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-Aryl-2(trifluoromethyl)benzo[][1,8]naphthyridin-4(1)-one as Convenient Platform to Design High Photostable and Long-Lived Dyad Fluorophore with Potential Application in Live-Cell Imaging. J Photochem Photobiol A Chem 2023. [DOI: 10.1016/j.jphotochem.2023.114619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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Romero AH, Cerecetto HE. High CT-Fluorophore Featuring a Basic Moiety into D-A Chain as a p Ka Probe. J Org Chem 2022; 87:7618-7634. [PMID: 35671375 DOI: 10.1021/acs.joc.1c03104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The determination of acidity represents a significant challenge within fluorometry, and no effective strategy has been developed successfully yet. It is attributed to the fact that acidity tends to be enhanced upon excitation, giving, in general, an overestimation of the ionization constant, pKa. Herein, we developed a strategy for pKa estimation of Brønsted acids in solution through fluorometry by using a convenient pKa probe, N1-aryl-7-methoxy-2-(trifluoromethyl)benzo[b][1,8]naphthyridin-4(1H)-one. It allowed us to obtain a linear log KSV versus pKa correlation derived from the selective quenching response of the probe by an interaction with different Brønsted acids. The key points of N1-aryl-7-methoxy-2-(trifluoromethyl)benzo[b][1,8]naphthyridin-4(1H)-one as a pKa probe were (i) the location of a weak basic moiety in the donor-acceptor chain of the fluorophore, which favors a selective quenching of the intramolecular charge-transfer process according to the acidity of acid, and (ii) the high CT character upon excitation that promotes higher quenching magnitudes and favors a wider pKa range (19.5pKa) for the log KSV versus pKa correlation. Other key principles were to delimit the study to pure proton transfer and nonfluorescent acids, which allowed restricting the quenching response to a process dependent mainly on the acid-base equilibrium. All these findings open a new perspective as a proof of concept to design effective fluorescent pKa probes.
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Affiliation(s)
- Angel H Romero
- Grupo de Química Orgánica Medicinal, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay
| | - Hugo E Cerecetto
- Grupo de Química Orgánica Medicinal, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay.,Área de Radiofarmacia, Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, Mataojo 2055, 11400 Montevideo, Uruguay
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Acosta M, Gotopo L, Gamboa N, Rodrigues JR, Henriques GC, Cabrera G, Romero AH. Antimalarial Activity of Highly Coordinative Fused Heterocycles Targeting β -Hematin Crystallization. ACS OMEGA 2022; 7:7499-7514. [PMID: 35284702 PMCID: PMC8908514 DOI: 10.1021/acsomega.1c05393] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 02/09/2022] [Indexed: 06/14/2023]
Abstract
The β-hematin formation is a unique process adopted by Plasmodium sp. to detoxify free heme and represents a validated target to design new effective antimalarials. Most of the β-hematin inhibitors are mainly based on 4-aminoquinolines, but the parasite has developed diverse defense mechanisms against this type of chemical system. Thus, the identification of other molecular chemical entities targeting the β-hematin formation pathway is highly needed to evade resistance mechanisms associated with 4-aminoquinolines. Herein, we showed that the highly coordinative character can be a useful tool for the rational design of antimalarial agents targeting β-hematin crystallization. From a small library consisting of five compound families with recognized antitrypanosomatid activity and coordinative abilities, a group of tetradentate 1,4-disubstituted phthalazin-aryl/heteroarylhydrazinyl derivatives were identified as potential antimalarials. They showed a remarkable curative response against Plasmodium berghei-infected mice with a significant reduction of the parasitemia, which was well correlated with their good inhibitory activities on β-hematin crystallization (IC50 = 5-7 μM). Their in vitro inhibitory and in vivo responses were comparable to those found for a chloroquine reference. The active compounds showed moderate in vitro toxicity against peritoneal macrophages, a low hemolysis response, and a good in silico ADME profile, identifying compound 2f as a promising antimalarial agent for further experiments. Other less coordinative fused heterocycles exhibited moderate inhibitory responses toward β-hematin crystallization and modest efficacy against the in vivo model. The complexation ability of the ligands with iron(III) was experimentally and theoretically determined, finding, in general, a good correlation between the complexation ability of the ligand and the inhibitory activity toward β-hematin crystallization. These findings open new perspectives toward the rational design of antimalarial β-hematin inhibitors based on the coordinative character as an alternative to the conventional β-hematin inhibitors.
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Affiliation(s)
- María
E. Acosta
- Unidad
de Bioquímica, Facultad de Farmacia, Universidad Central de Venezuela, Los Chaguaramos, Caracas 1041-A, Venezuela
| | - Lourdes Gotopo
- Laboratorio
de Síntesis Orgaínica, Escuela de Química, Facultad de Ciencias, Universidad Central de Venezuela, Los Chaguaramos, Caracas 1041-A, Venezuela
| | - Neira Gamboa
- Unidad
de Bioquímica, Facultad de Farmacia, Universidad Central de Venezuela, Los Chaguaramos, Caracas 1041-A, Venezuela
| | - Juan R. Rodrigues
- Unidad
de Bioquímica, Facultad de Farmacia, Universidad Central de Venezuela, Los Chaguaramos, Caracas 1041-A, Venezuela
| | - Genesis C. Henriques
- Unidad
de Bioquímica, Facultad de Farmacia, Universidad Central de Venezuela, Los Chaguaramos, Caracas 1041-A, Venezuela
| | - Gustavo Cabrera
- Laboratorio
de Síntesis Orgaínica, Escuela de Química, Facultad de Ciencias, Universidad Central de Venezuela, Los Chaguaramos, Caracas 1041-A, Venezuela
| | - Angel H. Romero
- Caítedra
de Química General, Facultad de Farmacia, Universidad Central de Venezuela, Los Chaguaramos, Caracas 1041-A, Venezuela
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Romero AH, Romero IE, Piro OE, Echeverría GA, Gotopo LA, Moller MN, Rodríguez GA, Cabrera GJ, Castro ER, López SE, Cerecetto HE. Photo-Induced Partially Aromatized Intramolecular Charge Transfer. J Phys Chem B 2021; 125:9268-9285. [PMID: 34357778 DOI: 10.1021/acs.jpcb.1c03747] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Diverse models of intramolecular charge transfer (ICT) have been proposed for interpreting the origin of the charge-transfer (CT) state in donor-acceptor (D-A) dyes. However, a large variety of fused-heterocyclic dyes containing a pseudo-aromatic ring in the rigid structure have shown to be incompatible with them. To approximate a solution within the ICT concept, we reported a novel ICT model called partially aromatized intramolecular charge transfer (PAICT). PAICT involves the generation of a CT state from an ICT that occurred within a pre-excited D-A fused-heterocyclic structure possessing a pseudo-aromatic or unstable aromatic ring as the acceptor moiety. The model was proposed from the multiple-emissive mesomeric D-A N1-aryl-2-(trifluoromethyl)benzo[b][1,8]naphthyridin-4(1H)-one, whose excited mesomeric states, which are defined by the aromatic and pseudo-aromatic forms of the pyrindin-4(1H)-one ring, led to a common partial aromatized CT state upon excitation via PAICT. The latter was supported through theoretical calculations on the excited mesomeric states, one-dimensional (1D) and two-dimensional (2D) excitation-emission measurements in different solvents, and the detection of three excited states by lifetime measurements upon 370 nm excitation. The existence of mesomerism was supposed from: (i) two overlapping bands at 370-390 (or 400-420 nm) in UV-vis spectra, (ii) the direct interaction between the pyridinic nitrogen of one molecule and the carbonylic oxygen of the other found in the solid state and, (iii) the detection of three excited states by lifetime measurements. The PAICT opens new perspectives for interpreting the charge-transfer phenomenon in fused-heterocyclic dyes, in particular, those containing a pseudo-aromatic or unstable aromatic ring as an acceptor moiety.
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Affiliation(s)
- Angel H Romero
- Grupo de Química Orgánica Medicinal, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Iguá 4225, Montevideo 11400, Uruguay
| | - Ivan E Romero
- Laboratorio de Síntesis Orgánica, Escuela de Química, Facultad de Ciencias, Universidad Central de Venezuela, Los Chaguaramos, Caracas 1040, Venezuela
| | - Oscar E Piro
- Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de la Plata, La Plata 1900, Argentina
| | - Gustavo A Echeverría
- Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de la Plata, La Plata 1900, Argentina
| | - Lourdes A Gotopo
- Laboratorio de Síntesis Orgánica, Escuela de Química, Facultad de Ciencias, Universidad Central de Venezuela, Los Chaguaramos, Caracas 1040, Venezuela
| | - Matías N Moller
- Laboratorio de Fisicoquímica Biológica, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Iguá 4225, Montevideo 11400, Uruguay
| | - Gonzalo A Rodríguez
- Grupo de Química Orgánica Medicinal, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Iguá 4225, Montevideo 11400, Uruguay
| | - Gustavo J Cabrera
- Laboratorio de Síntesis Orgánica, Escuela de Química, Facultad de Ciencias, Universidad Central de Venezuela, Los Chaguaramos, Caracas 1040, Venezuela
| | - Erick R Castro
- Instituto de Física da UFRGS, Av. Bento Gonçalves, Porto Alegre 9500, RS, Brazil
| | - Simón E López
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Hugo E Cerecetto
- Grupo de Química Orgánica Medicinal, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Iguá 4225, Montevideo 11400, Uruguay.,Área de Radiofarmacia, Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, Mataojo 2055, Montevideo 11400, Uruguay
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Dias-Lopes G, Zabala-Peñafiel A, de Albuquerque-Melo BC, Souza-Silva F, Menaguali do Canto L, Cysne-Finkelstein L, Alves CR. Axenic amastigotes of Leishmania species as a suitable model for in vitro studies. Acta Trop 2021; 220:105956. [PMID: 33979642 DOI: 10.1016/j.actatropica.2021.105956] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 04/28/2021] [Accepted: 04/30/2021] [Indexed: 12/26/2022]
Abstract
Leishmania spp. are etiological agents of infection diseases, which in some cases can be fatal. The main forms of their biological cycle, promastigotes and amastigotes, can be maintained in vitro. While promastigotes are easier to maintain, amastigotes are more complex and can be obtained through different ways, including infection assays of tissues or in vitro cells, and differentiation from promastigotes to axenic amastigotes. Several protocols have been proposed for in vitro differentiation for at least 12 Leishmania spp. of both subgenera, Leishmania and Viannia. In this review we propose a critical summary of axenic amastigotes induction, as well as the impact of these strategies on metabolic pathways and regulatory networks analyzed by omics approaches. The parameters used by different research groups show considerable variations in temperature, pH and induction stages, as highlighted here for Leishmania (Viannia) braziliensis. Therefore, a consensus on strategies for inducing amastigogenesis is necessary to improve accuracy and even define stage-specific biomarkers. In fact, the axenic amastigote model has contributed to elucidate several aspects of the parasite cycle, however, since it does not reproduce the intracellular environment, its use requires several precautions. In addition, we present a discussion about using axenic amastigotes for drug screening, suggesting the need of a more sensitive methodology to verify cell viability in these tests. Collectively, this review explores the advantages and limitations found in studies with axenic amastigotes, done for more than 30 years, and discuss the gaps that impair their use as a suitable model for in vitro studies.
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Alcazar W, Alakurtti S, Padrón-Nieves M, Tuononen ML, Rodríguez N, Yli-Kauhaluoma J, Ponte-Sucre A. Leishmanicidal Activity of Betulin Derivatives in Leishmania amazonensis; Effect on Plasma and Mitochondrial Membrane Potential, and Macrophage Nitric Oxide and Superoxide Production. Microorganisms 2021; 9:320. [PMID: 33557150 PMCID: PMC7913927 DOI: 10.3390/microorganisms9020320] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 01/24/2021] [Accepted: 01/29/2021] [Indexed: 11/25/2022] Open
Abstract
Herein, we evaluated in vitro the anti-leishmanial activity of betulin derivatives in Venezuelan isolates of Leishmania amazonensis, isolated from patients with therapeutic failure. METHODS We analyzed promastigote in vitro susceptibility as well as the cytotoxicity and selectivity of the evaluated compounds. Additionally, the activity of selected compounds was determined in intracellular amastigotes. Finally, to gain hints on their potential mechanism of action, the effect of the most promising compounds on plasma and mitochondrial membrane potential, and nitric oxide and superoxide production by infected macrophages was determined. RESULTS From the tested 28 compounds, those numbered 18 and 22 were chosen for additional studies. Both 18 and 22 were active (GI50 ≤ 2 µM, cytotoxic CC50 > 45 µM, SI > 20) for the reference strain LTB0016 and for patient isolates. The results suggest that 18 significantly depolarized the plasma membrane potential (p < 0.05) and the mitochondrial membrane potential (p < 0.05) when compared to untreated cells. Although neither 18 nor 22 induced nitric oxide production in infected macrophages, 18 induced superoxide production in infected macrophages. CONCLUSION Our results suggest that due to their efficacy and selectivity against intracellular parasites and the potential mechanisms underlying their leishmanicidal effect, the compounds 18 and 22 could be used as tools for designing new chemotherapies against leishmaniasis.
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Affiliation(s)
- Wilmer Alcazar
- Laboratory of Molecular Physiology, Institute of Experimental Medicine, School of Medicine Luis Razetti, Faculty of Medicine, Universidad Central de Venezuela, P.O. Box 50587, Caracas 1050, Venezuela; (W.A.); (M.P.-N.)
| | - Sami Alakurtti
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5 E, P.O. Box 56, FI-00014 Helsinki, Finland; (S.A.); (M.L.T.)
- VTT Technical Research Centre of Finland, Biologinkuja 7, P.O. Box 1000, FI-02044 Espoo, Finland
| | - Maritza Padrón-Nieves
- Laboratory of Molecular Physiology, Institute of Experimental Medicine, School of Medicine Luis Razetti, Faculty of Medicine, Universidad Central de Venezuela, P.O. Box 50587, Caracas 1050, Venezuela; (W.A.); (M.P.-N.)
| | - Maija Liisa Tuononen
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5 E, P.O. Box 56, FI-00014 Helsinki, Finland; (S.A.); (M.L.T.)
- VTT Technical Research Centre of Finland, Biologinkuja 7, P.O. Box 1000, FI-02044 Espoo, Finland
| | - Noris Rodríguez
- Laboratory of Genetic Engineering, Institute of Biomedicine, Universidad Central de Venezuela, P.O. Box 4043, Caracas 1010A, Venezuela;
| | - Jari Yli-Kauhaluoma
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5 E, P.O. Box 56, FI-00014 Helsinki, Finland; (S.A.); (M.L.T.)
| | - Alicia Ponte-Sucre
- Laboratory of Molecular Physiology, Institute of Experimental Medicine, School of Medicine Luis Razetti, Faculty of Medicine, Universidad Central de Venezuela, P.O. Box 50587, Caracas 1050, Venezuela; (W.A.); (M.P.-N.)
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Romero AH, Rodríguez N, Ramírez OG. Optimization of phthalazin-based aryl/heteroarylhydrazones to design new promising antileishmanicidal agents: synthesis and biological evaluation of 3-aryl-6-piperazin-1,2,4-triazolo[3,4- a]phthalazines. NEW J CHEM 2020. [DOI: 10.1039/d0nj01206h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
1-Monosubstituted and 1,4-substituted phthalazins based on aryl/heteroarylhydrazinyl have demonstrated attractive antileishmanial profiles against amastigote forms of the Leishmania braziliensis parasite.
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Affiliation(s)
- Angel H. Romero
- Cátedra de Química General
- Facultad de Farmacia
- Universidad Central de Venezuela
- Los Chaguaramos
- Caracas 1041-A
| | - Noris Rodríguez
- Laboratorio de Ingeniería Genética
- Instituto de Biomedicina
- Facultad de Medicina
- Universidad Central de Venezuela
- San Luis
| | - Oscar G. Ramírez
- Cátedra de Química General
- Facultad de Farmacia
- Universidad Central de Venezuela
- Los Chaguaramos
- Caracas 1041-A
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Romero AH, Rodríguez N, López SE, Oviedo H. Identification of dehydroxy isoquine and isotebuquine as promising antileishmanial agents. Arch Pharm (Weinheim) 2019; 352:e1800281. [PMID: 30994941 DOI: 10.1002/ardp.201800281] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 02/05/2019] [Accepted: 02/09/2019] [Indexed: 11/06/2022]
Abstract
Traditional antimalarial drugs based on 4-aminoquinolines have exhibited good antiproliferative activities against Leishmania parasites; however, their clinical use is currently limited. To identify new 4-aminoquinolines to combat American cutaneous leishmaniasis, we carried out a full in vitro evaluation of a series of dehydroxy isoquines and isotebuquines against two Leishmania parasites such as Leishmania braziliensis and Leishmania mexicana. First, the antiproliferative activity of the quinolines was studied against the promastigote forms of L. braziliensis and L. mexicana parasites, finding that five of them exhibited good antileishmanial responses with micromolar IC50 values ranging from 3.84 to 10 μM. A structure-activity relationship analysis gave evidence that a piperidine or a morpholine attached as N-alkyamino terminal substituent as well as the inclusion of an extra phenyl ring attached at the aniline ring of the isotebuquine core constitute important pharmacophores to generate the most active derivatives, with antileishmanial responses by far superior to those found for the reference drug, glucantime. All compounds showed a relatively low toxicity on human dermis fibroblasts, with CC50 ranging from 69 to >250 μM. The five most active compounds displayed moderate to good antileishmanial activity against the intracellular amastigote form of L. braziliensis, compared to the reference drug. In particular, compound 2j was identified as the most potent agent against antimony-resistant amastigotes of L. braziliensis with acceptable biological response and selectivity, emerging as a promising candidate for further in vivo antileishmanial evaluation. Diverse mechanism-of-action studies and molecular docking simulations were performed for the most active 4-aminoquinoline.
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Affiliation(s)
- Angel H Romero
- Cátedra de Química, Facultad de Farmacia, Universidad Central de Venezuela, Caracas, Venezuela.,Laboratorio de Ingeniería Genética, Instituto de Biomedicina, Facultad de Medicina, Universidad Central de Venezuela, Caracas, Venezuela
| | - Noris Rodríguez
- Laboratorio de Ingeniería Genética, Instituto de Biomedicina, Facultad de Medicina, Universidad Central de Venezuela, Caracas, Venezuela
| | - Simón E López
- Department of Chemistry, University of Florida, Gainesville, Florida
| | - Henry Oviedo
- Laboratorio de Ingeniería Genética, Instituto de Biomedicina, Facultad de Medicina, Universidad Central de Venezuela, Caracas, Venezuela
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