Phytochemical investigation on the Amygdalus lycioides Spach branchelets resulted in the isolation of four chiral flavanones: (2R,3R)-Taxifolin, (2R,3R)-aromadendrin, (S)-5,7,3',5'-tetrahydroxyflavanone and (S)-naringenin. The flavanones were isolated by semi-preparative HPLC, their structures elucidated based on spectroscopic data and their absolute configuration assigned. As a part of our ethnobotanical-directed search for novel TNFα inhibitors, the bioassay-guided fractionation of the n-hexane-acetone (n-Hex-Ac, 1:1 v/v) Amygdalus lycioides Spach branchelets extract was performed. In this way, (S)-naringenin was identified as the constituent responsible for the TNFα blocking effect, being effective in vitro and in vivo after oral administration. This is the first investigation on bioactive secondary metabolites of Amygdalus lycioides Spach branchelets.

In this study we addressed the role of chirality in the biological activity of RC-33, recently studied by us in its racemic form. An asymmetric synthesis procedure was the first experiment, leading to the desired enantioenriched RC-33 but with an enantiomeric excess (ee) not good enough for supporting the in vitro investigation. An enantioselective high-performance liquid chromatography (HPLC) procedure was then successfully carried out, yielding both RC-33 enantiomers in amounts and optical purity suitable for the pharmacological study. The absolute configuration of pure enantiomers was easily assigned exploiting the asymmetric synthesis previously devised. As emerged in the preliminary in vitro biological investigation, (S)- and (R)-RC-33 possess a comparable affinity towards the σ1 receptor and a very a similar behavior in the calcium influx assay, resulting in an equally effective σ1 receptor agonist. Overall, the results obtained so far suggest that the interaction with the biological target is nonstereoselective and leads us to hypothesize that there is a lack of stereoselectivity in the biological activity of RC-33.

A microwave protocol combined with isocratic HPLC analysis is proposed for the rapid screening of plant materials collected in different environmental conditions in order to evaluate the productivity of Crataegus monogyna Jacq. and to find out the best ecological conditions to cultivate hawthorn in Northern Italy.

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The synthesis and biological evaluation of a series of new derivatives of 2-substituted 5-phenyl-1,4-benzodiazepines, structurally related to tifluadom (5), are reported. Chemical and pharmacological studies on compounds 6 have been pursued with the aim of expanding the SAR data and validating the previously proposed model of interaction of this class of compounds with the kappa-opioid receptor. The synthesis of the previously described compounds 6 has been reinvestigated in order to obtain a more direct synthetic procedure. To study the relationship between the stereochemistry and the receptor binding affinity, compounds 6e and 6k were selected on the basis of their evident structural resemblance to tifluadom. Since a different specificity of action could be expected for the enantiomers of 6e and 6k, owing to the results shown by (S)- and (R)-tifluadom, their racemic mixtures have been resolved by means of liquid chromatography with chiral stationary phases (CSP), and the absolute configuration of the enantiomers has been studied by circular dichroism (CD) and (1)H NMR techniques. Moreover, some new 2-[(acylamino)ethyl]-1,4-benzodiazepine derivatives, 6a-d,f,g,j, have been synthesized, while the whole series (6a-o) has been tested for its potential affinity toward human cloned kappa-opioid receptor. The most impressive result obtained from the binding studies lies in the fact that this series of 2-[2-(acylamino)ethyl]-1,4-benzodiazepine derivatives binds the human cloned kappa-opioid receptor subtype very tightly. Indeed, almost all the ligands within this class show subnanomolar K(i) values, and the least potent compound 6o shows, in any case, an affinity in the nanomolar range. A comparison of the affinities obtained in human cloned kappa-receptor with the correspondent one obtained in native guinea pig kappa-receptor suggests that the human cloned kappa-receptor is less effective in discriminating the substitution pattern than the native guinea pig kappa-receptor. Furthermore, the results obtained are discussed with respect to the interaction with the homology model of the human kappa-opioid receptor, built on the recently solved crystal structure of rhodopsin. Finally, the potential antinociceptive and antiamnesic properties of compounds 6e and 6i have been investigated by means of the hot-plate and passive avoidance test in mice, respectively.