An indigenous religious ritual selects for resistance to a toxicant in a livebearing fish.

Human-induced environmental change can affect the evolutionary trajectory of populations. In Mexico, indigenous Zoque people annually introduce barbasco, a fish toxicant, into the Cueva del Azufre to harvest fish during a religious ceremony. Here, we investigated tolerance to barbasco in fish from sites exposed and unexposed to the ritual. We found that barbasco tolerance increases with body size and differs between the sexes. Furthermore, fish from sites exposed to the ceremony had a significantly higher tolerance. Consequently, the annual ceremony may not only affect population structure and gene flow among habitat types, but the increased tolerance in exposed fish may indicate adaptation to human cultural practices in a natural population on a very small spatial scale.

Toxicity and Activity of Ethanolic Leaf Extract of Paullinia pinnata Linn (Sapindaceae) in Shigella flexneri-Induced Diarrhea in Wistar Rats.

Herbal products from Paullinia pinnata Linn are widely used in African folk medicine to treat several infectious diseases. Although the extracts from this plant has been shown to possess antimicrobial potential, their activity in infectious diarrhea is less reported. Diarrhea was induced by oral administration of 1.2 × 109 CFU/mL of Shigella flexneri to the rats. The infected rats were treated for 5 days with the doses of 111.42, 222.84, and 445.68 mg/kg of P pinnata. The level of biochemical parameters was assessed and histology of organs examined by 14 days subacute toxicity. S flexneri stool load was considerably reduced after 4 days of treatment with the dose of 445.68 mg/kg, 5 days at the dose of 222.84 mg/kg for the extract, and 2 days with ciprofloxacin. The dose of 111.42 mg/kg appeared efficient after 5 days of treatment. The creatinine level increased at the dose of 445.68 mg/kg in both male and female rats and decrease at the dose of 222.84 mg/mL in female rats while an increase was noted in the male rats. Liver and kidney histology were modified at the dose of 445.68 mg/kg while no change was observed at the doses of 111.42 and 222.84 mg/kg. P pinnata leaf extract is efficient against infectious diarrhea at 111.42 mg/kg without side effect.

Acute and subchronic toxicological evaluation of the semipurified extract of seeds of guaraná (Paullinia cupana) in rodents.

We evaluated the toxicity of a semipurified extract (EPA fraction, containing caffeine and several flavan-3-ols and proanthocyanidins) of seeds of the native Amazon plant Paullinia cupana (guaraná) in rodents. Acute toxicity was tested in male Swiss mice, which received different doses orally (OR) and intraperitoneally (ip); control groups received water. These tests produced acute mortality, with LD(50) of 1.825 g/kg (OR) and 0.827 g/kg (ip), and a significant weight decrease in lungs of mice receiving a dose of 0.1g/kg. In the repeated-dose toxicity test, the EPA was administered OR daily to male and female Wistar rats at doses of 30, 150, and 300 mg/kg/day/90 days. Their behavior, mortality, weight changes, laboratory tests, and the weights and histopathology of organs were evaluated. No rats died during the tests. Males dosed at 150 or 300 mg/kg gained weight more slowly and lost kidney weight (absolute and relative weights, compared to the control group). Hematological and biochemical tests showed few changes, differing somewhat between males and females; the histopathological evaluation indicated no significant changes. These results indicate that the EPA fraction of guaraná caused no toxicity in rats at the smallest dose evaluated (30 mg/kg). No other species was evaluated.

Efecto de la temperatura sobre la acción tóxica del extracto acuoso de la raíz del Lonchocarpus nicou (barbasco) en ratas normales / Effect of temperature on the toxic action of the aqueous extract from the root of Lonchocarpus nicou (barbasco) in normal rats

Objetivo: Evaluar el efecto tóxico del extracto acuoso de la raíz del Lonchocarpus nicou (Aubl) D.C. "Barbasco" sometido a 100 grados C de temperatura durante 5, 10, 30 y 60 minutos de ebullición, al ser administrado oralmente durante 30 días a ratas normales. Materiales y Métodos: Estudio experimental, con grupos equivalentes randomizados, ciego para quien administró la solución, el analista de laboratorio, el anatomopatólogo y el estadístico. Se sometieron a 100 grados C de temperatura trozos pequeños de raíz desecados con agua destilada, obteniéndose extractos a 5, 10, 30 y 60 minutos de ebullición para efectuar ensayos fitoquímicos comparativos en cromatografía de capa fina, y evaluar del efecto tóxico en cuarenta ratas Holtzmann. El peso de las ratas fue (190±10 gr), se las dividió aleatoriamente en cinco grupos: al primero se le administró suero fisiológico 2 mL/kg, y a los otros grupos 10 mg/kg de extracto respectivamente durante 30 días. A continuación se extrajo muestra de sangre para observación hematológica, bioquímica, y luego se sacrificó los animales, retirándose cerebro, hígado, y riñón, los que se conservaron en formol al 10 por ciento para estudio histopatológico. Los datos obtenidos se analizaron mediante pruebas descriptivas y analíticas, considerando significativos una p<0,05. Resultados: Los metabolitos secundarios disminuyeron con la ebullición, los alcaloides del barbasco desaparecieron y los flavonoides tipo isoflavonas disminuyeron notoriamente con la calificación cualitativa. A mayor tiempo de exposición a la temperatura, se presentó menor daño en el perfil hepático. Conclusiones: En condiciones experimentales se ha observado en ratas normales disminución del efecto tóxico inducido por el extracto acuoso de barbasco sometido a altas temperatura, acción dependiente del tiempo de ebullición.

Objective: Assessing the toxic effect of aqueous extract of Lonchocarpus nicou roots (Aubl) S.D. "Barbasco" after being exposed at 100 grades C temperature during: 5, 10, 30, 60 minutes of boiling condition and then being administered during 30 days by oral intake in normal rats. Material and methods: The present research is experimental and prospective, with similar groups distributed randomly. It is blind not only for the ones who administered the concentration, made the lab analysis and the anatomopathologic examination but also for the ones who made the data processing. The extracts was exposed at 100 grades C of temperature then it was gotten extracts with 5, 10, 30 and 60 minutes of boiling exposition; it was done the comparative phytochemical examination in fine layer Chromatography in order to appreciate the main secondary metabolites that are present in each extract. To determine the toxic effects it was selected 40 Holtzmann rats with 190 +/- 10 gr. of body weight and about 2 months of age that didn't have any previous experimental treatments and belonging to the National Health Institute Lima-Peru; they were with appropriate feeding and water supply, living under environmental temperature. They were divided into 4 groups of examination to whom it was administered during 30 days by oral intake the aqueous extract of Lonchocarpus nicou roots (Barbasco) and a control group in which physiological serum was administered at dosage of 2mllkg, then it was extracted blood samples by cardiac puncture for Biochemical and Hematological exams; after that animals were killed to extract internal organs (Liver, Brain and Kidney) which were preserved in Formalin 10 per cent for Histopathological examination. It was done a descriptive and statistical analysis by means of the ANOVA of one way Test (or Kruskal-Wallis) to assess possible variations due to the effect of the extracts. The values were significant to a p<0.05. Results: It was gotten reduction of the toxic...