Evaluation of the schistosomicidal, antioxidant and anti-inflammatory activities of the ethyl acetate fraction from Ozoroa pulcherrima Schweinf. Roots on Schistosoma mansoni-induced liver pathology in mice and its phytochemical characterization

Ethnopharmacological relevance: Ozoroa pulcherrima Schweinf. (syn.: Heeria pulcherrrima Schweinf.) is a small shrub belonging to the family Anacardiaceae. In Africa, the stem and the leaves are used to treat dystocia, hyperthermia, and conjunctivitis, while the root is used to treat dysmenorrhea and intestinal helminthiasis.

Aim of the study: The aim of this study was to assess the schistosomicidal, antioxidant and anti-inflammatory effects of the ethyl acetate fraction from O. pulcherrima roots methanolic extract (EAOp) on S. mansoni- induced liver pathology in mice. Additionally, its phytochemical composition was elucidated.

Material and methods: The phytochemical characterization of EAOp was carried out by High-Performance Liquid Chromatography-Mass spectrometry (HPLC-MS). Total phenolic and flavonoid contents were also quantified in the fraction. S. mansoni-infected mice received daily and per os, for 28 days, EAOp at 200 or 400 mg/kg, starting from the 36^th day post-infection. Praziquantel was used as reference drug. Uninfected-untreated, uninfected-treated and infected-untreated mice served as controls. At the 65^th day post-infection mice were sacrificed and parasitological burden monitored. Transaminases, total bilirubin, and total proteins levels were determined in the plasma. Malondialdehyde (MDA), nitrites, superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH) levels were measured in the liver as biomarkers of the oxidative stress. Liver histology and morphometric analysis of granulomas were also conducted.

Results: The HPLC-MS analysis data of EAOp revealed the presence of four triterpenes namely oleaterminaloic acid, hydroxyoleanolic acid, moronic acid, and oleanolic acid; a flavonoid dipentoxybenzoic acid and two alkaloids. Its total phenolic content was 76.46 ± 0.01 mg GAE/g and total flavonoid content 6.26 ± 0.31 mg rutin equivalent/g. The reductions of worm burden (48.89 and 75.56%), fecal egg count (77.76 and 69.52%) and egg load in the liver (65.33 and 77.18%) and intestine (78.06 and 84.63%) were significant after EAOp treatment. EAOp at all doses significantly (p < 0.001) reversed the increasing transaminases activities and total bilirubin level induced by the infection. A normalization of total proteins concentration was also recorded. Treatment of S. mansoni-infected mice with EAOp at 200 or 400 mg/kg resulted in a significant reduction (p < 0.001) of MDA concentration by 73.20% and 67.78% respectively. The level of nitrites which was reduced by the infection significantly increased after the treatment. EAOp significantly increased by 4.67 and 5.69-fold the CAT activity and by 126.67% the GSH level. Histologically, a significant reduction of the number (66.39 and 57.82%) and the volume (52.25 and 34.81%) of liver inflammatory granulomas was recorded after EAOp treatment at all doses.

Conclusions: These results suggest that the liver pathology in S. mansoni infection is improved by EAOp which disclosed good schistosomicidal, antioxidant and anti-inflammatory activities. Its effects on the liver dysfunction and the hepatic oxidative stress were comparable to that of praziquantel. These findings justified the traditional use of O. pulcherrima for the treatment of intestinal helminthiasis. This fraction can be considered as a promising source for schistosomicidal agents.