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.

New Hybrid Scaffolds Based on 5-FU/Curcumin: Synthesis, Cytotoxic, Antiproliferative and Pro-Apoptotic Effect.

A series of 5-FU-Curcumin hybrids were synthesized, and their structures were elucidated by spectroscopic analysis. The synthesized hybrid compounds were evaluated in different colorectal cancer cell lines (SW480 and SW620) and in non-malignant cells (HaCaT and CHO-K1), to determine their chemopreventive potential. Hybrids 6a and 6d presented the best IC50 value against the SW480 cell line with results of 17.37 ± 1.16 µM and 2.43 ± 0.33 µM, respectively. Similarly, compounds 6d and 6e presented IC50 results of 7.51 ± 1.47 µM and 14.52 ± 1.31 µM, respectively, against the SW620 cell line. These compounds were more cytotoxic and selective than curcumin alone, the reference drug 5-fluorouracil (5-FU), and the equimolar mixture of curcumin and 5-FU. In addition, hybrids 6a and 6d (in SW480) and compounds 6d and 6e (in SW620) induced cell cycle arrest in S-phase, and, compounds 6d and 6e caused a significant increase in the sub-G0/G1 phase population in both cell lines. Hybrid 6e was also observed to induce apoptosis of SW620 cells with a respective increase in executioner caspases 3 and 7. Taken together, these results suggest that the hybrids could actively act on a colorectal cancer model, making them a privileged scaffold that could be used in future research.

Resveratrol/Hydrazone Hybrids: Synthesis and Chemopreventive Activity against Colorectal Cancer Cells.

A series of resveratrol/hydrazone hybrids were obtained and elucidated by spectroscopic analysis. All compounds were evaluated against colorectal cancer cells (SW480 and Sw620) and nonmalignant cell lines (HaCaT and CHO-K1) to establish the selectivity index. Among the hybrids evaluated, compounds 6e and 7 displayed the highest cytotoxic activity with IC50 values of = 6.5 ± 1.9 µM and 19.0 ± 1.4 µM, respectively, on SW480 cells. In addition, hybrid 7 also exhibited activity on SW620 cells with an IC50 value of 38.41 ± 3.3 µM. Both compounds were even more toxic against these malignant cells in comparison to the nonmalignant ones, as evidenced by higher selectivity indices 48 h after treatment. These compounds displayed better activity and selectivity than parental compounds (PIH and Resveratrol) and the reference drug (5-FU). In addition, it was observed that both compounds caused antiproliferative activity probably exerted by cell cycle arrest at the G2/M or G0/G1 phases, with the formation of cells in the subG0/G1 phase. Furthermore, it was noticed that compound 7 induced mitochondrial depolarization in SW480 cells and positive staining for propidium iodide in both cancer cell lines, suggesting cell membrane damage involving either apoptosis or other processes of death.

Chemopreventive Effect on Human Colon Adenocarcinoma Cells of Styrylquinolines: Synthesis, Cytotoxicity, Proapoptotic Effect and Molecular Docking Analysis.

Seven styrylquinolines were synthesized in this study. Two of these styrylquinolines are new and were elucidated by spectroscopic analysis. The chemopreventive potential of these compounds was evaluated against SW480 human colon adenocarcinoma cells, its metastatic derivative SW620, and normal cells (HaCaT). According to the results, compounds 3a and 3d showed antiproliferative activity in SW480 and SW620 cells, but their effect seemed to be caused by different mechanisms of action. Compound 3a induced apoptosis independent of ROS production, as evidenced by increased levels of caspase 3, and had an immunomodulatory effect, positively regulating the production of different immunological markers in malignant cell lines. In contrast, compound 3d generated a pro-oxidant response and inhibited the growth of cancer cells, probably by another type of cell death other than apoptosis. Molecular docking studies indicated that the most active compound, 3a, could efficiently bind to the proapoptotic human caspases-3 protein, a result that could provide valuable information on the biochemical mechanism for the in vitro cytotoxic response of this compound in SW620 colon carcinoma cell lines. The obtained results suggest that these compounds have chemopreventive potential against CRC, but more studies should be carried out to elucidate the molecular mechanisms of action of each of them in depth.

Synthesis and Chemopreventive Potential of 5-FU/Genistein Hybrids on Colorectal Cancer Cells.

A series of 5-FU-Genistein hybrids were synthesized and their structures were elucidated by spectroscopic analysis. The chemopreventive potential of these compounds was evaluated in human colon adenocarcinoma cells (SW480 and SW620) and non-malignant cell lines (HaCaT and CHO-K1). Hybrid 4a displayed cytotoxicity against SW480 and SW620 cells with IC50 values of 62.73 ± 7.26 µM and 50.58 ± 1.33 µM, respectively; compound 4g induced cytotoxicity in SW620 cells with an IC50 value of 36.84 ± 0.71 µM. These compounds were even more selective than genistein alone, the reference drug (5-FU) and the equimolar mixture of genistein plus 5-FU. In addition, hybrids 4a and 4g induced time- and concentration-dependent antiproliferative activity and cell cycle arrest at the S-phase and G2/M. It was also observed that hybrid 4a induced apoptosis in SW620 cells probably triggered by the extrinsic pathway in response to the activation of p53, as evidenced by the increase in the levels of caspases 3/8 and the tumor suppressor protein (Tp53). Molecular docking studies suggest that the most active compound 4a would bind efficiently to proapoptotic human caspases 3/8 and human Tp53, which in turn could provide valuable information on the biochemical mechanism for the in vitro cytotoxic response of this compound in SW620 colon carcinoma cell lines. On the other hand, molecular dynamics (MD) studies provided strong evidence of the conformational stability of the complex between caspase-3 and hybrid 4a obtained throughout 100 ns all-atom MD simulation. Molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) analyses of the complex with caspase-3 showed that the interaction between the ligand and the target protein is stable. Altogether, the results suggest that the active hybrids, mainly compound 4a, might act by modulating caspase-3 activity in a colorectal cancer model, making it a privileged scaffold that could be used in future investigations.

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.

Fe3+ chelating quinoline-hydrazone hybrids with proven cytotoxicity, leishmanicidal, and trypanocidal activities.

Neglected tropical diseases cause great concern in developing countries where there are millions of reported infected humans. It is well known that chelating agents inhibit parasite growth by depriving them of iron, an essential nutrient for cell growth and division; therefore, in this work, we use computational methods to explore the Fe3+ chelating abilities of a set of 10 quinoline-hydrazone hybrids (28 substructures in total) whose cytotoxicity, leishmanicidal, and trypanocidal activities are known. We quantify stabilizing effects in the bare molecules as well as in the iron complexes and show how iron complexation reduces the structural space. Most noticeably, we provide evidence to support a direct relationship between biological activity and the Fe3+ chelating ability.

Actividad leishmanicida y antioxidante de extractos de Piper daniel-gonzalezii Trel. (Piperaceae) / Leishmanicidal and antioxidant activity of extracts of Piper daniel-gonzalezii Trel. (Piperaceae)

Introducción: la leishmaniasis es la enfermedad protozoaria responsable de la mayor morbilidad y mortalidad en la población mundial. Los medicamentos utilizados para su tratamiento presentan serios problemas, entre estos la alta toxicidad y los efectos secundarios severos. Por otro lado, la producción de radicales libres debido al estrés oxidativo ocasiona la oxidación de lípidos, proteínas, DNA y enzimas que son responsables del daño del tejido celular. Algunas especies de la familia Piperaceae presentan un amplio espectro de actividades biológicas, lo cual incita a la exploración de la propiedad antioxidante y antiprotozoaria en miembros del género Piper, como una alternativa en la búsqueda de nuevos medicamentos contra la leishmaniasis y de nuevos antioxidantes naturales. Objetivo: evaluar la actividad leishmanicida, citotóxica y antioxidante de extractos alcohólicos y no alcohólicos de Piper daniel-gonzalezii Trel. Métodos: después de secado el material vegetal (tallos y hojas), se realizó un proceso de extracción por percolación con etanol. La solución obtenida se concentró a presión reducida y con el extracto crudo de las hojas se hizo la partición por cromatografía en columna, con solventes de diferente polaridad como hexano, diclorometano y acetato de etilo. Se evaluó la actividad leishmanicida en amastigotes axénicos e intracelulares para cada fracción y cada extracto etanólico. Se evaluó la citotoxicidad en células U-937 y la capacidad antioxidante mediante el método FRAP (ferric reducing ability of plasma). Resultados: la fracción obtenida por percolación con hexano (fracción de desengrase) y el extracto etanólico de los tallos resultaron los más activos contra amastigotes intracelulares de Leishmania panamensis, lo cual las hace fracciones promisorias en la búsqueda de nuevos compuestos con actividad leishmanicida. Los dos extractos y todas las fracciones, con excepción de la fracción de desengrase, mostraron una alta capacidad reductora, por lo tanto, estas fracciones, principalmente la de acetato de etilo, se consideran como potenciales fuentes de sustancias antioxidantes. Conclusiones: los resultados muestran que Piper daniel-gonzalezii presenta propiedades tanto leishmanicida como reductora, por lo cual tiene un alto potencial como fuente de compuestos para el desarrollo de nuevas alternativas terapéuticas contra la leishmaniasis, o como una fuente natural de antioxidantes con un alto uso potencial en la industria farmacéutica y de alimentos.

Introduction: leishmaniasis is the protozoal disease with the highest morbidity and mortality worldwide. The medications used to treat it have serious drawbacks, among which are their high toxicity and severe side effects. On the other hand, production of free radicals due to oxidative stress results in the oxidation of lipids, proteins, DNA and enzymes responsible for cell tissue damage. Some species of the family Piperaceae present a broad spectrum of biological activities, inviting exploration of the antioxidant and antiprotozoal properties of members of the genus Piper as an alternative in the search for new drugs against leishmaniasis and new natural antioxidants. Objective: evaluate the leishmanicidal, cytotoxic and antioxidant activity of alcoholic and non-alcoholic extracts of Piper daniel-gonzalezii Trel. Methods: drying of the plant material (stems and leaves) was followed by extraction by percolation with ethanol. The solution thus obtained was concentrated under reduced pressure, and the crude leaf extract was subjected to partition column chromatography with solvents of varying polarity, such as hexane, dichloromethane and ethyl acetate. Leishmanicidal activity in axenic and intracellular amastigotes was evaluated for each fraction and ethanolic extract. An evaluation was conducted of cytotoxicity in U-937 cells and of antioxidant capacity by the FRAP (ferric reducing ability of plasma) method. Results: the fraction obtained by percolation with hexane (degreasing fraction) and the ethanolic stem extract were the most active against intracellular amastigotes of Leishmania panamensis, a fact that turns them into promising fractions in the search for new compounds with leishmanicidal activity. The two extracts and all the fractions, except for the degreasing fraction, exhibited a high reducing capacity. These fractions, particularly the ethyl acetate fraction, are therefore considered to be potential sources of antioxidant substances. Conclusions: results show that Piper daniel-gonzalezii has both leishmanicidal and reducing properties, and thus great potential either as a source of compounds for developing new therapeutic alternatives against leishmaniasis, or as a natural source of antioxidants with great potential for use in the pharmaceutical and food industries.