Luisa Boffa

Phytotherapeutics: an evaluation of the potential of 1000 plants

Objective:  The aim of this review is to evaluate and summarize the available scientific information on the commonest plant extracts marketed in Western countries. In view of the intense, ongoing search for new plant extracts with powerful anti‐inflammatory activity, we paid particular attention to this topic. The aim is to provide broad coverage of as many potentially useful plants as possible and then to focus on those with the greatest therapeutic potential.

Ultrasound-Promoted Copper-Catalyzed Azide-Alkyne Cycloaddition

†Dipartimento di Scienza e Tecnologia del Farmaco, Universita di Torino, Via Giuria 9, 10125Torino, Italy, and Department of Chemistry, The Scripps Research Institute, 10550 North TorreyPines Road, La Jolla, California 92037The 1,3-dipolar cycloaddition reaction of azides and alkynes has been known for over 100years and was studied extensively by Huisgen and co-workers in the 1960s.

Preparation of Second Generation Ionic Liquids by Efficient Solvent-Free Alkylation of N-Heterocycles with Chloroalkanes

Non-conventional techniques, such as microwave (MW) and power ultrasound (US) as well as combined MW/US irradiation, have been used to promote one-pot synthesis of second-generation ionic liquids (ILs), cutting down reaction times and improving yields. However, the use of chloroalkanes in the alkylation of N-heterocycles requires more drastic conditions if results are to match those obtained with more reactive alkyl halides. The present paper describes a series of MW- or MW/US-promoted IL preparations starting from chloroalkanes and classic heterocycles (1-methylimidazole, pyridine and 1-methylpyrrolidine). When reactions were carried out under conventional heating in an oil bath they required longer reaction times and gave poorer yields. 1H-NMR analysis and ion-exchange chromatography showed that the present solventless procedure afforded ILs of satisfactory purity. The observed high yields (usually 70-98% isolated), and short reaction times showed that a straightforward access to ILs can be also achieved with the use of alkyl chlorides, resulting in a considerable reduction of costs.

Reticulated Pd(II)/Cu(I) cyclodextrin complexes as recyclable green catalyst for Sonogashira alkynylation

A Pd/Cu loaded polymeric cyclodextrin catalyst was easily prepared via in situ reticulation with diisocyanates under sonochemical conditions. Excellent yields were observed for Sonogashira reactions carried out in water and glycerol and the catalyst could easily be recovered and reused three times without a significant loss in catalytic activity.

A Speedy One-Pot Synthesis of Second-Generation Ionic Liquids Under Ultrasound and/or Microwave Irradiation

The present work describes an efficient one-pot synthesis of second-generation ionic liquids (ILs), combining in one step the Menshutkin reaction and anion metathesis. Working in a closed vessel under microwaves, or better still under simultaneous ultrasound and/or microwave irradiation, in a few minutes a series of ILs with 1-methylimidazole or pyridine cores were obtained in high yields (80–97% isolated). Under conventional heating, ILs could not be prepared in one pot in acceptable times and yields, whereas our protocol, carried out with commercially available equipment, was highly effective and reproducible. Moreover, 1H NMR analysis and ion-exchange chromatography showed that the present solventless procedure afforded satisfyingly pure ILs.

Chemical modifications of bile acids under high-intensity ultrasound or microwave irradiation

High-intensity ultrasound (HIU) and microwave (MW) irradiation, having emerged as effective promoters of organic reactions, were exploited for the synthesis of bile acids derivatives. Esterification, amidation, hydrolysis, oxidation, and reduction were investigated. Compared to conventional methods, both techniques proved much more efficient, increasing product yields and dramatically cutting down reaction times. Scaled-up studies are now under way.

A new class of cationic cyclodextrins: synthesis and chemico-physical properties

A new class of positively charged triazole-bridged β-cyclodextrin (β-CD) derivatives have been synthesized in excellent yields (over 70%) through a copper-catalyzed azide-alkyne cycloaddition (CuAAC), starting from 6I-azido-6I-deoxy-β-CD or its permethylated derivative and a series of 1-butyl-3-alkynylimidazolium salts. The regioselective azide/alkyne [3 + 2] cycloaddition was efficiently carried out using metallic copper as the catalyst, affording very clean products. Easy access to such hybrid molecules that combine the properties of CDs and ionic liquids, may pave the way to a number of new applications in analytical chemistry and catalysis.

Regio- and stereoselective reductions of dehydrocholic acid

Dehydrocholic acid (DHCA), an unnatural bile acid, is manufactured by oxidation of cholic acid. Its biotransformation by two basidiomycetes (Trametes hirsuta and Collybia velutipes) is reported. These mycelia showed different affinities for the substrate and selectivities of attack: T. hirsuta in particular regio- and stereoselectively reduced the 3-keto group to yield 3 alpha-hydroxy-7,12-diketo-5 beta-cholan-24-oic acid (7,12-diketolithocolic acid) as the main product. A number of different chemical reductions were carried out on DHCA; among them hydrogenation with Raney Nickel in water under high-intensity ultrasound proved highly regio- and stereoselective, yielding 7,12-diketolithocolic acid exclusively. (1)H and (13)C resonances were assigned in details thanks to a series of 1D and 2D NMR runs including DEPT, NOESY, H-H COSY, gHSQC and gHMBC.

Effects of ultrasonic and hydrodynamic cavitation on the treatment of cork wastewater by flocculation and Fenton processes.

This paper reports that ultrasonic (US) and hydrodynamic cavitation (HC) are efficient strategies for the environmental remediation of cork wastewater (CW). It is necessary to remove toxic, inhibitory or refractory organic matter from CW using physical and chemical techniques (pre-treatment) prior to performing conventional biological treatment. After this biological treatment, it is also critical to further decontaminate (post-treatment) in order to meet the discharge limitation. The pre-treatment of diluted CW using Fenton oxidation (FE) alone led to COD and polyphenol (PP) removal values of 30% and 61%, respectively, while HC and US resulted in 83-90% increases in COD reduction and 26-33% increases in PP reduction. Whereas 55% and 91% COD and PP removal were achieved using flocculation (Floc) alone, COD elimination was increased by a further 7-18% under HC and US. No noticeable improvement in PP elimination was observed. US did not enhance the Floc decontamination of the original concentrated CW, however, considerable quantities of white biofilm were surprisingly generated on the CW surface after the pre-treatment, thus indicating the improvement of biodegradability of the resulting liquid. In fact, the post-treatment stage, using FE alone after having filtered the biofilms, led to reductions of 53% in COD and 90% in PP. The HC and US protocols resulted in 26-34% increases in COD elimination. HC further enhanced PP elimination caused by FE, while US resulted in lower levels of PP elimination.

Predicting self-assembly and structure in diluted aqueous solutions of modified mono- and bis-β-cyclodextrins that contain naphthoxy chromophore groups

The water diluted solution behaviour of mono- and bis-β-cyclodextrin (mono- and bis-CD) derivatives, whose appended groups and inter-CD linkers contain a naphthoxy chromophore moiety, has been studied using steady-state and time-resolved fluorescence techniques, circular dichroism and molecular modelling. Mono-CD derivatives form non-covalent dimeric tail-to-tail supramolecular structures via the mutual partial penetration, through their primary sides, of axially oriented naphthoxy appended groups and the self-inclusion of the naphthoxy moiety is rather improbable. Non-covalent dimer formation may compete with any guest complexation. Nevertheless, these assemblies can be broken up by decreasing medium polarity or when the appended group is captured by macrorings such as cucurbit[7]urils or native βCDs. Bis-CD derivatives, however, do not exhibit self-association processes which were observed in the mono-derivatives. This is because the presence of the bulky naphthoxy group in the spacer keeps the βCD cavities, which are capable of accommodating an external guest, away from each other. The dinaphthoxy group, in the bis-NβCD, was located in a quasi-parallel plane conformation between both CDs.