Ocular anti-inflammatory effect of aqueous and ethanolic leaf extracts of Pistia stratiotes Linn (Araceae) in endotoxin-induced uveitis

Abstract

Background: Despite the numerous studies conducted on the anti-inflammatory effect of Pistia stratiotes, its traditional use in the treatment of conjunctivitis and iritis has not been scientifically evaluated. Materials and Methods: This study, therefore, investigated the anti-inflammatory effect of aqueous and ethanolic leaf extracts of P. stratiotes in endotoxin-induced uveitis. Uveitis was induced in Sprague-Dawley rats with lipopolysaccharides. Body temperature as well as erythrocyte sedimentation rate and C-reactive proteins of blood in Pistia extracts-treated, prednisolone-treated, and normal saline-treated (control) rats were measured. Clinical signs of uveitis were observed using a slit lamp and histopathological assessments of inflammation in ocular tissue made. Polymorphonuclear neutrophils and total proteins in the aqueous humor of the eyes were estimated. Results: A rise in body temperature after lipopolysaccharide inoculation was found to be associated with corresponding high erythrocyte sedimentation rate and elevated C-reactive protein levels. There were significant reductions in vasodilatation of iris vessels, exudation, polymorphonuclear neutrophil (inflammatory cells), and total proteins into the anterior chamber of the eyes in rats treated with the Pistia extracts compare to the untreated (control). Histopathological assessments revealed resolution of uveitis in treatment groups but not in the untreated. All effects exhibited by the extracts were similar to that of Prednisolone; the reference anti-inflammatory drug. Conclusion: This study has shown that curative oral administration of aqueous and ethanolic leaf extracts of P. stratiotes have ocular anti-inflammatory effect in Sprague-Dawley rats.