We report for the first time the efficient use of accelerated solvent extraction (ASE) for extraction of ricin to analytical purposes, followed by the combined use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and MALDI-TOF MS/MS method. That has provided a fast and unambiguous method of ricin identification for in real cases of forensic investigation of suspected samples. Additionally, MALDI-TOF MS was applied to characterize the presence and the toxic activity of ricin in irradiated samples. Samples containing ricin were subjected to ASE, irradiated with different dosages of gamma radiation, and analyzed by MALDI-TOF MS/MS for verification of the intact protein signal. For identification purposes, samples were previously subjected to SDS-PAGE, for purification and separation of the chains, followed by digestion with trypsin, and analysis by MALDI-TOF MS/MS. The results were confirmed by verification of the amino acid sequences of some selected peptides by MALDI-TOF MS/MS. The samples residual toxic activity was evaluated through incubation with a DNA substrate, to simulate the attack by ricin, followed by MALDI-TOF MS/MS analyses.

Recent events involving A-series nerve agents, a once elusive class of chemical warfare agents, have provoked a great concern in the international community. In this paper, continuing our research efforts in Medicinal Chemistry at IDQBRN, a OPCW Designated Laboratory for environmental samples, we explore ANMP, a A-230 surrogate, as an inhibitor, in the search for new treatment options for intoxication caused by these chemicals. We evaluated the potential of five isatin-pyridine oximes hybrids as reactivators using a modified Ellman’s assay. The results suggest that isatin-oxime monocationic hybrids structures with 5 methylene units and its oxa-analog could be promising for the design of new AChE reactivator.

The risk of use of toxic chemicals for unlawful acts has been matter of concern for different governments and multilateral agencies. The Organisation for the Prohibition of Chemical Weapons (OPCW), which oversees the implementation of the Chemical Weapons Convention (CWC), considering recent events employing chemical warfare agents as means of assassination, has recently included in the CWC “Annex on Chemicals” some organophosphorus compounds that are regarded asactingin a similar fashion to the classical G- and V-series of nerve agents, inhibiting the pivotal enzyme acetylcholinesterase. Therefore, knowledge of the activity of the pyridinium oximes, the sole class of clinically available acetylcholinesterase reactivators so far, is plainly justified. In this paper, continuing our research efforts in the Medicinal Chemistry on this class of toxic chemicals, we synthesized an A-230 nerve agent surrogate and applied a modified Ellman’s assay in order to evaluate its ability to inhibit our enzymatic model, acetylcholinesterase from Electrophorus eel, and if the clinically available antidotes are able to rescue the enzyme activity for the purpose of relating the findings to the previously disclosed in silico data for the authentic nerve agent and other studies with similar A-series surrogates. Our experimental data indicates that pralidoxime is the most efficient compound for reactivation of acetylcholinesterase inhibited by A-230 surrogate, which is the opposite to the in silico data previously disclosed.