3-styrylcoumarin scaffold-based derivatives as a new approach for leishmaniasis intervention: biological and molecular modeling studies.

Seven 3-styrylcoumarins were tested for antileishmanial activity against Leishmania (Viannia) panamensis amastigotes. Cytotoxic activity was also evaluated against mammalian U-937 cells. The 3-methoxy-4-hydroxy coumarin derivative 6 was the most active with an IC50 of 40.5 µM, and did not reveal any conspicuous toxicity toward mammalian U-937 cells. Therefore, it may have potential to be considered as candidate for antileishmanial drug development. Further, among several druggable Leishmania targets, molecular docking studies revealed that compound 6 had docking preference by the N-myristoyltransferase (Lp-NMT) of Leishmania panamensis, showing a higher docking score of - 10.1 kcal mol-1 than positive controls and making this protein as a presumably druggable target for this compound. On the other hand, molecular dynamics simulations affirm the docking hypothesis, showing a conformational stability of the 6/Lp-NMT complex throughout 100 ns simulation. Moreover, the molecular mechanics/Poisson-Boltzmann surface area method also support the docking findings, revealing a total free energy of binding of - 47.26 ± 0.08 kcal mol-1, and identifying through energy decomposition analysis that those key aminoacids are contributing strongly to ligand binding. Finally, an optimal pharmacokinetic profile was also estimated for 6. Altogether, coumarin 6 could be addressed as starting point for further pharmacological studies concerning the therapeutic leishmaniasis intervention.

Novel Multipotent Amantadine-M30D Hybrids with Highly Selective Butyrylcholinesterase Inhibition and Neuroprotective Effects as Effective Anti-Alzheimer's Agents.

As a contribution to the development of new dual/multifunctional drugs, a novel therapeutical scaffold merging key structural features from memantine and M30D was designed, synthesized, and explored for its AChE/BuChE inhibitory activity and neuroprotective effects. All synthetized hybrids were not able to inhibit AChE, but most of them exhibit inhibition with high selectivity toward butyrylcholinesterase (BuChE). Notably, among the tested compounds, amantadine/M30D hybrids with six, seven, nine, and twelve methylene groups in the spacer (5d, 5e, 5f, and 5g) not only highlighted having the best potency and selective butyrylcholinesterase inhibition greater than 83% but also, particularly 5e and 5d, elicited considerable neuroprotection when evaluated in pretreatment conditions, by reducing injury effects caused by glutamate with maximum protection reached about 47.82 ± 0.81% (5e) and 42 ± 2.20% (5d) in comparison with memantine (37.27 ± 2.69%). Likewise, we chose 5e as the hit compound, which in a glutamate excitotoxity coculture model prevented astroglia reactivity and neuronal death, as well as a 91% restoration of calcium levels and an increasing ATP level in both pre-/post-treatments of 61.48 ± 4.60 and 45.16 ± 10.55%, respectively. Regarding docking studies, a blockade of the NMDA channel pore by 5e would explain its neuroprotective response. Finally, the hit compound 5e exhibited in vitro blood-brain barrier (BBB) permeability and human plasma stability, as well as an optimal in silico neuropharmacokinetic profile. From a therapeutic perspective, merging key pharmacophoric features from memantine and M30D provides a new medicinal scaffold with dual-/multifunctional properties and human plasma stability for the future development of potential drugs for treating AD.

Proapoptotic Effect and Molecular Docking Analysis of Curcumin-Resveratrol Hybrids in Colorectal Cancer Chemoprevention.

Different hybrids based on curcumin and resveratrol were previously synthesized and characterized by spectroscopic techniques. The most active molecules (3a, 3e, 3i, and 3k) were evaluated in vitro as an approach to determine the possible mechanism of action of the hybrids. The results indicated that the evaluated curcumin/resveratrol hybrids induce mitochondrial instability in SW620 and SW480 cells. Moreover, these molecules caused a loss in membrane integrity, suggesting an apoptotic process mediated by caspases after the treatment with compounds 3i (SW480) and 3k (SW620). In addition, the results suggest that the mechanism of action of the hybrids could be independent of the p53 status. Furthermore, hybrids 3e and 3i caused G0/G1 phase arrest, which highlights the potential of these molecules not only as cytotoxic but also as cytostatic compounds. Hybrids 3e and 3i caused a negative modulation of the matrix metalloproteinase 7 (MMP7) on SW480 cells. These curcumin resveratrol hybrids could be potential candidates for further investigations in the search for potential chemopreventive agents, even in those cases with resistance to conventional chemotherapy because of the lack of p53 expression or function. Molecular docking simulations showed that compounds 3e, 3i, and 3k bind efficiently to proapoptotic human caspases 3/7 proteins, as well as human MMP-7 and p53, which, in turn, could explain at the molecular level the in vitro cytotoxic effect of these compounds in SW480 and SW620 colon cancer cell lines.

Promising Hybrids Derived from S-Allylcysteine and NSAIDs Fragments against Colorectal Cancer: Synthesis, In-vitro Evaluation, Drug-Likeness and In-silico ADME/tox Studies.

We synthesized twelve hybrids, S-allyl Cysteine methyl, ethyl and propyl ester-based non-steroidal anti-inflammatory drugs and their structures were elucidated by spectroscopic analysis. The chemopreventive potential of all compounds was evaluated against SW480 human colon adenocarcinoma cells and the non-malignant CHO-K1 cell line. Among the tested compounds, hybrids 10b-c, 11b and 12b displayed the best anticancer activity with IC50 values between 0.131-0.183 mM and selectivity indices higher than 1 after 48 h of treatment. Selectivity indices were comparable to those reported for the reference drug, 5-fluorouracil (SI > 1). The SAR analysis showed that compounds with two carbon atom alkylic chains displayed the best activity (10b, 11b and 12b). Modeling studies including drug-likeness, bioactivity score and ADME/tox studies using online tools like molinspiration and Osiris suggested that these designed hybrids have a good pharmacological profile and can be considered as promising scaffolds for further studies in the search for new therapeutic alternatives to treat colorectal cancer.

Antileishmanial and cytotoxic activities of four Andean plant extracts from Colombia.

BACKGROUND AND AIM: Licania salicifolia (L.S) Cuatrec., Persea ferruginea (P.F) Kunth, Oreopanax floribundus (O.F), and Psychotria buchtienii (P.B) belong to the families Chrysobalanaceae, Lauraceae, Araliaceae, and Rubiaceae, respectively, which have been used as medicines by communities in the Andes. This study evaluated the leishmanicidal and cytotoxic activities of alcohol and non-alcohol extracts from four Andean plant extracts (L.S, O.F, P.F, and P.B). MATERIALS AND METHODS: Extracts were obtained by percolation with solvents of different polarities - hexane, dichloromethane, ethyl acetate, and ethanol. Phytochemical screening was conducted based on reported methods. All products were evaluated in vitro to determine the leishmanicidal activity against amastigotes of Leishmania panamensis and cytotoxicity against U937 cells. RESULTS: Flavonoids, triterpenes, and tannins were the main secondary metabolites found. From the results, dichloromethane extracts from O.F and P.B, ethanol extract from P.B, and ethyl acetate extracts of all plants were active, with EC50 <30 µg/mL. Ethyl acetate was the most active extract, which showed EC50 values of 9.8, 14.1, 23.7, and 25.5 µg/mL, for L.S, P.B, O.F, and P.F, respectively. Hexane extracts from P.B and O.F exhibited moderate activity with EC50 values of 84.8 and 87.4 µg/mL, respectively. Hexane and ethanol extracts from O.F, ethyl acetate, and ethanol extracts from L.S, and all extracts from P.F were not toxic. Alternatively, hexane and dichloromethane extracts from L.S and P.B as well as dichloromethane and ethyl acetate extracts from O.F displayed high toxicity. CONCLUSION: Based on the activity we observed, ethyl acetate extract can continue in its usage in the search for new antileishmanial drugs, mainly ethyl acetate extract from L.S showed activity comparable to meglumine antimoniate and was not cytotoxic.

Hybrid Molecules: Promising Compounds for the Development of New Treatments Against Leishmaniasis and Chagas Disease.

Leishmaniasis and Chagas disease are endemic pathologies in tropical countries. These cause high morbidity and a public health problem. Current chemotherapies are based on conventional drugs with variable efficacy and toxicity related with the length of therapeutic schemes and high doses. When two pharmacological agents are combined into a single molecule, the result is the so-called hybrid molecule. In the search for new treatments against Chagas disease and leishmaniasis, several studies have shown that hybrid molecules display high antiprotozoal activity and this emerging strategy is quite promising in the field of new drug discovery and development. This review focuses on the antiprotozoal activity of different hybrids obtained from the hybridization of pharmacophores, showing that the most of the efforts have been concentrated in the molecular hybridization of quinoline, chalcone and hydrazone moieties.

A hydrogen-bonded tetramer in (2RS,4SR)-7-bromo-2-(2-methylphenyl)-2,3,4,5-tetrahydro-1H-naphtho[1,2-b]azepin-4-ol and a three-dimensional hydrogen-bonded framework in (2RS,4SR)-2-(3-methylthiophen-2-yl)-2,3,4,5-tetrahydro-1H-naphtho[1,2-b]azepin-4-ol.

(2RS,4SR)-7-Bromo-2-(2-methylphenyl)-2,3,4,5-tetrahydro-1H-naphtho[1,2-b]azepin-4-ol, C21H20BrNO, (I), and (2RS,4SR)-2-(3-methylthiophen-2-yl)-2,3,4,5-tetrahydro-1H-naphtho[1,2-b]azepin-4-ol, C19H19NOS, (II), both crystallize with Z' = 2 in the space groups P2(1)/c and Cc, respectively; compound (II) crystallizes as a nonmerohedral twin, with twin fractions 0.183 (2) and 0.817 (2). The molecules of (I) are linked by O-H···O and O-H···N hydrogen bonds to form a cyclic centrosymmetric R4(4)(16) tetramer. The molecules of (II) are linked by O-H···O hydrogen bonds to form a C2(2)(4) chain and these chains are weakly linked by a single C-H···π(thienyl) interaction to form a three-dimensional array. Comparisons are made with some related compounds.

Three closely related thienyl-substituted 1,4-epoxynaphtho[1,2-b]azepines: hydrogen-bonded assembly in one, two and three dimensions.

(2R,4S)-2-(3-Methylthiophen-2-yl)-2,3,4,5-tetrahydro-1,4-epoxynaphtho[1,2-b]azepine, C19H17NOS, (I), crystallizes with a single enantiomer in each crystal, whereas its geometrical isomer (2RS,4SR)-2-(5-methylthiophen-2-yl)-2,3,4,5-tetrahydro-1,4-epoxy-naphtho[1,2-b]azepine, (II), and (2RS,4SR)-2-(5-bromothiophen-2-yl)-2,3,4,5-tetrahydro-1,4-epoxynaphtho[1,2-b]azepine, C18H14BrNOS, (III), both crystallize as racemic mixtures. A combination of one C-H...O hydrogen bond and two C-H...π(arene) hydrogen bonds links the molecules of (I) into a three-dimensional framework; the molecules of (II) are linked into a C(4)C(4)[R2(2)(7)] chain of rings by a combination of C-H...N and C-H...O hydrogen bonds; and in (III), where Z' = 2, a combination of four C-H...π(arene) hydrogen bonds and two C-H...π(thienyl) hydrogen bonds links the molecules into complex sheets. Comparisons are made with the assembly patterns in some aryl-substituted 1,4-epoxynaphtho[1,2-b]azepines.

Six closely related 4,6-disubstituted 2-amino-5-formylpyrimidines: different ring conformations, polarized electronic structures, and hydrogen-bonded assembly in zero, one, two and three dimensions.

In each of ethyl N-{2-amino-5-formyl-6-[methyl(phenyl)amino]pyrimidin-4-yl}glycinate, C(16)H(19)N(5)O(3), (I), N-{2-amino-5-formyl-6-[methyl(phenyl)amino]pyrimidin-4-yl}glycinamide, C(14)H(16)N(6)O(2), (II), and ethyl 3-amino-N-{2-amino-5-formyl-6-[methyl(phenyl)amino]pyrimidin-4-yl}propionate, C(17)H(21)N(5)O(3), (III), the pyrimidine ring is effectively planar, but in each of methyl N-{2-amino-6-[benzyl(methyl)amino]-5-formylpyrimidin-4-yl}glycinate, C(16)H(19)N(5)O(3), (IV), ethyl 3-amino-N-{2-amino-6-[benzyl(methyl)amino]-5-formylpyrimidin-4-yl}propionate, C(18)H(23)N(5)O(3), (V), and ethyl 3-amino-N-[2-amino-5-formyl-6-(piperidin-4-yl)pyrimidin-4-yl]propionate, C(15)H(23)N(5)O(3), (VI), the pyrimidine ring is folded into a boat conformation. The bond lengths in each of (I)-(VI) provide evidence for significant polarization of the electronic structure. The molecules of (I) are linked by paired N-H···N hydrogen bonds to form isolated dimeric aggregates, and those of (III) are linked by a combination of N-H···N and N-H···O hydrogen bonds into a chain of edge-fused rings. In the structure of (IV), molecules are linked into sheets by means of two hydrogen bonds, both of N-H···O type, in the structure of (V) by three hydrogen bonds, two of N-H···N type and one of C-H···O type, and in the structure of (VI) by four hydrogen bonds, all of N-H···O type. Molecules of (II) are linked into a three-dimensional framework structure by a combination of three N-H···O hydrogen bonds and one C-H···O hydrogen bond.

2-Amino-6-methoxy-4-(4-methylanilino)-5-nitrosopyrimidine and ethyl N-[4-(adamantan-1-ylamino)-2-amino-5-nitrosopyrimidin-6-yl]-3-aminopropionate: polarized electronic structures and hydrogen-bonded supramolecular assembly in one and two dimensions.

In both 2-amino-6-methoxy-4-(4-methylanilino)-5-nitrosopyrimidine, C(12)H(13)N(5)O(2), (I), and ethyl N-[4-(1-adamantylamino)-2-amino-5-nitrosopyrimidin-6-yl]-3-aminopropionate, C(19)H(28)N(6)O(3), (II), the nitrosopyrimidine unit is planar and the bond distances provide evidence for significant polarization of the electronic structures. In (II), the ethoxycarbonyl fragment of the molecule is disordered over two sets of sites with occupancies of 0.910 (4) and 0.090 (4). In the molecules of both compounds, there is an intramolecular N-H···O hydrogen bond. The molecules of (I) are linked into a chain of rings by a combination of N-H···O and C-H···O hydrogen bonds, while the molecules of (II) are linked by a two-centre N-H···N hydrogen bond and a three-centre N-H···(N,O) hydrogen bond to form sheets containing four distinct types of ring.

(2RS,4SR)-7-bromo-2-exo-(2-chlorophenyl)-2,3,4,5-tetrahydro-1,4-epoxynaphtho[1,2-b]azepine: sheets built by the π-stacking of hydrogen-bonded chains.

The molecules of the title compound, C(20)H(15)BrClNO, are linked into chains by a C-H...π(arene) hydrogen bond, in which the acceptor is the brominated ring of the naphthalene unit, and these chains are linked by an aromatic π-π stacking interaction, again involving the naphthalene unit, into a sheet structure.

Ring conformations and intermolecular interactions in two fused dibenzoazocines.

5-Acetyl-2-chloro-8,11-dimethyl-5,6,11,12-tetrahydrodibenzo[b,f]azocine, C(19)H(20)ClNO, (I), crystallizes as a single fully ordered isomer, but 14-acetyl-8,11-dimethyl-7,8,13,14-tetrahydrobenzo[f]naphtho[1,2-b]azocine-14-acetyl-8,9-dimethyl-7,8,13,14-tetrahydrobenzo[f]naphtho[1,2-b]azocine (74/26), C(23)H(23)NO, (II), exhibits threefold whole-molecule disorder involving both configurational and structural isomers. In (I) and in the predominant form of (II), the azocine rings adopt very similar conformations, forming boat-shaped rings having approximate twofold rotational symmetry. There are no direction-specific intermolecular interactions in the crystal structure of (I), but the molecules of (II) are weakly linked into chains by an aromatic pi-pi stacking interaction. The compounds were made under green conditions using an acid-catalysed cyclization process having very high atom utilization.

(2R,4S)-7-Bromo-2-phenyl-2,3,4,5-tetrahydro-1,4-epoxynaphtho[1,2-b]azepine, (2RS,4SR)-7-bromo-2-(4-chlorophenyl-2,3,4,5-tetrahydro-1,4-epoxynaphtho[1,2-b]azepine and (2RS,4SR)-2-(4-fluorophenyl)-2,3,4,5-tetrahydro-1,4-epoxynaphtho[1,2-b]azepine: hydrogen-bonded structures in two and three dimensions.

(2R,4S)-7-Bromo-2-phenyl-2,3,4,5-tetrahydro-1,4-epoxynaphtho[1,2-b]azepine, C(20)H(16)BrNO, (I), exhibits evidence of a modest degree (ca 10%) of inversion twinning, while both (2RS,4SR)-7-bromo-2-(4-chlorophenyl)-2,3,4,5-tetrahydro-1,4-epoxynaphtho[1,2-b]azepine, C(20)H(15)BrClNO, (II), and (2RS,4SR)-2-(4-fluorophenyl)-2,3,4,5-tetrahydro-1,4-epoxynaphtho[1,2-b]azepine, C(20)H(16)FNO, (III), crystallize as genuine racemic mixtures. The molecules of (I) are linked into sheets by a combination of one C-H...O hydrogen bond and two C-H...pi(arene) hydrogen bonds, while those of (II) are linked into sheets of pi-stacked hydrogen-bonded chains. A combination of one C-H...O hydrogen bond and four independent C-H...pi(arene) hydrogen bonds links the molecules of (III) into a three-dimensional framework. The significance of this study lies in its finding, via comparison with the structures of some closely-related epoxybenzazepine analogues, of significant changes in crystal structures consequent upon small changes in the peripheral substituents.