title: Antiallergic effect of an aqueous leaf extract of Pistia stratiotes in murine model of ovalbumin-induced allergic conjunctivitis.
abstract: OBJECTIVE
  The aim was to investigate the antiallergic effect of an aqueous leaf extract of Pistia stratiotes (ALPS) in a murine model of ovalbumin (OVA)-induced allergic conjunctivitis (AC).
  
  
  METHODS
  Prior to topical challenge (instillation of 1.5 mg OVA in 10 μL phosphate buffered saline into their conjunctival sacs) to induce AC, groups of sensitized Imprinting Control Region mice (injected IP, on day 1 and 7, with 0.2 ml solution of 100 μg OVA and 0.01 mg aluminum hydroxide in phosphate buffered saline), were treated with 5 mg/kg cetirizine, 10, 50 or 100 mg/kg of ALPS, or 2 ml/kg normal saline per os. Conjunctival redness, lid edema, tearing and lid scratching (clinical symptoms of AC) were scored. Serum OVA specific immunoglobulins were determined using ELISA. Histopathological assessment of the conjunctival mucosal tissue was conducted. The extract was screened for secondary plant metabolites.
  
  
  RESULTS
  Pretreatment with the extract significantly (P ≤ 0.05-0.01) and dose-dependently reduced the scores for clinical symptoms, which were marked in vehicle-pretreated mice. Pretreatment also lowered (P ≤ 0.01-0.001) serum OVA specific immunoglobulins. Mast cell infiltration and degranulation in conjunctival stroma (measured by an inflammatory score) in histopathological studies was also significantly low (P ≤ 0.05-0.01) on pretreatment.
  
  
  CONCLUSIONS
  The ALPS exhibited interesting antiallergic activity and hence could be useful in managing AC.
authors.affiliation: Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi ; Department of Optometry, School of Physical Sciences, University of Cape Coast, Cape Coast, Kumasi, Ghana.
authors.forename: Samuel
authors.initials: S
authors.lastname: Abokyi
authors.affiliation: Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi.
authors.forename: George Asumeng
authors.initials: GA
authors.lastname: Koffuor
authors.affiliation: Department of Optometry, School of Physical Sciences, University of Cape Coast, Cape Coast, Kumasi, Ghana.
authors.forename: Samuel
authors.initials: S
authors.lastname: Kyei
authors.affiliation: Department of Pathology, Komfo Anokye Teaching Hospital, Kumasi, Ghana.
authors.forename: Emmanuel A
authors.initials: EA
authors.lastname: Asiamah
authors.affiliation: Department of Pathology, Komfo Anokye Teaching Hospital, Kumasi, Ghana.
authors.forename: Clement Nsobire
authors.initials: CN
authors.lastname: Atobiga
authors.affiliation: Department of Optometry, School of Physical Sciences, University of Cape Coast, Cape Coast, Kumasi, Ghana.
authors.forename: Agnes
authors.initials: A
authors.lastname: Awuah
keywords: Conjunctival redness; lid edema; mast cell degranulation; mast cell infiltration; tearing