Structure-Aided Computational Design of Triazole-Based Targeted Covalent Inhibitors of Cruzipain.

Cruzipain (CZP), the major cysteine protease present in T. cruzi, the ethiological agent of Chagas disease, has attracted particular attention as a therapeutic target for the development of targeted covalent inhibitors (TCI). The vast chemical space associated with the enormous molecular diversity feasible to explore by means of modern synthetic approaches allows the design of CZP inhibitors capable of exhibiting not only an efficient enzyme inhibition but also an adequate translation to anti-T. cruzi activity. In this work, a computer-aided design strategy was developed to combinatorially construct and screen large libraries of 1,4-disubstituted 1,2,3-triazole analogues, further identifying a selected set of candidates for advancement towards synthetic and biological activity evaluation stages. In this way, a virtual molecular library comprising more than 75 thousand diverse and synthetically feasible analogues was studied by means of molecular docking and molecular dynamic simulations in the search of potential TCI of CZP, guiding the synthetic efforts towards a subset of 48 candidates. These were synthesized by applying a Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) centered synthetic scheme, resulting in moderate to good yields and leading to the identification of 12 hits selectively inhibiting CZP activity with IC50 in the low micromolar range. Furthermore, four triazole derivatives showed good anti-T. cruzi inhibition when studied at 50 µM; and Ald-6 excelled for its high antitrypanocidal activity and low cytotoxicity, exhibiting complete in vitro biological activity translation from CZP to T. cruzi. Overall, not only Ald-6 merits further advancement to preclinical in vivo studies, but these findings also shed light on a valuable chemical space where molecular diversity might be explored in the search for efficient triazole-based antichagasic agents.

Thiocyanation of BODIPY dyes and their conversion to thioalkylated derivatives.

A high-yielding method for the direct thiocyanation of BODIPY dyes is described. In 1,3-dimethyl BODIPYs, the thiocyanato group adds at position 2, whereas the insertion occurs at position 5 in 3-amino BODIPYs. The transformation of the thiocyanato group enables the synthesis of thioalkylated BODIPYs. 2-Thioalkylated BODIPYs and 3-thiocyanato-5-piperidino BODIPYs exhibit interesting spectroscopical features. Hence, the described synthetic methodology can be used for the photophysical tuning of BODIPY dyes.

Insights from zebrafish and mouse models on the activity and safety of ar-turmerone as a potential drug candidate for the treatment of epilepsy.

In a previous study, we uncovered the anticonvulsant properties of turmeric oil and its sesquiterpenoids (ar-turmerone, α-, ß-turmerone and α-atlantone) in both zebrafish and mouse models of chemically-induced seizures using pentylenetetrazole (PTZ). In this follow-up study, we aimed at evaluating the anticonvulsant activity of ar-turmerone further. A more in-depth anticonvulsant evaluation of ar-turmerone was therefore carried out in the i.v. PTZ and 6-Hz mouse models. The potential toxic effects of ar-turmerone were evaluated using the beam walking test to assess mouse motor function and balance. In addition, determination of the concentration-time profile of ar-turmerone was carried out for a more extended evaluation of its bioavailability in the mouse brain. Ar-turmerone displayed anticonvulsant properties in both acute seizure models in mice and modulated the expression patterns of two seizure-related genes (c-fos and brain-derived neurotrophic factor [bdnf]) in zebrafish. Importantly, no effects on motor function and balance were observed in mice after treatment with ar-turmerone even after administering a dose 500-fold higher than the effective dose in the 6-Hz model. In addition, quantification of its concentration in mouse brains revealed rapid absorption after i.p. administration, capacity to cross the BBB and long-term brain residence. Hence, our results provide additional information on the anticonvulsant properties of ar-turmerone and support further evaluation towards elucidating its mechanism of action, bioavailability, toxicity and potential clinical application.

Synthesis, biological evaluation and molecular modeling of 4,6-diarylpyrimidines and diarylbenzenes as novel non-nucleosides HIV-1 reverse transcriptase inhibitors.

A series of novel 4,6-diarylpyrimidines (4,6-DAPY) and diarylbenzenes (DABE) compounds were synthesized and evaluated as inhibitors of human immunodeficiency virus type-1 (HIV-1). Among them, the most potent HIV-1 inhibitors were 8b, 8d, 14b and 18 (EC(50) = 0.049, 0.381, 0.599 and 0.398 µM, respectively), with HIV-1 inhibitory activity improved or similar to nevirapine (NVP, EC(50) = 0.097 µM) and delavirdine (DEV, EC(50) = 0.55 µM). The other compounds displayed moderate activity (8c, EC(50) = 5.25 µM) or were inactive (8a and 14a) against HIV-1 replication. Molecular modeling studies were performed with the synthesized compounds in complex with the wild-type reverse transcriptase (RT). A correlation was found between the anti-HIV activity and the electrostatic energy of interaction with Lys101 residue. These findings enrich the SAR of these Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs) families.

New Flavonoids from Boldoa purpurascens Cav.

Phytochemical analysis of the leaves of BOLDOA PURPURASCENS Cav. led to isolation of four flavone glycosides, three of which are new compounds. Their structures have been determined by mass spectrometry and by 1 D and 2 D NMR analysis, i. e., 4',5-dihydroxy-6,7-methylenedioxyflavonol 3- O-alpha- L-rhamnopyranosyl-(1-->2)-beta- D-xylopyranoside ( 1), 4',5-dihydroxy-6,7-methylenedioxyflavonol 3- O-beta- D-xylopyranoside ( 2), and 4',5-dihydroxy-6,7-methylenedioxyflavonol 3- O-alpha- L-rhamnopyranosyl-(1-->2)-beta- D-glucopyranoside ( 3). The known compound was 4',5-dihydroxy-6,7-methylenedioxyflavonol 3- O-beta- D-glucopyranoside ( 4). The aglycone 4',5-dihydroxy-6,7-methylenedioxyflavonol is known as gomphrenol. Compounds 1 and 2 failed to show antifungal activity when tested against three different strains of fungi, i. e., FUSARIUM CULMORUM, BOTRYTIS CINEREA, and ASPERGILLUS FLAVUS.