ABSTRACT
Schistosomiasis a prevalent parasitic disease in tropical and sub-tropical areas, which comes in the second place in terms of socioeconomic and public health burden. Around 600 million people in 74 countries are infected yearly, predominantly in the developing world. The aim of this work was to assess the efficiency of three extracts from Carica papaya (methanol, ethanol and butanol extracts) for their molluscicidal and anti-schistosomal activities. The LC50of methanol, ethanol and butanol extracts of Carica papaya against B. alexandrinea were 180, 499.3 and 509.1 mg/L while the respective LC90values were 220.3, 700.6, 769.6 mg/L respectively. The effect of these extracts on Biomphalaria alexandrina snails and larval stages of Schistosma mansoni, for miracidia the LC50of methanol, ethanol and butanol extracts ofCaricapapaya against miracidia were 3.4, 15.4and 8.1 mg/L, respectively, while the respective LC90values were 8.4, 38.2, 11.2 mg/L, and for cercariae the LC50of methanol, ethanol and butanol extracts ofCaricapapaya were 2, 20and 4mg/L, while the respective LC90values were 13.5, 80.5, 18.5mg/L respectively was evaluated, in addition to flowcytometric analysis of CD4, CD25, FOXP3 and TGF-βlevels during S. mansoniinfection in mice. The in-vivo results showed that the three extracts have variable potential against snails and miracidia and cercariae ofS. mansoni. The mortality rate in B. alexandrinasnails for methanol, ethanol and butanol extracts ofCarcia papaywere 86%, 45% and 64%, respectively. While it was 83%, 35% and 66%, respectively in miracidia and 92%, 40% and 70%, respectively in cercariae. The results indicated that methanol extract from Carica papaya recorded higher activity against snails, miracidia and cercariae. The levels of CD4, CD25, FOXP3 regulatory T (Treg) cells were decreased significantly (p<0.001) in infected mice compared to healthy controls. However, there was a significant (p<0.001) increase in levels of TGF-β. A significant increase in the levels of CD4, CD25, and FOXP3 Treg in Carica papaya treated group compared to infected control group, with a significant (p<0.001) decrease in TGF-βlevel than infected group. In conclusion, methanol extract was more effective at concentration of LC50 180 and LC90 220.3than ethanol and butanol extracts ofCaricapapaya therefore controlling B. alexandrinasnails by methanol extract is a promising way as it is an eco-friendly strategy in rural areas of developing countries, where schistosomiasis is endemic. Moreover, the increased immune defense mechanism in treated group with the same extracts is a promising target for new immune modulatory strategies against schistosomiasis