Estudo químico e da atividade biológica cardiovascular do óleo essencial de folhas de Alpinia zerumbet (Pers.) B.L.Burtt & R.M.Sm. em ratos / Phytochemistry and cardiovascular biological activity of the essential oil from leaves of Alpinia zerumbet (Pers.) B.L. Burtt & R.M.Sm. in rats

A espécie vegetal Alpinia zerumbet (Pers.) B.L.Burtt & R.M. Sm. é popularmente empregada para o tratamento de diversas enfermidades, entre elas a hipertensão. Avaliar a composição química, a atividade antihipertensiva e ação na hipertrofia cardíaca do óleo essencial das folhas de Alpinia zerumbet (OEAZ) em ratos foram os objetivos deste estudo. O OEAZ, obtido por hidrodestilação em aparelho Clevenger, teve sua composição química analisada em cromatografia gasosa acoplada à espectrometria de massas (CG-EM). Foram identificados 14 constituintes, sendo terpinen-4-ol (37,45 por cento) o majoritário, seguido pelos óxido de cariofileno (7,56 por cento), trans-hidrato de sabineno (6,61 por cento) e 1,8-cineol (4,02 por cento). A avaliação cardiovascular foi feita após o tratamento crônico de ratos espontaneamente hipertensos (SHR) e seus respectivos controles, ratos Wistar-Kyoto (WKY). Os dados hemodinâmicos revelaram redução da pressão arterial média (PAM) no grupo tratado (SHRP: 160 ± 7 mm Hg; p<0,01) em relação ao não tratado (SHR: 180 ± 5 mm Hg). A relação entre peso do ventrículo esquerdo e peso corporal (VE/PC) do SHRP (2,50 ± 0,03 mg g-1; p<0,01) mostrou-se inferior ao SHR (2,61 ± 0,01 mg g-1), confirmando a redução da hipertrofia cardíaca (HC). Os dados de PAM e VE/PC dos animais SHRP foram estatisticamente diferentes quando comparados com os ratos controle (WKY: 116 ± 2 mm Hg e WKYP: 119 ± 4 mm Hg; p<0,05; WKY: 2,15 ± 0,04 mg g-1 e WKYP: 2,17 ± 0,04 mg g-1 ; p<0,01), indicando não ter havido normalização dos mesmos. Conclui-se que o tratamento crônico com OEAZ foi capaz de determinar redução, mas não a normalização, da PAM e da HC de ratos SHR, provavelmente pela presença dos componentes terpinen-4-ol e 1,8-cineol. Estudos com doses maiores ou período de tratamento superior são necessários para avaliar a possibilidade de o OEAZ normalizar os parâmetros analisados (PAM e HC).

Alpinia zerumbet (Pers.) B.L. Burtt & R.M.Sm. is traditionally employed to treat several diseases such as hypertension. The aim of this study was to evaluate the chemical composition, the anti-hypertensive activity and the capacity to reduce cardiac hypertrophy of the essential oil of A. zerumbet leaves (EOAZ) in rats. EOAZ was obtained through hydrodistillation in Clevenger apparatus and its chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS). Several constituents (14) were identified, terpen-4-ol (37.45 percent) being the major component, followed by caryophyllene oxide (7.56 percent), trans-sabinene hydrate (6.61 percent) and 1,8-cineol (4.02 percent). The cardiovascular effect was investigated after chronic treatment with spontaneously hypertensive rats (SHR) and their respective controls, Wistar-Kyoto rats (WKY). The treated group showed a lower mean arterial pressure (MAP) (SHRP: 160 ± 7 mm Hg; p<0.01) than the untreated group (SHR: 180 ± 5 mm Hg). The ratio of left ventricle-to-body weight (LV/BW) for SHRP was lower (2.504 ± 0.03 mg g-1; p<0.01) than that for SHR (2.162 ± 0.01 mg g-1), confirming the cardiac hypertrophy (CH) reduction. There were significant differences in MAP and CH between SHRP animals and control rats (WKY: 116 ± 2 mm Hg and WKYP: 119 ± 4 mm Hg; p<0.05. WKY: 2.152 ± 0.04 mg g-1 and WKYP: 2.168 ± 0.04 mg g-1; p<0.01), indicating that these values were not normalized. Those data showed that the chronic treatment with EOAZ reduces MAP and CH in SHR probably due to the presence of the compounds terpinen-4-ol and 1,8-cineol. Studies with higher doses or longer treatment periods are necessary to evaluate whether EOAZ can reduce the analyzed parameters (MAP and CH) to normal values.

Efeito da administração do Allium sativum sobre as alterações cardiovasculares de ratos Wistar com infarto do miocárdio. / Effects of consumption of Allium sativum on the cardiovascular abnormalities observed in Wistar rats following cardiac infarction.

O alho (Allium sativum) apresenta várias ações benéficas ao sistema circulatório, tais como diminuição dos níveis de colesterol total, LDL-colesterol e da pressão arterial, além de efeito antioxidante. O objetivo deste estudo foi avaliar o efeito da administração do Allium sativum sobre as alterações da hemodinâmica cardiovascular e estruturais macroscópicas do coração de animais com infarto induzido experimentalmente. Ratos Wistar foram tratados, previamente e após indução do infarto, com homogeneizado de alho na dose de 125mg/Kg/dia durante 21 dias, por via oral (uma semana antes e duas depois do procedimento de infarto). Os grupos controle passaram por cirurgia fictícia (SHAM). Os animais foram divididos em grupos controles e infartados com (SHAMT, INFT; respectivamente) ou sem (SHAM, INF; respectivamente) tratamento com alho. Houve redução da hipertrofia do ventrículo direito (INF=0,75±0,05 vs. INFT=0,61±0,03 mg/Kg; p<0,01), da área de infarto (INF=29,7±4,8% vs. INFT=20,4±1,4%; p<0,05) e regularização dos níveis de pressão arterial sistólica (PAS; INF=100±8 vs. INFT=127±7 mmHg; p<0,05) e média (PAM; INF=94±4 vs. INFT=110±6 mmHg; p<0,01) dos animais INFT comparados com os INF. Houve um menor número de animais mortos após o procedimento de infarto no grupo INFT em relação ao grupo INF (20%, n=2; 45,5%, n=5; respectivamente). Esses achados indicam que o alho tem um importante papel na prevenção e no controle de alterações cardiovasculares, uma vez que houve redução do número de mortes pós-infarto e melhor perfil cardiovascular dos animais INFT.

Garlic (Allium sativum) has several beneficial effects on the cardiovascular system, such as reductions of the levels of total cholesterol, LDL-cholesterol and blood pressure, besides acting as an antioxidant. The aim of this study was to assess the effects of administering Allium sativum on changes in the cardiovascular hemodynamics and macroscopic structure that occur in the hearts of animals with experimentally induced cardiac infarction. Male Wistar rats were treated with homogenized garlic at a dose of 125mg/kg b.w./day for 21 days, given orally for one week before and two weeks after the procedure to induce myocardial infarction. The control group was subjected to a fictitious surgery (SHAM). The animals were divided into control and infarcted groups, treated (SHAMT, INFT) or untreated (SHAM, INF) with garlic. There were reductions in right ventricular hypertrophy (INF=0.75±0.05 vs. INFT=0.61±0.03 mg.kg-1; p<0.01) and infarcted area (INF=29.7±4.8 % vs. INFT=20.4±1.4 %; p<0.05) and regularization of the levels of systolic (SAP; INF=100±8 vs. INFT=127±7 mm Hg; p<0.05) and mean arterial pressure (MAP; INF=94±4 vs. INFT=110±6 mm Hg; p<0.01) in the INFT animals, compared to the INF group. Fewer animals died after the cardiac infarction procedure in the group INFT than in INF (20%, n=2; 45.5%, n=5; respectively). These findings suggest that garlic can have an important role in the prevention and control of cardiovascular abnormalities, since there was a reduction in the number of post-infarction deaths and an improvement of the cardiovascular profile in the INFT animals.

Effects of small doses of ouabain on the arterial blood pressure of anesthetized hypertensive and normotensive rats

Ouabain increases vascular resistance and may induce hypertension by inhibiting the Na+ pump. The effects of 0.18 and 18 æg/kg, and 1.8 mg/kg ouabain pretreatment on the phenylephrine (PHE; 0.1, 0.25 and 0.5 æg, in bolus)-evoked pressor responses were investigated using anesthetized normotensive (control and uninephrectomized) and hypertensive (1K1C and DOCA-salt treated) rats. Treatment with 18 æg/kg ouabain increased systolic and diastolic blood pressure in all groups studied. However, the magnitude of this increase was larger for the hypertensive 1K1C and DOCA-salt rats than for normotensive animals, while the pressor effect of 0.18 æg/kg ouabain was greater only in DOCA-salt rats. A very large dose (1.8 mg/kg) produced toxic effects on the normotensive control but not on uninephrectomized or 1K1C rats. Rat tail vascular beds were perfused to analyze the effects of 10 nM ouabain on the pressor response to PHE. In all animals, 10 nM ouabain increased the PHE pressor response, but this increase was larger in hypertensive DOCA-salt rats than in normotensive and 1K1C rats. Results suggested that a) increases in diastolic blood pressure induced by 18 æg/kg ouabain were larger in hypertensive than normotensive rats; b) in DOCA-salt rats, smaller ouabain doses had a stronger effect than in other groups; c) hypertensive and uninephrectomized rats were less sensitive to toxic doses of ouabain, and d) after treatment with 10 nM ouabain isolated tail vascular beds from DOCA-salt rats were more sensitive to the pressor effect of PHE than those from normotensive and 1K1C hypertensive rats. These data suggest that very small doses of ouabain, which might produce nanomolar plasma concentrations, enhance pressor reactivity in DOCA-salt hypertensive rats, supporting the idea that endogenous ouabain may contribute to the increase and maintenance of vascular tone in hypertension