RESUMEN
There are several reports suggesting that Spirulina (Arthrospira) may have a beneficial effect in the prevention of cardiovascular diseases. Here we review the results of studies on the effects of dietary Spirulina on the vasomotor reactivity of aortic rings excised from either lean or obese Wistar rats. We also review preliminary results on the effects of Spirulina intake on plasma lipids and blood pressure in humans. The results of the former studies strongly suggest that Spirulina induces a tone-related increase in the synthesis/release of nitric oxide by the endothelium as well as an increase in the synthesis/release of a vasodilating cyclooxygenase-dependent metabolite of arachidonic acid and/or a decrease in the synthesis/release of a vasoconstricting eicosanoid by the endothelium. In humans, Spirulina maxima intake decreases blood pressure and plasma lipid concentrations, especially triacylglycerols and low-density lipoprotein-cholesterol, and indirectly modifies the total cholesterol and high-density lipoprotein-cholesterol values.
Asunto(s)
Presión Sanguínea/efectos de los fármacos , LDL-Colesterol/sangre , Endotelio Vascular/efectos de los fármacos , Preparaciones de Plantas/farmacología , Spirulina , Triglicéridos/sangre , Sistema Vasomotor/efectos de los fármacos , Adolescente , Adulto , Anciano , Animales , Aorta/efectos de los fármacos , Ácido Araquidónico/metabolismo , Colesterol/sangre , Eicosanoides/metabolismo , Femenino , Humanos , Indometacina/farmacología , Masculino , Persona de Mediana Edad , Óxido Nítrico/metabolismo , Obesidad/metabolismo , Fenilefrina/farmacología , Fitoterapia , Ratas , Ratas Wistar , Adulto JovenRESUMEN
The mistletoe Psittacanthus calyculatus (Loranthaceae) is used in Mexican traditional medicine for the treatment of hypertension. In the present study the effects of a crude ethanolic extract of this mistletoe, on the vasomotor reactivity of superfused rat aortic rings (with or without a functional endothelium) were analyzed. Either in the absence or in the presence of L-NAME or indomethacin, the extract (12.5-800 microg/ml) had no effect on the basal tone of both types of rings. In phenylephrine-precontracted rings, low concentrations of the extract (up to 300 microg/ml) induced a small additional tension development in both types of rings; however, the tension increase was slightly larger in rings having an intact endothelium. At higher concentrations (400-800 microg/ml), the extract relaxed, concentration-dependently, phenylephrine-precontracted rings with an intact endothelium. This relaxation was completely reverted by the addition of L-NAME. When the extract was applied in the continuous presence of L-NAME to phenylephrine-precontracted rings, instead of a relaxation a marked additional tension development occurred. Indomethacin did not modify the relaxation induced by the extract. The results indicate that the ethanolic extract of this mistletoe induces, predominantly, an endothelium-dependent relaxation which seems to be mediated by the synthesis/release of nitric oxide.
Asunto(s)
Endotelio Vascular/efectos de los fármacos , Medicina Tradicional , Músculo Liso Vascular/efectos de los fármacos , Hojas de la Planta , Preparaciones de Plantas/farmacología , Proteínas de Plantas , Toxinas Biológicas/farmacología , Vasodilatación/efectos de los fármacos , Animales , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Masculino , México , NG-Nitroarginina Metil Éster/farmacología , Fenilefrina/farmacología , Preparaciones de Plantas/aislamiento & purificación , Ratas , Ratas Wistar , Proteínas Inactivadoras de Ribosomas Tipo 2 , Toxinas Biológicas/aislamiento & purificación , Vasoconstricción/efectos de los fármacos , Vasoconstrictores/farmacologíaRESUMEN
Ten Type 2 diabetic patients with moderately hyperglycemia, received a raw extract of Cucurbita ficifolia or potable water in a single dose of 4 ml/Kg body weight, in two different sessions at least separated by 1 week. Blood glucose levels were followed in both parts of the study by a period of 5 h. The patients had stopped their pharmacologic medication 24 h prior to each part of the study. As expected, no significant changes on blood glucose were observed after giving the vehicle; however, the oral administration of C. ficifolia was followed by a significant decrease in blood glucose levels, from 12.07+/-1.69 mM (217.2+/-30.4 mg/dl) to 9.42+/-1.96 mM (169.6+/-35.3 mg/dl) 3 h after and to 8.37+/-1.74 mM (150.8+/-31.3 mg/dl) 5 h after the extract administration. The hypoglycemic action of Cucurbita ficifolia agrees with its effects previously observed in laboratory animals. The results of this preliminary study do not give indications for the mechanism of this hypoglycemic effect.
Asunto(s)
Cucurbitaceae/uso terapéutico , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Hipoglucemiantes/uso terapéutico , Fitoterapia , Adulto , Glucemia/análisis , Glucemia/efectos de los fármacos , Diabetes Mellitus Tipo 2/sangre , Femenino , Humanos , Hiperglucemia/tratamiento farmacológico , Masculino , Persona de Mediana EdadRESUMEN
Dietary Spirulina decreases, endothelium-dependently, the responses to vasoconstrictor agonists and increases the endothelium-dependent, agonist-induced, vasodilator responses of rat aorta rings. The aim of this study was to analyze, in vitro, the effects of a raw ethanolic extract of Spirulina maxima on the vasomotor responses of rat aortic rings to phenylephrine and to carbachol. On rings with endothelium, the extract produced the following effects: (a) a concentration-dependent (60-1000 microg/ml) decrease of the contractile response to phenylephrine; (b) a rightward shift and a decrease in maximal developed tension, of the concentration--response curve to phenylephrine; (c) a concentration dependent relaxation of phenylephrine-precontracted rings. These effects were blocked by L-NAME, and not modified by indomethacin. The extract had no effect on the concentration-response curve to carbachol of rings with endothelium. On endothelium-denuded rings the extract caused a significant rightward shift of the concentration response curve to phenylephrine without any effect on maximal tension development. In the presence of the extract, indomethacin induced a marked decrease in the maximal phenylephrine-induced tension of endothelium-denuded rings. These results suggest that the extract increases the basal synthesis/release of NO by the endothelium and, also, the synthesis/release of a cyclooxygenase-dependent vasoconstricting prostanoid by vascular smooth muscle cells.
Asunto(s)
Aorta/efectos de los fármacos , Proteínas Bacterianas/efectos de los fármacos , Endotelio Vascular/efectos de los fármacos , Animales , Aorta/fisiología , Carbacol/farmacología , Relación Dosis-Respuesta a Droga , Endotelio Vascular/fisiología , Técnicas In Vitro , Masculino , Fenilefrina/farmacología , Ratas , Ratas Wistar , SpirulinaRESUMEN
The aim of the present work was to assess if the feeding of either the oil extract of Spirulina maxima or of its defatted fraction would prevent fatty liver development, induced in rats by a single intraperitoneal dose of carbon tetrachloride (CCl4). Liver and serum lipids were evaluated 4 days after treatment with this agent. Concentration of liver lipids did not differ in rats fed on a purified diet either without or with one of the fractions of Spirulina, except for total cholesterol, which showed a slight increase in the group receiving the oil extract of Spirulina. However, after CCl4 treatment, liver total lipids and triacylglycerols were significantly lower in rats fed on a diet containing any fraction of Spirulina (defatted or the oil fraction) than in rats without Spirulina in their diet. Furthermore, the increased liver cholesterol values, induced by CCl4 treatment, were not observed in rats receiving Spirulina. In addition, rats receiving whole Spirulina in their diet and treated only with the vehicle showed an increase in the percentage of HDL values. The changes in VLDL and LDL induced by CCl4 treatment were not observed in the whole Spirulina group. Furthermore, after CCl4 treatment the values of the liver microsomal thiobarbituric acid-reactive substances were lower in the whole Spirulina group than in the control group. These results support the potential hepatoprotective role of Spirulina.