title: Anti-giardia activity and acute toxicity of a methanol extract of Senna racemosa bark.
abstract: BACKGROUND
  Senna racemosa (Mill.) H.S. Irwin & Barneby (syn. Cassia racemosa Mill.) is a plant used in traditional Mayamedicinal practices to treat diarrhea. A methanol extract of S. racemosa bark has been shown to have in vitro activity against Giardia intestinalis. No studies of its efficacy and toxicity in in vivo models have been done. The present study objective was to analyze the activity of this methanol extract of S. racemosa bark against Giardia intestinalis trophozoites in experimentally infected mice, and evaluate its toxicological effects in rats.
  
  
  METHODS
  S. racemosa was collected in Merida, Yucatan, Mexico (21°58'N, 89°36'W) in June 2005. The bark methanol extract was obtained and high performance liquid chromatography (HPLC-DAD) was used to generate a constituent profile. In vivo anti-giardia activity was assayed with an experimental model of G. intestinalis infection in neonatal CD-1 mice. Nine doses ranging from 0.25-15mg extract/kg body weight were tested to determine the dose required to kill 50% of the trophozoites (ED50). An acute toxicity assay was run in which one of four single doses (200, 1000, 2000 and3000mg/kg body weight) was orally administered to adult Wistar rats. Animal weight, death rates, toxic effects and behavioral parameters were observed over a 14-d period. They were then euthanized and a necropsy performed.
  
  
  RESULTS
  The S. racemosa bark extract inhibited growth of G. intestinalis (ED50=1.14mg/Kg) in neonatal CD-1 mice. No toxic or lethal effects were observed even at the highest dosage (3000mg/Kg), and neither were signs of toxicity observed in internal organs. The active compounds chrysophanol and physcion were present in the extract at a 1.76 ratio.
  
  
  CONCLUSIONS
  The results strongly support traditional use of S. racemosa bark for treatment of diarrhea caused by Giardia intestinalis infection.
authors.affiliation: Departamento de Recursos del Mar, Centro de Investigación y de Estudios Avanzados, Carretera Antigua a Progreso Km. 6, 97310 Mérida, Yucatán, Mexico.
authors.forename: Edgar E
authors.initials: EE
authors.lastname: Caamal-Fuentes
authors.affiliation: Laboratorio de Espectrometría de Masas, Facultad de Química, Universidad Autónoma de Yucatán, Calle 43 No. 613 x C. 90, Col. Inalámbrica, 97069 Mérida, Yucatán, Mexico.
authors.forename: Manlio
authors.initials: M
authors.lastname: Graniel-Sabido
authors.affiliation: Laboratorio de Espectrometría de Masas, Facultad de Química, Universidad Autónoma de Yucatán, Calle 43 No. 613 x C. 90, Col. Inalámbrica, 97069 Mérida, Yucatán, Mexico.
authors.forename: Gonzalo J
authors.initials: GJ
authors.lastname: Mena-Rejón
authors.affiliation: Unidad de Investigación Médica Yucatán, Unidad Médica de Alta Especialidad, Centro Médico Ignacio García Téllez, Instituto Mex icano del Seguro Social, 41 No. 439 x 32 y 34, Col. Industrial, 97150 Mérida, Yucatán, Mexico. Electronic address: moopuc@gmail.com.
authors.forename: Rosa E
authors.initials: RE
authors.lastname: Moo-Puc
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000981:Antiprotozoal Agents / Q000302:isolation & purification / Q000494:pharmacology* / Q000627:therapeutic use / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D005872:Giardia / Q000187:drug effects*; D005873:Giardiasis / Q000188:drug therapy; D008297:Male; D000432:Methanol / Q000737:chemistry; D051379:Mice; D024301:Plant Bark / Q000737:chemistry* / Q000254:growth & development; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology* / Q000627:therapeutic use / Q000633:toxicity; D017208:Rats, Wistar; D029846:Senna Plant / Q000737:chemistry* / Q000254:growth & development; D023382:Toxicity Tests, Acute
chemical_list: D000981:Antiprotozoal Agents; D010936:Plant Extracts; D000432:Methanol
keywords: Acute toxicity; Anthraquinones; Anti-giardia activity; Fabaceae; Senna racemosa