Helminth communities of sigmonontine rodents in cocoa agroforestry systems in Brazil

Agroforestry is an alternative kind of land use where the native vegetation is surrounded or intercalated by crops of economic interest. This system may maintain species richness by promoting the habitat heterogeneity or serving as ecological corridors. The aim of this study was to describe the gastrointestinal helminth fauna and to analyse the parasitological parameters of the helminth communities of six sigmodontine rodents in a cocoa agroforestry system in the municipality of Ilhéus, state of Bahia, Northeast Brazil. This is a novel study of helminth fauna in this kind of agroforestry. Rodents were captured in live-traps and euthanised for helminth recovery. Specimens were counted and identified to the species level whenever possible. Helminth abundance, intensity, and prevalence were calculated for each species and each host. The total abundance and prevalence of helminths were compared among localities and three attributes of the host: species, gender and age using generalised linear models. Considering all rodents, 52.14% of them were parasitised with at least one helminth species. Eight nematode species were identified and another seven morphospecies were identified to the genus level. The most abundant species were Hassalstrongylus epsilon, Stilestrongylus eta, Guerrerostrongylus zetta, and Syphacia alata. The opportunistic host species Oligoryzomys nigripes and Akodon cursor, besides the water rat Nectomys squamipes, were the most infected species for helminth parasites. Hylaeamys seuanezi was also an important host with the highest helminth species richness. This is the first report of the helminth fauna for this host. The locality most distant from the native vegetation and closest to the city had the highest helminth prevalence and mean species richness. The species richness in the helminth communities of Euryoryzomys russatus, N. squamipes and O. nigripes in these Cabruca agroforestries were within the range found in studies carried out in Atlantic Forest areas.

Activity of cycloartane-type triterpenes and sterols isolated from Musa paradisiaca fruit peel against Leishmania infantum chagasi

The aim of the study was to evaluate in vitro the antileishmanial activity of triterpenes and sterols isolated from Musa paradisiaca (banana) fruit peel used traditionally to treat leishmaniasis. The compounds were isolated from the ethanolic extract of the peel of the banana fruit by column chromatography. The chemical structure of compounds was determined by (1)H and (13)C - nuclear magnetic resonance spectroscopy. The cytotoxicity was measured in RAW 264.7 cells and LLC-MK2. Leishmanicidal activity against L. infantum chagasi promastigotes was performed by the MTT colorimetric method and activity against amastigotes was assayed in mammalian cells using in situ ELISA method. Five compounds were identified, consisting of three triterpenes: cycloeucalenone, 31-norcyclolaudenone and 24-methylene-cicloartanol and a mixture of two sterols: beta-sitosterol and stigmasterol. With the exception of cycloeucalenone, all compounds showed statistically similar activity against promastigote to pentamidine. While, acting against amastigotes, excluding 31-norcyclolaudenone, other compounds showed activity similar to amphotericin B. All compounds showed low cytotoxicity in mammalian cells.

CONCLUSION

This study partially confirms the use of Musa paradisiaca in folk medicine against leishmaniasis. Further in vivo studies are necessary to evaluate the efficacy.