SOURCE:

Faculty: Pharmaceutical Sciences
Department: Pharmacology And Toxicology

CONTRIBUTORS:

Erhirhie, E. O;
Ilodigwe, E.E;

ABSTRACT:

The leaf decoction of Dryopterisfilix-mas (D. filix-mas) is used traditionally in Southern parts of Nigerian for the management of rheumatoid arthritis, wounds, inflammation, and other diseases, yet no scientific studies have been done to authenticate its anti-inflammatory property and safety profile.In this study, the anti-inflammatory, antioxidant activities and safety profile of the ethanol leaf extract of D. filix-mas were evaluated. The leaf extract was partitioned into four fractions (n-hexane, ethyl-acetate, butanol and water fractions). Phytochemical screening, total phenolic, total flavonoid contents, ferric reducing properties, 1-diphenyl-2-picrylhydrazil (DPPH) and Nitric oxide (NO) scavenging activities were evaluated on the extract and fractions. Anti-inflammatory properties of the extract and fractions were screened using egg-albumin induced paw edema, xylene induced topical edema, formaldehyde induced arthritis, vascular permeability, leukocyte migration and ulcerogenic models. The most effective fraction (VLC-E7) was tested on cyclooxygenase enzymes (COX-1 and COX-2). The fraction VLC-E7 was further purified by Sephadex chromatography and the structure was elucidated using high performance liquid chromatography mass spectrometry (HPLC-MS) and proton nuclear magnetic resonance (NMR).From the outcome of two weeks toxicity tests, 62.5, 125, 250 and 500 mg/kg of extract were selected for 90 days sub-chronic toxicity test and, samples were collected on day 31, 61 and 91for various assays. From the maximum tolerable dose (MTD) of sub-chronic toxicity test (125 mg/kg), 31.25, 62.5, 125 mg/kg of the extract were selected for chronic toxicity test for 180 days. Four weeks recovery studies were done for sub-chronic and chronic toxicity tests. Body weight gain, organ weights, haematological and biochemical parameters as well as histopathologies of liver and kidneys were also evaluated. Teratogenic study was done in mice using 250, 500 and 1000 mg/kg of the extract and morphological parameters and histopathologies of the liver, kidney, heart, lungs and femur of pups were evaluated.Ethyl acetate fraction (EAF) elicited higher total phenolic contents, free radical and nitric oxide scavenging activities as well as ferric reducing properties.EAF also elicited significant anti-inflammatory activities in the various models. The extract, ethyl acetate and butanolfractions did not produce irritation on the gastric mucosa. The promising fraction (VLC-E7) inhibited only the activities of COX - 2 enzyme by 1.53 and 25.40% at 50 and 100 µg/mL respectively. Further purification of VLC-E7 fraction resulted to the isolation of Quercetin-3O-αL-rhamnopyranoside. In 3 months sub-chronic toxicity test, 250 and 500 mg/kg of the extract produced liver and kidney toxicity that were reversed after recovery studies. In 6 months chronic toxicity test, 31.25, 62.5 and 125 mg/kg of extract produced nephrotoxicity that was reversed after withdrawal of the extract. The extractwas not teratogenic in mice at 250 and 500 mg/kg but at high dose (1000 mg/kg) it caused poor mineralization in pups’ femur.This study revealed that the leaf extract of D. filix-mas possesses anti-inflammatory and anti-oxidant properties which may be due to its isolated compound (Quercetin-3O-αL-rhamnopyranoside) which justifies its folkloric use in the management of rheumatoid arthritis and other diseases. However, its long term use may be nephrotoxic and teratogenic.