Antibacterial and antioxidant metabolites from the insect-associated fungus Aspergillus fumigatus.

The research on bioactive secondary metabolites from Aspergillus fumigatus afforded six compounds, which were identified by mass spectrometer (MS) and nuclear magnetic resonance (NMR) spectroscopic analysis as cyclopyazonic acid (1), trypacidin A (2), asterric acid (3), methyl asterrate (4), demethylcitreoviranol (5), as well as (5-hydroxy-2-oxo-2H-pyran-4-yl) methyl acetate (6). Cyclopyazonic acid (1) was found to have potent antibacterial effects, especially against Bacillus licheniformis with minimal inhibitory concentration (MIC) value of 3.7µg/mL. Its antibacterial effects were possibly related to the olefinic acid group in the structure. Phenyl ether derivatives 3 and 4, and trypacidin A (2) also exhibited antimicrobial effects. In addition, compound 6 showed significant antioxidant effects with half maximal effective concentration (EC50) value of 10.2µM in the ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) assay, which was better than the positive control.

Crystal structure of (E)-1-(4-chloro-phen-yl)ethanone O-de-hydro-abietyloxime.

The title compound, C28H34ClNO2 {systematic name: (E)-1-(4-chloro-phen-yl)ethanone O-[(1R,4aS,10aR)-7-isopropyl-1,4a-di-methyl-1,2,3,4,4a,9,10,10a-octa-hydro-phenanthrene-1-carbonyl]oxime}, was synthesized from de-hydro-abietic acid. In the de-hydro-abietyl moiety, the central and terminal cyclo-hexane rings display chair and half-chair conformations, respectively, and a trans-ring junction. The C=N bond is in an E conformation and the C-O-N=C torsion angle is 148.1 (5)°. No directional inter-actions except van der Waals contacts occur in the crystal structure.

Crystal structure of (E)-1-(4-meth-oxy-phen-yl)ethanone O-de-hydro-abietyloxime.

In the title compound, C29H37NO3 {systematic name: (E)-1-(4-meth-oxy-phen-yl)ethanone O-[(1R,4aS,10aR)-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octa-hydro-phenanthrene-1-carbon-yl]oxime}, a new derivative of de-hydro-abietic acid, the two cyclo-hexane rings exhibit a trans-ring junction and are in chair and half-chair conformations. The C=N double bond exhibits an E conformation.

Chitosan-coated mesoporous microspheres of calcium silicate hydrate: environmentally friendly synthesis and application as a highly efficient adsorbent for heavy metal ions.

Chitosan-coated calcium silicate hydrate (CSH/chitosan) mesoporous microspheres formed by self-assembly of nanosheets have been synthesized in aqueous solution under ambient conditions without using any toxic surfactant or organic solvent. The method reported herein has advantages of simplicity, low cost and being environmentally friendly. The BET specific surface area of CSH/chitosan mesoporous microspheres is measured to be as high as ~356 m(2) g(-1), which is considerably high among calcium silicate materials. The as-prepared CSH/chitosan mesoporous microspheres are promising adsorbent and exhibit a quick and highly efficient adsorption behavior toward heavy metal ions of Ni(2+), Zn(2+), Cr(3+), Pb(2+) Cu(2+) and Cd(2+) in aqueous solution. The adsorption kinetics can be well fitted by the pseudo second-order model. The maximum adsorption amounts of Ni(2+), Zn(2+), Pb(2+), Cu(2+) and Cd(2+) on CSH/chitosan mesoporous microspheres are extremely high, which are 406.6, 400, 796, 425 and 578 mg/g, respectively. The CSH/chitosan adsorbent exhibits the highest affinity for Pb(2+) ions among five heavy metal ions. The adsorption capacities of the CSH/chitosan adsorbent toward heavy metal ions are relatively high compared with those reported in the literature.