title: The standardized extract of Loeselia mexicana possesses anxiolytic activity through the γ-amino butyric acid mechanism.
abstract: BACKGROUND
  Loeselia mexicana (Lam.) Brand has been used in Mexican Traditional Medicine to treat "espanto" or "susto" (fear), which is a culturally affiliated syndrome whose symptomatology comprises loss of appetite, difficulty in sleeping, and also nausea and fatigue, with a sensation of fear or risk - real or imagined - to external stimuli.
  
  
  OBJECTIVE
  The anxiolytic effect of the standardized methanol extract of Loeselia mexicana, with regard to its content of coumarin daphnoretin, was researched utilizing the elevated plus maze (EPM) in order to demonstrate whether the biological effect produced by the plant is antagonized by drugs that block γ-amino butyric acid (GABA)ergic transmission.
  
  
  METHODS
  The methanolic extract of Loeselia mexicana (LmMeOH) was tested at different doses on the EPM and then the interaction of this extract was evaluated in the same model with different GABAergic drugs, such as flumazenil (FLU) 10mg/kg, bicuculline (BIC) 5mg/kg, pentylenetetrazole (PTZ) 10mg/kg, and picrotoxin (PTX) 2mg/kg. The effect of all of these treatments was evaluated by means of the open field test (OFT). Coumarin content was measured by the high performance liquid chromatography (HPLC) technique.
  
  
  RESULTS
  The 200- and 400-mg/kg doses of methanolic extract containing 3.14 and 6.28 mg of daphnoretin, respectively, induced an anxiolytic effect in the EPM without modification of the spontaneous motor activity. The anxiolytic activity of 200mg/kg of methanolic extract in EPM-exposed mice was antagonized by PTX, BIC, and FLU, but not by PTZ.
  
  
  CONCLUSIONS
  The data presented here indicate that the Loeselia mexicana Brand methanolic extract possesses a significant anxiolytic effect that appears to be mediated in part by activation of the GABAergic system.
authors: Departamento de Pharmacology and Chemistry of Medicinal Plants, Centro de Investigación Biomédica del Sur (CIBIS), Instituto Mexicano del Seguro Social (IMSS), Argentina 1, Col. Centro, 62790 Xochitpec, Morelos, Mexico.
authors: Maribel
authors: M
authors: Herrera-Ruiz
authors: Adolfo
authors: A
authors: González-Carranza
authors: Alejandro
authors: A
authors: Zamilpa
authors: Enrique
authors: E
authors: Jiménez-Ferrer
authors: Maira
authors: M
authors: Huerta-Reyes
authors: Víctor M
authors: VM
authors: Navarro-García
mesh_terms: D000818:Animals; D001007:Anxiety / Q000188:drug therapy*; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D019684:Magnoliopsida / Q000737:chemistry*; D018782:Maze Learning; D051379:Mice; D008813:Mice, Inbred ICR; D010936:Plant Extracts / Q000627:therapeutic use*; D010946:Plants, Medicinal / Q000737:chemistry*; D005680:gamma-Aminobutyric Acid / Q000737:chemistry*
chemical_list: D010936:Plant Extracts; D005680:gamma-Aminobutyric Acid