Antinociceptive activity of fruits extracts and "arrope" of Geoffroea decorticans (chañar).

ETHNOPHARMACOLOGICAL RELEVANCE: Geoffroea decorticans (chañar) fruits and their derivate product (arrope) have been traditionally used as food and a folk medicine for the treatment of a wide variety of diseases including bronchopulmonary disorders and to relieve dolorous process. AIM OF THE STUDY: In order to evaluate the pharmacology action of this plant, studies were performed of antinociceptive and antioxidant activities. MATERIALS AND METHODS: The aqueous and ethanolic extracts and arrope of chañar were evaluated in various established pain models, including chemical nociception induced by subplantar formalin and intraperitoneal acetic acid and thermal nociception method, such as tail immersion test in rats. To examine the possible connection of the opioid receptor to the antinociceptive activity of extracts and arrope it was performed a combination test with naloxone, a non-selective opioid receptor antagonist. RESULTS: The aqueous extract and arrope (1000 mg/kg) caused an inhibition of the pain in formalin test in the first phase, similar to morphine and decrease in the second phase. In a combination test using naloxone, diminished analgesic activity of aqueous extract and arrope were observed, indicating that antinociceptive activity is connected with the opioid receptor. The aqueous extract and arrope, caused an inhibition of the writhing response induced by acetic acid. Central involvement in analgesic profile was confirmed by the tail immersion test, in which the aqueous extract and arrope showed a significant analgesic activity by increasing latency time. The aqueous extract showed higher antioxidant activity than the arrope, it may be due to the cooking process. CONCLUSIONS: This study has shown that the aqueous extract and arrope of Geoffroea decorticans (chañar) fruits, does possess significant antinociceptive effects. It is further concluded that aqueous extract with maximum inhibition of free radical is the most potent extract amount tested extracts. At the oral doses tested the aqueous extract and arrope were non-toxic. The present results justifies their popular use and constitutes the first validation study of the antinociceptive action.

Actividad larvicida de extractos vegetales acuosos en larvas de Aedesaegypti: primeros ensayos / Larvicidal activity of aqueous plants extracts on Aedes aegypti larva: first trials

El dengue es una enfermedad epidémica muy común en regiones tropicales y subtropicales. La eliminación de criaderos y el control vectorial se encuentran entre las medidas en la lucha contra la enfermedad. Se han desarrollado diversas estrategias para mantener bajo índice poblacional del mosquito. Diversas investigaciones se han enfocado a la búsqueda de nuevos productos naturales, con actividad insecticida y larvicida, que puedan controlar la población de mosquitos, sin presentar riesgos al humano y animales domésticos. Realizamos una serie de bioensayos con extractos acuosos de plantas paraguayas, Annona muricata (chirimoya); Bulnesia sarmentoi (palo santo); Melia azederach (paraíso); Zanthoxylum chiloperone var. Angustifolium (tembetary hú) y Bixaorellana (urukú), para comprobar en cada planta, su actividad y eficacia como larvicida, contra larvas del mosquito Aedes agypti. Dichas larvas, fueron colectadas de diversas zonas de Asunción y el Gran Asunción, durante la epidemia de fiebre amarilla del año 2007. Las semillas de la Annona mucricata (chirimoya), presentaron una buena actividad larvicida, ya que a la mínima concentración del 5%, han tenido un efecto mortal para las larvas, comparable al observado en los controles positivos (que contenían temefos 1%). En cambio, M. aezsederach (paraíso) y Z. chiloperone (tembetary hú) no mostraron actividad larvicida a esa dosis, ni aún a otras superiores. Por otro lado B. sarmientoi (palo santo) y B. orellana (urukú), presentaron cierto efecto larvicida, eliminando al 18% delarvas a las 72 horas post-exposición. Se observó una marcada diferencia de actividad, entre el extracto de semillas chirimoya con los demás extractos probados.

Dengue is an common epidemic disease in tropical and subtropical regions. Theelimination of breeding sites and vector control are among the most widely usedmeasures in the fight against the disease. Many strategies have been developed to keep low rates of mosquito populations. Several research studies have been focused on findingnatural products with insecticide and larvicide activity that could effectively control these mosquito populations without risks for the human populations and domestic animals. In this work, we have performed a series of bioassays with aqueous extracts of Paraguayan plants: Annona muricata (cherimoya), Bulnesia sarmentoi (palo santo), Melia azederach (paradise), Zanthoxylum chiloperone var. Angustifolium (tembetary hú) and Bixa orellana(uruku) in order to check the effectiveness and activity as larvicide of each plant gainst Aedes aegypti larvae. The larvae were collected in various areas of Asuncion and Great Asuncion during the yellow fever outbreak of 2007. The seeds of A. mucricata (cherimoya or custard apple) showed good larvicidal activity, i.e. at the minimum concentration of 5%, showed lethality against larvae comparable to that observed in positive controls(containing 1% temephos). On the other hand, M. azederach (paradise) and Z. chiloperone (tembetary hú) did not show any larvicidal activity at the same dose and even at higher doses. B. sarmientoi (palo santo) and Bixa orellana (uruku) showed somelarvicidal effect killing larva (18%) at 72 hours post-exposure. There was a marked difference in activity between the cherimoya seeds extract and the other extracts tested.

Polyamine metabolism and glutamate receptor agonists-mediated excitotoxicity in the rat brain.

Putrescine (PUT) increases have been seen in a range of models of neuropathological disturbances. The present study was designed to compare the ability of various types of glutamate receptor agonist to promote excitotoxic brain damage and to examine whether a PUT increase is a general marker of excitotoxic brain damage. To that end, we evaluated features of brain damage associated with the excitotoxicity induced by both ionotropic glutamate receptor (iGluR) and metabotropic glutamate receptor (mGluR) agonists in the conscious rat and the changes produced in the regulation of polyamine metabolism. Intracerebroventricular infusion of N-methyl-D-aspartate (NMDA; 80 nmol), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA; 15 nmol), kainic acid (KA; 2.3 nmol), (R,S)-3,5-dihydroxyphenylglycine (3,5-DHPG; 1.5 micromol), and (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD; 2 micromol) produced similar seizure incidences (76-84%) in the rat. The convulsant episodes appeared sooner after iGluR (13-22 min) than after mGluR agonists (50-179 min). Histological analysis of the hippocampus 24 hr after seizures indicated several degrees of excitotoxic injury after equiconvulsive doses of the iGluR and mGluR agonists assayed. The agonists can be placed in the following order, according to the degree of damage they produce: AMPA > 3,5-DHPG approximately KA > NMDA > 1S,3R-ACPD. In the frontal cortex, moderate to low levels of damage were observed after all GluR agonists. Both iGluR- and mGluR-induced seizures produced an overshoot in the hippocampal and cortical PUT concentration, whereas spermidine and spermine levels were similar to control. Moreover, a concurrence of increased PUT levels and brain damage was observed, indicating that PUT is a general marker of excitotoxic brain damage.

New coumarins from Pterocaulon polystachyum.

Aerial parts of Pterocaulon polystachyum from Chaco province, Argentina, afforded the known coumarins ayapin, isoscopoletin, prenyletin, prenyletin methyl ether, virgatenol, obtusinin, 5-methoxy-6,7-methylenedioxycoumarin, 5-(3,3-dimethylallyloxy)-6,7-methylenedioxycoumarin, 5-(2',3'-dihydroxy-3-methylbutanoxy)-6,7-methylenedioxycoumarin, haplopinol methyl ether, 6-(1,1-dimethyl-2-propenyl)-7-hydroxycoumarin and demethylnieshoutin; the last two are new as natural products while the five new coumarins from the collection were isovirgatenol, 3'-deoxyobtusinin, 6-methoxy-7-(2'-hydroxyethoxy)-coumarin, 5-(2'-hydroxyethoxy)-6,7-methylenedioxycoumarin and a substance tentatively identified as 5-hydroxy-6,7-methylenedioxy-8-(3,3-dimethylallyl)-coumarin.

Concentration of putrescine in plasma, frontal cortex and hippocampus of rats after systemic administration of the convulsants N-methyl-D-aspartate, pentylentetrazol, picrotoxinine, lindane and 4-aminopyridine.

The motor responses (such as stereotypic behavior or convulsions induced in rats by N-methyl-D-aspartate (NMDA) administered systemically were followed by a rapid, moderate increase in the putrescine concentration in plasma which preceded an increase in this amine in the brain. This effect was not observed following the convulsions evoked by pentylentetrazol, picrotoxinine, lindane or 4-aminopyridine. However, all the convulsants assayed induced a mild increase in the concentration of putrescine in the frontal cortex and hippocampus. A differential activation of the ornithine decarboxylase (ODC)/polyamine system in both cerebral and peripheral tissues could account for these results.