Capillary electrophoresis separation of aminoalkanol derivatives of 1,7-dimethyl-8,9-diphenyl-4-azatricyclo[5.2.1.0(2,6)]dec-8-ene-3,5,10-trione as potential anticancer drugs.

The purpose of this study, the direct separation of aminoalkanol derivatives I and II of 1,7-dimethyl-8,9-diphenyl-4-azatricyclo[5.2.1.0(2,6) ]dec-8-ene-3,5,10-trione, which was found in earlier studies as potential anticancer drugs, were performed. Capillary electrophoresis offers the possibility of fast, cheap, and reproducible separations for compounds I and II. In this paper, the simultaneous separation of I and II by capillary zone electrophoresis has been achieved within 8 min by use of 50 mM phosphate buffer of pH 2.5. Analysis of the two compounds in the serum plasma standards was conducted. Limits of detection of I and II by UV absorbance at 200 nm were achieved in the range of 156.3-156.6 ng/mL. The method was validated for linearity, accuracy, precision, limits of detection, and quantification. The calibration equation revealed a good linear relationship (r(2) = 0.998-0.999). Sufficient recovery was observed in the range of 96.3-99.5%. The method showed good reproducibility with intra- and interday precision of 0.97 and 1.76%, respectively. The quantification limits for the compounds were in the range of 477.0-479.8 ng/mL. The proposed method was applied to the analysis of real serum samples.

Extraction of imide fungicides in water and juice samples using magnetic graphene nanoparticles as adsorbent followed by their determination with gas chromatography and electron capture detection.

In this paper, a sensitive analytical method for four fungicides (procymidone, folpet, vinclozolin and ditalimfos) in environmental water and juice samples was developed by using magnetic solid-phase extraction (MSPE) with magnetic graphene nanocomposite (G-Fe3O4) as the adsorbent, followed by determination with gas chromatography and electron capture detection. Parameters such as the amount of G-Fe3O4, extraction time, ionic strength and pH of the sample solution, desorption solvent and desorption time were optimized. Under the optimum conditions, the enrichment factors of the method for the analytes were in the range from 1495 to 1849. The limits of detection for the fungicides ranged from 1.0 to 7.0 ng L(-1). The recoveries of the method for the analytes were in the range from 79.2 to 102.4%. The developed G-Fe3O4-MSPE method was simple and efficient for the extraction and determination of the four fungicides in water and grape juice samples.

A new diimide derivative from the co-culture broth of two mangrove fungi (strain no. E33 and K38).

A new diimide derivative, named (-)-byssochlamic acid bisdiimide (1), was isolated from the mixed broth of two mangrove fungi (strain no. K38 and E33) from the South China sea coast. The structure of 1 was determined by comprehensive spectroscopic methods, including 1D and 2D NMR (COSY, HMQC, and HMBC) and semi-synthesis. Primary bioassays showed that 1 had weak cytotoxic activity against Hep-2 and HepG2 cells.

Yeast glycogen synthase kinase-3beta pathway inhibitors from an organic extract of Streptomyces sp.

Investigation of a microbial fermentation organic extract of Streptomyces sp. H7667 led to the isolation of three new imides, 3-[(5E)-5-methyl-4-oxo-2-hydroxy-5-octenyl]glutarimide (1), 2-amino-N-2'-(phenylacetyl)propanimide (5), and 2-amino-N-(2'-(cyclohex-2''-enyl)acetyl)acetimide (6), and one new isoflavonoid glycoside, 6-O-methyl-7-O-alpha-rhamnopyranosyldaidzein (7), along with four known compounds. Their structures were elucidated by HRESIMS, 1H and 13C NMR, COSY, HMQC, HMBC, and NOESY spectra. Compounds 1-8 were evaluated for their inhibitory activities in the yeast glycogen synthase kinase-3beta assay.

Inter- and intraspecific comparisons of antiherbivore defenses in three species of rainforest understory shrubs.

Plants defend themselves against herbivores and pathogens with a suite of morphological, phenological, biochemical, and biotic defenses, each of which is presumably costly. The best studied are allocation costs that involve trade-offs in investment of resources to defense versus other plant functions. Decreases in growth or reproductive effort are the costs most often associated with antiherbivore defenses, but trade-offs among different defenses may also occur within a single plant species. We examined trade-offs among defenses in closely related tropical rain forest shrubs (Piper cenocladum, P. imperiale, and P. melanocladum) that possess different combinations of three types of defense: ant mutualists, secondary compounds, and leaf toughness. We also examined the effectiveness of different defenses and suites of defenses against the most abundant generalist and specialist Piper herbivores. For all species examined, leaf toughness was the most effective defense, with the toughest species, P. melanocladum, receiving the lowest incidence of total herbivory, and the least tough species, P. imperiale, receiving the highest incidence. Although variation in toughness within each species was substantial, there were no intraspecific relationships between toughness and herbivory. In other Piper studies, chemical and biotic defenses had strong intraspecific negative correlations with herbivory. A wide variety of defensive mechanisms was quantified in the three Piper species studied, ranging from low concentrations of chemical defenses in P. imperiale to a complex suite of defenses in P. cenocladum that includes ant mutualists, secondary metabolites, and moderate toughness. Ecological costs were evident for the array of defensive mechanisms within these Piper species, and the differences in defensive strategies among species may represent evolutionary trade-offs between costly defenses.

Cantharimide dimers from the Chinese blister beetle, Mylabris phalerate PALLAS.

Five cantharidin-related compounds were isolated from the Chinese blister beetle, Mylabris phalerate PALLAS (Meloidae). Their structures were determined based on spectroscopic and chemical evidence. Three of them were identified as cantharimide dimers, which consist of two units of cantharimide combined with a tri-, tetra-, or penta-methylene group.

Isolation and biological activity of frankiamide.

An antibiotic produced by the symbiotic actinomycete Frankia strain AiPs1 was isolated from culture broth using optimized thin-layer chromatography and high-performance liquid chromatography (HPLC) methods. The novel compound that was isolated, dubbed frankiamide, displayed antimicrobial activity against all 14 Gram-positive bacterial strains and six pathogenic fungal strains tested. The pathogenic actinomycete Clavibacter michiganensis and the oomycete Phytophthora were especially susceptible. In addition to displaying antimicrobial activity, frankiamide also strongly inhibited 45Ca(2+) fluxes in clonal rat pituitary GH4C1 tumor cells and was comparable to a frequently used calcium antagonist, verapamil hydrochloride. The results of HPLC analysis, supported by both nuclear magnetic resonance and mass spectroscopy studies, showed that frankiamide has a high affinity for Na(+) ions.

Gas chromatographic-mass spectrometric separation, identification and determination of C6-C12 cyclic imides in thermally treated epoxy and alkyd resins to locate hot spots inside large electricity generators.

A simple and rapid GC-MS method for separation, identification and quantitative determination of long-chain cyclic imides in the 300 degrees C thermally treated epoxy and alkyd resins has been developed. The method provides a positive means of identifying C6-C12 cyclic imide derivatives by GC-MS and enables the specific area of overheating to be identified, thereby averting catastrophic failures of power generators in service.

Two new cytotoxic carbonimidic dichlorides from the nudibranch Reticulidia fungia.

Two new sesquiterpenes, reticulidins A (1) and B (2), containing a rare functional group, N=CCl(2), have been isolated together with known congeners from the nudibranch Reticulidia fungia and their structures elucidated by spectroscopic data. Both 1 and 2 were cytotoxic against KB and L1210 cells.

Production, isolation, and preliminary toxicity studies of brevianamide A from cultures of Penicillium viridicatum.

Brevianamide A, one of a novel group of alkaloids first obtained from Penicillium brevi-compactum, has also been isolated as a principal metabolite from two key isolates of P. viridicatum. Procedures for bioproduction and purification are described. This compound was not toxic when fed or injected into mice and had no antibiotic properties against several common bacterial and fungal microorganisms. Brevianamides A and B are among at least four yellow metabolites that may be formed by isolates of P. viridicatum.