In recent years, considerable progress in the knowledge of the biology and pharmacology of sigma receptors has encouraged research on the potential benefits of sigma modulators in a wide range of pathologies. So far, only few potent agonists and antagonists of sigma receptors are in clinical trial for acute and chronic neurodegenerative diseases (SA4503 and ANAVEX 2-73) or neuropathic pain (E-52862).

Our recent research efforts identified racemic RC-33 as a potent and metabolically stable σ₁ receptor agonist. Herein we describe the isolation of pure RC-33 enantiomers by chiral chromatography, assignment of their absolute configuration, and in vitro biological studies in order to address the role of chirality in the biological activity of these compounds and their metabolic processing. The binding of enantiopure RC-33 to the σ₁ receptor was also investigated in silico by molecular dynamics simulations. Both RC-33 enantiomers showed similar affinities for the σ₁ receptor and appeared to be almost equally effective as σ₁ receptor agonists. However, the R-configured enantiomer showed higher in vitro hepatic metabolic stability in the presence of NADPH than the S enantiomer. Overall, the results presented herein led us to select (R)-RC-33 as the optimal candidate for further in vivo studies in an animal model of amyotrophic lateral sclerosis.

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Measurable levels of anticancer agents are still detected on work surfaces in health-care settings. However, application of recent guidelines for the protection of workers' safety and health has resulted in lowered contamination levels. To assess occupational exposure to antineoplastic agents, very sensitive and specific procedures for environmental sampling and analysis are therefore needed. In the present study an assay for simultaneous determination of gemcitabine, taxol, cyclophosphamide, and ifosfamide in wipe samples, using two internal standards (trofosfamide and cephalomannine), was developed and validated by high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS). Solid-phase extraction (SPE) was used for sample concentration and cleanup. The assay was found to be linear up to 1000 ng/wipe, with limits of quantitation of 25.0 ng/wipe for gemcitabine and taxol, and 12.5 ng/wipe for cyclophosphamide and ifosfamide. In order to investigate the effectiveness of the surface sampling, removal efficiency tests were repeated on different types of surfaces. Recovery rates of between 62 and 81% were obtained at two contamination levels (50.0 and 250 ng/100 cm2). Precision and trueness were determined on three different days. The within-day precision was found to be always less than 12.1% for all the analytes. The overall precision, expressed as relative standard deviation (RSD), was always less than 9.4%. Recoveries varying from 75.0 (gemcitabine) to 95.0% (taxol) were obtained at three levels. In order to obtain a quantitative indication of the quality of the result, the overall uncertainty of measurement (UOM) was evaluated according to the EURACHEM/CITAC guide. The relative combined uncertainty was found to be always less than 9.5%. The relative expanded uncertainty was also calculated, at three contamination levels.

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.