title: Antinociceptive effect of methanol extract of leaves of Persicaria hydropiper in mice.
abstract: BACKGROUND
  Persicaria hydropiper (Linn.) Delarbre is a common plant of Polygonaceae family commonly called Bishkatali in Bangladesh. Leaves of the plant are traditionally used in the treatment of rheumatic pain, gout, and skin diseases such as ringworms, scabies, boils, abscesses, carbuncles, bites of snakes, dogs or insects. This study evaluated the antinociceptive effect of the methanol extract of P. hydropiper leaves (MEPH).
  
  
  METHODS
  The antinociceptive activity of MEPH was investigated using heat-induced (hot-plate and tail-immersion test) and chemical-induced (acetic acid, formalin, glutamic acid, cinnamaldehyde) nociception models in mice at 25, 50, and 75 mg/kg doses. Involvement of opioid system, cyclic guanosine monophosphate (cGMP) pathway, and ATP-sensitive K(+) channel pathway were also tested using naloxone, methylene blue and glibenclamide respectively.
  
  
  RESULTS
  MEPH showed antinociceptive activity in both heat- and chemical induced pain models. In both hot plate and tail immersion tests MEPH significantly increases the latency to the thermal stimuli. In acetic acid-induced writhing test the extract inhibited the number of abdominal writhing. Likewise, MEPH produced significant dose-dependent inhibition of paw licking in both neurogenic and inflammatory pain induced by intraplantar injection of formalin. Besides, MEPH also significantly inhibited the glutamate-induced pain and cinnamaldehyde-induced pain in mice. It was also clear that pretreatment with naloxone significantly reversed the antinociception produced by MEPH in hot plate and tail immersion test suggesting the involvement of opioid system in its effect. In addition, administration of methylene blue, a non specific inhibitor of NO/guanylyl cyclase, enhanced MEPH induced antinociception while glibenclamide, an ATP-sensitive K(+) channel antagonist, could not reverse antinociceptive activity induced by MEPH.
  
  
  CONCLUSIONS
  Based on the results of the current study it can be said that MEPH possesses significant antinociceptive activity which acts in both peripheral and central mechanisms.
authors.affiliation: Department of Pharmacy, Stamford University Bangladesh, 51 Siddeswari Road, 1217, Dhaka, Bangladesh. arin_ambia@yahoo.com.
authors.forename: Ambia
authors.initials: A
authors.lastname: Khatun
authors.affiliation: Department of Pharmacy, Stamford University Bangladesh, 51 Siddeswari Road, 1217, Dhaka, Bangladesh. zafarimam@gmail.com.
authors.forename: Mohammad Zafar
authors.initials: MZ
authors.lastname: Imam
authors.affiliation: Department of Pharmacy, Jahangirnagar University, 1342, Dhaka, Savar, Bangladesh. sohelrana.ju@gmail.com.
authors.forename: Md Sohel
authors.initials: MS
authors.lastname: Rana
mesh_terms: D019342:Acetic Acid; D000171:Acrolein / Q000031:analogs & derivatives; D000700:Analgesics / Q000494:pharmacology* / Q000627:therapeutic use; D000701:Analgesics, Opioid / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology / Q000627:therapeutic use; D001459:Bangladesh; D001522:Behavior, Animal / Q000187:drug effects; D005557:Formaldehyde; D018698:Glutamic Acid; D008297:Male; D008519:Medicine, Traditional; D051379:Mice; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D010146:Pain / Q000139:chemically induced / Q000188:drug therapy; D010147:Pain Measurement; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology* / Q000627:therapeutic use; D018515:Plant Leaves; D028502:Polygonum
chemical_list: D000700:Analgesics; D000701:Analgesics, Opioid; D000893:Anti-Inflammatory Agents; D009292:Narcotic Antagonists; D010936:Plant Extracts; D005557:Formaldehyde; D009270:Naloxone; D018698:Glutamic Acid; D000171:Acrolein; D019342:Acetic Acid; C012843:cinnamaldehyde