Entamoeba histolytica is a major public health problem in tropical and subtropical countries.
Treatment failure with specific chemotherapy suggested the development of new plant origin
therapy. Different parts of Carica papaya Linn. have anti-parasitic agent. The study evaluated
the efficacy of C. papaya fruit methanolic and aqueous extracts against Entamoeba histolytica as
compared with the used Albendazole® in experimentally infected mice. Male CD-1 mice were
divided into two groups of 50 each; immunocompetent (IC) and dexamethasone immunosuppressed
(IS). Each group was subdivided into 5 subgroups, normal, infected and infected treated
with crude & pure C. papaya extracts (500mg/kg) or albendazole (200mg/kg). Each mouse was
infected orally with 1000 E. histolytica cysts. Six weeks after infection, treatment with pure and
crude extracts (3doses/ week) for 3 weeks which started from the 3rd week after oral administration
of dexamethasone, significantly reduced the trophozoites (78.20% & 76.29%, respectively)
in IC mice compared to albendazole (88.72% & 81.81%). Serum IgG, IgM, IgA antibody levels
and IFN-γ significantly (P< 0.001) increased in treated mice compared to normal ones. Histopathological
results showed improvement in the hepatic and intestinal architecture of infected
mice treated with papaya extracts and albendazole with various degrees. Results of IS groups
were the same as those of IC ones but, with lower levels.