Molecular Docking Assessment of Cathinones as 5-HT2AR Ligands: Developing of Predictive Structure-Based Bioactive Conformations and Three-Dimensional Structure-Activity Relationships Models for Future Recognition of Abuse Drugs.

Commercially available cathinones are drugs of long-term abuse drugs whose pharmacology is fairly well understood. While their psychedelic effects are associated with 5-HT2AR, the enclosed study summarizes efforts to shed light on the pharmacodynamic profiles, not yet known at the receptor level, using molecular docking and three-dimensional quantitative structure-activity relationship (3-D QSAR) studies. The bioactive conformations of cathinones were modeled by AutoDock Vina and were used to build structure-based (SB) 3-D QSAR models using the Open3DQSAR engine. Graphical inspection of the results led to the depiction of a 3-D structure analysis-activity relationship (SAR) scheme that could be used as a guideline for molecular determinants by which any untested cathinone molecule can be predicted as a potential 5-HT2AR binder prior to experimental evaluation. The obtained models, which showed a good agreement with the chemical properties of co-crystallized 5-HT2AR ligands, proved to be valuable for future virtual screening campaigns to recognize unused cathinones and similar compounds, such as 5-HT2AR ligands, minimizing both time and financial resources for the characterization of their psychedelic effects.

A Multiparametric Approach to Cerium Oxide Nanoparticle Toxicity Assessment in Non-Biting Midges.

Cerium oxide nanoparticles (CeO2 NPs) are included in the Organisation for Economic Co-operation and Development (OECD) priority list of engineered nanomaterials for assessment of their environmental impact. The present study was carried out to assess the CeO2 NP toxicity to the freshwater midge Chironomus riparius larvae at concentrations of 2.5, 25, 250, and 2500 mg of CeO2 NP/kg of sediment. Experiments were designed to assess the prolonged exposure of midges to CeO2 NPs while adhering to OECD test guideline 218. The following parameters were investigated: CeO2 NP uptake by larvae, oxidative stress parameters, in vivo genotoxic effects, and life trait parameters. Inductively coupled plasma-mass spectrometry analysis showed a significant positive correlation between the concentration of CeO2 NPs in the sediment and its uptake by the larvae. No significant mortality was observed in C. riparius, and oxidative stress was not detected. The only significantly induced sublethal effect was genotoxicity, which began to manifest at a lowest-observed-effect concentration of 25 mg kg-1 of sediment and progressively increased at higher concentrations. Our results indicate that exposure to CeO2 NP-contaminated freshwater sediments does not pose a risk to chironomids at environmentally realistic concentrations. However, the significant accumulation of CeO2 NPs by chironomid larvae may pose a risk through trophic transfer to organisms further up the food chain. Environ Toxicol Chem 2019;39:131-140. © 2019 SETAC.

In vitro and in vivo assessment of the genotoxicity and antigenotoxicity of the Filipendula hexapetala and Filipendula ulmaria methanol extracts.

ETHNOPHARMACOLOGICAL RELEVANCE: The two species of Filipendula genus, Filipendula hexapetala Gilib. and Filipendula ulmaria (L.) Maxim are a traditional herbal medicine widely used to treat haemorrhoids, diarrhoea, fever, rheumatism and arthritic pain, kidney problems, to stop bleeding, and the common cold, as well as food supplements. However, no scientific study has been performed to validate genotoxic and/or antigenotoxic potentials of these two Filipendula species. AIM OF THE STUDY: The aim of the present study was to examine the genotoxic and possible in vitro and in vivo DNA protection potential of methanol extracts of F. hexapetala and F. ulmaria. MATERIALS AND METHODS: The genotoxicity of different concentrations of F. hexapetala and F. ulmaria methanol extracts from roots and aerial parts (20, 40 and 80 mg/ml), mixed with standard food for Drosophila, was evaluated in vivo in the anterior midgut of Drosophila melanogaster using a modified alkaline comet assay. The protective effects of the highest dose of extracts were observed in somatic cells of third-instar larvae against ethyl methanesulphonate (EMS)-induced genotoxicity. Also, DNA protection activity of methanol extracts from F. hexapetala and F. ulmaria (100, 200, and 400 µg/ml) against hydroxyl radical-induced DNA damage was determined under in vitro conditions. RESULTS: The results showed that methanol extracts from the root and aerial part of F. hexapetala at a concentration of 20mg/ml indicated the absence of genotoxicity. Also, there were no statistically significant differences in total scores between any of the groups treated with F. ulmaria root extract and the negative control group, while F. ulmaria aerial part extract possess weak genotoxic effects depending on the concentrations. The percentage reduction in DNA damage was more evident in the group of larvae simultaneously treated with EMS and the highest dose of F. hexapetala root or aerial part extracts and F. ulmaria root extract (91.02, 80.21, and 87.5%, respectively) and less expressive in the group simultaneously treated with F. ulmaria aerial part extract (54.7%). F. hexapetala root and aerial part extracts and F. ulmaria root extract possess strong capabilities to protect DNA from being damaged by hydroxyl radicals. CONCLUSIONS: It can be concluded that F. hexapetala root and aerial part extracts and F. ulmaria root extract demonstrated the absence of genotoxic activity. The extracts appeared to have antigenotoxic effect, reducing the levels of DNA damage induced by EMS by more than 80%. Also, F. hexapetala root and aerial part extracts and F. ulmaria root extracts could effectively protect against hydroxyl radical-induced DNA damage.

Combining molecular docking and 3-D pharmacophore generation to enclose the in vivo antigenotoxic activity of naturally occurring aromatic compounds: myricetin, quercetin, rutin, and rosmarinic acid.

Considering the controversial results concerning the antimutagenicity of some phenolic compounds recorded in the literature, the antigenotoxic effects of four selected phenolic compounds, myricetin, quercetin, rutin, and rosmarinic acid, against DNA damage induced by alkylation with ethyl methanesulfonate (EMS), were evaluated in Drosophila melanogaster males using the sex-linked recessive lethal (SLRL) test. To assess the protective effects against DNA damage, D. melanogaster males were exposed to a monofunctional alkylating agent EMS in concentration of 0.75 ppm, 24 h prior to one of the selected phenolic compounds in the concentration of 100 ppm. The possible differences in mechanisms of protection by selected compounds were determined by molecular docking, after which structure-based 3-D pharmacophore models were generated. EMS induced considerable DNA damage as shown by significant increase in the frequency of germinative mutations. The frequency decreased with high significance (p<0.001***) after post-treatments with all selected phenolic compounds. Further, docking analysis revealed EMS pre-bond conformations against guanine and thymine as a necessary condition for alkylation, after which resulting O6-ethylguanine and O4-ethylthimine were docked into the active site of O6-alkylguanine-DNA alkyltransferase to confirm that particular lesions are going to be repaired. Finally, myricetin and quercetin protected dealkylated nucleotides from further EMS alkylation by forming the strong hydrogen bonds with O6-guanine and O4-thymine via B ring hydroxyl group (bond lengths lower than 2.5 Å). On the other side, rutin and rosmarinic acid encircled nucleotides and by fulfilling the EMS binding space they made an impermeable barrier for the EMS molecule and prevented further alkylation.

In vivo antigenotoxic potential and possible mechanism of action of selected 4-hydroxy-2H-chromen-2-one derivatives.

The in vivo sex-linked recessive lethal test was carried out in Drosophila melanogaster to investigate whether or not five substituted 4-hydroxy-2H-chromen-2-ones can modulate the genotoxicity of the well-established mutagenic agent ethyl methanesulfonate (EMS). For this purpose, 3 days old Canton S males were treated with the potent mutagen EMS alone in concentration of 0.75 ppm, as well as in combination with one of the five 4-hydroxycoumarins, namely diethyl 2-(1-(4-hydroxy-2-oxo-2H-chromen-3-yl)ethylidene)malonate (2b), 3-(1-(4-hydroxy-2-oxo-2H-chromen-3-yl)ethylidene)pentane-2,4-dione (6b), 4-(4-(4-hydroxy-2-oxo-2H-chromen-3-yl)thiazol-2-ylamino) benzenesulfonic acid (4c), 4-hydroxy-3-(2-(2-nitropheny lamino)thiazol-4-yl)-2H-chromen-2-one (9c), and (E)-4-hydroxy-3-(1-(m-tolylimino)ethyl)-2H-chromen-2-one (5d), in concentration of 70 ppm. The frequency of germinative mutations increased significantly after the treatment with EMS and decreased after treatments with coumarins. The maximum reduction was observed after treatments with 2b, 6b, 4c, and 5d. By the formation of hydrogen bonds or electrostatic interactions with O(6) of DNA guanine, tested coumarins prevent EMS-induced alkylation. The results indicate a protective role of five 4-hydroxycoumarins under the action of a strong mutagen.