Potential antiparasitic activity of pomegranate extracts against schistosomules and mature worms of Schistosoma mansoni: in vitro and in vivo study.

The use of medicinal plants has gained much attention in the last decade, and among those plants commonly used as medication in folk medicine, various extracts have been the subject of many pharmacological studies. Pomegranate (Punica granatum) a fruit with rich ethnomedical applications, has been also introduced as potential anti-microbial and anti-helminthic agent. This study was designed to estimate its in vivo and in vitro effects on S. mansoni. The in vitro bioassay of Punica granatum, (P. granatum) peels and leaves extracts was carried out using ascending doses. V iability of worms and schistosomules was examined using negative (DMSO) and positive (PZQ) controls. This study revealed that P. granatum had significant effect on both adult S. mansoni worms and schistosomules reaching 100% death rate, 24 hours post exposure to extracted plant. Concerning the in vivo activity, P. granatum peels and leaves exhibited antischistosomal properties by the oral administration of either extract, in a dose of 800mg/kg, 45 days post-infection and on 3 consecutive days; this dose was given following a pilot study to evaluate the highest safe dose. Parasitological parameters showed remarkable decrease manifested by high percentage of dead adult worm (77.30 and 72.2) with either leaves or peels extract respectively. The tissue egg load also revealed marked reduction in both liver and intestinal ova counts. The percentage reduction of adult worms reached (90.9 and 55.4) with extracted leaves or peels respectively, when P.granatum extracts were given 21 days post-infection using the same dose(800mg/kg),denoting a high significant effect of leaves extracts on schistosomule s.Electron microscopic examination of perfused adult worms, confirmed the parasitological results and revealed the effect of the methanolic extracts of P.granatum in inducing major ultrastructural alterations in the tegument and the male genital systems of the worms that lead to their death. In this study EM examination of bone marrow taken from S. mansoni infected mice, treated with either leaves or peels extracts of P.granatum showed complete degranulation of eosinophils and activated lymphocytes with extended projections and increased mitochondria in addition to activated monoblast with increased number of phagolysosomes.Since secretions of the different stages of S.mansoni have inhibitory effect on eosinophilic degranulation and monoblasts, as part of their parasite evasion mechanism, the apparent degranulation would indicate the decreased activity of S.mansoni. The leaves and peels extracts of Punica granatum could represent promising bioactive natural agents that deserve further investigation, with the aim of introducing novel anti-schistosomal agent.