RESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Croton urucurana Baill. (Euphorbiaceae), popularly known as 'sangue de dragão' is a Brazilian species widely used in traditional medicine for cardiovascular ailments. AIM: To investigate the cardiovascular effects of the C. urucurana extract in spontaneously hypertensive rats (SHRs). MATERIALS AND METHODS: Leaves from C. urucurana were collected and morphoanatomically characterized. The ethanol-soluble fraction (ESCU) was obtained and analyzed by LC-DAD-MS. Using female Wistar rats we investigated the acute toxicity of ESCU. Then, SHRs (six months old) received vehicle, hydrochlorothiazide (25 mg/kg), or ESCU (30, 100, 300 mg/kg) for 28 days. At the beginning and at the end of treatments, urine samples were obtained to assess renal function. At the end of the trial period, the blood pressure, mesenteric vascular beds (MVBs) reactivity, and electrocardiographic profile were evaluated. Serum angiotensin-converting enzyme activity, as well as urea, creatinine, sodium, potassium, nitrite, malondialdehyde, nitrotyrosine, and aldosterone levels were determined. Relative organ weights and histopathological analysis were performed. Finally, the cardiac function on a Langendorff system, as well as the molecular mechanisms involved in the vasodilator effects of ESCU in MVBs were also investigated. RESULTS: The compounds annotated from ESCU by LC-DAD-MS included mainly phenylpropanoid derivatives, alkaloids, O-glycosylated megastigmanes, glycosylated flavonoids, flavan-3-ols, and others, such as quercetin O-deoxyhexosyl-hexoside, magnoflorine, reticuline, and taspine. None of the animals showed any signs of toxicity. Male SHRs treated only with the vehicle showed important cardiovascular changes, including a reduction in renal function, increase in serum oxidative stress, and hemodynamic, electrocardiographic, and morphological changes typical of hypertensive disease. Moreover, parameters of cardiac function, including left ventricular developed pressure, peak rate of contraction, peak rate of relaxation, and the rate pressure product were significantly altered, showing a significant impairment of ventricular function. All ESCU-doses presented a significant cardioprotective effect in SHRs rats. The 28-day treatment normalized the hemodynamic, electrocardiographic, morphological, and renal impairments, as well as reversed the changes in ventricular function induced by hypertension. In MVBs with an intact endothelium, ESCU (0.1, 0.3, and 1 mg) dose-dependently induced vasodilation. Endothelium removal or the inhibition of nitric oxide synthase prevented the vasodilatory effect of ESCU. Perfusion with a physiological saline solution that contained KCl, tetraethylammonium, or apamin also abolished the vasodilatory effect of ESCU. CONCLUSION: Prolonged ESCU-treatment showed significant cardioprotective effects in SHRs. Moreover, the data showed the role of nitric oxide and calcium-activated small conductance potassium channels in the cardiovascular effects of ESCU.
Assuntos
Croton , Hipertensão , Animais , Pressão Sanguínea , GMP Cíclico/metabolismo , Endotélio Vascular , Feminino , Hipertensão/induzido quimicamente , Hipertensão/tratamento farmacológico , Masculino , Óxido Nítrico/metabolismo , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Ratos , Ratos Endogâmicos SHR , Ratos Wistar , Canais de Potássio Ativados por Cálcio de Condutância BaixaRESUMO
Croton urucurana Baill. is a native Brazilian tree, popularly known as "sangra-d'água" or "sangue-de-dragão," based on the red resinous sap of the trunk. Its use has been transmitted through generations based on popular tradition that attributes analgesic, anti-inflammatory, and cardioprotective properties to the tree. However, its cardioprotective effects have not yet been scientifically investigated. Thus, the present study investigated the pharmacological response to an ethanol-soluble fraction from the leaves of C. urucurana in Wistar rats exposed to smoking and dyslipidemia, two important cardiovascular risk factors. The extract was evaluated by high-performance liquid chromatography. Wistar rats received a 0.5% cholesterol-enriched diet and were exposed to cigarette smoke (9 cigarettes/day for 10 weeks). During the last 5 weeks, the animals were orally treated with vehicle (negative control group), C. urucurana extract (30, 100, and 300 mg/kg), or simvastatin (2.5 mg/kg) + enalapril (15 mg/kg). One group of rats that was not exposed to these risk factors was also evaluated (basal group). Electrocardiograms and systolic, diastolic, and mean blood pressure were measured. Blood was collected to measure total cholesterol, triglycerides, urea, and creatinine. The heart and kidneys were collected and processed for oxidative status and histopathological evaluation. The phytochemical analysis revealed different classes of flavonoids and condensed tannins. The model induced dyslipidemia and cardiac and renal oxidative stress and increased levels of urea and creatinine in the negative control group. Treatment with the C. urucurana extract (300 mg/kg) and simvastatin + enalapril decreased cholesterol and triglyceride levels. In contrast to simvastatin + enalapril treatment, the C. urucurana extract exerted cardiac and renal antioxidant effects. No alterations of electrocardiograms, blood pressure, or histopathology were observed between groups. These findings indicate that C. urucurana exerts lipid-lowering, renal, and cardioprotective effects against oxidative stress in a preclinical model of multiple risk factors for heart disease.
RESUMO
Information on the health benefits of ethanolic extracts obtained from Blutaparon portulacoides stem (EEBP) hasn´t been consistently described in the literature until the present moment. This study investigated the antimycobacterial, anti-inflammatory and toxicological effects of EEBP in models of inflammation/infection, as well as its chemical composition. Chemical analysis of EEBP by electrospray ionization-mass spectrometry/HPLC-MS/MS identified 3,5,3'-Trihydroxy-4'-methoxy-6,7-methylenedioxy-flavone, gomphrenol, ferulic, vanillic, and caffeic acids. The minimum inhibitory concentration of EEBP and isoniazid in the presence of Mycobacterium tuberculosis was 123.4 and 0.030 µg/ml, respectively. EEBP oral administration (p.o.) (300-1000 mg/kg) or dexamethasone subcutaneous injection (s.c.) (1 mg/kg) significantly inhibited leukocytes and proteins resulting from carrageenan-induced pleurisy in Swiss mice. In the BCG-induced pleurisy model, the oral treatments performed once a day for 7 days, with EEBP (30 and 100 mg/kg) and isoniazid (25 mg/kg), inhibited the increase in plasmatic IL-1ß levels and in pleural exudate from C57BL-6 mice, and reduced M. tuberculosis growth in organs (colony forming units assays). EEBP (30-300 mg/kg, p.o.) and dexamethasone (1 mg/s.c.) significantly prevented carrageenan-induced oedema and mechanical hyperalgesia in Swiss mice. The treatments (once a day for 22 days) with EEBP (30 mg/kg, p.o.) and dexamethasone (1 mg/s.c.) substantially inhibited oedema and mechanical- and cold-hyperalgesia at 11, 16 and 22 days after the administration of Freund's Complete Adjuvant in C57bL6 mice. No evidence of physio-pathologic was observed in Wistar rats acutely treated with EEBP (2000 mg/kg, p.o.). This study confirms the anti-inflammatory and antibiotic properties of EEBP, opening possibilities for the development of safe new drugs with dual anti-inflammatory/antimycobacterial activities which could be favorable from a pharmacoeconomic perspective.