title: Anti-nociceptive activity of Pereskia bleo Kunth. (Cactaceae) leaves extracts.
abstract: BACKGROUND
  Local communities in Malaysia consume Pereskia bleo Kunth. (Cactaceae) leaves as raw vegetables or as a concoction and drink as a tea to treat diabetes, hypertension, rheumatism, cancer-related diseases, inflammation, gastric pain, ulcers, and for revitalizing the body.
  
  
  OBJECTIVE
  To evaluate anti-nociceptive activity of the extracts and vitexin, isolated for the first time in this species, in two analgesic models; formalin-induced licking and acetic acid-induced abdominal writhing.
  
  
  METHODS
  Three and a half kilos of P. bleo leaves were extracted using Soxhlet apparatus with ethanol for 72 h. The crude ethanol extract was treated with activated charcoal overnight and subjected to a liquid-liquid partition yielding hexane, dichloromethane, ethyl acetate and butanol extracts. All extracts, including the crude ethanol and vitexin isolated from the ethyl acetate partition were tested for peripheral anti-nociceptive activity using formalin test and acetic acid-induced abdominal writhing, besides having their acute toxicity assays performed.
  
  
  RESULTS
  The phytochemical analyses resulted in the isolation of vitexin (1), β-sitosterol glucoside (2) and β-sitosterol (3) isolated from the ethyl acetate, dichloromethane and hexane extracts, respectively. This is the first time vitexin and β-sitosterol glucoside are isolated from this species. The anti-nociceptive activities for all extracts were only moderate. Vitexin, which was isolated from the ethyl acetate extract did not show any activity in all models tested when used alone at the same concentration as it appears in the extract.
  
  
  CONCLUSIONS
  This study showed that all the extracts possess moderate anti-nociceptive activity. Vitexin is not the compound responsible for the anti-nociceptive effect in the ethyl acetate extract. Further investigations are needed to identify the compound(s) that might be responsible for the anti-nociceptive activity in this plant.
authors.affiliation: School of Pharmacy and Pharmaceutical Sciences, Trinity College, Dublin 2, Dublin, Ireland.
authors.forename: Ikarastika Rahayu
authors.initials: IR
authors.lastname: Abdul-Wahab
authors.forename: Carolina Carvalho
authors.initials: CC
authors.lastname: Guilhon
authors.forename: Patricia Dias
authors.initials: PD
authors.lastname: Fernandes
authors.forename: Fabio
authors.initials: F
authors.lastname: Boylan
mesh_terms: D019342:Acetic Acid; D000700:Analgesics / Q000627:therapeutic use*; D000818:Animals; D047310:Apigenin / Q000302:isolation & purification / Q000627:therapeutic use*; D001522:Behavior, Animal / Q000187:drug effects; D029421:Cactaceae; D005557:Formaldehyde; D008297:Male; D051379:Mice; D010146:Pain / Q000139:chemically induced / Q000188:drug therapy*; D010936:Plant Extracts / Q000627:therapeutic use*; D018515:Plant Leaves; D012855:Sitosterols / Q000302:isolation & purification; D023382:Toxicity Tests, Acute
chemical_list: D000700:Analgesics; D010936:Plant Extracts; D012855:Sitosterols; D005557:Formaldehyde; C025473:gamma-sitosterol; D047310:Apigenin; C032731:vitexin; D019342:Acetic Acid; C011015:lyoniside