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Dive into the research topics where Ismael León-Rivera is active.

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Featured researches published by Ismael León-Rivera.


Diabetes, Obesity and Metabolism | 2008

Antidiabetic and toxicological evaluations of naringenin in normoglycaemic and NIDDM rat models and its implications on extra-pancreatic glucose regulation

Rolffy Ortiz-Andrade; Juan Carlos Sánchez-Salgado; Gabriel Navarrete-Vázquez; Scott P. Webster; Margareth Binnie; Sara García-Jiménez; Ismael León-Rivera; P. Cigarroa-Vazquez; Rafael Villalobos-Molina; Samuel Estrada-Soto

Aim:  The present investigation was designed to determine the in vivo antidiabetic effect of naringenin (NG) in normoglycaemic and diabetic rat models through blood glucose (GLU) measurements following acute and subchronic time periods. Possible modes of action of NG were investigated and its acute toxicity determined.


Bioorganic & Medicinal Chemistry Letters | 2008

Design, synthesis and in vitro antiprotozoal activity of benzimidazole-pentamidine hybrids

Héctor Torres-Gómez; Emanuel Hernández-Núñez; Ismael León-Rivera; Jorge Guerrero-Álvarez; Roberto Cedillo-Rivera; Rosa Moo-Puc; Rocío Argotte-Ramos; María del Carmen Rodríguez-Gutiérrez; Manuel Jesús Chan-Bacab; Gabriel Navarrete-Vázquez

A series of ten novel hybrids from benzimidazole and pentamidine were prepared using a short synthetic route. Each compound was tested in vitro against the protozoa Trichomonas vaginalis, Giardia lamblia, Entamoeba histolytica, Leishmania mexicana, and Plasmodium berghei, in comparison with pentamidine and metronidazole. Some analogues showed high bioactivity in the low micromolar range (IC(50)<1 microM) against the first four protozoa, which make them significantly more potent than either standard. 1,5-bis[4-(5-methoxy-1H-benzimidazole-2-yl)phenoxy]pentane (2) was 3- and 9-fold more potent againstG. lamblia than metronidazole and pentamidine, respectively. This compound was 23-, 108-, and 13-fold more active than pentamidine against T. vaginalis, E. histolytica and L. mexicana, respectively. Studying further structure-activity relationships through the use of bioisosteric substitution in these hybrids should provide new leads against protozoal diseases.


Bioorganic & Medicinal Chemistry Letters | 2008

Antidiabetic activity of N-(6-substituted-1,3-benzothiazol-2-yl)benzenesulfonamides

Hermenegilda Moreno-Diaz; Rafael Villalobos-Molina; Rolffy Ortiz-Andrade; Daniel Díaz-Coutiño; José L. Medina-Franco; Scott P. Webster; Margaret Binnie; Samuel Estrada-Soto; Maximiliano Ibarra-Barajas; Ismael León-Rivera; Gabriel Navarrete-Vázquez

N-(6-Substituted-1,3-benzothiazol-2-yl)benzenesulfonamide derivatives 1-8 were synthesized and evaluated for their in vivo antidiabetic activity in a non-insulin-dependent diabetes mellitus rat model. Several compounds synthesized showed significant lowering of plasma glucose level in this model. As a possible mode of action, the compounds were in vitro evaluated as 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) inhibitors. The most active compounds (3 and 4) were docked into the crystal structure of 11beta-HSD1. Docking results indicate potential hydrogen bond interactions with catalytic amino acid residues.


Biochemical Pharmacology | 2009

Antihypertensive and vasorelaxant effects of tilianin isolated from Agastache mexicana are mediated by NO/cGMP pathway and potassium channel opening

Oswaldo Hernández-Abreu; Patricia Castillo-España; Ismael León-Rivera; Maximiliano Ibarra-Barajas; Rafael Villalobos-Molina; Judith González-Christen; Jorge Vergara-Galicia; Samuel Estrada-Soto

Current investigation was undertaken to elucidate the mode of action of tilianin, isolated from Agastache mexicana, as a vasorelaxant agent on in vitro functional rat thoracic aorta test and to investigate the in vivo antihypertensive effect on spontaneously hypertensive rats (SHR). Tilianin (0.002-933 microM) induced significant relaxation in a concentration- and endothelium-dependent and -independent manners in aortic rings pre-contracted with noradrenaline (NA, 0.1 microM), and serotonin (5-HT, 100 microM). Effect was more significant (p < 0.05) in endothelium-intact (+E) aorta rings than when endothelium was removed(E). Pre-treatment with N-nitro-L-arginine methyl ester (L-NAME; 10 microM) or 1-H-[1,2,4]-oxadiazolo-[4,3a]-quinoxalin-1-one (ODQ, 1 microM) produced a significant change of the relaxant response and activity was markedly inhibited, but not by indomethacin (10 microM) or atropine (1 microM). Furthermore, tilianin (130 microM) provoked a significant displacement to the left in the relaxation curve induced by sodium nitroprusside (SNP; 0.32 nM to 0.1 microM). Moreover, tilianin induced significant in vitro NO overproduction (1.49 +/- 0.86 microM of nitrites/g of tissue) in rat aorta compared with vehicle (p < 0.05). In addition, pre-treatment with tetraethylammonium (TEA, 5 mM) and 2-aminopyridine (2-AP, 0.1 microM) shifted to the right the relaxant curve induced by tilianin (p < 0.05). Finally, a single oral administration of tilianin (50 mg/kg) exhibited a significant decrease in systolic and diastolic blood pressures (p < 0.05) in SHR model. Results indicate that tilianin mediates relaxation mainly by an endothelium-dependent manner,probably due to NO release, and also through an endothelium-independent pathway by opening K+ channels, both causing the antihypertensive effect.


Synthetic Communications | 2007

Microwave‐Assisted One‐Pot Synthesis of 2‐(Substituted phenyl)‐1H‐benzimidazole Derivatives

Gabriel Navarrete-Vázquez; Hermenegilda Moreno-Diaz; Samuel Estrada-Soto; Mariana Torres-Piedra; Ismael León-Rivera; Hugo Tlahuext; Omar Munoz-Muniz; Héctor Torres-Gómez

Abstract A series of 2‐(substituted phenyl)‐1H‐benzimidazole derivatives with various 5‐and 6‐position substituents (‐H, ‐CH3, ‐CF3) were synthesized via microwave irradiation using a short synthetic route and Na2S2O5 as oxidant. This simple, fast, and efficient preparation of benzimidazole derivatives has been developed using readily available and inexpensive reagents (aldehydes and 1,2‐phenylenediamines) under solvent‐free conditions.


Bioorganic & Medicinal Chemistry | 2009

Synthesis, in vitro and computational studies of protein tyrosine phosphatase 1B inhibition of a small library of 2-arylsulfonylaminobenzothiazoles with antihyperglycemic activity

Gabriel Navarrete-Vázquez; Paolo Paoli; Ismael León-Rivera; Rafael Villalobos-Molina; José L. Medina-Franco; Rolffy Ortiz-Andrade; Samuel Estrada-Soto; Guido Camici; Daniel Díaz-Coutiño; Itzell Gallardo-Ortiz; Karina Martínez-Mayorga; Hermenegilda Moreno-Diaz

The 2-arylsulfonylaminobenzothiazole derivatives 1-27 were prepared using a one step reaction. The in vitro inhibitory activity of the compounds against protein tyrosine phosphatase 1B (PTP-1B) was evaluated. Compounds 4 and 16 are rapid reversible (mixed-type) inhibitors of PTP-1B with IC(50) values in the low micromolar range. The most active compounds (4 and 16) were docked into the crystal structure of PTP-1B. Docking results indicate potential hydrogen bond interactions between the nitro group in both compounds and the catalytic amino acid residues Arg 221 and Ser 216. Both compounds were evaluated for their in vivo antihyperglycemic activity in a type 2 diabetes mellitus rat model, showing significant lowering of plasma glucose concentration, during the 7h post-intragastric administration.


Journal of Natural Products | 2008

Tyrianthinic Acids from Ipomoea tyrianthina and Their Antimycobacterial Activity, Cytotoxicity, and Effects on the Central Nervous System #

Ismael León-Rivera; Gumersindo Mirón-López; Gloria María Molina-Salinas; Maribel Herrera-Ruiz; Samuel Estrada-Soto; María del Carmen Gutiérrez; Daniel Alonso-Cortes; Gabriel Navarrete-Vázquez; María Yolanda Rios; Salvador Said-Fernández

Four new partially acylated tetrasaccharides of 11-hydroxyhexadecanoic acid (1-4) were isolated from a methanolic extract of Ipomoea tyrianthina. The structures of these compounds were elucidated by spectroscopic and chemical methods. The resin glycoside composition of I. tyrianthina varied with the location of growth in Mexico. Compounds 1-4 showed antimycobacterial activity, were cytotoxic against the KB cell line, and, in a mouse model, exhibited potentiation of hypnosis induced by pentobarbital, protected against seizures induced by pentylenetetrazole, and released GABA and glutamic acid.


Bioorganic & Medicinal Chemistry | 2010

Synthesis, vasorelaxant activity and antihypertensive effect of benzo[d]imidazole derivatives

Gabriel Navarrete-Vázquez; Sergio Hidalgo-Figueroa; Mariana Torres-Piedra; Jorge Vergara-Galicia; Julio Rivera-Leyva; Samuel Estrada-Soto; Ismael León-Rivera; Berenice Aguilar-Guardarrama; Yolanda Rios-Gómez; Rafael Villalobos-Molina; Maximiliano Ibarra-Barajas

A series of 1H-benzo[d]imidazole analogues of Pimobendan, substituted at position 5 with either -CF(3) or -NO(2), were synthesized using a short synthetic route. All the nitro derivatives were potent, and exhibited a concentration- and partial endothelium-dependent vasorelaxant effects, with EC(50)s <5microM. 2-Methoxy-4-[5-nitro-1H-benzo[d]imidazol-2-yl]phenol (compound 13) was the most potent derivative of the series, showing an EC(50) value of 1.81microM and E(max) of 91.7% for ex vivo relaxant response in intact aortic rings, resulting in a 2.5-fold higher activity compared to Pimobendan. The closely related 5-CF(3) analogue (compound 8), was 19 times less potent than 13. The antihypertensive activity of compound 13 was evaluated at doses of 25, 50 and 100mgkg(-1), using spontaneously hypertensive rats (SHR), showing a statistically significant dose-dependent effect.


Archives of Pharmacal Research | 2011

Synthesis and preliminary evaluation of selected 2-aryl-5(6)-nitro- 1H-benzimidazole derivatives as potential anticancer agents

Aurelio Romero-Castro; Ismael León-Rivera; Laura Citlalli Ávila-Rojas; Gabriel Navarrete-Vázquez; Alejandro Nieto-Rodríguez

In this study we report the synthesis and preliminary evaluation of a series of six 2-aryl-5(6)-nitro-1H-benzimidazole derivatives (1–6) as potential anticancer agents. Cytotoxicity was evaluated against seven human neoplastic cell lines using the MTT assay. Compound 6 [2-(4-chloro-3-nitrophenyl)-5(6)-nitro-1H-benzimidazole] was the most active of the series, showing an IC50 of 28 nM against the A549 cell line. This compound displayed a selective in vitro cytotoxic activity index (>700) in non neoplastic HACAT cells (IC50 = 22.2 μM). Compounds 3 and 6 induce arrest in the S phase of the cell cycle, and compounds 1–6 induce apoptosis in the K562 cell line. Compound 6 induces poly (ADP-ribose) polymerase (PARP) inhibition activity as a potential mechanism of action. These results suggest that compound 6 could be a potent anticancer agent. Compound 3 displayed the best inhibitory activity against PARP with an IC50 value of 0.05 μM, compared to the activity shown by the positive control 3-aminobenzamide (IC50 = 28.5 μM).


Natural Product Research | 2009

Active compounds against tinea pedis dermatophytes from Ageratina pichinchensis var. bustamenta.

Berenice Aguilar-Guadarrama; Víctor Navarro; Ismael León-Rivera; María Yolanda Rios

Secondary metabolites 5-acetyl-3β-angeloyloxy-2β-(1-hydroxyisopropyl)-2,3-dihydrobenzofurane (1), 5-acetyl-3β-angeloyloxy-2β-(1-hydroxyisopropyl)-6-methoxy-2,3-dihydrobenzofurane (2), espeletone (3), encecalinol (4), O-methylencecalinol (5), encecalin (6), sonorol (7), taraxerol (8), (+)-β-eudesmol (9), and a mixture of β-sitosterol and stigmasterol, were isolated from the aerial parts of Ageratina pichinchensis var. bustamenta. The antimicrobial activity of compounds 6, 8 and 9, together with derivatives 9a and 9b against the most important dermatophytes responsible for tinea pedis infection, Trichophyton rubrum and T. mentagrophytes, and against Candida albicans and Aspergillus niger were determined, showing that the three natural products were active against both Trichophyton species. Ageratina pichinchensis var. bustamenta is used in folk medicine to treat skin infections and wounds, and this study confirms that the n-hexane extract contains metabolites which are responsible for these utilities.

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Samuel Estrada-Soto

Universidad Autónoma del Estado de Morelos

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Gabriel Navarrete-Vázquez

Universidad Autónoma del Estado de Morelos

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María Yolanda Rios

Universidad Autónoma del Estado de Morelos

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Rafael Villalobos-Molina

National Autonomous University of Mexico

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Maribel Herrera-Ruiz

Mexican Social Security Institute

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María del Carmen Gutiérrez

Universidad Autónoma del Estado de Morelos

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Rolffy Ortiz-Andrade

Universidad Autónoma de Yucatán

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Sergio Hidalgo-Figueroa

Universidad Autónoma del Estado de Morelos

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Francisco Aguirre-Crespo

Universidad Autónoma del Estado de Morelos

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Gumersindo Mirón-López

Universidad Autónoma de Yucatán

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