also obviously improved under acidic and basic conditions, but the stabilizing effect was absent under neutral conditions. Conclulsions The solubility, dissolution rate and chemical stability of PGE1 are markedly improved by complexation with HP-β-CD. It is quite possible to prepare a stable PGE1 inclusion complex-containing solid dosage forms, but almost impossible to obtain a stable aqueous preparation of PGE1 formulated with HP-β-CD.