Schistosoma mansoni: In vivo evaluation of Phyllanthus amarus hexanic and ethanolic extracts.

Human schistosomiasis is an important neglected tropical disease caused by blood flukes of the genus Schistosoma and is responsible for more than 280,000 deaths annually. Treatment for this disease relies currently on a single drug, praziquantel (PZQ). Concerns regarding PZQ resistance and insensitivity of juvenile schistosomes have increased the interest in resorting to medicinal plants for alternative drug therapies. This study aimed to perform an in vivo schistosomicidal activity evaluation of crude hexanic (HE) and ethanolic (EE) extracts obtained from Phyllanthus amarus in mice infected with Schistosoma mansoni (BH strain). Mice were treated orally with a single dose of 100 or 250 mg/kg, on two different infection periods, 30 and 45 days post-infection (dpi). Parameters such as worm recovery, faecal egg count, intestinal tissue egg count and liver histopathology were evaluated. Treatment against young adult (30 dpi) and adult (45 dpi) worms were more effective compared to the control group treated with PZQ. At a concentration of 250 mg/kg (30 dpi) EE showed a 54.4% female reduction and a 61.2% total worm reduction whilst at a concentration of 100 mg/kg (45 dpi) HE showed a 40.6% female worm reduction and a 45.3% total worm reduction. Histopathological examination showed a granuloma decrease in both number and size for groups treated with 250 mg/kg of HE (45 dpi) or EE (30 or 45 dpi). From these results, it can be concluded that both hexanic and ethanolic extracts have antischistosomal activities, however, act differently according to the parasites age. The schistosomicidal activity results in groups treated 30 days post infection is extremely important since praziquantel does not show activity against the juvenile forms of Schistosoma.