Pesquisa da ação tripanomicida da própolis: estudos "in vitro" e "in vivo"

Abstract

Chagas disease is one of the most important parasitic diseases in Latin America, due to its high incidence, prevalence and socioeconomic repercussions that this endemic cause to countries. Despite efforts, a very small number of drugs have been indicated for the specific treatment of the disease, all with side effects, efficacy on some strains and action restricted to the acute phase of the disease. Studies carried out “in vitro” demonstrated that preparations with propolis, obtained in bee hives, have high activity against T. cruzi, inhibiting proliferation within the host cell. The gift The work consists of characterizing the best solvent, period of treatment and pre-treatment, extract dose to reduce parasitemia and the survival time “in vivo” in Swiss mice infected with 5 x 10 ^ 4 infective forms of strain Y of T. I crossed. Crude propolis of Apis mellifera (100 g), collected in the Patrocínio region - MG, was immersed in 500 ml of deionized water, crushed and heated to 80 ° C for 120 minutes, filtered, lyophilized and resuspended in desired concentrations, obtaining desired concentrations. the aqueous extract of propolis (EAP). The tweenolic propolis extract (ETP) was obtained by immersing propolis from Apis mellifera in 500 ml of Tween 80 (5%) in deionized water and following the same preparation as the EAP. The propolis ethanol extract (EEP) was obtained by dissolving 100 g of crude propolis in 500 ml of 80% (v / v) ethanol, heated to 80ºC for 120 minutes, crushed, filtered and evaporated in a hot plate at 75ºC . The residue dry was resuspended in 80% (v / v) ethanol in desired concentrations. The EAP proved to be better than ETP in both “in vitro” and “in vivo” trials.The EEP presented interference in the “in vitro” tests due to the influence of ethanol. The WBS was administered in increasing doses, intraperitoneally, up to 1849.6 mg / kg and orally, up to 1230.7 mg / kg, in mice infected with T.cruzi, which showed a reduction in parasitemia and increased survival time. The best oral doses and intraperitoneal were 153.8 mg / kg and 924.8 mg / kg, respectively, with a percentage of reduction of parasitemia by 81.9% and 68.6%. The previous treatment of animals with WBS, in dose of 153.8 mg / kg (orally) and 924.8 mg / kg (intraperitoneal), proved to be efficient when performed 24 hours (orally) and 72 hours (i.p.) before infection with T.cruzi. THE treatment period, “in vivo”, most effective was 5 days for both routes of administration. To investigate the possible involvement of the nitric oxide system in mechanism of action of EAP, NOSi inhibitors (L — NAME and NOARG) were tested “in in vitro ", demonstrating that the EAP has a trypanomicidal action even in the presence of inhibitors, indicating a mechanism independent of NO. The results obtained in this work suggest that the aqueous propolis extract has a component (s) capable of act on the parasitemia of mice infected with T.cruzi, reducing significantly, the number of parasites during infection, by a mechanism of action dose dependent.