ABSTRACT
Laetiporus sulphureus is a saprophyte belonging to a specific group of wood-decomposing Basidiomycetes growing on deciduous trees. This fungus has been characterized as a herbal medicine and is also known for its antimicrobial properties. In the present study, high energy extraction techniques using different solvents were compared to obtain maximum yield of the edible fungus Laetiporus sulphureus total lipids. The lipid classes and fatty acid composition of the fruiting bodies' total lipids has been studied using GC-FID and Iatroscan TLC-FID analysis. Among the lipids, the neutral lipids predominated followed by phospholipids and glycolipids. Triglycerides were the most abundant in the neutral lipid fraction, whereas phosphatidylcholine in phospholipids. The existence of relatively high amount of sterols may be correlated to fungus pharmaceutical properties. Total lipids were found to contain high unsaturated degree fatty acids (UFA/SFA>3.4) and dominated of C18:2ω-6, C18:1ω-9 and C16:0 fatty acids. Antibacterial and antifungal properties of mushrooms' lipid extracts from two different solvents were also examined. Results indicated that hexane extracts possessed better antifungal and slightly better antibacterial activity compared to chloroform extracts though both were less active than the commercial antimicrobial agents.
ABSTRACT
We herein describe an environmentally friendly microwave-assisted oxidative esteriï¬cation of alcohols and aldehydes in the presence of molecular oxygen and a heterogeneous catalysis (Pd/C, 5 mol %). This efficient and ligandless conversion procedure does not require the addition of an organic hydrogen acceptor. The reaction rate is strongly enhanced by mild dielectric heating. Furthermore, it is a versatile green procedure which generally enables the isolation of esters to be carried out by simple filtration in almost quantitative yields.
ABSTRACT
Bridged cyclodextrin dimers and trimers, in which respectively two and three hydrophobic cavities lie in close proximity, display much higher binding affinities and molecular selectivities than do parent cyclodextrins (CDs). By joining betaCD units with links inserted at different positions (2-2', 3-2', 6-2' or 6-2'-6'') and interposing spacers of different lengths and shapes, multicavity structures can be synthesized that are precisely tailored to fit specific guest molecules. This enzyme-mimicking strategy can also be used to generate stable supramolecular adducts. A series of CD dimers and trimers was prepared in good yields by carrying out the critical synthetic steps under power ultrasound (US) or microwave (MW) irradiation. Starting from azide and acetylenic CD derivatives, we exploited an efficient MW-promoted Huisgen 1,3-dipolar cycloaddition in the presence of Cu(I) salts. The resulting bridged CD derivatives gave stable adducts with magnetic-resonance-imaging contrast agents (MRI CAs) containing gadolinium(III) chelates. These inclusion complexes were found to be 2 to 3 orders of magnitude more stable than those formed by betaCD and to be endowed with high relaxivity values.
Subject(s)
Cyclodextrins/chemistry , Cyclodextrins/chemical synthesis , Dimerization , Ligands , Microwaves , Models, Molecular , Polymers/chemistry , UltrasonicsABSTRACT
Recently there is a great interest in using high energy techniques (HET) which involve microwave or ultrasound-assisted extraction (MAE and UAE) for isolation of natural bioactive compounds from plant foods. Such bioactive compounds are phenolics which were determined from sunflower (Helianthus annuus L.) kernels and hulls (defatted) utilising two different high energy extraction techniques, ultrasound and microwave assisted solvent extraction. All samples were characterised by ultra-high-performance liquid chromatography-electrospray ionization-mass spectrometry (UHPLC-ESI-MS). The effect of parameters such as the nature of the solvent, volume of solvent, temperature and time is discussed. It is proved that the techniques applied had reduced solvent consumption and shorter extraction times, and extraction yields of the analytes were equal to or to some extent higher than those obtained with conventional techniques. Total Phenolic Composition (TPC) of samples examined was studied by the Folin-Ciocalteu method and results were presented in µg gallic acid equivalents (GAE)/g dry extract. Kernels proved to have the higher amount of TPC while the press residues had shown comparable TPC results. The antioxidant activity of samples was spectrophotometrically determined by 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) assay using Butylated hydroxyl toluene (BHT) as reference compound to compare with samples. Sunflower seeds (kernels) showed again the highest antiradical efficiency (AE) compared to hulls and press-residue extract. Afterwards, ferric reducing ability of plasma (FRAP) and trolox equivalent antioxidant capacity (TEAC) assays were used for measuring the antioxidant capacity of samples. Press residue, a by-product of sunflower oil extraction, contained phenolics as shown by UHPLC-ESI-MS analysis. Hence, later on these compounds can be possibly utilised by food or neutraceutical industries. Phenolic substances characterised in hulls, kernels, and press residue were phenolic acids, mainly chlorogenic, caffeic, cinnamic, 4-hydroxybenzoic and p-coumaric.
ABSTRACT
omega-Phenoxy alcohols, PhO(CH(2))(n)()OH (n = 2-7), have been subjected to metalation with 2 equiv of n-butyllithium in tetrahydrofuran/methylcyclohexane solvent. Reaction of the resulting lithiated compounds with carbon dioxide (n = 2-7), benzaldehyde (n = 2-6), benzophenone (n = 2, 3), dimethylformamide (n = 2), ethyl formate (n = 2), and chlorodiphenylphosphine (n = 3) afforded the corresponding ortho-substituted hydroxyalkoxybenzenes in yields ranging from 45 to 83%. The synthesis is also reported of five new bis[o-(omega-hydroxyalkoxy)phenyl]mercury compounds (n = 2-6), four crystal structures of which have been determined.