Antihypertensive Effect of New Agonist of Adenosine Receptor in Spontaneously Hypertensive Rats. / Efeito Anti-Hipertensivo de Novos Agonistas do Receptor de Adenosina em Ratos Espontaneamente Hipertensos.

BACKGROUND: Systemic arterial hypertension is a risk factor for cardiac, renal, and metabolic dysfunction. The search for new strategies to prevent and treat cardiovascular diseases led to the synthesis of new N-acylhydrazones to produce antihypertensive effect. Adenosine receptors are an alternative target to reduce blood pressure because of their vasodilatory action and antioxidant properties, which may reduce oxidative stress characteristic of systemic arterial hypertension. OBJECTIVE: To evaluate the antihypertensive profile of novel selenium-containing compounds designed to improve their interaction with adenosine receptors. METHODS: Vascular reactivity was evaluated by recording the isometric tension of pre-contracted thoracic aorta of male Wistar rats after exposure to increasing concentrations of each derivative (0.1 to 100 µM). To investigate the antihypertensive effect in spontaneously hypertensive rats, systolic, diastolic, and mean arterial pressure and heart rate were determined after intravenous administration of 10 and 30 µmol/kg of the selected compound LASSBio-2062. RESULTS: Compounds named LASSBio-2062, LASSBio-2063, LASSBio-2075, LASSBio-2076, LASSBio-2084, LASSBio-430, LASSBio-2092, and LASSBio-2093 promoted vasodilation with mean effective concentrations of 15.5 ± 6.5; 14.6 ± 2.9; 18.7 ± 9.6; 6.7 ± 4.1; > 100; 6.0 ± 3.6; 37.8 ± 11.8; and 15.9 ± 5.7 µM, respectively. LASSBio-2062 (30 µmol/kg) reduced mean arterial pressure in spontaneously hypertensive rats from 124.6 ± 8.6 to 72.0 ± 12.3 mmHg (p < 0.05). Activation of adenosine receptor subtype A3 and potassium channels seem to be involved in the antihypertensive effect of LASSBio-2062. CONCLUSIONS: The new agonist of adenosine receptor and activator of potassium channels is a potential therapeutic agent to treat systemic arterial hypertension.

FUNDAMENTO: A hipertensão arterial sistêmica é um fator de risco para disfunções cardíacas, renais e metabólicas. A busca por novas estratégias para prevenir e tratar doenças cardiovasculares levou à síntese de novas N-acilidrazonas para produzir efeito anti-hipertensivo. Os receptores de adenosina são um alvo alternativo para reduzir a pressão arterial devido à sua ação vasodilatadora e propriedades antioxidantes, que podem reduzir o estresse oxidativo característico da hipertensão arterial sistêmica. OBJETIVO: Avaliar o perfil anti-hipertensivo de novos compostos contendo selênio desenvolvidos para melhorar sua interação com os receptores de adenosina. MÉTODOS: Foi avaliada a reatividade vascular, registrando-se a tensão isométrica da aorta torácica pré-contraída de ratos Wistar machos após exposição a concentrações crescentes de cada derivado (0,1 a 100 µM). Para investigar o efeito anti-hipertensivo em ratos espontaneamente hipertensos, foram determinadas a pressão arterial sistólica, pressão arterial diastólica, pressão arterial média e a frequência cardíaca após administração intravenosa de 10 e 30 µmol/kg do composto selecionado LASSBio-2062. RESULTADOS: Os compostos denominados LASSBio-2062, LASSBio-2063, LASSBio-2075, LASSBio-2076, LASSBio-2084, LASSBio-430, LASSBio-2092 e LASSBio-2093 promoveram vasodilatação com concentrações efetivas médias de 15,5 ± 6,5; 14,6 ± 2,9; 18,7 ± 9,6; 6,7 ± 4,1; > 100; 6,0 ± 3,6; 37,8 ± 11,8; e 15,9 ± 5,7 µM, respectivamente. O LASSBio-2062 (30 µmol/kg) reduziu a pressão arterial média em ratos espontaneamente hipertensos de 124,6 ± 8,6 para 72,0 ± 12,3 mmHg (p < 0,05). A ativação do receptor de adenosina subtipo A3 e dos canais de potássio parece estar envolvida no efeito anti-hipertensivo do LASSBio-2062. CONCLUSÕES: O novo agonista do receptor de adenosina e ativador dos canais de potássio é um potencial agente terapêutico para o tratamento da hipertensão arterial sistêmica.

Efeito Anti-Hipertensivo de Novos Agonistas do Receptor de Adenosina em Ratos Espontaneamente Hipertensos / Antihypertensive Effect of New Agonist of Adenosine Receptor in Spontaneously Hypertensive Rats

Resumo Fundamento A hipertensão arterial sistêmica é um fator de risco para disfunções cardíacas, renais e metabólicas. A busca por novas estratégias para prevenir e tratar doenças cardiovasculares levou à síntese de novas N-acilidrazonas para produzir efeito anti-hipertensivo. Os receptores de adenosina são um alvo alternativo para reduzir a pressão arterial devido à sua ação vasodilatadora e propriedades antioxidantes, que podem reduzir o estresse oxidativo característico da hipertensão arterial sistêmica. Objetivo Avaliar o perfil anti-hipertensivo de novos compostos contendo selênio desenvolvidos para melhorar sua interação com os receptores de adenosina. Métodos Foi avaliada a reatividade vascular, registrando-se a tensão isométrica da aorta torácica pré-contraída de ratos Wistar machos após exposição a concentrações crescentes de cada derivado (0,1 a 100 μM). Para investigar o efeito anti-hipertensivo em ratos espontaneamente hipertensos, foram determinadas a pressão arterial sistólica, pressão arterial diastólica, pressão arterial média e a frequência cardíaca após administração intravenosa de 10 e 30 μmol/kg do composto selecionado LASSBio-2062. Resultados Os compostos denominados LASSBio-2062, LASSBio-2063, LASSBio-2075, LASSBio-2076, LASSBio-2084, LASSBio-430, LASSBio-2092 e LASSBio-2093 promoveram vasodilatação com concentrações efetivas médias de 15,5 ± 6,5; 14,6 ± 2,9; 18,7 ± 9,6; 6,7 ± 4,1; > 100; 6,0 ± 3,6; 37,8 ± 11,8; e 15,9 ± 5,7 μM, respectivamente. O LASSBio-2062 (30 μmol/kg) reduziu a pressão arterial média em ratos espontaneamente hipertensos de 124,6 ± 8,6 para 72,0 ± 12,3 mmHg (p < 0,05). A ativação do receptor de adenosina subtipo A3 e dos canais de potássio parece estar envolvida no efeito anti-hipertensivo do LASSBio-2062. Conclusões O novo agonista do receptor de adenosina e ativador dos canais de potássio é um potencial agente terapêutico para o tratamento da hipertensão arterial sistêmica.

Abstract Background Systemic arterial hypertension is a risk factor for cardiac, renal, and metabolic dysfunction. The search for new strategies to prevent and treat cardiovascular diseases led to the synthesis of new N-acylhydrazones to produce antihypertensive effect. Adenosine receptors are an alternative target to reduce blood pressure because of their vasodilatory action and antioxidant properties, which may reduce oxidative stress characteristic of systemic arterial hypertension. Objective To evaluate the antihypertensive profile of novel selenium-containing compounds designed to improve their interaction with adenosine receptors. Methods Vascular reactivity was evaluated by recording the isometric tension of pre-contracted thoracic aorta of male Wistar rats after exposure to increasing concentrations of each derivative (0.1 to 100 μM). To investigate the antihypertensive effect in spontaneously hypertensive rats, systolic, diastolic, and mean arterial pressure and heart rate were determined after intravenous administration of 10 and 30 μmol/kg of the selected compound LASSBio-2062. Results Compounds named LASSBio-2062, LASSBio-2063, LASSBio-2075, LASSBio-2076, LASSBio-2084, LASSBio-430, LASSBio-2092, and LASSBio-2093 promoted vasodilation with mean effective concentrations of 15.5 ± 6.5; 14.6 ± 2.9; 18.7 ± 9.6; 6.7 ± 4.1; > 100; 6.0 ± 3.6; 37.8 ± 11.8; and 15.9 ± 5.7 μM, respectively. LASSBio-2062 (30 μmol/kg) reduced mean arterial pressure in spontaneously hypertensive rats from 124.6 ± 8.6 to 72.0 ± 12.3 mmHg (p < 0.05). Activation of adenosine receptor subtype A3 and potassium channels seem to be involved in the antihypertensive effect of LASSBio-2062. Conclusions The new agonist of adenosine receptor and activator of potassium channels is a potential therapeutic agent to treat systemic arterial hypertension.

Design, Synthesis and Phenotypic Profiling of Simplified Gedatolisib Analogues.

Targeted antitumour therapy has revolutionized the treatment of several types of tumours. Among the validated targets, phosphatidylinositol-3 kinase (PI3K) deserves to be highlighted. Several PI3K inhibitors have been developed for the treatment of cancer, including gedatolisib (4). This inhibitor was elected as a prototype and molecular modifications were planned to design a new series of simplified gedatolisib analogues (5a-f). The analogues were synthesised, and the comparative cytotoxic activity profile was studied in phenotypic models employing solid and nonadherent tumour cell lines. Compound 5f (LASSBio-2252) stood out as the most promising of the series, showing good aqueous solubility (42.38 µM (pH = 7.4); 39.33 µM (pH = 5.8)), good partition coefficient (cLogP = 2.96), cytotoxic activity on human leukemia cell lines (CCRF-CEM, K562 and MOLT-4) and an excellent metabolic stability profile in rat liver microsomes (t1/2 = 462 min; Clapp = 0.058 mL/min/g). The ability of 5f to exert its cytotoxic effect through modulation of the PI3K pathway was demonstrated by flow cytometry analysis in a comparative manner to gedatolisib.

LASSBio-596: a New Pre-clinical Candidate for Rheumatoid Arthritis?

Pain and inflammatory disorders are significant health problems because of prevalence and associated disabilities. In this context, LASSBio-596 is a hybrid compound able to modulate TNF-α and phosphodiesterases 4 and 5, exhibiting an anti-inflammatory effect in the pulmonary inflammatory model. Aiming at a better description of the activities of LASSBio-596, we initially conducted nociception tests (acetic acid-induced abdominal writhing, glutamate, and formalin-induced nociception and hot plate test) and later inflammatory tests (acute, peritonitis; and chronic, arthritis) that directed us to this last one. In the abdominal writhing test, there was a dose-dependent inhibition, whose response occurred at the maximum dose (50 mg/kg, p.o.), used in the subsequent tests. LASSBio-596 also inhibited nociception induced by chemical (glutamate by 31.9%; and formalin, in both phases, 1st phase: 25.7%; 2nd phase: 23.9%) and thermal agents (hotplate, by increased latency for pain at two different times). These effects were independent of the motor function, legitimated in rotarod. As there was a response in the inflammatory component of nociception, we performed the peritonitis test, in which migration was inhibited by LASSBio-596 by 39.9%. As the inflammatory process is present in autoimmune diseases, we also performed the arthritis test. LASSBio-596 reduced paw edema from the 15th day to the 21st day of treatment (no liver changes and with fewer paw injuries). In addition, LASSBio-596 decreased serum levels of TNF-α by 67.1%. These data demonstrated the antinociceptive effect of LASSBio-596 and reinforces its anti-inflammatory property (i.e., RA), amplifying the therapeutic potential of this molecule.

In Vitro, In Vivo and In Silico Effectiveness of LASSBio-1386, an N-Acyl Hydrazone Derivative Phosphodiesterase-4 Inhibitor, Against Leishmania amazonensis.

Leishmaniasis are group of neglected diseases with worldwide distribution that affect about 12 million people. The current treatment is limited and may cause severe adverse effects, and thus, the search for new drugs more effective and less toxic is relevant. We have previously investigated the immunomodulatory effects of LASSBio-1386, an N-acylhydrazone derivative. Here we investigated the in vitro and in vivo activity of LASSBio-1386 against L. amazonensis. LASSBio-1386 inhibited the proliferation of promastigotes of L. amazonensis (EC50 = 2.4 ± 0.48 µM), while presenting low cytotoxicity to macrophages (CC50 = 74.1 ± 2.9 µM). In vitro incubation with LASSBio-1386 reduced the percentage of Leishmania-infected macrophages and the number of intracellular parasites (EC50 = 9.42 ± 0.64 µM). Also, in vivo treatment of BALB/c mice infected with L. amazonensis resulted in a decrease of lesion size, parasitic load and caused histopathological alterations, when compared to vehicle-treated control. Moreover, LASSBio-1386 caused ultrastructural changes, arrested cell cycle in G0/G1 phase and did not alter the membrane mitochondrial potential of L. amazonensis. Aiming to its possible molecular interactions, we performed docking and molecular dynamics studies on Leishmania phosphodiesterase B1 (PDB code: 2R8Q) and LASSBio-1386. The computational analyses suggest that LASSBio-1386 acts against Leishmania through the modulation of leishmanial PDE activity. In conclusion, our results indicate that LASSBio-1386 is a promising candidate for the development of new leishmaniasis treatment.

LASSBio-1586, an N-acylhydrazone derivative, attenuates nociceptive behavior and the inflammatory response in mice.

Pain and inflammation are complex clinical conditions that are present in a wide variety of disorders. Most drugs used to treat pain and inflammation have potential side effects, which makes it necessary to search for new sources of bioactive molecules. In this paper, we describe the ability of LASSBio-1586, an N-acylhydrazone derivative, to attenuate nociceptive behavior and the inflammatory response in mice. Antinociceptive activity was evaluated through acetic acid-induced writhing and formalin-induced nociception tests. In these experimental models, LASSBio-1586 significantly (p<0.05) reduced nociceptive behavior. Several methods of acute and chronic inflammation induced by different chemical (carrageenan, histamine, croton oil, arachidonic acid) and physical (cotton pellet) agents were used to evaluate the anti-inflammatory effect of LASSBio-1586. LASSBio-1586 exhibited potent anti-inflammatory activity in all tests (p<0.05). Study of the mechanism of action demonstrated the possible involvement of the nitrergic, serotonergic and histamine signaling pathways. In addition, a molecular docking study was performed, indicating that LASSBio-1586 is able to block the COX-2 enzyme, reducing arachidonic acid metabolism and consequently decreasing the production of prostaglandins, which are important inflammatory mediators. In summary, LASSBio-1586 exhibited relevant antinociceptive and anti-inflammatory potential and acted on several targets, making it a candidate for a new multi-target oral anti-inflammatory drug.

Lung and liver responses to 1- and 7-day treatments with LASSBio-596 in mice subchronically intoxicated by microcystin-LR.

Microcystin-LR (MC-LR) can cause serious injuries upon short- and long-term exposures that can be prevented by LASSBio-596 (LB-596), an anti-inflammatory compound. We aimed to test LB-596 following subchronic exposure to MC-LR. Swiss mice received 10 intraperitoneal injections of distilled water (DW) or MC-LR (20 µg/kg bw) every 2 days. On the 10th injection animals receiving DW were gavaged with DW or 50 mg/kg bw of LB-596 for 1 or 7 days (C1D, C7D, CL1D and CL7D groups), whereas those exposed to MC-LR received either DW or 50 mg/kg of LB-596 for 1 or 7 days (T1D, T7D, TL1D and TL7D groups). Twelve hours after the last gavage we assessed respiratory mechanics, and extracted lung and liver for histology, apoptosis, inflammatory biomarkers and MC-LR content. C1D, C7D, CL1D and CL7D were all similar. Mechanical parameters were significantly higher in T1D and T7D compared to the other groups. LB-596 reversed these changes on day 1 of administration. LB-596 reduced inflammatory mediators in lung and liver on day 1 of treatment. On day 7 apoptosis in liver and lung fell even more. Briefly, 7-day administration completely reversed lung and liver changes.

Respiratory and Systemic Effects of LASSBio596 Plus Surfactant in Experimental Acute Respiratory Distress Syndrome.

BACKGROUND/AIMS: Exogenous surfactant has been proposed as adjunctive therapy for acute respiratory distress syndrome (ARDS), but it is inactivated by different factors present in the alveolar space. We hypothesized that co-administration of LASSBio596, a molecule with significant anti-inflammatory properties, and exogenous surfactant could reduce lung inflammation, thus enabling the surfactant to reduce edema and improve lung function, in experimental ARDS. METHODS: ARDS was induced by cecal ligation and puncture surgery in BALB/c mice. A sham-operated group was used as control (CTRL). After surgery (6 hours), CTRL and ARDS animals were assigned to receive: (1) sterile saline solution; (2) LASSBio596; (3) exogenous surfactant or (4) LASSBio596 plus exogenous surfactant (n = 22/group). RESULTS: Regardless of exogenous surfactant administration, LASSBio596 improved survival rate and reduced collagen fiber content, total number of cells and neutrophils in PLF and blood, cell apoptosis, protein content in BALF, and urea and creatinine levels. LASSBio596 plus surfactant yielded all of the aforementioned beneficial effects, as well as increased BALF lipid content and reduced surface tension. CONCLUSION: LASSBio596 exhibited major anti-inflammatory and anti-fibrogenic effects in experimental sepsis-induced ARDS. Its association with surfactant may provide further advantages, potentially by reducing surface tension.

Investigating the therapeutic effects of LASSBio-596 in an in vivo model of cylindrospermopsin-induced lung injury.

The cyanotoxin cylindrospermopsin (CYN) has lately been reported with a notorious toxicity to mammals. LASSBio-596 is a compound with anti-inflammatory actions. We aimed at evaluating the therapeutic effects of LASSBio-596 in a model of CYN-induced lung injury. Protocol #1: BALB/c mice received intratracheally (i.t.) 50-µL of saline or semi-purified extract of CYN (70 µg/kg). 18 h later, animals that received saline were gavaged with saline (SALSAL) or 50 mg/kg of LASSBio-596 (SALLAS), and mice that received CYN were gavaged with either saline (TOXSAL) or 50 mg/kg of LASSBio-596 (TOXLAS). Pulmonary mechanics was measured 6 h after gavage. Lungs were prepared for histology and inflammatory mediators determination. Protocol #2: Mice received 50-µL of CYN (70 µg/kg, i.t.) and 18 h later were gavaged with saline (NOT TREATED), or 50 mg/kg of LASSBio-596 (TREATED). Survival rates and pulmonary mechanics of the survivors were assessed. CYN exposure increased mechanical components, alveolar collapse, PMN cells and fiber deposition in the lungs, as well as the production of IL-1ß, IL-6 and KC in Protocol #1. LASSBio-596 attenuated those changes. TREATED mice in Protocol #2 presented significantly higher survival rates and tended to improve lung mechanics. Briefly, LASSBio-596 showed positive effects in mice exposed to CYN.

Vasodilator and antihypertensive effects of a novel N-acylhydrazone derivative mediated by the inhibition of L-type Ca²âº channels.

New bioactive N-acylhydrazone derivatives synthesized from safrole previously have been found to promote intense vasodilation and antihypertensive activity. In this study, we describe the synthesis and the cardiovascular effects of the new N-acylhydrazone derivative (E)-N-methyl-N'-(thiophen-3-ylmethylene)benzo[d][1,3]dioxole-5-carbohydrazide (LASSBio-1289). Thoracic aorta and left papillary muscles from Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) were prepared for isometric tension recording. LASSBio-1289 promoted relaxation of endothelium-intact and denuded aortic rings with respective pIC50 (-log IC50) values of 5.07 ± 0.09 and 4.26 ± 0.09 (P < 0.001) for WKY rats and 5.43 ± 0.05 and 5.58 ± 0.07 (P > 0.05) for SHR. The vasodilator activity of LASSBio-1289 was increased in the KCl-contracted aorta. LASSBio-1289 attenuated the contracture elicited by Ca(2+) in depolarized aorta from both WKY rats and SHR. In endothelium-intact aorta from WKY rats, LASSBio-1289-induced relaxation was unchanged after incubation with propranolol, ZM 241385, atropine, diphenhydramine, and HOE140, but was significantly reduced by L-NAME and ODQ. LASSBio-1289 decreased papillary muscles contractility only at concentrations above 200 µm. Acute intravenous injection of LASSBio-1289 (3 mg/kg) produced a significant hypotensive response in SHR but not in WKY rats, suggesting its antihypertensive profile. The antihypertensive effect was also observed in SHR during 14 days of intraperitoneal and oral administration. In conclusion, our data demonstrated that LASSBio-1289 induces both endothelium-independent vasorelaxation involving the inhibition of Ca(2+) influx through L-type Ca(2+) channels in aorta from WKY rats and SHR, and endothelium-dependent relaxation mediated by the NO/cyclic GMP pathway in WKY rats.

N-acylhydrazone improves exercise intolerance in rats submitted to myocardial infarction by the recovery of calcium homeostasis in skeletal muscle.

AIMS: This work investigated the effects of 3,4-methylenedioxybenzoyl-2-thienylhydrazone (LASSBio-294) treatment on the contractile response of soleus (SOL) muscle from rats submitted to myocardial infarction (MI). MAIN METHODS: Following coronary artery ligation, LASSBio-294 (2mg/kg, i.p.) or vehicle was administrated once daily for 4 weeks. KEY FINDINGS: The run time to fatigue for sham rats was 17.9 ±2.6 min, and it was reduced to 3.3 ± 0.8 min (P<0.05) in MI rats. In MI rats treated with LASSBio-294, the time to fatigue was 15.1 ± 3.6 min. During the contractile test, SOL muscles from sham rats showed a response of 7.12 ± 0.54N/cm(2) at 60 Hz, which was decreased to 5.45 ± 0.49 N/cm(2) (P<0.05) in MI rats. The contractility of SOL muscles from the MI-LASSBio-294 group was increased to 9.01 ± 0.65N/cm(2). At 16 mM caffeine, the contractility was reduced from 2.31 ± 0.33 to 1.60 ± 0.21 N/cm(2) (P<0.05) in the MI group. In SOL muscles from MI-LASSBio-294 rats, the caffeine response was increased to 2.62 ± 0.33 N/cm(2). Moreover, SERCA2a expression in SOL muscles was decreased by 0.31-fold (31%) in the MI group compared to the Sham group (P<0.05). In the MI-LASSBio-294 group, it was increased by 1.53-fold (153%) compared to the MI group (P<0.05). Meanwhile, the nuclear density in SOL muscles was increased in the MI group compared to the Sham group. Treatment with LASSBio-294 prevented this enhancement of cellular infiltrate. SIGNIFICANCE: LASSBio-294 treatment prevented the development of muscular fatigue and improved exercise intolerance in rats submitted to MI.

Anti-atherogenic effects of a new thienylacylhydrazone derivative, LASSBio-788, in rats fed a hypercholesterolemic diet.

The compound LASSBio-788 (N-Allyl (2-thienylidene) 3,4-methylenedioxybenzoylhydrazine) is a thienylacylhydrazone derivative shown to have antiplatelet, vasodilatory, and anti-inflammatory properties in vitro. We hypothesize that LASSBio-788 may exert beneficial effects on atherosclerosis. Male wistar rats were divided into 4 groups: Control group received standard rat chow, hypercholesterolemic group (HC) and HC+788 (compound LASSBio-788 group) received hypercholesterolemic diet for 45 days. HC+788 group received compound LASSBio-788 (100 µmol/kg) once daily in the last 15 days. LASSBio-788 reduced the levels of total cholesterol (109.1 ± 4.3 vs. 361.0 ± 12.8 mg/dl), triglycerides (66.1 ± 1.1 vs. 186.9 ± 17.7 mg/dl), LDLc (63.2 ± 6.1 vs. 330.9 ± 9.7 mg/dl), VLDLc (9.8 ± 1.1 vs. 45.0 ± 4.6 mg/dl) and malondialdehyde (4.8 ± 0.3 vs. 9.4 ± 0.5 nmol/ml) compared to the HC group. LASSBio-788 presented antiplatelet properties and decreased inflammatory markers levels. LASSBio-788 promoted a decrease in contractile response to phenylephrine and an improvement in endothelium-dependent vasorelaxant response by increasing two-fold the expression of nitric oxide synthase (eNOS). Our results suggest that the compound LASSBio-788 represents a new multi-targeted drug candidate for the treatment of atherosclerosis.

A novel Ca2+ channel antagonist reverses cardiac hypertrophy and pulmonary arteriolar remodeling in experimental pulmonary hypertension.

This work investigates the actions of LASSBio-1289, (E)-N-methyl-N'-(thiophen-3-methylene)benzo[d][1,3]dioxole-5-carbohydrazide, on monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH) in rats. Two weeks following the MCT injection, LASSBio-1289 (50 or 75mg/kg, p.o.) or vehicle was administrated once daily for 14 days. LASSBio-1289 (75 mg/kg) treatment caused a significant decrease in right ventricular systolic pressure (31.89±0.82 mmHg) compared to the MCT-vehicle group (52.74±6.19 mmHg; P<0.05). Oral treatment with LASSBio-1289 (50 or 75 mg/kg) effectively decreased pulmonary artery diameter and right ventricle (RV) area, assessed by echocardiography. LASSBio-1289 (75 mg/kg) reduced RV area (10.00±0.58 mm(2)) compared to the MCT-vehicle group (20.50±1.44 mm(2); P<0.05). LASSBio-1289 (75 mg/kg) also partially recovered the pulmonary artery acceleration time in MCT-treated rats. Oral treatment with LASSBio-1289 (50mg/kg) decreased the pulmonary arteriolar wall thickness (68.57±2.21%) compared to the MCT-vehicle group (81.07±1.92%; P<0.05). In experiments with isolated pulmonary arteries, the concentration of LASSBio-1289 necessary to produce 50% relaxation in the phenylephrine- or KCl-induced contraction was 27.31±6.94 and 2.72±0.99 µM, respectively, P<0.05. In the presence of LASSBio-1289 (50 µM), the maximal contraction induced by 10mM CaCl2 was reduced to 36.00±8.28% of the maximal contraction of the control curve (P<0.05). LASSBio-1289 was effective in attenuating MCT-induced PAH in rats, and its beneficial effects were likely mediated by the inhibition of extracellular Ca(2+) influx through L-type voltage-gated Ca(2+) channels in the pulmonary artery.

Oral antithrombotic effects of acylhydrazone derivatives.

AIM: In the search for new antithrombotic drug candidates, the synthesis and anti-platelet activity of a new series of N-acylhydrazones that were designed as thrombin inhibitors has been previously described. The aim of this work was to further characterize the effects of these compounds on thrombin-induced platelet aggregation and induced thrombosis in vivo. METHODS: In this work, four compounds were tested, LASSBio-693, 694, 743 and 752, on platelet aggregation induced by thrombin, ADP and TRAP-4A. These compounds were further tested using a mouse pulmonary thromboembolism model induced by collagen (500 µg/kg) and norepinephrine (80 µg/kg) or thrombin (2,000 UI), and a deep venous thrombosis model. RESULTS: At 200 µM, the compounds showed between 36% and 82% inhibition (for L-743 and L-752, respectively) of thrombin-induced platelet aggregation. The receptor agonist of PAR-4, TRAP-4A (250 µM), was used and inhibition between 43% and 77% was observed for each compound (200 µM).Compounds LASSBio-752 and 743 were the most effective in the venous thrombosis model, increasing the survival of the treated animals to 63% and 46%, respectively, in the model of collagen-induced thromboembolism and increasing to 80% (both) in the thrombin-induced model. LASSBio 743 was more effective for deep vein thrombosis, reducing the weight of the thrombus by approximately 70%. CONCLUSION: All compounds were administered orally and have shown effective antithrombotic action independently of the thrombotic stimulus. These results indicate that compounds LASSBio-743 and 752 are potential candidates for the treatment of cardiovascular diseases.

Antihypertensive profile of 2-thienyl-3,4-methylenedioxybenzoylhydrazone is mediated by activation of the A2A adenosine receptor.

Several N-acylhydrazone derivatives synthesized from safrole have been found to promote intense vasodilation and antihypertensive activity. The present work describes the synthesis and antihypertensive profile of 2-thienyl-3,4-methylenedioxybenzoylhydrazone (LASSBio-1027), a new analogue of the lead compound 3,4-methylenedioxybenzoyl-2-thienylhydrazone. Thoracic aortas from Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) were prepared for isometric tension recording. Noninvasive blood pressure measurements were made during 14 days of intraperitoneal (10 mg/kg) or oral (20 mg/kg) administration of LASSBio-1027. LASSBio-1027 exhibited partially endothelium-dependent vasorelaxant activity, which was attenuated in the presence of l-NAME, glibenclamide, or ZM 241385. LASSBio-1027 exhibited an antihypertensive effect in SHR during 14 days of intraperitoneal or oral administration, but did not induce a hypotensive effect in normotensive WKY rats. LASSBio-1027-induced vascular relaxation of aortas from WKY rats was mediated by the activation of A(2A) adenosine receptors. Docking studies and binding assays suggested that LASSBio-1027 has affinity for A(2A) and A(3) adenosine receptors. This new N-acylhydrazone derivative represents a potential strategy for the treatment of arterial hypertension.

Benzenesulfonamide attenuates monocrotaline-induced pulmonary arterial hypertension in a rat model.

In this study, we examined the effects of LASSBio-965 (N-[2-(3,4-dimethoxyphenyl) ethyl]-benzenesulfonamide), a compound designed as a simplified structure of a non-selective phosphodiesterase 4 inhibitor, on vascular smooth muscle in vitro as well as in a rat model of monocrotaline (MCT)-induced pulmonary arterial hypertension. LASSBio-965 (50 mg/kg) treatment caused a significant decrease in right systolic ventricular pressure (32.47 ± 3.09 mmHg) compared to the MCT-vehicle group (51.88 ± 3.23 mmHg; P<0.05) and in the ratio of right ventricular weight to left ventricular weight plus septum (0.42 ± 0.03 g compared to 0.59 ± 0.06 g, respectively; MCT-vehicle group; P<0.05). LASSBio-965 induced a concentration-dependent relaxation of rat aortic rings, which was decreased by mechanical removal of the endothelium. Milrinone, rolipram, and sildenafil reduced the maximum relaxation (100%) to 22.4 ± 5.8, 69.5 ± 5.6 and 80.1 ± 10.7%, respectively (P<0.05). Maximum relaxation responses of aortic and pulmonary artery rings were decreased in the MCT-vehicle group (54.80 ± 5.69 and 35.87 ± 4.78, respectively) compared to the control (91.51 ± 4.79 and 54.32 ± 2.39, respectively) but improved with LASSBio-965 treatment (50mg/kg; 88.43 ± 4.54 and 59.36 ± 4.83, respectively). These results indicate that LASSBio-965 can attenuate the pulmonary arterial hypertension in an animal model most likely through the nonselective inhibition of phosphodiesterases 3, 4, and 5.

Vasodilatory activity and antihypertensive profile mediated by inhibition of phosphodiesterase type 1 induced by a novel sulfonamide compound.

LASSBio-985 is a sulfonamide compound designed as a simplified structure of a nonselective phosphodiesterase type 4 (PDE-4) inhibitor that promotes vasodilatory activity in vitro. PDE are enzymes responsible for the hydrolysis of cyclic adenosine 3',5'- monophosphate and cyclic guanosine 3',5'-monophosphate. Five different isozymes of PDE are found in vascular smooth muscle (PDE1-PDE5). Aortic rings, with or without endothelium, from male normotensive and spontaneously hypertensive rats (SHR) were prepared for isometric tension recording. Blood pressure was measured in Wistar Kyoto (WKY) rats and SHR during intravenous infusion of LASSBio-985 (10 mg/kg/min) during 15 min. LASSBio-985 induced a concentration-dependent vasodilation in aortic rings from normotensive and SHR, which was almost completely inhibited in endothelium-denuded vessels. Vasodilatory activity was also reduced in endothelium-intact aortic rings that had been pretreated with N(ω)-nitro-L-arginine methyl ester hydrochloride (L-NAME), a nitric oxide synthase inhibitor and 1H-[1,2,4]oxadiazolod[4,3-a]quinoxalin-1-one (ODQ), a guanylate cyclase inhibitor. LASSBio-985-induced vasodilation was also inhibited by sildenafil (100 µm) and SQ 22536, a PDE5 inhibitor and adenylate cyclase inhibitor, respectively. To evaluate the involvement of some endothelial receptors, atropine, diphenhydramine, HOE 140, naloxone, propranolol, indomethacin, and wortmannin were tested, but none inhibited the effects of LASSBio-985. The residual effect observed on endothelium-denuded aortic rings was abolished by nicardipine, a voltage-sensitive-Ca(2+)-channel blocker. Intravenous infusion of LASSBio-985 (10 mg/kg/min) significantly reduced systolic and diastolic pressures in both WKY and SHR. LASSBio-985 is a compound with vasodilatory activity, which could be consequent to PDE1 inhibition and voltage-sensitive-Ca(2+)-channel blockade.

Cardiovascular effects induced by N-(4'-dihydro)-piperoylthiomorpholine in normotensive rats.

OBJECTIVES: We have tested the cardiovascular effects of N-(4'-dihydro)-piperoylthiomorpholine (LASSBio 365) on rats using an in-vivo and in-vitro approach. METHODS: LASSBio 365 (0.025, 0.05, 0.1, 0.25, 0.5 or 1 mg/kg, randomly injected) was administered to conscious unrestrained rats and the mean arterial pressure and heart rate were measured. The effects of LASSBio 365 (3 x 10⁻6-3 x 10⁻4 m) on rat isolated aortic rings with and without endothelium were investigated. Key findings LASSBio 365 induced a dose-dependent decrease in mean arterial pressure and heart rate (ED50 = 158 ± 53 µg/kg). The effects evoked by LASSBio 365 (0.5 mg/kg) were inhibited by pretreatment with atropine. In anaesthetized rats, electrocardiogram recordings revealed second/third degree sinoatrial and atrioventricular blockade induced by the compound, which were completely inhibited after cardiac muscarinic blockade or cervical bilateral vagotomy. In rat isolated aortic rings, LASSBio 365 (3 x 10⁻6-3 x 10⁻4 m) was capable of antagonizing the contractile effects induced by phenylephrine (1 µm) or KCl (80 mm) (IC50 = 107 ± 6; 92 ± 6 µm, respectively). This effect was not inhibited after removal of the vascular endothelium (IC50 = 84 ± 4; 92 ± 10 µm, respectively). LASSBio 365 (10⁻6-10⁻4 m) antagonized CaCl2-induced contractions in a concentration-dependent manner. Furthermore, LASSBio 365 (98 µm) inhibited contractions produced by noradrenaline (1 µm), but not those induced by caffeine (20 mm). CONCLUSIONS: These results suggested that LASSBio 365 produced negative chronotropism and reduced peripheral resistance that were probably due to the stimulation of cardiac muscarinic pathways. Peripheral vasodilation was probably linked to voltage-dependent Ca²+-channel blockade and/or specific inhibition of Ca²+ release from noradrenaline-sensitive intracellular stores.

Antimicrobial activity of Pterogyne nitens Tul., Fabaceae, against opportunistic fungi / Atividade antimicrobiana de Pterogyne nitens Tul., Fabaceae, contra fungos oportunistas

As part of our ongoing research on antifungal agents from Brazilian flora, eight extracts and twelve fractions from Pterogyne nitens Tul., Fabaceae, were screened for antimicrobial activity against four opportunistic fungi species (Candida albicans, Candida krusei, Candida parapsilosis and Cryptococcus neoformans) using a broth microdilution method. The present investigation reveals that P. nitens extracts and fractions were more effective against C. krusei and C. parapsilosis than against C. neoformans. The growth of C. albicans was moderately affected by all tested extracts and fractions. The strongest effects were observed for n-butanol fractions from branches (MIC = 15.6 μg/mL) and roots (MIC = 31.2 μg/mL) against C. krusei. Additionally, the chromatographic fractionation of the n-butanol fraction from branches afforded four guanidine alkaloids; N-1,N-2,N-3-triisopentenylguanidine (1), described for the first time in the Fabaceae family, and nitensidines A-C (2-4), which showed moderate activity towards C. krusei (MIC = 62.5 μg/mL) and C. parapsilosis (MIC = 31.2 μg/mL).

No contexto de nossas pesquisas por novos agentes antifúngicos obtidos da flora brasileira, oito extratos e doze frações de Pterogyne nitens Tul., Fabaceae, foram submetidos ao ensaio antifúngico pelo método de microdiluição, contra quatro espécies de fungos oportunistas, Candida albicans, Candida krusei, Candida parapsilosis e Cryptococcus neoformans. Este trabalho revelou que os extratos e frações de P. nitens foram mais ativos contra C. krusei e C. parapsilosis quando comparados a C. neoformans, sendo que o crescimento de C. albicans foi moderadamente afetado por todos os extratos e frações. As atividades mais potentes foram observadas para as frações n-butanólica dos galhos (CIM = 15,6 μg/mL) e raízes (CIM = 31,2 μg/mL) contra C. krusei. Adicionalmente, a fração n-butanólica dos galhos foi submetida ao fracionamento cromatográfico, resultando no isolamento de quatro alcaloides guanidínicos, sendo N-1,N-2,N-3-tri-isopentenilguanidina (1), descrito pela primeira vez em espécies da família Fabaceae e nitensidinas A-C (2-4), os quais apresentaram atividade antifúngica moderada contra C. krusei (CIM = 62,5 μg/mL) e C. parapsilosis (CIM = 31,2 μg/mL).