Calix[n]arene-based immunogens: A new non-proteic strategy for anti-cocaine vaccine.

Introduction: Cocaine use disorder is a significant public health issue without a current specific approved treatment. Among different approaches to this disorder, it is possible to highlight a promising immunologic strategy in which an immunogenic agent may reduce the reinforcing effects of the drug if they are able to yield sufficient specific antibodies capable to bind cocaine and/or its psychoactive metabolites before entering into the brain. Several carriers have been investigated in the anti-cocaine vaccine development; however, they generally present a very complex chemical structure, which potentially hampers the proper assessment of the coupling efficiency between the hapten units and the protein structure. Objectives: The present study reports the design, synthesis and preclinical evaluation of two novel calix[n]arene-based anti-cocaine immunogens (herein named as V4N2 and V8N2) by the tethering of the hydrolysis-tolerant hapten GNE (15) on calix[4]arene and calix[8]arene moieties. Methods: The preclinical assessment corresponded to the immunogenicity and dose-response evaluation of V4N2 and V8N2. The potential of the produced antibodies to reduce the passage of cocaine analogue through the blood-brain-barrier (BBB), modifying its biodistribution was also investigated. Results: Both calix[n]arene-based immunogens elicited high titers of cocaine antibodies that modified the biodistribution of a cocaine radiolabeled analogue (99mTc-TRODAT-1) and decreased cocaine-induced behavior, according to an animal model. Conclusion: The present results demonstrate the potential of V4N2 and V8N2 as immunogens for the treatment of cocaine use disorder.

In vivo evaluation of anti-Leishmania activity of alkyltriazoles and alkylphosphocholines by oral route.

The failures in the treatment of leishmaniasis is an increasing problem around the world, especially related to resistance. Thus, we describe the synthesis and in vivo anti-Leishmania activity of alkylphosphocholine and alkyltriazoles; besides, their likely action mechanisms stem from some eventual inhibition of parasite enzymes using computational tools. These compounds were tested in an in vivo hamster model infected with Leishmania Leishmania infantum chagasi. Fifty days after parasite inoculation, the two compounds 12-azidedodecylphosphocholine (3) and 3-(1-(12-fluorododecyl)-1H-1,2,3-triazol-1-yl)propano-1-ol (9), were separately administered once a day as oral suspensions (25 and 12.5 mg/kg/day, respectively) during ten days, and their efficacy was compared to the reference compound pentavalent antimonial Glucantime (GLU). Compound 3 significantly reduced the number of parasites in the spleen (4.93 × 102 amastigotes/g) and liver (4.52 × 103 amastigotes/g). Compound 9 reduced the number of amastigotes in the spleen to 1.30 × 104 and 1.36 × 103 amastigotes/g in the liver. GLU was the most effective overall treatment (7.50 × 101 and 2.28 × 102 amastigotes/g in the spleen and liver, respectively). The high activity levels of these compounds in vivo may stem from their high in vitro leishmanicidal activity and lipophilicity. The in silico absorption, distribution, metabolism, and excretion studies also showed some anti-Leishmania potential. Compound 9 had more lipophilic characteristics than those of compound 3. In silico studies of the nine enzymes of compounds 3 and 9 showed significant evidence of interactions with nicotimidase and tyrosine aminotransferase, demonstrating possible inhibition enzymes present in L. (L.) infantum chagasi. These compounds could be a promising template for developing a new class of leishmanicidal agents, by oral route, and deserve further investigation to explore different therapeutic regimens.

Synthesis of Novel 1,2,3-Triazole Derivatives of Isocoumarins and 3,4-Dihydroisocoumarin with Potential Antiplasmodial Activity In Vitro.

BACKGROUND: Malaria greatly affects the world health, having caused more than 228 million cases only in 2018. The emergence of drug resistance is one of the main problems in its treatment, demonstrating the need for the development of new antimalarial drugs. OBJECTIVE: Synthesis and in vitro antiplasmodial evaluation of triazole compounds derived from isocoumarins and a 3,4-dihydroisocoumarin. METHODS: The compounds were synthesized in 4 to 6-step reactions with the formation of the triazole ring via the Copper(I)-catalyzed 1,3-dipolar cycloaddition between isocoumarin or 3,4- dihydroisocoumarin azides and terminal alkynes. This key reaction provided compounds with an unprecedented connection of isocoumarin or 3,4-dihydroisocoumarin and the 1,2,3-triazole ring. The products were tested for their antiplasmodial activity against a Plasmodium falciparum chloroquine resistant and sensitive strains (W2 and 3D7, respectively). RESULTS: Thirty-one substances were efficiently obtained by the proposed routes with an overall yield of 25-53%. The active substances in the antiplasmodial test displayed IC50 values ranging from 0.68-2.89 µM and 0.85-2.07 µM against W2 and 3D7 strains, respectively. CONCLUSION: This study demonstrated the great potential of isocoumarin or 3,4-dihydroisocoumarin derivatives because practically all the tested substances were active against Plasmodium falciparum.

Cocaethylene, the in vivo product of cocaine and ethanol, is a narcotic more potent than its precursors.

The molecular conformation and supramolecular architecture of cocaethylene [systematic name: ethyl (1R,2R,3S,5S)-3-benzoyloxy-8-methyl-8-azabicyclo[3.2.1]octane-2-carboxylate], C18H23NO4, have been determined for the first time. Cocaethylene is a narcotic produced in vivo when cocaine and ethanol are administered concomitantly. The intra- and intermolecular features of cocaethylene and its less potent narcotic precursor cocaine are very similar. The only molecular difference is in the conformation of the methyl group of the ethoxycarbonyl group. Similar to cocaine, the carboxylate atoms and the α-C atom are coplanar in cocaethylene, but the methyl C atom of the ethyl group is bent by ca 90° away from this plane in the narcotic reported here. The main supramolecular motif is a one-dimensional chain stabilized by weak C-H...O contacts.

Brephedrone: A new psychoactive substance seized in Brazil.

At the beginning of 2015, sixty-two capsules containing red-brown crystals seized in a historical city in Brazil were sent to this forensic laboratory for drug testing analysis. The material was identified as being Brephedrone, a new psychoactive substance and a bromine synthetic cathinone that is related to serotonin transportation. This substance was analyzed by ATR-FTIR, GC-MS, LC-MS, 1H, 13C and 2D NMR. Brephedrone apprehensions have been previously reported in Finland, France and Spain. It was the first detection of this substance in the State of Minas Gerais. No reports or information regarding any other apprehension nor identification of Brephedrone in Brazil were known prior to the present case.

Leishmanicidal, antiproteolytic, and mutagenic evaluation of alkyltriazoles and alkylphosphocholines.

A series of 16 simple long-chain alkyltriazoles and two novel alkylphosphocholine derivatives containing an azide moiety were evaluated in vitro for their leishmanicidal activity against. Among the 18 compounds tested, the eight most active compounds against promastigote forms were selected for further evaluation against amastigote forms. These compounds were also evaluated for their cytotoxicity against murine macrophages and tested as inhibitors of cysteine protease rCPB2.8, an important target for development of antileishmanial drugs. The mutagenicity of some of these compounds was also evaluated in prokaryotic and eukaryotic cells to assess any genetic effects of the leishmanicidal candidates. The compound 4, an alkylphosphocholine derivative, was found to be the most potent against amastigote forms with an IC50 of 3.81 µM, comparable to that of pentamidine (IC50 = 6.62 µM) and amphotericin B (IC50 = 6.10 µM), two established leishmanicidal drugs. Compound 4 also exhibited the best selectivity index (SI) values of the series, demonstrating low toxicity against macrophages and a cLogP value higher than 5. Among the alkyltriazoles, compounds 13 and 14 were the most active against promastigote and amastigote forms. They were then evaluated for their mutagenicity in vitro; the mutagenicity index (MI) values were lower than 2, suggesting that these compounds are not mutagenic.

Synthesis, kinetic studies and molecular modeling of novel tacrine dimers as cholinesterase inhibitors.

This study presents the synthesis of 15 new tacrine dimers as well as the Ki and IC50 results, studies of the kinetic mechanism, and molecular docking analysis of the dimers in relation to the cholinesterases hAChE, hBChE, EeAChE and eqBChE. In addition to spectroscopic characterization, X-ray structure determination was performed for two of the new compounds. These new dimers were found to be mixed nanomolar inhibitors of the evaluated targets with a broad and significant selectivity profile, and these properties are dependent on both the type of the linker and the volume of the hydroacridine alicyclic ring. The results indicate that the aromatic linkers play a significant role in generating specific interactions with the half-gorge region of the catalytic center. Thus, these types of linkers can positively modulate the electronic properties of the tacrine dimers studied with an improvement of their cholinesterase inhibition activity.