Abstract: The purpose of the present study was to isolate and characterize ailanthone-rich materials from the bark of the deciduous tree Ailanthus
altissima (Mill.) Swingle and to assess their herbicide activity on selected herbaceous species. Ailanthone-rich fractions were obtained from
A. altissima bark by extraction with dichloromethane and ethyl acetate and subsequent purification of these crude extracts, and of the
remaining water mixture after solvent extraction, by means of gel permeation chromatography. A number of fractions were isolated and
characterized for ailanthone content. A dichloromethane fraction was shown to contain 92% w/w of ailanthone, as demonstrated by HPLC
and NMR analysis. A significant pre-emergence herbicide activity was found for most of the extracts which was directly correlated to
ailanthone concentration. A remarkable combined pre- and post-emergence herbicide activity was found for a specific fraction. These results
indicate that the bark of A. altissima may represent an interesting source for the production of natural herbicides for use in agriculture.
Abstract: Functionalized carbon nanotube (CNT) derivatives are currently under thorough investigation in different biomedical investigations. In this field of research, the composition of sample either in terms of covalently attached or physisorbed moieties can greatly affect the observed results and hamper the comparison between different studies. Therefore, the availability of a fast and reliable analytical technique to assess both the type of interaction (covalent vs noncovalent) and the composition of CNT conjugates is of great importance. Here we describe that the two-dimensional diffusion-ordered (DOSY) NMR spectroscopy is extremely useful to discriminate between conjugated and unconjugated polyethylene glycol groups in samples obtained by condensation with oxidized single-walled carbon nanotubes (SWNTs). This fast and nondestructive technique allows us to follow the removal of unconjugated polyethylene glycol chains during the purification. In particular, DOSY analysis reveal that about 1/3 (wt %) of the polyethylene glycol used for the condensation remained physisorbed to functionalized SWNTs after dialysis. Complete elimination of physisorbed polyethylene glycol was achieved using diafiltration.
Abstract: Selective halogenation of hyaluronan and partial halogen substitution by methotrexate led to 6-chloro-6-deoxy-6-O-methotrexylhyaluronan, a potential antitumor drug. The remaining halogen could be further substituted by a second organic carboxylate, leading to mixed esters. 6-O-Acetyl-6-O-methotrexylhyaluronan and 6-O-butyryl-6-O-methotrexylhyaluronan were thus synthesized and characterized by NMR spectroscopy.
Abstract: A novel methodology for making drug conjugates using hyaluronan as a carrier was developed. This strategy involves a completely regioselective two-step synthesis of 6-amino-6-deoxyhyaluronan, which is then easily functionalized with drugs through a suitable linker. The case of hyaluronan-camptothecin conjugates is described, making use of a simple succinate linker. The antitumor activity of new hyaluronan derivatives prepared is at present under evaluation.
Abstract: We report the synthesis of three novel, versatile fullerene intermediates whose main feature is the presence of an amino end group. Simple condensation reactions of these intermediates under standard conditions produce new derivatives that are useful for applications in materials science and medicinal chemistry.
