Avaliação da atividade in vitro dos extratos da semente de Garcinia brasiliensis e do isolado Guttiferona-A em vermes adultos do Schistosoma mansoni

Abstract

Schistosomiasis is a severe parasitic disease with large geographical distribution, affecting nearly 200 million people worldwide and at least 700 million live in risk areas. In Brazil the disease is known as “xistose” and “water belly” and is caused by Schistosoma mansoni, a parasite who belongs to the flatworm phylum, in which the adult worm lives in the portal system of the liver. The etiologic agent has a heterogenic life cycle, in which the intermediate hosts are snails of the Biomphalaria genus, and humans are the primary hosts. The main prophylactic measures include basic sanitation and public orientation. The treatment must also be considered in the control and prophylactics of the disease, which is based on the use of oxamniquine and praziquantel. Since only praziquantel has been used during schistosomiasis therapy there is a need for the discovery of new medications for parasite treatment; along with the urgent demand in relationship to resistant strains of the parasite. The justification for new, alternative therapy is guided by a shorter term treatment, with fewer side effects, and one that doesn’t provide resistance to the parasite. Thus, this work has as its objective to evaluate the schistosomicidal effect of the ethanolic extract of the Garcinia brasiliensis seed, along with the hexonic fractions, ethylic-acetate, and aquose, obtained through partition, from the ethanolic extract of the seed. The activity of a pure constituent which was isolated from this species, a benzophenone named Guttiferona-A. The evaluation of the seed extract, fraction, and pure compound effects on S. mansoni were done on adult worms in vitro, in which the mortality rate was quantified and excretory system, surface membrane damage was monitored. These observations were also made using the fluorescent markers Hoechst 33258 e Resorufin, respectively. On studies using GUT-A, significant schistosomicidal activity was witnessed in tests in vitro starting with concentrations of 18.0 μg/mL, where it was able to kill 100% of parasites, after 24 hours of incubation, allowing it to reach the ED50 value of 21.8 μg/mL. The results show a high schistosomicidal effect from the seed extract, from the fractions, and from GUT-A on adult worms used in tests in vitro. The fluorescent markets proved the effects of the compounds tested, showing the damaged caused to the excretory system, along with lesions to the integument, after exposure to various concentrations were examined. Further tests will be made having as a main approach the effect mechanism of GUT-A on S.mansoni adult worms and organisms in other phases of the life cycle, in tests in vitro and in vivo.